Re: [Emc-users] Cutting cast iron with a dry diamond blade

[BRIAN GLACKIN]

Diamonds will cut just about anything.  The trick is matching the matrix
holding the diamond bits to the material being cut.  I have dealt with
diamond drilling quite a bit in my profession (mining of industrial
minerals).  The harder the materials to be cut, often the better the
diamonds like it provided the matrix wears out slightly faster than the
diamonds to prevent faceting of the exposed bits.  Always want to prevent
polishing of the diamonds.  Saw this in upstate New York gneiss where a
crew drilled 300 feet in 12 hours with an NQ bit (75.7mm dia with a 10.5mm
thick annulus).  Normal rates are 100-175ft in a 12 hour shift.  This
included punching through several seams of magnetite.  I would be more
worried about trying to cut aluminum where it would likely cold weld the
bit with or without water.

In drilling rock, water is key.  While I have not seen it, I have heard the
drillers talk of welding the drillbit to the end of the hole  several
hundred to thousands of feet downhole when they lost water circulation.
When that happens the pull out whatver part of the drilling head they can,
send a new bit downhole and drill through the parts stuck in the hole and
keep on trucking.

On Tue, May 10, 2016 at 6:02 PM, Dave Cole  wrote:

> On 5/10/2016 2:56 PM, Gene Heskett wrote:
> > On Tuesday 10 May 2016 11:47:13 Dave Cole wrote:
> >
> >> I've been doing the controls for a manufacturer of large core drill
> >> machines for about 10 years. The machines are made to drill holes in
> >> concrete structures that make up sewer systems.
> >> The machines can drill up to 60" holes using diamond segmented tipped
> >> bits.
> >>
> >> Diamond bits work great for concrete and stone and they do ok when
> >> sawing through the wire reinforcement in the concrete as well (up to
> >> about 1/2" rebar reinforcement).
> >> Water is always used with those bits for maximum life.   However they
> >> don't need a lot of water.  Just enough to wash away the grindings.
> >> With smaller bits (12-24") in diameter, the machines can achieve feed
> >> rates of 4-5 inches per minute even when chewing through wire
> >> reinforcement.   Diamond tipped saw blade "teeth" are really tiny
> >> diamonds in an alloy matrix which rubs against the material to be cut.
> >> Its really more of a grinding process than a cutting process.   A good
> >> diamond tipped concrete core drill can drill through 100+ feet of
> >> concrete before needing to be re-tipped if the core drill is treated
> >> properly.
> >>
> >> I've never heard of diamond bits being used to solely cut cast iron.
> >> I would think that Carbide or HSS would be preferable.
> > Both would need large amounts of torque I don't have.  My mill spindle is
> > 1 HP, and not enough backgear to pull that off.  So slow, dry, no sparks
> > allowed, has now done the job with a $45 10 continuous edge Dewalt
> > blade.  And it seems to be taking less power to deepen its kerf now than
> > when I started. Piece is now chucked in the lathe's 4 jaw, and I'm
> > trying to make it round, but my backs stand up time has been exceeded
> > for a couple hours.  So I'm fielding email and may even see if I can get
> > some afternoon nap in since I was up, in pain, about 1/2 the night last
> > night.
> >
> > Cheers, Gene Heskett
>
> And you probably don't want to use a water hose to wet down the blade
> even if it makes the blade last longer ..  ;-)
>
> I've had good luck using 7 1/4" circular saw blades designed to cut
> steel.   They have come down in price quite a bit.   I used them to cut
> 1/2" and 3/4" plate steel.
> I used it with a worm drive circular saw.The sparks were pretty
> spectacular.   I think that first blade I bought cost $60 or so probably
> 15 years ago.I think they are about half that now.
> They also work well cutting steel angle and bar if you don't have a
> bandsaw.   Just need to feed the blade into the steel carefully so it
> doesn't grab and wear a face mask and gloves.
>
> Dave
>
>
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Re: [Emc-users] Cutting cast iron with a dry diamond blade

[Dave Cole]

