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Beginner, need to make six S/S pieces .090" dia, +.001 X 2" +/- .005"

berol

Aluminum
Joined
Jan 5, 2006
Location
Florida
Trying to turn down a 3/16 X 3" round piece of 303, S/S to a finished .090" X 2" on my 10EE Monarch. Collet on one end and a 1/2, MT2, small nose live center at the tailstock end. Also, tried an MT2, 1/2 dead center. Both did not allow me anywhere near enough clearance. Need six pieces. Two questions; (1) What MT2 piece of equipment might be available or that I could make for the tailstock that would give me the support and clearance necessary. (2) What might be an appropriate work around to accomplish the finished pieces. Also do not have a .090" collet. Please be specific with your suggestions. Thanks!
 
Look up lathe box tool.

It has a bushing/guides/or rollers, that support work very close to where material is removed. Support moves with cutter.

Deflection is no longer an issue.

I would think a swiss style lathe, or a grinder would be a better way to get the job done...
 
Seems like it would be easier to make it from 3/32" stock. In my shop, I would use a Levin lathe that I can lift with one hand for little pieces like that. I have seen a 10EE and know it is nice, but too heavy for me to move, so I never bought one.

Anyway, a roller box tool, once adjusted, could do the job with ease. I use 2 and 3 Morse taper end mill holders in my conventional tailstocks to hold 5/8, 3/4 and 1" straight shank turret tooling for simple one-tool jobs.

Larry
 
Are you trying to make spaghetti???

Find a company that grinds stock for swiss machines, buy a length and be done with it.

I've been forced to do stupid shit like that, and there are some things that are just
better off being sent out to the right people that have the right equipment to do the
job..

Box tool would be worth a shot..


And a thought.. Tailstock.. Instead of pushing or letting it run dead.. Anybody ever
tried grabbing the material in the tail stock with a collet or something and pulling back..
Put the material in tension??? Just a thought.
 
And a thought.. Tailstock.. Instead of pushing or letting it run dead.. Anybody ever
tried grabbing the material in the tail stock with a collet or something and pulling back..
Put the material in tension??? Just a thought.

It is impossible to pull on something hard enough axially to prevent radial deflection in the middle, the vectors won't allow it.
 
It is impossible to pull on something hard enough axially to prevent radial deflection in the middle, the vectors won't allow it.

You are never going to eliminate deflection.. But I can push a lot harder on a rope that is in tension than I can
on one that is in compression. The more tension its under, the harder I can push.

I know metal isn't rope, but 2" of .090" 303 isn't too far off.

As an aside, at what diameter does it go from "bar stock" to "wire"??
 
You are never going to eliminate deflection.. But I can push a lot harder on a rope that is in tension than I can
on one that is in compression. The more tension its under, the harder I can push.

I know metal isn't rope, but 2" of .090" 303 isn't too far off.

As an aside, at what diameter does it go from "bar stock" to "wire"??
Lol, I wonder about the same thing with sheet and plate.

You're right, as nothing is perfectly rigid. Where this gets all weird is that since the shaft is presumably straight the tensioning would only produce vectors in the item's axis until it was deflected into a catenary of sorts. For the tension to provide any straightening the shaft would have to deflect well beyond his +.001" spec.
 
Pin-Turning Jig

This type of problem can be solved with a pin-turning jig. This sort of thing is not sold anymore that I know of, at least for any reasonable amount of money, but you can make one as follows:

pin_jig_1.jpgpin_jig_2.jpgpin_jig_3.jpg

A pin turning jig can be used to turn pins either on a lathe, mill or drill press. On a lathe the arm of the pin turning jig should be sized to mount on whatever rest you have. On a mill or drill press, the arm of the pin turning jig is clamped to the table.

The parts needed are the:

- the frame of the jig cut from 0.5" plate
- 0.5" bushing
- 3/16" cutter
- a small toe clamp
- (2) 1/8" x 1/2" steel pins
- 3/16"-32 7/8" cap screw
- (2) 6-32 1/4" set screws

[Frame] Cut out the frame. A plasma cutter could be used or even a hacksaw. Grind and finish the edges to be straight and smooth. Drill and ream the hole for the bushing.

[Bushing] Ideally, the bushing should be turned from D2 tool steel and hardened. A bevel can be added to the back of the bushing to make it easier to feed the work into it. A hacksaw/file or a mill can be used to cut the notches out from the bushing to form its tongue. You could alternatively use a milling attachment on a lathe.

Insert the bushing, tongue up, into the frame and scribe a line across it and the frame. This can be used later to make adjustments.

The set screws can be used to rotate the bushing and adjust the depth of cut.
 
I have a Geometric head that I use for that sort of thing. I have one set of inserts with the threads ground off that I can run up on to a small diameter pin to cut a smaller size and no deflection involved.
 
So I take it you need a 3" long part with two diameters on it? 2" of .090 and the rest 3/16" stock diameter? What is it's use, does it have to be .303? Can you just press an .090 pin into a 3/16 slug?
 
Information is lacking, but I'm going on the assumption the finished part is a cylinder 0.090" diameter (+0.001/-0.000) x 2.000" long(+/- 0.005). Although I have a feeling there are probably other ways to do whatever the OP is trying to do without making such a crazy little part on a machine not designed to make it, we'll just ignore that for now. :)

I figure you can probably find some kind of SS rod that's either exact or very close. Welding rod comes to mind, though I can't recall offhand what's common for diameters. Purchasing some kind of small diameter stock is probably the most efficient way to go as long as you can convert it into what you need. Google is your friend, my friend.

A quick search of McMaster-Carr resulted in 3/32" (0.094") 316 SS shaft that comes in various lengths that you could cut and grind to length. I figure I could probably carefully hand-polish it down a
thou or three in a pin vice on a lathe to the required diameter, so I'm sure you can too.

McMaster-Carr

The cost is less than the value of the time you've already spent typing your question, so there isn't much point trying to make it on your lathe if it works.
 
Do they have to be 303?

Easy cheater way to do shit like that is buy some gauge pins or perforator pins.

.09" perf pins on mcmaster are $5 each, gauge pin $3.xx



Or turn them down in steps and polish to size. Or buy some bigger stock and take one big cut and then polish to size.
 
Not enough clearance between cutting tool and nose of the live or dead center in the tail stock.

All lathes have that problem. Best to make a different tool. Narrow and long. A lantern tool post and matching tool holder might do it too. A photo of your attempts would go a long way in describing the details of your setup.
 








 
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