Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Wednesday 08 July 2020 21:24:56 Jon Elson wrote:

> On 07/08/2020 08:03 PM, Gene Heskett wrote:
> > Absolutely Jon. But to do it right requires a machine with little or
> > no backlash so it can't pull the work.
>
> Or else, you always did a climb mill finish pass with a very
> shallow cut.  That's what I did on my ancient Bridgeport
> before I did the CNC conversion.  You could get away with it
> like that.
>
> Jon

I don't recall doing any metalwork on the g0704 before I converted it.  
So much of the metal cutting code has a last finishing pass thats climb 
cut, written as a separate loop.  Even then its first major project was 
furniture, cuttin out and carving the green & green style big box joints 
for a series of blanket chests. In fact I cut out the first one with the 
hf mill and while I did get it done, that mill took way too long and 
several setups just to do one board, the impetus to buy the g0704 in the 
first place. I need to move the assembly of the last of those into the 
house and get them finished before I miss roll call. I am out of 
woodworking room in the garage.
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/08/2020 08:03 PM, Gene Heskett wrote:


Absolutely Jon. But to do it right requires a machine with little or no
backlash so it can't pull the work.

Or else, you always did a climb mill finish pass with a very 
shallow cut.  That's what I did on my ancient Bridgeport 
before I did the CNC conversion.  You could get away with it 
like that.


Jon


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Wednesday 08 July 2020 19:44:13 Jon Elson wrote:

> On 07/08/2020 04:01 PM, Gene Heskett wrote:
> > Its the next edge coming round to do another cut, which has to cut
> > thru the oxide that forms on the raw alu after the previous edge
> > clears the scene.
>
> And, that's why climb milling works so much better that
> conventional milling.  With conventional,
> the cutting edge rides up on the shallow slope until enough
> pressure develops to break through.
> With climb milling, the cutting edge punches immediately
> through the full depth of the cut, never sliding.
> The difference in cutter life is quite amazing.
>
Absolutely Jon. But to do it right requires a machine with little or no 
backlash so it can't pull the work.
> Jon
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/08/2020 04:01 PM, Gene Heskett wrote:


Its the next edge coming round to do another cut, which has to cut thru
the oxide that forms on the raw alu after the previous edge clears the
scene.


And, that's why climb milling works so much better that 
conventional milling.  With conventional,
the cutting edge rides up on the shallow slope until enough 
pressure develops to break through.
With climb milling, the cutting edge punches immediately 
through the full depth of the cut, never sliding.

The difference in cutter life is quite amazing.

Jon


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Re: [Emc-users] More cbn headaches

[N]

> wrote:
> > > No you would not have to do this in an inert atmosphere.  The only
> > > difficult part would be collecting all the chips.
> >
> > I would expect that the newly-cut surface is hermetically sealed to
> > the cutting edge until it isn't, and then it isn't damaging the edge,
> > no matter how hard it gets.
> 
> Its the next edge coming round to do another cut, which has to cut thru 
> the oxide that forms on the raw alu after the previous edge clears the 
> scene.

Sounds like protective gas should be used as then welding to keep oxygen 
"locally" away in the cutting area.

Regarding scales oxidation may not be the only problem, have a scale in the 
workshop at my workplace and heard rumors spring had been elongenated due to 
use then fishing.


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Wednesday 08 July 2020 16:47:22 andy pugh wrote:

> On Wed, 8 Jul 2020 at 19:03, Todd Zuercher  
wrote:
> > No you would not have to do this in an inert atmosphere.  The only
> > difficult part would be collecting all the chips.
>
> I would expect that the newly-cut surface is hermetically sealed to
> the cutting edge until it isn't, and then it isn't damaging the edge,
> no matter how hard it gets.

Its the next edge coming round to do another cut, which has to cut thru 
the oxide that forms on the raw alu after the previous edge clears the 
scene.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[Todd Zuercher]

This does bring back fond memories of taking Analytical Chemistry course in 
college. 

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street 
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: Chris Albertson  
Sent: Wednesday, July 08, 2020 2:10 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] More cbn headaches

[EXTERNAL EMAIL] Be sure links are safe.

If you had a good scale, All you need to do is weight the stock.  Then chuck it 
is a lathe and make some long ribbon-like swarf until you have
what you think is enough.Then weigh the remaining stock.   Assume the
difference is the amount of aluminum removed.Yes the surface area is
reduced but it is like close enough to just assume the weight loss is all 
aluminum

Then weigh the ribbons.   If you made these very thin then there is a huge
surface area and the added oxygen will make then weigh more.   You should
be able to find then mass of the oxygen.

If you have ever used a good analytic balance like the ones in a university lab 
where students to lab work you can weigh a paper index card.  Then write your 
name on it with a pencil and re-weight the card to find the
weight of the pencil lead used to write your name.   These scales are
common in labs.

What I'm describing is something no more complex thatwhat a first or second 
year chemistry student would do as a textbook exercise maybe 40 years ago.


If I were a student, I'd be asked to guess the result, then go and do the
experiment and see if I guessed right.So my guess...I think that
the oxide film thickness will be hundreds of times or even thousands of times 
less than the thickness of the ribbons so the amount of oxidized
aluminum is trivial and so is the amount ofheat generated.  I could be
right or wrong, one would need to do the experiment.   But as said, this is
a student-level experiment and all you need is a very nice analytic balance 
scale.