On 5/10/2016 2:56 PM, Gene Heskett wrote:
> On Tuesday 10 May 2016 11:47:13 Dave Cole wrote:
>
>> I've been doing the controls for a manufacturer of large core drill
>> machines for about 10 years. The machines are made to drill holes in
>> concrete structures that make up sewer systems.
>> The machines can drill up to 60" holes using diamond segmented tipped
>> bits.
>>
>> Diamond bits work great for concrete and stone and they do ok when
>> sawing through the wire reinforcement in the concrete as well (up to
>> about 1/2" rebar reinforcement).
>> Water is always used with those bits for maximum life.   However they
>> don't need a lot of water.  Just enough to wash away the grindings.
>> With smaller bits (12-24") in diameter, the machines can achieve feed
>> rates of 4-5 inches per minute even when chewing through wire
>> reinforcement.   Diamond tipped saw blade "teeth" are really tiny
>> diamonds in an alloy matrix which rubs against the material to be cut.
>> Its really more of a grinding process than a cutting process.   A good
>> diamond tipped concrete core drill can drill through 100+ feet of
>> concrete before needing to be re-tipped if the core drill is treated
>> properly.
>>
>> I've never heard of diamond bits being used to solely cut cast iron.
>> I would think that Carbide or HSS would be preferable.
> Both would need large amounts of torque I don't have.  My mill spindle is
> 1 HP, and not enough backgear to pull that off.  So slow, dry, no sparks
> allowed, has now done the job with a $45 10 continuous edge Dewalt
> blade.  And it seems to be taking less power to deepen its kerf now than
> when I started. Piece is now chucked in the lathe's 4 jaw, and I'm
> trying to make it round, but my backs stand up time has been exceeded
> for a couple hours.  So I'm fielding email and may even see if I can get
> some afternoon nap in since I was up, in pain, about 1/2 the night last
> night.
>
> Cheers, Gene Heskett

And you probably don't want to use a water hose to wet down the blade 
even if it makes the blade last longer ..  ;-)

I've had good luck using 7 1/4" circular saw blades designed to cut 
steel.   They have come down in price quite a bit.   I used them to cut 
1/2" and 3/4" plate steel.
I used it with a worm drive circular saw.The sparks were pretty 
spectacular.   I think that first blade I bought cost $60 or so probably 
15 years ago.I think they are about half that now.
They also work well cutting steel angle and bar if you don't have a 
bandsaw.   Just need to feed the blade into the steel carefully so it 
doesn't grab and wear a face mask and gloves.

Dave

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Re: [Emc-users] Cutting cast iron with a dry diamond blade

[Gene Heskett]

On Tuesday 10 May 2016 15:41:57 andy pugh wrote:

> On 10 May 2016 at 14:28, Roland Jollivet  
wrote:
> > I once watched a contractor dry cut rebar with a diamond blade using
> > a cut-off saw. I wanted to tell him you can't do that,
>
> http://www.husqvarna.com/us/construction/products/diamond-blades-for-p
>ower-cutters/di5-ductile-iron-blade/

If I can put yet another oar in this water, it seems to me that Husqvarna 
et all, is far more interested in selling you another blade at quite a 
nice profit margin than in doing a job correctly.

Diamond, spinning at those speeds, will shatter from impact, and if not 
adequately cooled, will get hot enough to ablate/evaporate the diamond, 
both of which will result in the premature destruction of the blades 
ability to cut anything.

Unfortunately, when you are paying the person who needs to cut such by 
the hour, it quickly becomes expedient to buy the fresh blade to replace 
the one destroyed by the pressure to "get the job done".  It becomes a 
C.O.D.B.

By running it wet, you can somewhat alleviate the heat that evaporates 
the diamond.  But note the "somewhat" because the heating is localized, 
confined to the actual contact of that grain of diamond with the 
material being cut, and at the rim speeds of a modern power saw, there 
is 100x more air at the contact interface than water as its carried into 
the slot being cut by the rapidity of the rim, which itself is busily 
throwing that water away from the blade and generally makeing a huge 
mess of the environment up to 15 or 20 feet away.

