Tuning a midi lathe

[sbwertz]

One of our Jet midi lathes at the center is slightly out of alignment. When I put a dead center in the headstock and a live center in the tailstock, they do not meet by about a 32nd of an inch. How would I go about correcting this? It is making our pens slightly out of round.

 

[monophoto]

My lathe has four bolts holding the headstock on the bed; loosening those bolts allows for realignment. You need to look for something similar on your lathe.

If the misalignment is horizontal, loosening the bolts allows the head to be rotated slightly to line up with the tailstock. If the misalignment is vertical with the headstock lower than the tailstock, it is necessary to loosen the bolts, and then put shimming material under the headstock. If the headstock is higher than the tailstock, the problem is more challenging. You might be able to correct that problem by shimming up the other end of the headstock. Alternatively, you might have to remove some material from the bottom of the headstock - very carefully, using a file or sandpaper.

 

[jttheclockman]

Might be of interest to you.

Alignment tool

http://www.penturners.org/forum/f30/lathe-alignment-procedure-how-64835/

 

[sbwertz]

My lathe has four bolts holding the headstock on the bed; loosening those bolts allows for realignment. You need to look for something similar on your lathe.

If the misalignment is horizontal, loosening the bolts allows the head to be rotated slightly to line up with the tailstock. If the misalignment is vertical with the headstock lower than the tailstock, it is necessary to loosen the bolts, and then put shimming material under the headstock. If the headstock is higher than the tailstock, the problem is more challenging. You might be able to correct that problem by shimming up the other end of the headstock. Alternatively, you might have to remove some material from the bottom of the headstock - very carefully, using a file or sandpaper.

The misalignment is horizontal. I will try loosening the bolts and realigning it. Thanks a lot.

 

[Charlie_W]

Sharon,
Also to the above info, if the lathe is bolted down to a solid bench, you may need to loosen one of the bolts and shim beneath the lathe to make sure the lathe is not being twisted.
If you think the misalignment is from the lathe being moved around, maybe bumped, I would lean more towards adjusting the headstock on the bed as noted by MonoPhoto.

 

[sbwertz]

Sharon,
Also to the above info, if the lathe is bolted down to a solid bench, you may need to loosen one of the bolts and shim beneath the lathe to make sure the lathe is not being twisted.
If you think the misalignment is from the lathe being moved around, maybe bumped, I would lean more towards adjusting the headstock on the bed as noted by MonoPhoto.

It isn't bolted down, and it hasn't been moved. We are approaching our semester break, (this is our last week of classes) so I will experiment with trying to correct the problem during the break. Thank you all so much for your input.

 

[Charlie_W]

Always double check to make sure the morse tapers are clean and free from debris which could skew your centers a tad.

Also, check the centers themselves in case one has a burr that could prevent perfect seating into the morse tapers on the lathe.

 

[sschering]

If it's the tail stock riding high I'd look at cleaning the bed and maybe removing the tail stock to see if there is any debris trapped between it and the bed.