I see that scales that can measure 0.1 milligram are cheap now in eBay

On Wed, Jul 8, 2020 at 9:18 AM Gene Heskett  wrote:

> On Monday 06 July 2020 00:43:30 Chris Albertson wrote:
>
> > On Sun, Jul 5, 2020 at 3:33 AM andy pugh  wrote:
> > > You say this a lot, but I have never heard anyone else say it. 
> > > What is your source?
> >
> > THis might be a "Chemistry 101" question.  It should be easy enough 
> > to figure out except that I last studied this stuff in the last 
> > 1970s
> >
> > We all know that burning carbon produces a lot of heat.  The 
> > chemical equation is C + O2 --> CO2  -394 kJ / mole
> >
> > The corresponding equation of aluminum is 4Al + 3O2 --> 2Al2O3  
> > -1676 kJ/mole Aluminum produces more heat per mole than carbon and 
> > also more heat
> > per gram than carbon.   It would make good fuel except for combustion
> > stops once the oxide layer is formed.
> >
> > Next, I looked up the specific heat of aluminum.  It is very close 
> > to
> > 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of 
> > aluminum one degree K.
> >
> > So there is plenty of energy and the metal is also easy to heat.  But
> > what we don't know is the fraction of aluminum that is oxidized.   You
> > could figure this out if you had a good enough scale and could 
> > collect all the chips.  We could see how much mass the chips gained 
> > from the added oxygen.
>
> Difficult to do since the chips would have to be collected in an inert 
> atmosphere, weighed, then exposed to normal air for perhaps 1 second, 
> then weighed again. 99% of the weight gain would be in the first 
> millisecond of normal air exposure. As would the temp gain. One 
> rapidly runs into the real world while trying to imagine the lab 
> lashup to measure that. And I don't think excedrin can fix that 
> headache :)
>
> Long term alox vs weight story:  I bought an Ohaus 505 powder scale in 
> the early '60's to weigh powder for reloading my own ammo with, for a 
> wildcat cartridge called the 30-06 Ackley-Improved, and which I have 
> subsequently burned up/used up 4 barrels shooting at about 5k round 
> per barrel.
>
> This scale has an aluminum pan that is stamped but was not given a 
> protective coating.  Its a very good scale, accurate to about .05 gr. 
> No trouble at all seeing a single ball of H414 powder hitting the pan 
> But the gradual buildup of the oxide on this pan has caused it to gain 
> around .25 gr in the past nearly 60 years, and has required me to hit 
> its edge with a file to remove enough weight to restore its zero 
> balance point with the balance beam dead level. Not even cleaning it 
> with a green scotchbrite pad will restore that balance, I must file 
> away a teeny bit of alu.  So the effect is there, but h

Re: [Emc-users] More cbn headaches

[Chris Albertson]

Again.It is not hard.   We did stuff like this in school at UCLA.  I
whole room full of 19 and 20 year olds did just fine.

It is even easier then I fist wrote.  Just three steps.

1) Measure the weight of the bar stock using a scale that works in 0.0001
grams  (tenths of mg)
2) Turn the bars into chips, save all the chips
3) Measure the leftover bar and all the chips.

The difference in mass between step 3 and 1 must be added oxygen (or some
other contaminant.)   To avoid contamination you'd have the full glove and
face mask setup or you might try and bake the chips to remove fingerprint
oil, spit and so on.  Better to just keep it clean.







On Wed, Jul 8, 2020 at 10:55 AM Gene Heskett  wrote:

> On Wednesday 08 July 2020 12:47:17 N wrote:
>
> > On Wed, 8 Jul 2020 12:15:21 -0400
> >
> > Gene Heskett  wrote:
> > > On Monday 06 July 2020 00:43:30 Chris Albertson wrote:
> > > > On Sun, Jul 5, 2020 at 3:33 AM andy pugh 
> wrote:
> > > > > You say this a lot, but I have never heard anyone else say it.
> > > > > What is your source?
> > > >
> > > > THis might be a "Chemistry 101" question.  It should be easy
> > > > enough to figure out except that I last studied this stuff in the
> > > > last 1970s
> > > >
> > > > We all know that burning carbon produces a lot of heat.  The
> > > > chemical equation is
> > > > C + O2 --> CO2  -394 kJ / mole
> > > >
> > > > The corresponding equation of aluminum is
> > > > 4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
> > > > Aluminum produces more heat per mole than carbon and also more
> > > > heat per gram than carbon.   It would make good fuel except for
> > > > combustion stops once the oxide layer is formed.
> > > >
> > > > Next, I looked up the specific heat of aluminum.  It is very close
> > > > to 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of
> > > > aluminum one degree K.
> > > >
> > > > So there is plenty of energy and the metal is also easy to heat.
> > > > But what we don't know is the fraction of aluminum that is
> > > > oxidized.   You could figure this out if you had a good enough
> > > > scale and could collect all the chips.  We could see how much mass
> > > > the chips gained from the added oxygen.
> > >
> > > Difficult to do since the chips would have to be collected in an
> > > inert atmosphere, ...
> >
> > If you want to avoid oxidation you could use inert gas, maybe nitrogen
> > or co2 as then welding?
> >
> Then you have to worry about leaks, since both are lethal. And co2 might
> not be a useable atmosphere since it by definition is one carbon atom
> and two oxygen atoms, The chemical activity of the alu could possibly
> contaminate the results by borrowing an oxygen atom from the co2,
> leaving co, and thats not healthy either because taking the victim to
> fresh air takes too long to restore the blood oxygen to life supporting
> levels.  Fresh air is a much quicker life saver with nitrogen because it
> doesn't bind in the blood like co, so the victim can be re-oxygenated
> much quicker.
>
> We in broadcasting commonly use dry nitrogen as line pressurizer at 2 or
> 3 psi to keep rain water from migrating in thru small leaks.  But in the
> event we have to vent several hundred feet of coax to do maintenance on
> it, I have always put a hose going outside from the venting valve in
> order to not load up the interior of the building with the nitrogen.
> 2000 feet of 6.125 75 ohm line contains around 2 big bottles of dry
> nitrogen and can be quite lethal as it has no odor.  For that reason, we
> often have a small container of ethyl mercapton in the path from the
> tank to the line. 1 molecule of that per cubic foot can be smelled by
> the human nose on the first breath.
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] More cbn headaches

[Chris Albertson]

If you had a good scale, All you need to do is weight the stock.  Then
chuck it is a lathe and make some long ribbon-like swarf until you have
what you think is enough.Then weigh the remaining stock.   Assume the
difference is the amount of aluminum removed.Yes the surface area is
reduced but it is like close enough to just assume the weight loss is all
aluminum

Then weigh the ribbons.   If you made these very thin then there is a huge
surface area and the added oxygen will make then weigh more.   You should
be able to find then mass of the oxygen.

