Messages

6601

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 09:23:37 PM »

RC,
Pulse setup here is just like in the manual with a single  slotted disc and the opening width based on the calculation they gave in the manual ( slightly under ). For the thread test i just posted, the max variation in rpm was 1.46%  and the turn readout will just flicker once in a while from the 100 to 99 rpm in the display. I don't even do an rpm check anymore with the speed indicator anymore as I trust what Mach is telling me.

I can fool wiith my punny lathe manualy, by hand,slowi ng the spindle down and seeing what happens and must say that Art took care of the hobbiest. As you well know, when it comes to thread tolerance, we haven't gone there yet in this thread.

I tend to agree with you that Bob's problem may be the index pulse. I am only quessing, but if the pulse triggers Z start at say a diifferent point of the mark on the shaft, then you will see it by the change of the scribed line. Will need to waite for Bob to get back from the garage.
In the mean time wine and pitza, moma's nice, so i hope he dosn't take too long.
RICH  

6602

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 08:37:00 PM »

RC / HOOD,
Is G76 all fixed up now? I havn't tried it in a while.

RICH

6603

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 08:15:24 PM »

BOB,
I believe i was looking at your lathe on your site  and noticed that the wiring from your sensor was not shielded and ran under the motor. Not good as you'll get noise from the motor brushes getting into the pulse to MACH
Whip out that old specturm analyzer of your's and sniff around!   NY3P here!
Shield wires as close as possible to the al box and ground the shield back at the controller.
You mess up the timing pulses and start the z too soon or late relatiive to what was prior cut  and your thread is history.
RICH

6604

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 07:58:38 PM »

BOB,
POST#2 MORE PIC'S

RICH

6605

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 07:55:23 PM »

BOB,
I am attaching a file's in two posts which you can use to test your lathe out with.
I still suggest you just do a clean up cut and then color the end of the shaft as shown in
shaft setup pic. Use your 1/4" stock and note that I have the threading tool point at the end of 
and on centerline of the stock. Set your cutter the same ( you don't have to have the diameter
the same as mine ) and then set the "X" value to 0.246 in the DRO and also set Z to 0.0.
Set the spindle to 100 rpm.

Note that you can use the diagnostics pulldown to see what is happening as your threading.
You will see the variation of the speeds and also a percent which MACH compensates for.
Additionaly there will be status and also show triggering of the thread cycles. This is a nice feature.

Since the depth of cut is only 0.0001" and 78 passes your should only get a small scribed
line around the shaft.I have attached pictures of the thread path at 20, 40 , 78 passes.
You should get the same results if the all is set up. The last pic is at 30x showing pitch
and width of the cut. Sorry about the picbut it was off hand thru the microscope and the scale turned.

Doing this will enable you to save your brass and check out your system.
If you can't get these kind of results you will never cut a thread worth a darn.


Hope this helps,
RICH      POST#1

6606

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 23, 2009, 06:33:23 AM »

bOB,
Just a few program setting checks here:
1.In config>input signals> index is checked and port & pin iis assigned along with proper pulse setting
            "  >spindle setup> in special functions box, the spindle feedback in sync is checked and  also
                                       spindle speed averaging
2.in config>general config>  I use .005 for shuttle accel, 500 for debounce interval / 100 for index debounce
3. in plug control>turn diagnostics - you can use this to monitor the threading as it shows info on rpm, index etc

Don't get frustrated. There is more to just putting in a piece into the stock and running a program.
Why i say this is that, to do threading, a number of things all need to be in place or else poor results.
More so for a punny lathe.
For now all we want to know is the machine is set within it's capabilities, the program settings are correct,
basic threading movements are working correctly. Accurate threads is another story in itself  which is greating
influenced by the machine and tool .
So, with just doing a skim cut numerous times we can eliminate some influences which can screw up a thread and check things out plus you waste no material.
Sorry, i walked along your same path and there is no short cut to do a thread.
RICH

    

6607

SmoothStepper USB / Re: Smoothstepper disconnect safety concerns

« on: January 22, 2009, 05:34:52 PM »

Hi All,
In design of industrial facilities most sites go through what we call Hazards Review and What If ( just a few of the buzz words ) thinking around what will be built, operated and maintained. The discussions are intense in review of each and every component that can cause personal or physical injury or damage. These reviews are well led, documented and provide basis for control by responsible individuals. As the complexity of machine systems increase, even at the amateur
level, it behoves us to stop and pull back and go through a thought process and address any and all hazards which are
identified. An e-stop is just one component of the system. In the big picture the dollars spent are appropriate for pre-defined base guidelines as they relate to investment. Safety on the other hand is defiined as goal of "0" ZERO incident and appropriate safeguards, procedures, training, supervisory controls etc are implemented to achieve the goal.
 
RICH

6608

LazyTurn / Re: LazyTurn

« on: January 22, 2009, 05:03:05 PM »

Wolfram,
Hats off to you as that is a lot of work. The Lazyturn manual will just mature as the program develops. Still a lot of
work to be done in it and feel free to post in the other thread with any comments you may have.
RICH

6609

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 21, 2009, 10:59:35 PM »

Bob,
Wimpy is yours and punny is mine.
I just posted 1 min before you.
Take a cleanup cut for say .75", and use the wizard to generate gode based on the cleaned up diameter,
use the 100 RPM, .....BUT......set the pass depth for .0001" in the wizard. This way you are checking the threading cycle. You won't do any deep cutting so slipage of belts or motor slow down should not influence the following of the tool along the thread. It should repeatedly just give you a fine scroll around the rod at pitch.

BTW make sure the Z  starts some distance , .1 or .2" before threading starts as this will give some time
for the stepper to accelerate.

RICH

6610

General Mach Discussion / Re: Questions on Threading With Turn on Sherline - From Yahoo SherlineCNC Group

« on: January 21, 2009, 10:34:24 PM »

Bob,
You have the newer motor. The T/S curve I was refering to was for the steppers you currently have.
It's your decision on the purchase of new drives. My point was, that with your current controller you will be limited
on what can be deliver to the new steppers should you purchase them.

Suggest you try cutting 40tpi on the 1/4" stock at a slower speed and say .003" pass depths. Brass is fine, but you can also buy some of that cheap 1/4" gummy Al from the hardware store and save the brass for a later project.
This way you will able to tell how all is working.  While in Turn try  the thread wizard to generate the code.
RICH