-Original Message-
From: andy pugh
Sent: Tuesday, January 05, 2021 12:26 PM
To: Enhanced Machine Controller (EMC)
Subject: [Emc-users] I wonder if I can fix it?
>I bought an FHA-17C actuator from eBay. It was cheaper than normal, for parts
>or not working.
>It clearly had the cables
I bought an FHA-17C actuator from eBay. It was cheaper than normal,
for parts or not working.
It clearly had the cables cut off, so I decided to gamble.
It turns out that things were worse than I hoped.
https://photos.app.goo.gl/p3SL2Bwv2b9yd5XJ9
I am seriously considering trying to make a new
Looks a lot like the harmonic drive that failed in one of our machine's tool
changers. We bought the machine used and the previous owner tried to weld it
back together. Their repair lasted for about 6 months after we bought it. Our
break wasn't quite as bad though because ours only went
The flexspline is the secret sauce of harmonic gearboxes. If you can make
one (that can last), you can print money because these harmonics are used
in so many robotic applications. The Harmonic Drive patents expired a few
years ago and there was one competitor (forget who??) who was coming out
On Tue, 5 Jan 2021 at 18:15, Mark Johnsen wrote:
> back, pushed back again, and I think they finally gave up (not sure).
> Why? Because their flexspline kept breaking because of fatigue. At least,
> that's what I had heard.
I found this interesting article:
On Tuesday 05 January 2021 10:47:16 andy pugh wrote:
> On Tue, 5 Jan 2021 at 15:40, Thomas J Powderly
wrote:
> > Thats a max step/sec of 1 for that particular sequence of 2
> > steps.
> >
> > That sequence can happen at anytime in a cnc path.
>
> Not so. A stepper will only ever reverse at
Fascinating. I hope mine never fails. Thanks for that posting.
John
> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: January-05-21 10:32 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] I wonder if I can fix it?
>
> On Tue, 5 Jan 2021 at
Ouch!
> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: January-05-21 9:26 AM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] I wonder if I can fix it?
>
> I bought an FHA-17C actuator from eBay. It was cheaper than normal,
> for parts or not
On Tuesday 05 January 2021 12:25:42 andy pugh wrote:
> I bought an FHA-17C actuator from eBay. It was cheaper than normal,
> for parts or not working.
> It clearly had the cables cut off, so I decided to gamble.
>
> It turns out that things were worse than I hoped.
>
>
On Tue, 5 Jan 2021 at 18:23, Gene Heskett wrote:
> That one I'd hazard a guess, has been over torqued,
I think it is fatigue, starting at the root of one tooth and growing
through the whole cup.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial
This is easily repaired by throwing it in the nearest round bin and buying
a more robust Spinea cycloidal reducer and servo from ebay
On Tue, 05 Jan 2021 12:25:42 -0500, andy pugh wrote:
I bought an FHA-17C actuator from eBay. It was cheaper than normal,
for parts or not working.
It
Thx Andy
I will look for what the code says it does when there's a zero speed
reversal.
So I take it is true that the 4 values _are_ up rounded to the base
period length.
but , a special case ignores/allows for when the velocity is zero.
I didnt see that yet.
TomP
On 1/5/21 10:47 PM,
I've noticed what appears to be a lot of new development of new GUIs for
Linuxcnc lately. Here is an idea that I would love to see implemented in a new
GUI, but I do not have the programming skills to implement it. For our
production machines it would be nice for the supervisors to be able to
On Tue, 5 Jan 2021 at 15:40, Thomas J Powderly wrote:
> Thats a max step/sec of 1 for that particular sequence of 2 steps.
>
> That sequence can happen at anytime in a cnc path.
Not so. A stepper will only ever reverse at zero speed, when the step
rate is zero. So you don't need to make
Hello
I am studying the stepgen.c code.
I see that the 4 parameters
steplen stepspace dirhold and dirsetup
are rounded up ( ulceil() )
to the next larger interger value of the BASE period.
That means for my Gecko 540, the 1uS Steplen 2uSstepspace 200nSdirhold
and 200uS dirsetup
all
On Tue, 5 Jan 2021 at 16:24, Thomas J Powderly wrote:
> but , a special case ignores/allows for when the velocity is zero.
I don't think that it is a special case, just that because the
reversals always happen at very low step rates you don't need to
factor in the setup time when calculating
On Tue, 5 Jan 2021 at 20:36, Rafael Skodlar wrote:
> > I am seriously considering trying to make a new flexspline. I mean,
> > how hard can it be?
> >
>
> Based on what I know about harmonic drives, extremely hard.
Yes, I was being a little sarcastic. But if I don't expect to make a
_good_ one,
> From: andy pugh [mailto:bodge...@gmail.com]
>
> On Tue, 5 Jan 2021 at 21:31, John Dammeyer wrote:
>
> > Turn the inside to a predefined diameter and press in a support hub that
> > has a center hole that will be used for support.
