HELP turning titanium. Locking up.

[L1A1Rocker]

Well, I finally started on the titanium build. It didn't last long.

I set the Grade 5 bar up in the headstock and steady rest and got ready to do a facing cut on the end. The brass fingers were set just like my other projects - the brass fingers were set to just touch the roundstock and locked down. My newly purchased mysting midget was aimed at the facing tool. I turned on the lathe and it ran just long enough for me to engage the cross-feed before the lathe locked up and stopped dead.

What appears to be happening is that the titanium (at the contact points of the steady rest) is heating up, expanding out, and binding on the steady rest.

Any suggestions?

[john.t.little1]

Part off 3" sections and machine without the steady rest

[Bendersquint]

I seriously doubt it is expanding and binding against the steady, it would have to be near white hot to have that much expansion to size up the lathe.

How far out were you machining that you needed to use a steadyrest?

[pyrofx]

Part off 3" sections and machine without the steady rest

That and also make sure you Dont try and take lite cuts like Al. It will work harden real fast and in a hurry!
I flood the crap out of my cuts and Ti turns like a dream. After i found the correct inserts. The first two cones cost me an insert per cone.
Greg

[Bendersquint]

Part off 3" sections and machine without the steady rest

That and also make sure you Dont try and take lite cuts like Al. It will work harden real fast and in a hurry!
I flood the crap out of my cuts and Ti turns like a dream. After i found the correct inserts. The first two cones cost me an insert per cone.
Greg

What geometry are you using now?

What geometry were you using before you found the good one?

[pyrofx]

Part off 3" sections and machine without the steady rest

That and also make sure you Dont try and take lite cuts like Al. It will work harden real fast and in a hurry!
I flood the crap out of my cuts and Ti turns like a dream. After i found the correct inserts. The first two cones cost me an insert per cone.
Greg

What geometry are you using now?

What geometry were you using before you found the good one?

You and Joe helpes me find them. We started with the cnmg and that wasnt so good.. But they were uncoated. Part of the problem . Went to Kennametal KC5025. They are pretty amazing . Get about an hour per edge.
Greg

[L1A1Rocker]

Part off 3" sections and machine without the steady rest

That doesn't work so well on my old Atlas 12 x 36. I tried something like that with some stainless a long time ago. The work will wobble and on one occasion the work popped out of the jaws. IIRC the Atlas manual recommends a two point mount using the steady to better secure the work, and give more accurate work.

I seriously doubt it is expanding and binding against the steady, it would have to be near white hot to have that much expansion to size up the lathe.

How far out were you machining that you needed to use a steadyrest?

It's definitely binding in the steady some how. I can release the steady and the binding immediately stops. I moved the mysting midget over to the steady and it would run a lot longer before binding up. IIRC I once read somewhere to set up a steady with a peace of waxed paper (or some such) between the steadies fingers and the work to get the "correct" bearing. That may be worth a try I guess.

I'm using 12 inch long Grade 5 "drops".

Part off 3" sections and machine without the steady rest

That and also make sure you Dont try and take lite cuts like Al. It will work harden real fast and in a hurry!
I flood the crap out of my cuts and Ti turns like a dream. After i found the correct inserts. The first two cones cost me an insert per cone.
Greg

I recall reading that, just not how deep to actually cut it. Also run the rotation speed slow, and feed rate fast.



Thanks for the replies folks. I'm going to try and give a bit of clearance between the steady and the work with a peace of waxed paper. I really didn't want to go with a set of roller fingers on the steady but that may be needed.

[saigatechusa]

wrap part with 1 wrap coarse crocus cloth 1-2" wide grit side out

lube inside of cloth with lube oil

lightly snug fingers

cut all day without hurting fingers or part

[T-Rex]

wrap part with 1 wrap coarse crocus cloth 1-2" wide grit side out

lube inside of cloth with lube oil

lightly snug fingers

cut all day without hurting fingers or part

you think 1000 wet/dry paper would work?

[Bendersquint]

I will put money on it that the steady rest fingers are expanding or siezing NOT the titanium

Why not chop into short block and skip the steadyrest? I would never just run a 12" section and make a baffle on the end of it.

[cal50]

As others have said I would wager that your problem lies with your steady rest.

I just spun my titanium tube in my steady rest without any issues. I did indicate the tube end in within .001" run-out then adjusted my steady rest pads to make light contact with the tube and double checked the run out after the pads were locked in place. I used some way lube oil on the pads & tube for lube.

[Kuraki]

Great opportunity for a general shop project.

Spend some time turning something like this with solid bronze resting points:



Into something like this with bearings:


Never worry about heat expansion or marking a finished surface again.

[Gunfixr]

I got news for you.
Roller bearings will mark a finished surface, just differently than pads.
They will warm up, too, if your part is either quite heavy (probably not applicable here), or you're running a pretty good speed. Not really hot, but warm, depending on bearing size versus material size.
I have run leather strap in between very large, heavy parts and pads, because the friction would burn grease right out in minutes. Never tried it with titanium, but may be worth a try. Oil it real well on the material side, and clamp the ends between the upper and lower halves of the rest body. Because of the thickness, it will settle some in the beginning.

When doing my Ti suppressor, I did have problems with threading the tube using a steady rest and pads, but tubing expands much more rapidly than bar stock.
It may be more of a friction problem than heat expansion, as I find it hard to believe that bar stock would expand that much before you even got started cutting. The two materials may be galling, which would lock up the machine pretty quick, and only take surface heat.