At nominally 400 revs on a 10" wheel, the impact shock that shatters the 
diamond is reduced by 10x, reducing the cutting degradation rate by an 
estimated 10,000%.  And if not pushing the blade, but just letting the 
diamond carry away the cutting dust its making, the heating will also be 
reduced.  In making those two cuts thru a solid casting about 4.25" in 
diameter, I watched the rim temp with an IR thermometer, and never saw 
it exceed 120F at about 3/8" in from the blades edge.  It appeared the 
actual edge of the blade was running 15F cooler.

Yes, it took a long time to do those 2 cuts.  Had I been physically able 
to attend to the mill full time, about a day a cut.  But that blade can 
do that, at that cut rate, probably another 100 times.

Running that slow and easy, wet or dry has relatively little effect on 
blade longevity because there is not enough heat, or a high enough 
impact shock to damage the diamond.

All of this seduction of the canine could have been alleviated had I been 
able to back the clock up to about 1948 when an uncle of mine landed a 
contract to cut the mounting bosses off an eyeglass lens makers cast 
iron forms so his forms would be usable in a newer machine.  My uncle 
built the first abrasive cutup saw I ever saw, and he didn't have any 
lawyers telling him what he could not do.  In '48, the abrasive wheels 
came in 10 or 11", you wrapped them on a shield of steel about 1/4" 
thick to catch the shrapnel as the recommended rpms for those wheels was 
pretty close to 9500.  So he first used a pulley ratio that gave about 
7500, but it wasn't fast enough to easily start the fire.  So he went to 
town and got the next smaller pulley, which gave it almost exactly 10 
grand.

Bringing the wheel to the casting, it only took 3 or 4 seconds to start 
the fire, and it literally fell thru the 1.25" square block of cast they 
were cutting off in another 2 or 3 seconds.  He blew up one wheel in 
cutting about 200 of them off that way.

But can I buy an abrasive saw that will cut like that today?  Not no, but 
hell no, at least not without putting 5 grand or more into it.  The best 
OTC saw turns a 14" wheel about 4 grand, and it cannot get the fire 
started in a 1/2x2" bar of cold roll without 3 or 4 minutes of leaning 
heavily on the blade just to get the fire started.  The damned lawyers 
and bean counters have caused the wheel speed to be reduced (14" wheels 
are rated for 6500) and the shrapnel catchers are a piece of Prince 
Albert can.  Scary.

Modern tech, by the time the lawyers get thru with it, sucks.

My Dad worked in '52-55, in the tool & die room at a place in Des Moines 
called Solar Aircraft, that was making jet engine parts out of SS and 
titanium.  Somebody shaved the JIT schedule and they ran out of bandsaw 
blades on Thursday, with the next shipment due in Monday next.  While 
those blades did have teeth, the teeth were intended more for carrying 
air into the cut to carry away the molten metal as they actually cut by 
friction heating.  Daddy picked up a steel shipping strap, welded it up 
at the length needed for the bandsaw.  It worked fairly well so he made 
about 40 more with each one lasting about an hour.  That kept production 
going until the new blades arrived.  And he got a nice little present 
for saving those 2 days downtime.

First, we kill ALL the lawyers, still sounds like a heck of a 

Re: [Emc-users] Cutting cast iron with a dry diamond blade

[andy pugh]

On 10 May 2016 at 14:28, Roland Jollivet  wrote:
> I once watched a contractor dry cut rebar with a diamond blade using a
> cut-off saw. I wanted to tell him you can't do that,


http://www.husqvarna.com/us/construction/products/diamond-blades-for-power-cutters/di5-ductile-iron-blade/



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atp
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Re: [Emc-users] OT: lapping machine disc

[Dave Caroline]

Interesting that someone else is looking at this subject. A few days
ago I dug out an old machine I rescued from factory about to be
redeveloped, it has no grooves and also rotation is from above if
wanted.
http://www.collection.archivist.info/searchv13.php?searchstr=cooke+polishing

Dave Caroline

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Re: [Emc-users] Cutting cast iron with a dry diamond blade

[Gene Heskett]

On Tuesday 10 May 2016 11:47:13 Dave Cole wrote:

> I've been doing the controls for a manufacturer of large core drill
> machines for about 10 years. The machines are made to drill holes in
> concrete structures that make up sewer systems.
> The machines can drill up to 60" holes using diamond segmented tipped
> bits.
>
> Diamond bits work great for concrete and stone and they do ok when
> sawing through the wire reinforcement in the concrete as well (up to
> about 1/2" rebar reinforcement).
> Water is always used with those bits for maximum life.   However they
> don't need a lot of water.  Just enough to wash away the grindings.
> With smaller bits (12-24") in diameter, the machines can achieve feed
> rates of 4-5 inches per minute even when chewing through wire
> reinforcement.   Diamond tipped saw blade "teeth" are really tiny
> diamonds in an alloy matrix which rubs against the material to be cut.
> Its really more of a grinding process than a cutting process.   A good
> diamond tipped concrete core drill can drill through 100+ feet of
> concrete before needing to be re-tipped if the core drill is treated
> properly.
>
> I've never heard of diamond bits being used to solely cut cast iron.  
> I would think that Carbide or HSS would be preferable.

Both would need large amounts of torque I don't have.  My mill spindle is 
1 HP, and not enough backgear to pull that off.  So slow, dry, no sparks 
allowed, has now done the job with a $45 10 continuous edge Dewalt 
blade.  And it seems to be taking less power to deepen its kerf now than 
when I started. Piece is now chucked in the lathe's 4 jaw, and I'm 
trying to make it round, but my backs stand up time has been exceeded 
for a couple hours.  So I'm fielding email and may even see if I can get 
some afternoon nap in since I was up, in pain, about 1/2 the night last 
night.

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)
Genes Web page 

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[Emc-users] OT: lapping machine disc

[Roland Jollivet]

Hi All

I've been looking at lapping machines, like this,


and wondered if anyone knew more about the theory of the grooves. While I
understand how there is constant velocity on the conditioning ring
periphery, if the plate is grooved then surely there will be more wear on
the inside? The picture that I drew up, below, exaggerates the effect, but
the principle remains. The load area in the centre of the plate is much
smaller.

http://www.fotothing.com/photos/37e/37e8a4e3e10d84bbc8e987788f150cb3.jpg

I've read up some, and the grooves are never mentioned as affecting the
process in terms of the loading, but if one was to use a smooth plate, or a
grooved plate(radial), how can the grooves not affect the plate loading?
Also, nothing is negligible when these machines lap to nanometre resolution.

Roland
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[Emc-users] Cutting cast iron with a dry diamond blade

[Roland Jollivet]

I once watched a contractor dry cut rebar with a diamond blade using a
cut-off saw. I wanted to tell him you can't do that, but he was quite
burly, so I left it alone.
He said it was a diamond blade, so I'll never know for sure.

I presume diamond blades work in cutting reinforced concrete because the
concrete is there to temper the feed rate..

Roland


On 10 May 2016 at 17:47, Dave Cole  wrote:

