I have read in several posts that cast iron beds can twist if the
lathe is not correctly "set up" in a level and "true" fashion.

I know my gap bed lathe isn't excatly "true" when I move the
tailstock centre up to a drive centre. It has a 4 foot cast iron ways
(including an 8" gap) and a fixed headstock. The headstock shows no
sign of ever having moved from its original position and the tailstock
is certainly too solid to have deformed in any way. There is no
adjustment on the tailstock to permit it to be adjusted sideways.

When I set up the lathe about a year ago, I endeavoured to eliminate
any rocking by the use of shims under the legs of the stand, though
did not use a level to pack it horizontal side to side and front to
back.

Could a bed of this length be out of allignment as a result of a poor
set up? I suppose I assumed the cast Iron bed would not deform and
hence perhaps didn't spend the necessary time when I first set it in
place.

Many thanks,
Alan

Hi Alan

Alan this is not a metal lathe where the carriage rides along the bed
and holds the tool, then a twist in the bed will be a problem, in a wood
lathe unless it's out a lot, like 1/16" or so I would not worry.
If you want to check your lathe for twist, beg borrow or steal a
precision level, check your ways across the ways and do so from one end
to the other, if there is a difference from one end to the other loosen
the appropriate bolts, shim and check till your satisfied.
If your tailstock is still out of line, you can get some brass shimming
stock, and get your tailstock aligned by shimming the tailstock, to keep
the shim in place I would make the shim long enough so that you can
bend the ends over and then fasten with a rivet, screw or glued in pin.

Have fun and take care
Leo Van Der Loo

Alan wrote:
I have read in several posts that cast iron beds can twist if the
lathe is not correctly "set up" in a level and "true" fashion.

I know my gap bed lathe isn't excatly "true" when I move the
tailstock centre up to a drive centre. It has a 4 foot cast iron ways
(including an 8" gap) and a fixed headstock. The headstock shows no
sign of ever having moved from its original position and the tailstock
is certainly too solid to have deformed in any way. There is no
adjustment on the tailstock to permit it to be adjusted sideways.

When I set up the lathe about a year ago, I endeavoured to eliminate
any rocking by the use of shims under the legs of the stand, though
did not use a level to pack it horizontal side to side and front to
back.

Could a bed of this length be out of allignment as a result of a poor
set up? I suppose I assumed the cast Iron bed would not deform and
hence perhaps didn't spend the necessary time when I first set it in
place.

Many thanks,
Alan

For a quick check, put a drive center in the head stock and a center in the
tail stock. Move the tailstock center up to almost touching the drive
center and observe any misalighment. It will generally be horizontal rather
than vertical misalignment. If the centers don't align by more than a
1/32", loosen the bolts that fasten to lathe to the stand it is sitting on.
Presumably the points will come into alignment, or certainly improve from
where it was. Now, tighten one bolt at a time while observing any movement
of the centers. It is likely that one pad/foot on the lathe will not be
touching the mounting surface when the points are in alignmnet and you will
have to come up with a suitable shim, preferably metal, to put under that
pad so the bolt can be tightened down. This process should take well less
than an hour and will probably resolve your problem.
If, on the otherhand, the misalignment is vertical, you have another set
of problems that I can't help with.
"Alan" wrote in message
...
I have read in several posts that cast iron beds can twist if the
lathe is not correctly "set up" in a level and "true" fashion.

I know my gap bed lathe isn't excatly "true" when I move the
tailstock centre up to a drive centre. It has a 4 foot cast iron ways
(including an 8" gap) and a fixed headstock. The headstock shows no
sign of ever having moved from its original position and the tailstock
is certainly too solid to have deformed in any way. There is no
adjustment on the tailstock to permit it to be adjusted sideways.

When I set up the lathe about a year ago, I endeavoured to eliminate
any rocking by the use of shims under the legs of the stand, though
did not use a level to pack it horizontal side to side and front to
back.

Could a bed of this length be out of allignment as a result of a poor
set up? I suppose I assumed the cast Iron bed would not deform and
hence perhaps didn't spend the necessary time when I first set it in
place.

Many thanks,
Alan

Leo and Jim,
Many thanks for the advice. The misallignment is predominantly
horizontal so adjustment would seem possible. I will plan my attack
and hopefully post positive results very soon.
Best regards,
Alan

The biggest problem is when the alignment is perfect say at the headstock
and then moves around at varying positions down the bed. I think, the
biggest effect on turning problems would be misaligment at the headstock end
since misalignment over a long length wouldn't be as drastic.
Have a look at your headstock and see if adjustment screws or whatever exist
for it. My General has the headstock bolted to the bed but there are
set-screws at each of the 4 corners for aligning. If you are aligning
headstock center point to a center point in the tailstock make sure the
points are true. Live center points can easily be bent the amount you are
worrying about.
Billh

"Alan" wrote in message
...
Leo and Jim,
Many thanks for the advice. The misallignment is predominantly
horizontal so adjustment would seem possible. I will plan my attack
and hopefully post positive results very soon.
Best regards,
Alan