south bend headstock alignment?

I have a 10" South Bend lathe (serial RKL) that I'm
having a problem with. I've used it to turn small
pieces until now. I was making a shaft about 5.25"
long and .75 diameter. I kept checking the diameter
and was satisfied at the tailstock end but found that
headstock end was about .008" larger. I am not
using the tailstock so alignment to the tailstock
is not an issue. I have to assume that the headstock
is not aligned with the bed. Does anyone know the
correct procedure to re-align the headstock with the
bed for the given lathe?
Reply to
asdfasdf
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The shaft was probably flexing since you were not supporting it with the tailstock.
Reply to
Pete C.
No I checked that pretty well. I blued the part after the cut and ran the cutter down the length. It scribed a light line down the length and never put any pressure on the tool. I took very light cuts and had a great finish with no chatter. I took maybe a couple of thousandths off the last pass. I'm pretty sure it's misaligned.
Reply to
asdfasdf
Correct. The tailstock end was being pushed away from the cutter and it was allowed to move
The rule of them is 3 diameters at most before you should use something to hold the shaft. You are about 6 diameters
Gunner
Reply to
Gunner
I'm not sure but doesn't the South Bend headstock align on one of the bed Vee ways?
Reply to
John B.
I'd still say the workpiece may be flexing. Try the same test with a piece of 3/4"-1" rod. that shouldn't flex.
JB
Reply to
JB
RKL means unhardened, right? My 10L is an RKX with hard ways. Could they be worn at the head end enough to shift the carriage? jsw
Reply to
Jim Wilkins
The shaft could still be moving a little or misaligned in the chuck. If you want to check the alignment you can use a test bar or make one but the readings would be meaningless unless it is supported and centered on the tailstock, AFAIK.
Reply to
ATP
 I kept checking the diameter
I am confused. If the tailstock end is being pushed away from the cutter, wouldn't the tailstock end be bigger?
Dan
Reply to
dcaster
The tailstock end is the smaller diameter. As the piece approaches the headstock it gets larger.
Reply to
asdfasdf
It started as 1.25 and I took it down to .75. The tailstock end was the smaller end.
Reply to
asdfasdf
Yes and that is not the problem. I am pretty sure it is an alignment issue.
Reply to
asdfasdf
If the spindle isn't parallel to the ways I think you would see a difference in how a pointed rod that spins true aligns with the tailstock when chucked close, and when extended. This assumes the inner ways that align the head and tail aren't worn or damaged.
The rod could be a sharp pencil in a 4-jaw, adjusted to not wobble at the point.
There might be a chip under the headstock if a previous owner had removed it. Can you detect a gap at either end with a magnifier and bright light? jsw
Reply to
Jim Wilkins
Google "rollies dads method" to first check alignment , then if you do indeed find it's off check for chips or swarf between the head and the vee way that's supposed to align it . Any chance the head bolts got loose and were re-tightened without checking for debris under it ?
Reply to
Snag
Then perhaps the bed is twisted? phil k.
Reply to
Phil Kangas
If the RKL is on a sheet-metal cabinet like mine that is very possible. There is a bed twist adjuster in the base on the tailstock end, the two screws in the round tags. jsw
Reply to
Jim Wilkins
Eeep!!....absolutely correct. I once again, read it wrong while I was doing something else. I need to pay far more attention or keep my mouth shut.
Indeed...his head stock is out of alignment...or...more likely the ways are worn close to the headstock.
Gunner, who just woke up and will let others tell him how to determine if this is whats happening
Reply to
Gunner
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This is a very good way to check alignment or wear..or both
Gunner
Reply to
Gunner
1) Hang a piece of 1" material about 6 inches out of the chuck and then carefully turn the last 1/2 inch or so that is closest to the tailstock down to exactly .950 diameter.
2) Cut away all of the rest of the bar except for the last 1/2 or so that is nearest to the chuck down to about .900 or so, for clearance.....
3) Carefully cut the last 1/2 in or so that is nearest to the chuck down to exactly .950 diameter.
4) Finally, loosen and re-align your headstock by bumping /shimming/ scraping or otherwise adjusting until an indicator placed on the carriage produces the same reading at both of the .900 diameters.
Reply to
PrecisionmachinisT
See correction below...
Reply to
PrecisionmachinisT

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