If you have ever used a good analytic balance like the ones in a university
lab where students to lab work you can weigh a paper index card.  Then
write your name on it with a pencil and re-weight the card to find the
weight of the pencil lead used to write your name.   These scales are
common in labs.

What I'm describing is something no more complex thatwhat a first or second
year chemistry student would do as a textbook exercise maybe 40 years ago.


If I were a student, I'd be asked to guess the result, then go and do the
experiment and see if I guessed right.So my guess...I think that
the oxide film thickness will be hundreds of times or even thousands of
times less than the thickness of the ribbons so the amount of oxidized
aluminum is trivial and so is the amount ofheat generated.  I could be
right or wrong, one would need to do the experiment.   But as said, this is
a student-level experiment and all you need is a very nice analytic balance
scale.

I see that scales that can measure 0.1 milligram are cheap now in eBay

On Wed, Jul 8, 2020 at 9:18 AM Gene Heskett  wrote:

> On Monday 06 July 2020 00:43:30 Chris Albertson wrote:
>
> > On Sun, Jul 5, 2020 at 3:33 AM andy pugh  wrote:
> > > You say this a lot, but I have never heard anyone else say it. What
> > > is your source?
> >
> > THis might be a "Chemistry 101" question.  It should be easy enough to
> > figure out except that I last studied this stuff in the last 1970s
> >
> > We all know that burning carbon produces a lot of heat.  The chemical
> > equation is
> > C + O2 --> CO2  -394 kJ / mole
> >
> > The corresponding equation of aluminum is
> > 4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
> > Aluminum produces more heat per mole than carbon and also more heat
> > per gram than carbon.   It would make good fuel except for combustion
> > stops once the oxide layer is formed.
> >
> > Next, I looked up the specific heat of aluminum.  It is very close to
> > 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of
> > aluminum one degree K.
> >
> > So there is plenty of energy and the metal is also easy to heat.  But
> > what we don't know is the fraction of aluminum that is oxidized.   You
> > could figure this out if you had a good enough scale and could collect
> > all the chips.  We could see how much mass the chips gained from the
> > added oxygen.
>
> Difficult to do since the chips would have to be collected in an inert
> atmosphere, weighed, then exposed to normal air for perhaps 1 second,
> then weighed again. 99% of the weight gain would be in the first
> millisecond of normal air exposure. As would the temp gain. One rapidly
> runs into the real world while trying to imagine the lab lashup to
> measure that. And I don't think excedrin can fix that headache :)
>
> Long term alox vs weight story:  I bought an Ohaus 505 powder scale in
> the early '60's to weigh powder for reloading my own ammo with, for a
> wildcat cartridge called the 30-06 Ackley-Improved, and which I have
> subsequently burned up/used up 4 barrels shooting at about 5k round per
> barrel.
>
> This scale has an aluminum pan that is stamped but was not given a
> protective coating.  Its a very good scale, accurate to about .05 gr. No
> trouble at all seeing a single ball of H414 powder hitting the pan But
> the gradual buildup of the oxide on this pan has caused it to gain
> around .25 gr in the past nearly 60 years, and has required me to hit
> its edge with a file to remove enough weight to restore its zero balance
> point with the balance beam dead level. Not even cleaning it with a
> green scotchbrite pad will restore that balance, I must file away a
> teeny bit of alu.  So the effect is there, but hard to measure without
> the right tools, and an O-Haus powder scale is about as good as you can
> get that is still affordable.
>
> IIRC it was close to a 90 dollar bill in 1963 or 1964. To put that in
> scale, custom dies were still $16.50 from RCBS, and my original 20+ lb's
> of cast iron framed Herters O frame press cost $14.95.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___

Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Wednesday 08 July 2020 12:47:17 N wrote:

> On Wed, 8 Jul 2020 12:15:21 -0400
>
> Gene Heskett  wrote:
> > On Monday 06 July 2020 00:43:30 Chris Albertson wrote:
> > > On Sun, Jul 5, 2020 at 3:33 AM andy pugh  
wrote:
> > > > You say this a lot, but I have never heard anyone else say it.
> > > > What is your source?
> > >
> > > THis might be a "Chemistry 101" question.  It should be easy
> > > enough to figure out except that I last studied this stuff in the
> > > last 1970s
> > >
> > > We all know that burning carbon produces a lot of heat.  The
> > > chemical equation is
> > > C + O2 --> CO2  -394 kJ / mole
> > >
> > > The corresponding equation of aluminum is
> > > 4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
> > > Aluminum produces more heat per mole than carbon and also more
> > > heat per gram than carbon.   It would make good fuel except for
> > > combustion stops once the oxide layer is formed.
> > >
> > > Next, I looked up the specific heat of aluminum.  It is very close
> > > to 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of
> > > aluminum one degree K.
> > >
> > > So there is plenty of energy and the metal is also easy to heat. 
> > > But what we don't know is the fraction of aluminum that is
> > > oxidized.   You could figure this out if you had a good enough
> > > scale and could collect all the chips.  We could see how much mass
> > > the chips gained from the added oxygen.
> >
> > Difficult to do since the chips would have to be collected in an
> > inert atmosphere, ...
>
> If you want to avoid oxidation you could use inert gas, maybe nitrogen
> or co2 as then welding?
>
Then you have to worry about leaks, since both are lethal. And co2 might 
not be a useable atmosphere since it by definition is one carbon atom 
and two oxygen atoms, The chemical activity of the alu could possibly 
contaminate the results by borrowing an oxygen atom from the co2, 
leaving co, and thats not healthy either because taking the victim to 
fresh air takes too long to restore the blood oxygen to life supporting 
levels.  Fresh air is a much quicker life saver with nitrogen because it 
doesn't bind in the blood like co, so the victim can be re-oxygenated 
much quicker.