>
> That mirrors what I was thinking of doing, though as the
On Tue, 5 Jan 2021 at 21:31, John Dammeyer wrote:
> Turn the inside to a predefined diameter and press in a support hub that has
> a center hole that will be used for support.
That mirrors what I was thinking of doing, though as the part is only
50mm diameter there is probably no need to
Instead of carving away over 90% to make one I wonder it an outside of the box
approach might work.
Start with a piece of pipe stock close to the right size. Turn bevels on the
bottom edge and a disk to fit against the bottom.
Weld in a disk at the bottom. Heat treat and allow to cool to
On 1/5/21 9:25 AM, andy pugh wrote:
I bought an FHA-17C actuator from eBay. It was cheaper than normal,
for parts or not working.
It clearly had the cables cut off, so I decided to gamble.
It turns out that things were worse than I hoped.
https://photos.app.goo.gl/p3SL2Bwv2b9yd5XJ9
I am
Quite a lot of the drive is still in perfect shape. That flex cup part is
toast.
What you can do is try and 3D print a new flex cup but do NOT repeat the #1
mistake that almost everyone does. They try and duplicate a metal design
but use plastic. That approach is doomed to fail. A plastic
Interesting.
One could do an experiment. Cut a cup the size of the gear but without the
teeth. Then mount it and run an offset skateboard wheel inside it to flex it
about the amount the gear would flex. Count revolutions and let it go. How
many days, weeks etc before failure?
And while
> > After heat treating it would probably require some grinding or polishing
> > unless you can cover it in a way that it won't oxidize.
>
> I am wondering about using something like P20.
>
>
What is P20?
John
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
>
https://www.makeitfrom.com/compare/SAE-AISI-4140-SCM440-G41400-Cr-Mo-Steel/SAE-AISI-P20-T51620-Low-Carbon-Mould-Steel
-Original Message-
From: John Dammeyer
Sent: January 5, 2021 5:57 PM
To: 'Enhanced Machine Controller (EMC)'
Subject: Re: [Emc-users] I wonder if I can fix it?
> >
On Wed, 6 Jan 2021 at 00:07, John Dammeyer wrote:
> One could do an experiment. Cut a cup the size of the gear but without the
> teeth. Then mount it and run an offset skateboard wheel inside it to flex it
> about the amount the gear would flex. Count revolutions and let it go. How
> many
Andy,
Are you able to CAD model the existing broken one or is it too far gone?
I suspect the Hob will be the most work.
John
> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: January-05-21 4:18 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re:
On Tue, 5 Jan 2021 at 22:26, John Dammeyer wrote:
> After heat treating it would probably require some grinding or polishing
> unless you can cover it in a way that it won't oxidize.
I am wondering about using something like P20.
--
atp
"A motorcycle is a bicycle with a pandemonium
On Tue, 5 Jan 2021 at 23:05, wrote:
>
> https://www.makeitfrom.com/compare/SAE-AISI-4140-SCM440-G41400-Cr-Mo-Steel/SAE-AISI-P20-T51620-Low-Carbon-Mould-Steel
Possibly a little more informative:
http://harrisonspecialiststeels.co.uk/tool-steel/p20-mould-steel/
--
atp
"A motorcycle is a bicycle
On Wed, 6 Jan 2021 at 00:30, John Dammeyer wrote:
> Are you able to CAD model the existing broken one or is it too far gone?
I think I can work it out from knowing where it belongs.
> I suspect the Hob will be the most work.
I think it might be a job for a single-lip cutter.
I would struggle
On 01/05/2021 06:05 PM, John Dammeyer wrote:
Interesting.
One could do an experiment. Cut a cup the size of the gear but without the
teeth. Then mount it and run an offset skateboard wheel inside it to flex it
about the amount the gear would flex. Count revolutions and let it go. How
Greetings all;
I find on a simple jobs tonight, that the bed isn't flat, and that I need
to scan it for lincurve data.
But this would be a true 3d need as it needs correction in both X and Y
travel. lincurve isn't made to do that. So how might that be done?
Thanks.
Cheers, Gene Heskett
--
On 2021-01-06 04:25, Bruce Layne wrote:
Why don't you just install a spoil board and machine it flat like most
people do with a CNC router?
When I converted my mill, I followed some published instructions for an
identical mill, and added ballscrews. That involved machining a shallow
'trench'
Why don't you just install a spoil board and machine it flat like most
people do with a CNC router?
On 1/5/21 10:48 PM, Gene Heskett wrote:
> Greetings all;
>
> I find on a simple jobs tonight, that the bed isn't flat, and that I need
> to scan it for lincurve data.
>
> But this would be a
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