> I've been doing the controls for a manufacturer of large core drill
> machines for about 10 years. The machines are made to drill holes in
> concrete structures that make up sewer systems.
> The machines can drill up to 60" holes using diamond segmented tipped bits.
>
> Diamond bits work great for concrete and stone and they do ok when
> sawing through the wire reinforcement in the concrete as well (up to
> about 1/2" rebar reinforcement).
> Water is always used with those bits for maximum life.   However they
> don't need a lot of water.  Just enough to wash away the grindings.
> With smaller bits (12-24") in diameter, the machines can achieve feed
> rates of 4-5 inches per minute even when chewing through wire
> reinforcement.   Diamond tipped saw blade "teeth" are really tiny
> diamonds in an alloy matrix which rubs against the material to be cut.
> Its really more of a grinding process than a cutting process.   A good
> diamond tipped concrete core drill can drill through 100+ feet of
> concrete before needing to be re-tipped if the core drill is treated
> properly.
>
> I've never heard of diamond bits being used to solely cut cast iron.   I
> would think that Carbide or HSS would be preferable.
>
> Dave
>
> On 5/9/2016 11:13 PM, Gene Heskett wrote:
> > On Monday 09 May 2016 22:40:45 andy pugh wrote:
> >
> >> I am not an expert in diamond sawing, so take that as a caveat.
> >> However, as far as I know diamond turning of iron-based materials is
> >> almost never done. For iron-based materials the abrasive of choice is
> >> CBN.
> >> The reason for this is, as I understand it, is because carbon is
> >> soluble in iron. In fact the whole marvellous thing that is ferrous
> >> metallurgy is just playing games with the various things that
> >> solutions of carbon dissolved in iron can do when you heat and cool
> >> them.
> >>
> >> Diamond turning of aluminium and copper alloy parts has been standard
> >> for 50 years or more. You won't find many references to
> >> diamond-turning of iron alloys.
> > Thanks Andy.  I should point out that I am not turning it just yet, but
> > sawing off a slice, nominally 1.75" thick, that I can turn, eventually
> > into a block the same height as the compound carriage is, to add some
> > mass to the crossfeed, and to offset the QC holder to the rear and
> > right, thereby putting the typical cutting tool much closer to the
> > center of the Z carriage so the cutting forces are essentially straight
> > down on the center of the Z carriage.  And that I am not achieving a
> > temperature where the carbon (in the diamond dust) can dissolve into the
> > iron.  At no time has the blade or the workpiece been heated to the
> > point I can't rest my hand on either.  Slow, but it seems to be a pretty
> > precise way to do it, so far.  Got a huge pile of grey cast iron dust
> > though.
> >
> > Ignore that thumping sound, thats just me, knocking on wood. ;-)
> >
> > Cheers, Gene Heskett
>
>
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Re: [Emc-users] 7mmx1.0 decently hard cap screw, how scarce are they?

[Chris Albertson]

McMaster Carr has M7 cap screws.  they are "class 12.1" screws made of
alloy steel.  Not cheap $3 to $7 each.  Look them up on-line.  They
"everything" even aluminum and left hand thread cap screws.
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Re: [Emc-users] 7mmx1.0 decently hard cap screw, how scarce are they?

[Dave Cole]

On 5/10/2016 7:27 AM, Mark wrote:
> On 05/09/2016 04:49 PM, andy pugh wrote:
>> On 9 May 2016 at 18:22, Dave Cole  wrote:
>>> Andy is probably going to want to stop there and pickup some arms since
>>> I heard he is coming to the Detroit area probably to hang out at the
>>> Ford glass house.  ;-)
>> Actually, I am sat in the office at Roush based in what appears to be
>> an abandoned police station. I amnot sure what to read into the fact
>> that there is an abandoned police station in Dearborn.
>>
>>
> It's not Dearborn anymore. We now lovingly call it "Dearbornistan."
>
> Mark
>
Dearborn is actually in much better shape since the Arabs moved in 20+ 
years ago.   That area was a lot like Detroit before the Arabs started 
pumping money into the area.
There is a large Arab population (compared to the rest of MI) there but 
also a substantial Jewish and Christian population there as well.I 
know families of each that live there and I go there several times per 
year.  Compared to the rest of the Detroit area, the area is very 
safe.However if you go to the far east end of Dearborn... or 
northeast ...
well then you've been warned.  Downtown Detroit is pretty safe,  the 
outer Detroit burbs are pretty safe, however the donut area around 
downtown is not so safe.That's why you can buy houses there for a 
few hundred dollars and back taxes in the "donut" area (seriously - 
check Zillow).

Dave


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Re: [Emc-users] Cutting cast iron with a dry diamond blade

[Dave Cole]

I've been doing the controls for a manufacturer of large core drill 
machines for about 10 years. The machines are made to drill holes in 
concrete structures that make up sewer systems.
The machines can drill up to 60" holes using diamond segmented tipped bits.

Diamond bits work great for concrete and stone and they do ok when 
sawing through the wire reinforcement in the concrete as well (up to 
about 1/2" rebar reinforcement).
Water is always used with those bits for maximum life.   However they 
don't need a lot of water.  Just enough to wash away the grindings.  
With smaller bits (12-24") in diameter, the machines can achieve feed 
rates of 4-5 inches per minute even when chewing through wire 
reinforcement.   Diamond tipped saw blade "teeth" are really tiny 
diamonds in an alloy matrix which rubs against the material to be cut.   
Its really more of a grinding process than a cutting process.   A good 
diamond tipped concrete core drill can drill through 100+ feet of 
concrete before needing to be re-tipped if the core drill is treated 
properly.