We in broadcasting commonly use dry nitrogen as line pressurizer at 2 or 
3 psi to keep rain water from migrating in thru small leaks.  But in the 
event we have to vent several hundred feet of coax to do maintenance on 
it, I have always put a hose going outside from the venting valve in 
order to not load up the interior of the building with the nitrogen. 
2000 feet of 6.125 75 ohm line contains around 2 big bottles of dry 
nitrogen and can be quite lethal as it has no odor.  For that reason, we 
often have a small container of ethyl mercapton in the path from the 
tank to the line. 1 molecule of that per cubic foot can be smelled by 
the human nose on the first breath.
>
> ___
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[N]

On Wed, 8 Jul 2020 12:15:21 -0400
Gene Heskett  wrote:

> On Monday 06 July 2020 00:43:30 Chris Albertson wrote:
> 
> > On Sun, Jul 5, 2020 at 3:33 AM andy pugh  wrote:
> > > You say this a lot, but I have never heard anyone else say it. What
> > > is your source?
> >
> > THis might be a "Chemistry 101" question.  It should be easy enough to
> > figure out except that I last studied this stuff in the last 1970s
> >
> > We all know that burning carbon produces a lot of heat.  The chemical
> > equation is
> > C + O2 --> CO2  -394 kJ / mole
> >
> > The corresponding equation of aluminum is
> > 4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
> > Aluminum produces more heat per mole than carbon and also more heat
> > per gram than carbon.   It would make good fuel except for combustion
> > stops once the oxide layer is formed.
> >
> > Next, I looked up the specific heat of aluminum.  It is very close to
> > 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of
> > aluminum one degree K.
> >
> > So there is plenty of energy and the metal is also easy to heat.  But
> > what we don't know is the fraction of aluminum that is oxidized.   You
> > could figure this out if you had a good enough scale and could collect
> > all the chips.  We could see how much mass the chips gained from the
> > added oxygen.
> 
> Difficult to do since the chips would have to be collected in an inert 
> atmosphere, ...

If you want to avoid oxidation you could use inert gas, maybe nitrogen or co2 
as then welding?


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Monday 06 July 2020 00:43:30 Chris Albertson wrote:

> On Sun, Jul 5, 2020 at 3:33 AM andy pugh  wrote:
> > You say this a lot, but I have never heard anyone else say it. What
> > is your source?
>
> THis might be a "Chemistry 101" question.  It should be easy enough to
> figure out except that I last studied this stuff in the last 1970s
>
> We all know that burning carbon produces a lot of heat.  The chemical
> equation is
> C + O2 --> CO2  -394 kJ / mole
>
> The corresponding equation of aluminum is
> 4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
> Aluminum produces more heat per mole than carbon and also more heat
> per gram than carbon.   It would make good fuel except for combustion
> stops once the oxide layer is formed.
>
> Next, I looked up the specific heat of aluminum.  It is very close to
> 1.0 kJ / (Kg K).  So it only takes 1 Joule to heat one gram of
> aluminum one degree K.
>
> So there is plenty of energy and the metal is also easy to heat.  But
> what we don't know is the fraction of aluminum that is oxidized.   You
> could figure this out if you had a good enough scale and could collect
> all the chips.  We could see how much mass the chips gained from the
> added oxygen.

Difficult to do since the chips would have to be collected in an inert 
atmosphere, weighed, then exposed to normal air for perhaps 1 second, 
then weighed again. 99% of the weight gain would be in the first 
millisecond of normal air exposure. As would the temp gain. One rapidly 
runs into the real world while trying to imagine the lab lashup to 
measure that. And I don't think excedrin can fix that headache :)

Long term alox vs weight story:  I bought an Ohaus 505 powder scale in 
the early '60's to weigh powder for reloading my own ammo with, for a 
wildcat cartridge called the 30-06 Ackley-Improved, and which I have 
subsequently burned up/used up 4 barrels shooting at about 5k round per 
barrel.

This scale has an aluminum pan that is stamped but was not given a 
protective coating.  Its a very good scale, accurate to about .05 gr. No 
trouble at all seeing a single ball of H414 powder hitting the pan But 
the gradual buildup of the oxide on this pan has caused it to gain 
around .25 gr in the past nearly 60 years, and has required me to hit 
its edge with a file to remove enough weight to restore its zero balance 
point with the balance beam dead level. Not even cleaning it with a 
green scotchbrite pad will restore that balance, I must file away a 
teeny bit of alu.  So the effect is there, but hard to measure without 
the right tools, and an O-Haus powder scale is about as good as you can 
get that is still affordable.

IIRC it was close to a 90 dollar bill in 1963 or 1964. To put that in 
scale, custom dies were still $16.50 from RCBS, and my original 20+ lb's 
of cast iron framed Herters O frame press cost $14.95.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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[Emc-users] More cbn headaches

[Roland Jollivet]

See here

;

Pferd will usually have what you need. There are 6mm shanks


On Sat, 4 Jul 2020 at 19:02, Gene Heskett  wrote:

> Greetings all;
>
> Specifically, my inability to find a wheel in cbn similar to the $20
> dremel diamond disk, something with a 6mm or 6.35mm shank that would fit
> in the er20 chuck on the 6040 mill.
>
> I'd like to put a prop under the front of my A axis to establish heel
> clearance then rotate the chuck after touching it off straight up, to
> the side angles needed to do the v-belt pulley John D. was asking about.
> That or most any other shape an HSS lathe tool needs sharpened at.
> Attacking HSS with diamond is a waste of time and burns up the expen$ive
> diamond.
>
> I have a 4" cup cbn wheel, but the arbors are junk, so its contact isn't
> true. At 3k revs, thats hard on the wheel by the time you can hear
> contact.
>
> So where can I src a cbn wheel small enough to run at 10k+ revs in the
> 6040's spindle?  Nearly 2 hours of googling came up empty below 3".
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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Re: [Emc-users] More cbn headaches

[Chris Albertson]

On Sun, Jul 5, 2020 at 3:33 AM andy pugh  wrote:

>
> You say this a lot, but I have never heard anyone else say it. What is
> your source?
>

THis might be a "Chemistry 101" question.  It should be easy enough to
figure out except that I last studied this stuff in the last 1970s

We all know that burning carbon produces a lot of heat.  The chemical
equation is
C + O2 --> CO2  -394 kJ / mole

The corresponding equation of aluminum is
4Al + 3O2 --> 2Al2O3  -1676 kJ/mole
Aluminum produces more heat per mole than carbon and also more heat per
gram than carbon.   It would make good fuel except for combustion stops
once the oxide layer is formed.

