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jwoitasek
02-22-2002, 09:20 AM
Hey Guy's
I've got a question.
I have a production run of 19 parts.
I have to face-off both sides of Stainless steel rods.
I'm going to use the lathe but I do not have collets for it, So i'm going to use the 3 jaw chuck.
I have to keep the finished lenght 2.313" +.001 -.000
Is their a way I can fabricate a stop in the lathe spindle so I dont have to stop and measure, stop and measure,etc.
Or am I going about this the wrong way?
Any Idea's ?
Thanks
JRW

bspooh
02-22-2002, 10:29 AM
I don't know what diameter you're doing, but what I usually do when I have to use the 3 jaw, is I put a parralel in the chuck, then put your piece up against the parralel and tighten the chuck, then REMOVE THE PARRALEL, and this repeats very well..Thats the quick and easy way for me...good luck...

brent

halfnut
02-22-2002, 10:42 AM
Sure is, I built one for Clausing at work, works well.

This machine has a 3 1/16" spindle hole so I started with chunk of plastic about 4" long 3" diameter. Bored a 1" diameter hole thru, cut an internal taper each end 90 deg included out to around 2", cut o-ring grooves each end to below surface, then split into three sections on bandsaw. The o-ring grooves hold o-rings of course, they act to hold things together.

Made 2 steel plugs, one with 1/2+ thru hole, yea long,2" diameter, 45 angle down to 1" dia on end 1/4 long. The other plug longer, 1/2-13 drilled and tapped thru. In this longer plug I use a length of all thread, and I have different ends to fit on the end of all thread.

This longer chuck end plug must be long enough to accomodate both the all thread extention and the clamping bolt, the 1" diameter stubs on end of tapers on plugs let the expanding plastic part collapse to that point, all being held together by the o-ring rubber bands.

I also made up a long tee allen wrench to tighten up and loosen this thing.

It works well, of course you will have to scale it to fit your machine.

BTW I tried to use it in our new Asian made lathe the other day, I was worried that it might be too loose. I couldn't get it to go into spindle hole, seems that only the end of this spindle bore is 3 1/8 as the liturature says, it tapers in to around 3.020, and the spindle bore is rough as a cob.

metal mite
02-22-2002, 11:12 AM
jwo,
I'd set em up in the mill with a vise stop, and mill em off.
Works best for me.
metal

Thrud
02-22-2002, 10:33 PM
Brent has the best idea for the least amount of effort. Building a "Collet Stop" for your chuck is the other way as halfnut suggests is more work. Milling them off to length is good too - if the vise can hold it properly perpindicular to the table - do not try multiple pieces this way unless you have a vise with hydraulic equalizing jaws.

Dave

halfnut
02-23-2002, 01:50 AM
I was going to describe the working end of this stopping arrangement, but things got long. I'm back now.

The extention of all thread has the adapter mounted to it. This adapter I make just a few thousands under the dia of part, letting it center within the chuck jaws. Also I face this adapter in place assuring squareness, helps to have a healthy champher on outer edge to prevent hitting chuck jaws when doing this facing. If small diameter use what works, including a small contacting area offset from center to clear the little facing bump that might be there. You didn't mention diameter, nor if there is hole of any sort in middle.

Good repeatable accuracy with this set up. Kind of complicated but a nice accessory for any lathe. The o-rings work good.

I have often used a lenth of drill rod for a stop, used similarly to parrellels, but can be used with jaws closed up tighter. Take a fair lenth of STRAIGHT drill rod, or drill blank small enough to go in gap between chuck jaws lay against face of chuck, tighten chuck till part just barely slides, push back till you just feel it bump end of rod. Tighten chuck same tightness as closely as you can each time.

+.001 -.000 pretty tight tolerance, if these were short and bigger and made of steel I'd finish the lenth with surface grinder.

Good luck, and hold your mouth right. Might have to cut out a couple extras for scrappage. Thats part of the game.