Manual Lathe Aligning Tip

Neat idea; but I really, REALLY didn't like the part where the guy turned his back on the machine, even for just a second, and left the chuck wrench in the chuck. Bad juju that.

KG

Yup, and wiping off the bearing after having turned the spindle on. I tell my students to never take their hands off the chuck key (or Bridgeport spindle wrench) until they've finished their task, then put the tool in a safe area before starting the machine.

Still managed to have a student drop a drill chuck out of a mill onto his finger - he didn't appreciate how heavy it was (he does now...).

Toolpost

A good idea that I hadn't heard before. How about, on at least the cylindrical part, get it close using the "tool" then using the indicator to push it in that last little bit?

Also, how many machinists use the term "one thousance"? I've known a few :)

RR

Do it all the time. Align the side of the insert with the part, and run the machine in reverse. Real machinists don't need no stinkin' special tool! ;)

Real machinists us a 4 jaw chuck and get it to run within a tenth thats .0001 to all you button monkeys :)

John

OK, I am NOT a machinist but I work with some and I thought this was interesting. We have a home built diamond turning CNC for turning very long thin parts. The lathe uses a rotating tail stock with a collet to hold the part in tension while it is turned. The shape of the parts are either paraboloidal or ellipsoidal or combinations of these. We have two problems that this may help solve: The tail stock centerline may be off by a couple tenths and that is too much. Would this help to align the tail stock if we use a very accurately ground cylinder betwen the head and tail stock, loosened the tail stock bolts and placed the bearing against the cylinder" Problem #2 it might help with: Very thin and very long parts deflect no matter how small the force on the diamond tool. Could a bearing ride along with the diamond pressing against the opposite side of the part? Does the accuracy of the bearing determine how well aligned the parts can be?

Thanks

What's that Lassie? You say that Frogwatch fell down the old alt.machines.cnc mine and will die if we don't mount a rescue by Sun,

28 Dec 2008 16:46:18 -0800 (PST):

Sounds like what you need is a follow rest. Similar to a steady rest, but moves with the tool. The stock will need to be smooth, and true. Ground stock would be best.

See also swiss screw machine.

Why does this appear on a French youtube site?

Magic marker stripes on the BB might help, you can see when it spins with 100% contact.

Thank You, Randy

Remove 333 from email address to reply.

Even a change in the amount of coolant flow will cause dimensional changes in the part.

John

A box turning tool might help if the parts were straight.

Here's an ebay link that shows a box turning tool

Best, Steve

Generally easy enough to make your own. see

Here is an example also;

Can't recommend a design for the OP without more information. Would be good to see a sketch or print of the part. And since his couple of tenths runout (.0002") on the tail stock is too much I would like to see a photo of this "home made cnc lathe" as well.

Tom

What's that Lassie? You say that john fell down the old alt.machines.cnc mine and will die if we don't mount a rescue by Mon,

29 Dec 2008 17:35:05 -0500:

On which setup. The follow rest or swiss screw machine?

I see a small change when I use the high pressure pump to break chips, but other than that, coolant flow doesn't effect the size of the parts. Not that I can measure anyway.