Next, I looked up the specific heat of aluminum.  It is very close to 1.0
kJ / (Kg K).  So it only takes 1 Joule to heat one gram of aluminum one
degree K.

So there is plenty of energy and the metal is also easy to heat.  But what
we don't know is the fraction of aluminum that is oxidized.   You could
figure this out if you had a good enough scale and could collect all the
chips.  We could see how much mass the chips gained from the added oxygen.



-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/05/2020 08:55 PM, Gregg Eshelman via Emc-users wrote:
That was my clue that I was never going to light a smith 
wrench anywhere near mag.
If you've ever seen a magnesium engine or transmission case 
burn, it is quite a show.
And, when the fire department doesn't have foam in their 
truck, the only thing they have is water.
LOTS of water will put out burning magnesium, but will cause 
a white-hot explosion at first, the firemen have to have the 
high temperature suits to get away with it.


I've seen a VW microbus go up, and they only had one tiny 
foam can. The foam knocked it down for a few seconds quite 
nicely, but then when they hit it with water it looked like 
a 4th of July display gone wrong!


Jon


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Re: [Emc-users] More cbn headaches

[Gregg Eshelman via Emc-users]

There are ways to make magnesium very hard to burn. NeXT did it to the cases on 
their computers. https://simson.net/ref/1993/cubefire.html
I assume that laptop computers with magnesium cases use similar alloys.
Mongoose BMX bicycles back in the 80's did a sneaky thing for their factory 
team. Their production wheels were die cast aluminum. But in the dead of night 
they cast and machined a run in pure magnesium. Quite tricky to not end up with 
their wheel casting plant and machine shop on fire. Didn't bother getting 
inspection or permits etc for working with molten magnesium because it was a 
one off to make wheels for company use.

On Sunday, July 5, 2020, 7:08:36 AM MDT, Gene Heskett 
 wrote:  
 On Sunday 05 July 2020 06:30:13 andy pugh wrote:

> On Sun, 5 Jul 2020 at 07:05, Gene Heskett  wrote:
> > quicker because alox is the 2nd hardest abrasive we have.
>
> No, that's CBN, second after diamond.
>
> > That, and if
> > cutting dry, the heat of oxidation of the chip coming off is 98% of
> > the heat generated.
>
> [citation needed]
>
> You say this a lot, but I have never heard anyone else say it. What is
> your source?

Almost any src discussing the properties of alu.  It is a very active 
metal, oxidizing (burning IOW) in microseconds behind the passage of a 
cutting edge that exposes the bare metal to the oxygen in our air. This 
process continues at a rapid rate until a layer of oxide has been made 
that protects it by covering the surface with an oxide coat that must be 
cut by the next oncoming tool edge.  The rate of burn slows until the 
oxide, which is also a perfect insulator, has reached a thickness to 
withstand around 50 volts, I've read about a millisecond by which time 
it takes additional chemical help to get to its best withstand of about 
400 volts. Coloring of this oxide coat, commonly called anodizing, takes 
place at this time also.
Getting something, almost anything, to coat that bare alu as the cutting 
edge passes, slows this burn rate and prolongs the life of the cutting 
tool by many times as it reduces the oxide the tool has to cut again 
with the next passing edge.

Because its colorfull as it burns, and can be colored  by contaminates, 
its powdered form is commonly used in fireworks made for aerial 
displays.  The fireworks delayed explosives are used as an igniter. That 
and magnesium which generally are the brighter whiter ones.  The trick 
for the fireworks experts is to have it all burned before it gets to the 
ground and starts a real fire.

Back in the middle 50's, in Iowa City, we burned up a mercury outboard 
motor block, on purpose as part of a welding class I took, doing it on 
some very poor condition sidewalk 50 feet away from the welding shop on 
the front of a vacant lot. The shop owner had a string of military 
welding certs in his wallet, and first showed us that mag can be welded 
with a smith wrench, aka acetylene torch, and put the stuff knocked out 
of that big 6 block back in place that an errant con rod had knocked 
out.  And once we had looked at the work, he said "and this is what 
happens if you aren't carefull" and lit that block up. Took it about 20 
minutes to burn and made to good sized pit in the ground doing it. But 
the local fire dept had to be restrained for dousing it with water when 
they arrived like the 7nth cavalry, which the magnesium would have 
loved, creating a much larger pit from the explosion. So they did the 
next best thing and wrote him up. But he'd planned that show in advance 
and by the time the court date rolled around, the pit had been filled 
and a brand new sidewalk the length of that block had been graded and 
poured, pix of which got the cite laughed out of court, the city was 
glad to get that 40 yo sidewalk fixed at no cost to them.  That was my 
clue that I was never going to light a smith wrench anywhere near mag.  
The smoke is not healthy to start with.  
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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Sunday 05 July 2020 06:30:13 andy pugh wrote:

> On Sun, 5 Jul 2020 at 07:05, Gene Heskett  wrote:
> > quicker because alox is the 2nd hardest abrasive we have.
>
> No, that's CBN, second after diamond.
>
> > That, and if
> > cutting dry, the heat of oxidation of the chip coming off is 98% of
> > the heat generated.
>
> [citation needed]
>
> You say this a lot, but I have never heard anyone else say it. What is
> your source?

