Tail stock alignment...(kinda long)

Re: Tail stock alignment...(kinda long)

John Lucas

Years ago I bought a powermatic contractors table saw. The middle of the table top casting was out .050" This was like a large dip in the table top. It caused problems when cutting segments. I now use a sliding miter table which eliminates those problems but back to the story. I called Powermatic and asked what to do about it and they said .050 was within tolerance.

Talking to Vic who owns Bestwoodtools and is a master machinist, most wood turning lathes headstocks and tailstocks are not dead on. At least not compared to metal lathes and it has caused him grief trying to explain this to customers who purchased a high end lathe and think they are perfect. For the most part this causes very few problems for woodturners.

Yours is a good example of a potential problem. I had problems with screw threads no cutting to the same depth on both sides of the box. I thought it was the Threading jig and took it over to Vic and he measured it and found it to be within .0004 of dead on everywhere, so it was my lathe that was off. apparently the headstock has some lateral misalignment that is very small and only shows up when I do the threaded boxes. I put a boresight in my headstock morse taper and put a dead center in the tailstock. The laser rotates around the center of the dead center as you rotate the headstock spindle. The problem is I'm not a good machinist and don't know if the adaptor I made to fit the headstock was dead on accurate or the headstock is off. Since I have the problem I mentioned I'm leaning toward the headstock.

Re: Tail stock alignment...(kinda long)

Lyle Jamieson

Ron, one-fiftieth of an inch is not likely to affect the reverse chucking method. That's half the thickness of one playing card. Almost all wood will move after turned. The wetter the wood the more movement of course. So by the time you get to the reversing part, the wood is not running true, it will always have some wobble. I expect it to wobble as the wood dries enough to sand. Slow the lathe way down to sand the transition between the reversed turned portion and the done part.

That's a good question, on what the manufacturers tolerances are, is Nick Cook watching??

Re: Tail stock alignment...(kinda long)

Roger Chandler

While your issue may very well be a machining problem, just one thing I will mention about centers aligning. I have seen numerous lathes where the centers were off because the bed ways of the level were torqued a bit by the legs not being leveled precisely. The longer the bed on a lathe, the more the level issue will manifest itself if they are off.

I have seen just one turn of a bolt on a foot torque the bed enough to make the centers off by 1/16th"

I took great pains to level my bed ways front to back, end to end, and diagonally in several different places along the bed of my lathe which is 47" between centers.

It was off when I took it out of the crate, new, but with the painstaking adjustment procedure, I managed to get my centers to align at any point along the ways I set up my headstock and tailstock.

Again, your issue might be in the machining, but this is just something to check and adjust in case! Good luck!

Re: Tail stock alignment...(kinda long)

Bill McWhirter

The lathe bed will torque as unlikely as it seems. All it takes is moving one foot in or out just a bit to get it back into alignment. I have to re-adjust my 3520 occasionally. Vibrations will invariably move the lathe a bit or one of the jam nuts will loosen.

Re: Tail stock alignment...(kinda long)

Ron Bauer

Roger, Bill very good point on the long bed ways getting torqued out of kilter. I had taken the time to level front and back and end to end prior to filing the tail stock. But certainly it can change over time with vibration. Perhaps I am a little anal about this but I have a metal lathe and that is adjusted to less than a thou. Certainly wood doesn't require those tolerances. That being said I wonder what it would add to the cost if the tail stock had lateral adjustment like a metal lathe tail stock? Hmmmh. Ron.

Re: Tail stock alignment...(kinda long)

Dwight Rutherford

I have both a woodturning lathe and a metal lathe. To me there is a world of difference between the two. When I am using the metal lathe, I am machineening to lose tolerances and require precision. When I am using the wood lathe I am using hand held tools to turn a shape that is pleasing to the eye. Almost all of my woodturnings are finished without the need for the tailstock to be engaged. If the workpiece is secured to the headstock and turned with handheld tools, I will get a finished product that is round regardless of headstock-tailstock alignment.

My2cents

Re: Tail stock alignment...(kinda long)

Ron Bauer

I, like you, turn round without the tail stock. But I also drill holes using the tail stock. When I drill a 0.375" hole I like it to be pretty close, not oversize by twice the offset. In my case over by 40 or 50 thousandth. Additionally the TS spindle was was not aligned with the HS spindle causing trouble in long boring's. Some of us just want our equipment to be right.