Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Overloaded on September 12, 2008, 08:41:14 PM
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:)
Followed the Yahoo group intently on the topic of threading.....for a LONG time.
Before .008, the parts I was threading made BEAUTIFUL pictures like all the rest. But getting to the nitty gritty, the were in and out of the specified tolerance.
I purchased precision ring gauges that were certified with a tolerance of +/- .00075 on the PD. (48 TPI)
The parts would come and go, + and - and I would get about 7 or 8 out of 10 good parts on average. TOTALLY unacceptable.
After .008, only a slight variation in the PD, so little that 400 parts were made, every single one checked and ALL were good.
Needless to say, I was pleasantly surprised and impressed. The only variations were most likely mechanically related.
I have 12,000 pieces to run. If this holds up the way it's going now.......well, lets just hope I didn't speak too soon.
Just couldn't hold it in.
Thanks Brian for whatever you did.
RC
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RC,
Good for you and happy that the bug in Mach is about to perish to it's hole in the ground!
I assume that the lathe being used has ball screws, min backlash, and your using servos.
Can't make money from scrap!
RICH
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Glad to hear that RC, as I said before I never had a problem with threading but I know a lot of others did, looks like Brian and Art have got most people sorted and I know Arts thinks he can figure out the problems for the rest that are still having issues.
Hood
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Hello RICH,
Actually...I need to post a pic of this "RIG".
It's the oldest Hardinge lathe I've ever seen. It had a 3 step flat belt drive and a 4C spindle with a manual collet closer.
It also had a cross slide (rack & pinion) and some other custom fixtures on the bed.
And it had a box of parts including a set of new spindle bearings. The ones in it are fine though so I have spares.
$129
Then I found some brand new Gilman dovetail slides, still in the grease paper....4" x 12" 3 for $30
I keyed 1 of these to the Hardinge slotted bed for the Z axis and used THK rails and trucks that I had on hand for the X.
I had to buy 2 new ballscrews...THK 10x2mm...$200 ea.
I machined everything else, used double bearings for the screw blocks and put a GE 2hp VFD ($60) to a 1 hp inverter duty motor that I "found" lying around.
Using PMDX 122 and 106 boards.
Backlash is .001 or less. OK for threading, it's always taken up in the same direction.
If this works out....I will be PLENTY busy.
Next on the list: An automatic feeder and a dang CHIP CONVEYOR !
Thanks for you continued encouragement and support RICH,
RC
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Thanks Hood,
If the majority of us had a BEAST of a lathe as you do, no one would have known that there was a problem.
It was difficult enough to convince them as it was.
Thanks for you support as well,
RC
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Oh...RICH, I forgot to include...Automation Direct Sure Step steppers and their drives as well, 50 micro step, 45 or 60 khz kernel..not sure.
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Post the picture RC and check out the link below as you may just find info on that old lathe.
RICH
http://www.lathes.co.uk/
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Holy Smokes...What a Site.
If it ain't there, it probably dont exist.
Thanks Rich, I'll see if I can find my model and will post the pic soon.
RC
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How about adding it to the links in Resouces.
RICH
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An EXCELLENT idea. Not sure if a Mod. can do that.
May need an Admin.
Will try.
RC
I got:
"Your link needs to be approved befor being visible"
Need Admin. i Guess,
RC
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Believe it or not...it's not there.
They do sell a book though.
Here is a pic of what is closest.
Mine is just a bit heavier.
RC