Almost any src discussing the properties of alu.  It is a very active 
metal, oxidizing (burning IOW) in microseconds behind the passage of a 
cutting edge that exposes the bare metal to the oxygen in our air. This 
process continues at a rapid rate until a layer of oxide has been made 
that protects it by covering the surface with an oxide coat that must be 
cut by the next oncoming tool edge.  The rate of burn slows until the 
oxide, which is also a perfect insulator, has reached a thickness to 
withstand around 50 volts, I've read about a millisecond by which time 
it takes additional chemical help to get to its best withstand of about 
400 volts. Coloring of this oxide coat, commonly called anodizing, takes 
place at this time also.
Getting something, almost anything, to coat that bare alu as the cutting 
edge passes, slows this burn rate and prolongs the life of the cutting 
tool by many times as it reduces the oxide the tool has to cut again 
with the next passing edge.

Because its colorfull as it burns, and can be colored  by contaminates, 
its powdered form is commonly used in fireworks made for aerial 
displays.  The fireworks delayed explosives are used as an igniter. That 
and magnesium which generally are the brighter whiter ones.  The trick 
for the fireworks experts is to have it all burned before it gets to the 
ground and starts a real fire.

Back in the middle 50's, in Iowa City, we burned up a mercury outboard 
motor block, on purpose as part of a welding class I took, doing it on 
some very poor condition sidewalk 50 feet away from the welding shop on 
the front of a vacant lot. The shop owner had a string of military 
welding certs in his wallet, and first showed us that mag can be welded 
with a smith wrench, aka acetylene torch, and put the stuff knocked out 
of that big 6 block back in place that an errant con rod had knocked 
out.  And once we had looked at the work, he said "and this is what 
happens if you aren't carefull" and lit that block up. Took it about 20 
minutes to burn and made to good sized pit in the ground doing it. But 
the local fire dept had to be restrained for dousing it with water when 
they arrived like the 7nth cavalry, which the magnesium would have 
loved, creating a much larger pit from the explosion. So they did the 
next best thing and wrote him up. But he'd planned that show in advance 
and by the time the court date rolled around, the pit had been filled 
and a brand new sidewalk the length of that block had been graded and 
poured, pix of which got the cite laughed out of court, the city was 
glad to get that 40 yo sidewalk fixed at no cost to them.  That was my 
clue that I was never going to light a smith wrench anywhere near mag.  
The smoke is not healthy to start with. 

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[andy pugh]

On Sun, 5 Jul 2020 at 07:05, Gene Heskett  wrote:

> quicker because alox is the 2nd hardest abrasive we have.

No, that's CBN, second after diamond.

> That, and if
> cutting dry, the heat of oxidation of the chip coming off is 98% of the
> heat generated.

[citation needed]

You say this a lot, but I have never heard anyone else say it. What is
your source?

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 21:12:57 Jon Elson wrote:

> On 07/04/2020 04:26 PM, Gene Heskett wrote:
> > IIRC no sparks, 200 or so revs, could just barely hear it touching,
> > peeled two strips down to the alu about 1/4" wide. Not at all
> > impressed. Up to that point, I was watching a very thin cloud of
> > steel dust drifting away in the work light and figured it would get
> > to where it should be in about half an hour.  I wound up doing it on
> > the bench grinder with a glass of water to keep from burning my
> > fingers.
>
> Unless you are whetting the edge on a scalpel, no need to
> use diamond to shape a lathe tool.
>
> A coarse alumina wheel will do a fine job.
>
> Jon
>
That depends on how long you want that edge to last. On a wood plane 
iron, nothing compares to the edge that 12,000 grit rouge wheel leaves. 
I touch it up about yearly, and a touch is all it needs. On a piece of 
3/8 HSS tool steel cutting alu, that mirror like finish goes away much 
quicker because alox is the 2nd hardest abrasive we have. That, and if 
cutting dry, the heat of oxidation of the chip coming off is 98% of the 
heat generated.  The heat from the chip sliding off the top of the tool 
is nothing compared to the heat generated by the rapid burning of the 
freshly cut alu surface, both on the bottom of the chip as the airborn 
oxygen attacks it, and on the workpieces freshly exposed surface. If you 
can put the work in a dry nitrogen atmosphere, you can machine alu at 
20x faster rates, and the swarf still won't burn you until its flown 
thru a couple foot of normal air. Water, delivered as a mist, possibly 
with other contaminants, even though its 2 parts oxy, is harder for the 
alu to oxidize rapidly than plain dry air.  And if directed at the back 
edge of the tool, can easily extend the life of a carbide tool by 5 to 
20x, depending on how fast you can get the alu wet behind the passage of 
the cutting edge. Microseconds count. So high pressure air pushing that 
mist is the key, not so much the quantity of water or mix delivered. As 
an experiment 20 years back, I had to make bearing spacer block to move 
a blower bearing out of the groove cut in the shaft by 50 years of its 
spinning in the fafner eccentric collar. About an inch thick and 5" 
square, I rigged a mister using safflower oil, all this on the only mill 
I had at the time, the teeny little hf I had cnc'd. Took about 4 hours 
working on a block bandsawn from a 7"x7"x24" of solid alu I'd found at 
one of our recycle places and stolen for a 40 dollar bill.  And misted 
about 3 oz of oil.  That block never got warm. But with that much oil in 
the air, I couldn't see the 16 foot length of the shop building and my 
lungs complained for several days.  Its still under that bearing today, 
but that whole 1956 transmitter was turned off forever at midnight June 
30, 2008.

Proving to me that keeping airborn oxygen away from the alu makes 
machining it much easier. But making that environment was harder than I 
thought. And hard on the human involved. I can certainly see why 
machining centers pump coolant by the hundreds of gallons peer hour, 
unless you get legionaires growing in the sump, much easier on the 
humans nearby.

