(Tip) Pressure on a mandrel saver

[Sabaharr]

I have often wondered how much pressure is enough vs too much pressure to put on a mandrel saver. Not enough and the blank stops spinning. Too much and you are putting a lot of pressure on saver and headstock bearings. So here is what I did. I got a 1/4" split washer and 2 flat washers. I made a sandwich of them and slid them on the mandrel shaft. Then I loaded on the blanks with bushings and slid the tail stock in place, locking it down at contact with the last bushing. I then cranked out the tailstock until the split washer at the other end was flattened out in the sandwich. It didn't take much effort and the blanks haven't stopped on me once. I was putting much more pressure than this when I was just guessing. Just a tip I thought others might try.

 

[Skie_M]

I have an issue with my lathe where my tailstock keeps slipping a tiny bit during use... which is why I recommend others NEVER oil or wax their lathe bed. My issue isn't caused by that, but by bits of debris getting stuck under the tailstock and thereby reducing the friction when I lock it down.

So ... while I'm turning something on my lathe, if it stops spinning while I'm working, I just tighten the tailstock handwheel a quarter turn or so and keep working. Basically, I can't over-tighten. If I try to really crank down and tighten it harder, the tailstock moves and the pressure is relieved. (I can watch the tailstock base just SLIDE ON DOWN THE LATHE BED as I turn the handwheel).

 

[CrimsonKeel]

I have an issue with my lathe where my tailstock keeps slipping a tiny bit during use... which is why I recommend others NEVER oil or wax their lathe bed. My issue isn't caused by that, but by bits of debris getting stuck under the tailstock and thereby reducing the friction when I lock it down.

So ... while I'm turning something on my lathe, if it stops spinning while I'm working, I just tighten the tailstock handwheel a quarter turn or so and keep working. Basically, I can't over-tighten. If I try to really crank down and tighten it harder, the tailstock moves and the pressure is relieved. (I can watch the tailstock base just SLIDE ON DOWN THE LATHE BED as I turn the handwheel).

have you tried removing your tailstock and turning the little plate a few turns one way or the other? i had this same issue and that is what solved it for me.

 

[tomtedesco]

Tightening the locking bolt on the bottom of the tailstock should fix the problem. I always wax my bed and have had no trouble with tailstock creep. To the first question, I try to use enough pressure to keep the blank turning while roughing it to shape. Before my final pass I back off the tailstock hand wheel to allow the blank to stop turning, then apply enough pressure to make it spin on the last light cut. If I applied too much pressure at the start this allows the blank re-center itself and keep the blank running true.

 

[Skie_M]

Yeah, I regularly perform maintenance on my lathe, which includes removing tool rest and tailstock from the lathe ways and cleaning them underneath to removed the trapped particles that cause my problem. I've already tightened the locking mechanism for both, and they work great, but if I get anything under them, they start sliding around when locked. Generally the tool rest has no issues, it's the tailstock, because I'm always moving it around and something gets under it.

To ensure that my tailstock slides smoothly, I've always just sanded the lathe bed lightly with 500 grit and wiped it down with dry paper towels. I want it to lock in place as much as possible. It seems that the locking mechanism on harbor freight mini wood lathes just isn't strong enough to prevent it sliding around if I use wax (which is what I had applied to the lathe bed while assembling it when I first got it... turned out to be a very bad idea, couldn't lock the tailstock worth a crap). I ended up removing every trace of the wax and it worked much better.

 

[TurtleTom]

I lock my tailstock and advance the live center till it starts spinning then lock sleeve. If it hums, I forgot to lock the sleeve or it's too loose somehow.

 

[Tim'sTurnings]

I always struggle with how tight to make the mandrel saver too. Too much pressure and mine is noisy. I am going to try the lock washer/flat washer thing. Thank you Sabaharr.
Tim.

 

[WriteON]

The tip is good. Thanks. As for myself I simply adjust/tighten as needed. I do apply a thin film of Breakfree once in a while and clean the bed & tailstock as needed.

 

[TurtleTom]

Took the plunge and ordered a mandrel saver today. Like the tension device Sabaharr invented. Will probably need it too. Thanks.

 

[Skie_M]

I think I might could use a lockwasher, yup .....

 

[WriteON]

Took the plunge and ordered a mandrel saver today.

Good purchase. You will like having/using it.

 

[TurtleTom]

Given this situation I would probably get a small piece of 1/4" plate and clamp it behind the tailstock on the ways with a small C clamp. I know it's extra work but you gotta have the tailstock rigid I think. I suppose you could redesign the tailstock lock system to make it beefier. Even if you get another lathe you'll still need this one.

 

[Fish30114]

If my tailstock was sliding around, I would put a small strip of adhesive backed sandpaper on the locking plate, I bet that would stop it from moving.
I keep my lathe 'ways' waxed and even spray them with a slide enhancing non oil based spray--I have no issues with anything slipping-in fact the only issues I have is that my tool rest gets grabby on the bedways all the time!

 

[Skie_M]

Actually thinking that I need to get some grit glued to the upper side of my locking mechanism's washers that bind against the bottom of my lathe bed ways. From down there, they cant throw off my centers or affect my lathe bed's smoothness. I could then also get away with waxing the lathe bed for additional protection against moisture and glue/finish...

I can buy some 100-grit diamond grinding dust and some epoxy that is meant to secure it to the surface of a metal grinding wheel (for wet-grinding lapidary work) .... that would definitely do the trick.

 

[TurtleTom]

Actually thinking that I need to get some grit glued to the upper side of my locking mechanism's washers that bind against the bottom of my lathe bed ways. From down there, they cant throw off my centers or affect my lathe bed's smoothness. I could then also get away with waxing the lathe bed for additional protection against moisture and glue/finish...

I can buy some 100-grit diamond grinding dust and some epoxy that is meant to secure it to the surface of a metal grinding wheel (for wet-grinding lapidary work) .... that would definitely do the trick.

Skie, a cheap valve grinding compound would do the same thing, comes in 2 grits.

 

[Skie_M]

Probably true, especially if it's aluminum oxide ...


But I need that diamond grit anyways for other lapidary work so ....