[CMV]

Dumb question, but gotta ask, do you have a bearing surface on the stock for the fingers to run on? If you're trying to put something with a rough or out-of-round surface in a 3-finger steady that will cause issues. If you don't have a good bearing surface & don't have a way to make one you can use a cat head and then use it as a bearing surface for the steady.

It will probably lead to more material waste, but if it were me, I'd get the stock cut into smaller pieces & not dick around with all that setup & tinkering needed to work that far away from the chuck. You'll need a shop with a decent bandsaw & experience cutting Ti stock. An abrasive chop saw won't do it (but will put on a brilliant display if you try ) My local metal yard charges $10/cut which sounds like a lot but it takes time & not at all hard to wreck a blade.

[plodder]

I just got in from turning 1.75" titanium round stock in my little Smithy on a bronze fingered steady rest. I turned it for about 2 hours, occasionally squirting a little 30w oil onto the turning path. No problems at all with the steady rest.

Now, as to the cutting tool attrition and frequent re-sharpening, that's a whole nother story!

[Bendersquint]

Now, as to the cutting tool attrition and frequent re-sharpening, that's a whole nother story!

If you are using coolant or the proper geometries that is mitigated. I get phenomenal time out of my indexables.

[300sniper]

Well, I finally started on the titanium build. It didn't last long.

I set the Grade 5 bar up in the headstock and steady rest and got ready to do a facing cut on the end. The brass fingers were set just like my other projects - the brass fingers were set to just touch the roundstock and locked down. My newly purchased mysting midget was aimed at the facing tool. I turned on the lathe and it ran just long enough for me to engage the cross-feed before the lathe locked up and stopped dead.

What appears to be happening is that the titanium (at the contact points of the steady rest) is heating up, expanding out, and binding on the steady rest.

Any suggestions?

What were you lubing the contact points with?

[Samson104]

Sounds like you need a good 4 jaw chuck.
What size chuck does it use

[Dr.K]

I've never had these issues! I do use a steady now and then, but mine has bearings. I can imagine the frustration though! Will it not fit through the spindle bore?

[T-Rex]

Sounds like you need a good 4 jaw chuck.
What size chuck does it use

If the pairing between work and chuck is solid enough to seize the lathe, why would he need a different chuck?

I've never had these issues! I do use a steady now and then, but mine has bearings. I can imagine the frustration though! Will it not fit through the spindle bore?

I believe its an Atlas 9"? He mentioned it in his build thread.

[Samson104]

A better chuck may allow him the get a better bite on his part preventing the need for a steady rest to provide lateral stability

[Bendersquint]

A better chuck may allow him the get a better bite on his part preventing the need for a steady rest to provide lateral stability

Won't help, cutting titanium 8+ inches away from the chuck would need a steady.

Can't eliminate deflection.

[Historian]

Well, I finally started on the titanium build. It didn't last long.

I set the Grade 5 bar up in the headstock and steady rest and got ready to do a facing cut on the end. The brass fingers were set just like my other projects - the brass fingers were set to just touch the roundstock and locked down. My newly purchased mysting midget was aimed at the facing tool. I turned on the lathe and it ran just long enough for me to engage the cross-feed before the lathe locked up and stopped dead.

What appears to be happening is that the titanium (at the contact points of the steady rest) is heating up, expanding out, and binding on the steady rest.

Any suggestions?

If your steady diameter is large enough you could machine a 1/8" ± thick SS ring
that slips onto the Ti tube; lube the fingers. Saw this trick so long ago in 1956
by Institute's machinist who working on a long thin walled metal tube ( ~ 12" ).

I once threaded a polycarbonate tube to make
my own darkroom water filter holder with the equatorial ring.

[Samson104]

A better chuck may allow him the get a better bite on his part preventing the need for a steady rest to provide lateral stability

Won't help, cutting titanium 8+ inches away from the chuck would need a steady.

Can't eliminate deflection.

Which is why it should be cut off and cut closer to the chuck , general rule is1.5x the stock diameter hanging out of the chuck.
so we are assuming that the spindle bore is not big enough for the round stock

[L1A1Rocker]

wrap part with 1 wrap coarse crocus cloth 1-2" wide grit side out

lube inside of cloth with lube oil

lightly snug fingers

cut all day without hurting fingers or part

I think I'll give that a try.

I will put money on it that the steady rest fingers are expanding or siezing NOT the titanium

Why not chop into short block and skip the steadyrest? I would never just run a 12" section and make a baffle on the end of it.

That doesn't work so well on my old Atlas 12 x 36. I tried something like that with some stainless a long time ago. The work will wobble and on one occasion the work popped out of the jaws. IIRC the Atlas manual recommends a two point mount using the steady to better secure the work, and give more accurate work.

Dumb question, but gotta ask, do you have a bearing surface on the stock for the fingers to run on? If you're trying to put something with a rough or out-of-round surface in a 3-finger steady that will cause issues. If you don't have a good bearing surface & don't have a way to make one you can use a cat head and then use it as a bearing surface for the steady.

It will probably lead to more material waste, but if it were me, I'd get the stock cut into smaller pieces & not dick around with all that setup & tinkering needed to work that far away from the chuck. You'll need a shop with a decent bandsaw & experience cutting Ti stock. An abrasive chop saw won't do it (but will put on a brilliant display if you try ) My local metal yard charges $10/cut which sounds like a lot but it takes time & not at all hard to wreck a blade.

See above response. Plus, the nearest "local" metal yard for me is probably more than 100 miles away. (I'm in the Texas Hill Country - boonies)

Re Bearing serface: I'm just putting in the roundstock and going with the procedures oulined in the Atlas Manual. I have no idea how to machine a bearing surface on roundstock without first doing what I'm trying to so. No idea what a "cat's head" is either.