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Author Topic: Need Encoder for threading  (Read 13733 times)

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Offline Hood

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Re: Need Encoder for threading
« Reply #20 on: June 30, 2012, 09:25:02 AM »
Thats good to hear Jim :)
Hood
Re: Need Encoder for threading
« Reply #21 on: July 02, 2012, 09:09:05 AM »
I'm now cutting threads and love the way this works.

Encoder:


Tachometer:


First thread:


Video of thread cutting
Jim

Offline Hood

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Re: Need Encoder for threading
« Reply #22 on: July 02, 2012, 09:35:43 AM »
Looking good, better do a long thread before John S says its not really working ;D

Hood

Edit
Too late I see he already has ;D
« Last Edit: July 02, 2012, 09:45:51 AM by Hood »
Re: Need Encoder for threading
« Reply #23 on: July 02, 2012, 11:34:36 AM »
How did you know John was going to do that.   He already said it wouldn't work. ;D

I ran a test piece with 10 TPI and cut threads 5" long.    I measured with an eyeglass and steel rule and the last of 50 threads was off about .010".  Much better than I expected actually.   Not bad for a $5 encoder and $175 for Mach3 program.

I did calibrate my "Z" axis.     Before I calibrated Z, I was off 1/2 thread in 5".
Jim
« Last Edit: July 02, 2012, 11:41:47 AM by jglass »

Offline Hood

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Re: Need Encoder for threading
« Reply #24 on: July 02, 2012, 01:19:01 PM »
May have been your chamfer amount that you were seeing the discrepancy in the last  thread.
Hood
Re: Need Encoder for threading
« Reply #25 on: July 02, 2012, 09:38:24 PM »
Here is my test result.    This  was after two passes.   I thought Mach3 did a great job, better than I expected.    The thread pitch is consistant and the second pass proves Mach3 is repeatable.



Jim
« Last Edit: July 02, 2012, 09:43:40 PM by jglass »

Offline Hood

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Re: Need Encoder for threading
« Reply #26 on: July 03, 2012, 02:58:09 AM »
Saw your pic on the other forum and I think your issue with the last turn being off pitch, is due to the slow acceleration that steppers have. Try setting a chamfer angle of maybe 360 or more and see. I am sure Grahame sorted the macro about 3 or so years ago so that the chamfer worked correctly, it should start pulling out at the value you set, ie 360 degrees before the last rotation, that should help things be cleaner at the end.
Hood