I've never heard of diamond bits being used to solely cut cast iron.   I 
would think that Carbide or HSS would be preferable.

Dave

On 5/9/2016 11:13 PM, Gene Heskett wrote:
> On Monday 09 May 2016 22:40:45 andy pugh wrote:
>
>> I am not an expert in diamond sawing, so take that as a caveat.
>> However, as far as I know diamond turning of iron-based materials is
>> almost never done. For iron-based materials the abrasive of choice is
>> CBN.
>> The reason for this is, as I understand it, is because carbon is
>> soluble in iron. In fact the whole marvellous thing that is ferrous
>> metallurgy is just playing games with the various things that
>> solutions of carbon dissolved in iron can do when you heat and cool
>> them.
>>
>> Diamond turning of aluminium and copper alloy parts has been standard
>> for 50 years or more. You won't find many references to
>> diamond-turning of iron alloys.
> Thanks Andy.  I should point out that I am not turning it just yet, but
> sawing off a slice, nominally 1.75" thick, that I can turn, eventually
> into a block the same height as the compound carriage is, to add some
> mass to the crossfeed, and to offset the QC holder to the rear and
> right, thereby putting the typical cutting tool much closer to the
> center of the Z carriage so the cutting forces are essentially straight
> down on the center of the Z carriage.  And that I am not achieving a
> temperature where the carbon (in the diamond dust) can dissolve into the
> iron.  At no time has the blade or the workpiece been heated to the
> point I can't rest my hand on either.  Slow, but it seems to be a pretty
> precise way to do it, so far.  Got a huge pile of grey cast iron dust
> though.
>
> Ignore that thumping sound, thats just me, knocking on wood. ;-)
>
> Cheers, Gene Heskett

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Re: [Emc-users] 7mmx1.0 decently hard cap screw, how scarce are they?

[Mark]

On 05/09/2016 04:49 PM, andy pugh wrote:
> On 9 May 2016 at 18:22, Dave Cole  wrote:
>> Andy is probably going to want to stop there and pickup some arms since
>> I heard he is coming to the Detroit area probably to hang out at the
>> Ford glass house.  ;-)
> Actually, I am sat in the office at Roush based in what appears to be
> an abandoned police station. I amnot sure what to read into the fact
> that there is an abandoned police station in Dearborn.
>
>
It's not Dearborn anymore. We now lovingly call it "Dearbornistan."

Mark

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Re: [Emc-users] Where to post LinuxCNC issues?

[Gene Heskett]

On Tuesday 10 May 2016 01:49:17 Marius Alksnys wrote:

> The issue tracker wiki
> pagehttp://wiki.linuxcnc.org/cgi-bin/wiki.pl?Trackers refers to does
> not accept new issues. Where should I post them?
>
> In documentation, html/gcode/g-code.html#gcode:g90.1-g91.1:
>
> G90.1 - absolute distance mode for I, J & K offsets. When G90.1 is in
> effect I and J both must be specified with G2/3 for the XY plane or J
> and K for the XZ plane or it is an error.
>
> I think it is incomplete and incorrect.

You may be correct, Marius. I certainly have had my troubles getting the 
results I desired from those 2 commands.

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)
Genes Web page 

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Re: [Emc-users] Where to post LinuxCNC issues?

[Sebastian Kuzminsky]

On 05/09/2016 11:49 PM, Marius Alksnys wrote:
> The issue tracker wiki
> pagehttp://wiki.linuxcnc.org/cgi-bin/wiki.pl?Trackers refers to does not
> accept new issues. Where should I post them?

Yep, another out of date wiki page.

We're using the github issue tracker now:

https://github.com/LinuxCNC/linuxcnc/issues

The main webpage has the correct link:

http://linuxcnc.org/community/


-- 
Sebastian Kuzminsky

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