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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/04/2020 04:26 PM, Gene Heskett wrote:


IIRC no sparks, 200 or so revs, could just barely hear it touching,
peeled two strips down to the alu about 1/4" wide. Not at all impressed.
Up to that point, I was watching a very thin cloud of steel dust
drifting away in the work light and figured it would get to where it
should be in about half an hour.  I wound up doing it on the bench
grinder with a glass of water to keep from burning my fingers.


Unless you are whetting the edge on a scalpel, no need to 
use diamond to shape a lathe tool.


A coarse alumina wheel will do a fine job.

Jon


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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/04/2020 04:23 PM, andy pugh wrote:

On Sat, 4 Jul 2020 at 22:08, Eric Keller  wrote:


Steel bonds to diamond, and then you are cutting with steel.

My understanding of the problem was that it is due to carbon being
soluble in steel. And diamonds are just expensive carbon.

This is likely to be much more of a problem with single-point turning
than with grinding, however,
Yes, but you have to get the diamond hot for the iron to be 
able to dissolve into it.
Since the wheel has a bit of time to cool off as it turns 
around, the diamond is always
cooler than the thing you are grinding.  Either 
water-cooling the diamond or just keeping the surface speed 
down will allow the diamond to last a long time.  Of course, 
that also slows the cutting rate.


Jon


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 16:43:12 Jon Elson wrote:

> On 07/04/2020 12:54 PM, andy pugh wrote:
> > On Sat, 4 Jul 2020 at 18:02, Gene Heskett  
wrote:
> >> Attacking HSS with diamond is a waste of time and burns up the
> >> expen$ive diamond.
> >
> > Whilst it is meant to be a terrible idea, in practice it works OK.
>
> I think it depends on surface speed.  If the speed is high
> enough that the sparks are totally white-hot, it will alloy
> with the diamond.  At lower speeds, especially where the
> sparks are barely glowing, it doesn't seem to hurt the
> diamond at all.

IIRC no sparks, 200 or so revs, could just barely hear it touching, 
peeled two strips down to the alu about 1/4" wide. Not at all impressed. 
Up to that point, I was watching a very thin cloud of steel dust 
drifting away in the work light and figured it would get to where it 
should be in about half an hour.  I wound up doing it on the bench 
grinder with a glass of water to keep from burning my fingers.

> Jon
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[andy pugh]

On Sat, 4 Jul 2020 at 22:08, Eric Keller  wrote:

> Steel bonds to diamond, and then you are cutting with steel.

My understanding of the problem was that it is due to carbon being
soluble in steel. And diamonds are just expensive carbon.

This is likely to be much more of a problem with single-point turning
than with grinding, however,

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 16:15:53 andy pugh wrote:

> On Sat, 4 Jul 2020 at 20:59, Gene Heskett  wrote:
> > > This sort of thing: https://www.ebay.com/itm/402313154494
> >
> > At that price I'd get 4, but there is a slim we may have snow by the
> > time they get here. Late August?  Even a junk moves faster than
> > that.
>
> What's the US version of Arc-Eurotrade?
> https://www.arceurotrade.co.uk/Catalogue/Diamond-Tools/Diamond-Grindin
>g-Wheels/Diamond-Grinding-Wheels---Cup

No clue, but thats about 40 euros each, compared to $6.68?  No thanks.
I might give this cbn another chance to do a decent lathe tool now that 
I've recut the face of that arbor.  I just bought another 5 pack of 
250-201 tool holders and I have plenty of the 5/16 and 3/8 tools to 
shape as I can.

I need a set of metric reamers too. Found some affordable ones too, so I 
bought them and a 60/1 worm box for the BS-1.  I'll have to make 
adapters for both ends of it.  Might be fun. :)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[Eric Keller]

On Sat, Jul 4, 2020 at 4:45 PM Jon Elson  wrote:

> On 07/04/2020 12:54 PM, andy pugh wrote:
> > On Sat, 4 Jul 2020 at 18:02, Gene Heskett  wrote:
> >
> >> Attacking HSS with diamond is a waste of time and burns up the expen$ive
> >> diamond.
> > Whilst it is meant to be a terrible idea, in practice it works OK.
> I think it depends on surface speed.  If the speed is high
> enough that the sparks are totally white-hot, it will alloy
> with the diamond.  At lower speeds, especially where the
> sparks are barely glowing, it doesn't seem to hurt the
> diamond at all.
>

Steel bonds to diamond, and then you are cutting with steel.  Maybe the
resin bonded wheels just present new edges to the steel pretty easily.

Diamond turning of steel is the holy grail of precision engineering. I
don't think the speed has to be that high.  We helped out a company that
heats the steel with lasers, and it seems to work.  Haven't seen what they
have been up to lately.
Eric Keller
Boalsburg, Pennsylvania

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Re: [Emc-users] More cbn headaches

[Jon Elson]

On 07/04/2020 12:54 PM, andy pugh wrote:

On Sat, 4 Jul 2020 at 18:02, Gene Heskett  wrote:


Attacking HSS with diamond is a waste of time and burns up the expen$ive
diamond.

Whilst it is meant to be a terrible idea, in practice it works OK.
I think it depends on surface speed.  If the speed is high 
enough that the sparks are totally white-hot, it will alloy 
with the diamond.  At lower speeds, especially where the 
sparks are barely glowing, it doesn't seem to hurt the 
diamond at all.


Jon


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Re: [Emc-users] More cbn headaches

[andy pugh]

On Sat, 4 Jul 2020 at 20:59, Gene Heskett  wrote:

> > This sort of thing: https://www.ebay.com/itm/402313154494
>
> At that price I'd get 4, but there is a slim we may have snow by the time
> they get here. Late August?  Even a junk moves faster than that.

