Re: [multimachine] Re: Another tool to consider/Yeomans BIG shaper
- Hello DavidDo you think that a planer could be build useing some flat ways?What about useing some roller chain to move the table?A # 50 roller chain would be good, or would stretch be a problem?Keith
Deep Run Portage
" The Lizard Works"
--- On Mon, 10/4/10, David G. LeVine <dlevine@...> wrote:
From: David G. LeVine <dlevine@...>
Subject: Re: [multimachine] Re: Another tool to consider/Yeomans BIG shaper
Date: Monday, October 4, 2010, 12:28 PMOn 09/25/2010 04:12 PM, Pat wrote:
> Could not a long bed Yeomans type lathe also be a really long shaper?
Nope, by definition a shaper has a ram which moves parallel to the
workpiece. What you are describing is neither a shaper nor a planer.
It may be a different tool.
> We would already have long and rigid ways and an aligned heavy carriage. The workpiece (bar to be cut into 3' dovetails etc.) could be held by a fixture bolted to the base of the lathe and the advancable? cutting tool (clapper) mounted on the leading or trailing edge of the carriage.
> What do you think?
Let's start with the area available for the workpiece. The ways are
supported or they will flex all over the place, therefore the workpiece
must be narrower than the ways.
How will you drive the carriage? Manual operation seems unlikely to
succeed. Pneumatic is a horror show for shaper/planer operations.
This leaves hydraulic or mechanical. Hydraulic is expensive and makes
the lathe useless as a lathe. Not the best idea unless the lathe drive
(for threading and power feed) is already in place and does not
interfere with the operation. Due to the loading, the hydraulics must
drive both sided or the carriage will twist badly. Just putting the
cylinders in parallel won't work, a precision flow control system would
be needed. This means a mechanical linkage is likely to better fit the
The best case looks like a pair of rack and pinion drives. A Scotch
Yoke won't work for something that long. The ways are supported only in
the vertical mode, they are much less rigid in the horizontal mode.
Side forces will torque the carriage and will wear it excessively. Two
rack and pinion gear sets might reduce the torques by enough to keep
wear to an acceptable level. And a lathe tends to move the carriage one
pass per minute or less, a planer or shaper will do that 10-100 times
more. A lathe which will last for 50 years could be worn out in 1/2
year! Leadscrews also have problems when they drive a reciprocating load.
And the heavy carriage is not a great idea, starting and stopping it
50-100 times each minute will take a bunch of power.
A spindle in the carriage might not be a bad idea, then grinding or
milling the surface might be done.
On 10/10/2010 04:24 PM, Gordon Haag wrote:
If we had a really stiff lathe with a really stiff carriage, couldnt we just mount a horizontal milling cutter on an arbor and drive it between centers with the workpiece mounted on the carriage? Vertical adjustment would be easy to work out.
Let's start with the description. Really stiff AND REALLY MASSIVE would be desirable.
But, in all honesty, that will work, however many lathes are really stiff in the vertical axis, not so stiff in other directions. It may be worth noting that Yeomans designs are less stiff perpendicular to the way length and parallel to the ground. There is no stiffening system in place for that axis.