What's the US version of Arc-Eurotrade?
https://www.arceurotrade.co.uk/Catalogue/Diamond-Tools/Diamond-Grinding-Wheels/Diamond-Grinding-Wheels---Cup

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 14:56:29 andy pugh wrote:

> On Sat, 4 Jul 2020 at 19:47, Gene Heskett  wrote:
> > > Whilst it is meant to be a terrible idea, in practice it works OK.
> >
> > Not for me. Between the $20 dremel disks, and a $120 diamond plated
> > on one side, 5" in diameter that I peeled the diamond off of,
>
> The plated-on wheels don't work, but the resin-bonded ones seem to.
> And they are very cheap.
> This sort of thing: https://www.ebay.com/itm/402313154494

At that price I'd get 4, but there is a slim we may have snow by the time 
they get here. Late August?  Even a junk moves faster than that.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 13:54:05 andy pugh wrote:

> On Sat, 4 Jul 2020 at 18:02, Gene Heskett  wrote:
> > Attacking HSS with diamond is a waste of time and burns up the
> > expen$ive diamond.
>
> Whilst it is meant to be a terrible idea, in practice it works OK.
>
> > I have a 4" cup cbn wheel, but the arbors are junk, so its contact
> > isn't true.
>
> As bad as this one?
> https://www.youtube.com/watch?v=Y1NwskdkFv4
> (I got my money back on that one. And confidently predict that the URL
> won't work for Gene)
>
> You have a lathe? Re-machine the wheel and/or the arbor.

My memory seemed to tell me I made that arbor BEFORE I found the bent 
spindle, so I just went out and dissed the arbor out of it and sure 
enough I had to shave about 3 thou off the face to get clean steel all 
around.  The BS-1 is in the way so I can't test it, but it looks dead 
true in the lathe now.  But it would be about an hours work to rebuild 
the sharpening rig on the table and its north of 90F out there.

Finally found the AC remote and started it.  That should help.  Theres a 
lot of mass to cool, but that 2008 garage I built is way better 
insulated than this early 1970's house.  Even a toy 5k btu AC works 
quite well given enough time to pump the heat out. 6" walls full of 
cocoon, a foot of it on the ceiling. Even the garage door has another 
R-11 glued to the inside face.  Worst heat leak is probably the back 
door, which opens to the back yard.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[andy pugh]

On Sat, 4 Jul 2020 at 19:47, Gene Heskett  wrote:

> > Whilst it is meant to be a terrible idea, in practice it works OK.
>
> Not for me. Between the $20 dremel disks, and a $120 diamond plated on
> one side, 5" in diameter that I peeled the diamond off of,

The plated-on wheels don't work, but the resin-bonded ones seem to.
And they are very cheap.
This sort of thing: https://www.ebay.com/itm/402313154494

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] More cbn headaches

[Gene Heskett]

On Saturday 04 July 2020 13:54:05 andy pugh wrote:

> On Sat, 4 Jul 2020 at 18:02, Gene Heskett  wrote:
> > Attacking HSS with diamond is a waste of time and burns up the
> > expen$ive diamond.
>
> Whilst it is meant to be a terrible idea, in practice it works OK.

Not for me. Between the $20 dremel disks, and a $120 diamond plated on 
one side, 5" in diameter that I peeled the diamond off of, I've wore out 
or wrecked a good $300 worth just making a single tooth threading tool 
for a 10 tpi square thread on a 6.5 creedmoor barrel I was putting in 
old meat in the pot.
 
> > I have a 4" cup cbn wheel, but the arbors are junk, so its contact
> > isn't true.
>
> As bad as this one?
> https://www.youtube.com/watch?v=Y1NwskdkFv4

I'd say half that bad.  And the link worked just fine as it never 
triggered the word wrap, too short.

> (I got my money back on that one. And confidently predict that the URL
> won't work for Gene)

See above.

> You have a lathe? Re-machine the wheel and/or the arbor.

Two of them, but this was 2+ years ago, before I found the spindle was 
bent on this Sheldon. That lathe is now running at under a thou runout 
several inches away from the chuck face.  With a bent spindle, its been 
quite a chore to get to that.  That lathe came to me with a smashed and 
broken compound from landing on the compound handle in a fallover I 
wasn't told about, and apparently the mounted 3 jaw was heavy enough to 
bend it when it fell. The MT-5 has been reground true again, both 
faceplates remachined true. The MT-5 rebore was about 7 thou to make it 
true again.  And at least a 20 thou wobble cut back off the faces of 
both backing plates, and the registration ledge cut back enough to let 
me tap it true as I tightened the bolts.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More cbn headaches

[andy pugh]

On Sat, 4 Jul 2020 at 18:02, Gene Heskett  wrote:

> Attacking HSS with diamond is a waste of time and burns up the expen$ive
> diamond.

Whilst it is meant to be a terrible idea, in practice it works OK.

> I have a 4" cup cbn wheel, but the arbors are junk, so its contact isn't
> true.

As bad as this one?
https://www.youtube.com/watch?v=Y1NwskdkFv4
(I got my money back on that one. And confidently predict that the URL
won't work for Gene)

You have a lathe? Re-machine the wheel and/or the arbor.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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[Emc-users] More cbn headaches

[Gene Heskett]

Greetings all;

Specifically, my inability to find a wheel in cbn similar to the $20 
dremel diamond disk, something with a 6mm or 6.35mm shank that would fit 
in the er20 chuck on the 6040 mill.

I'd like to put a prop under the front of my A axis to establish heel 
clearance then rotate the chuck after touching it off straight up, to 
the side angles needed to do the v-belt pulley John D. was asking about.  
That or most any other shape an HSS lathe tool needs sharpened at.  
Attacking HSS with diamond is a waste of time and burns up the expen$ive 
diamond.

I have a 4" cup cbn wheel, but the arbors are junk, so its contact isn't 
true. At 3k revs, thats hard on the wheel by the time you can hear 
contact.

So where can I src a cbn wheel small enough to run at 10k+ revs in the 
6040's spindle?  Nearly 2 hours of googling came up empty below 3".

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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