On Fri, 29 Mar 2013 14:03:49 -0700, "PrecisionmachinisT"
wrote:
"Ed Huntress" wrote in message ...
On Thu, 28 Mar 2013 15:58:54 -0700, "PrecisionmachinisT"
wrote:
"Ed Huntress" wrote in message ...
On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT"
wrote:
"Ed Huntress" wrote in message news
On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT"
wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70...
Ned Simmons fired this volley in
:
He's probably running the grinder on the tailstock ways
I might have to take that back... PT later on down mentioned that the L&S
carriage runs on both front and back ways.
That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember.
It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility.
If this L&S lathe bed is representative:
http://www.lathes.co.uk/lodgeshipley/
...then it's the same as my SB, only reversed back-to-front. The
tailstock rides on an inner flat and an inner V, while the carriage
rides on the pair of outer Vs.
Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front.
I don't think so.
Read the text at the site you linked me to.
Oh, good grief. I see what you mean. It doesn't surprise me that they
dropped it in the 1960s.
Frankly, I don't believe it worked as they say. To keep the saddle
from floating off of the flat horizontal way or off of one of the Vs
from time to time would require vertical positioning on the pair of
V-ways that was accurate to within 5 or 10 microinches relative to the
flat. I don't believe they could do that. They probably floated a bit
with light loads, but spring compression of the bed or the saddle
might have maintained contact with heavy tool loads.
I think you're correct.
If so, fitting the carriage would mostly be the same as with any other lathe that runs in a pair of vees--exception being that any actual contact occurs on the flat section(s) you'd juist scrape a smidge off, for clearance...
Benefit being that during a heavy cut, the brunt falls onto the flat ways instead of wearing away the vees.
Yeah, and L&S lathes were heavy-duty production machines, so it could
be that it worked out well in practice.
The thing that makes me skeptical is that L&S's bedways were chilled,
and chilled deep. Wear, as in all lathes, is going to be preferential
in the area where the saddle rides the most -- typically somewhere
between the middle of the bed and the headstock. You'd wind up with a
different clearance to the horizontal flat there than at any other
place on the bed and it would change over time -- you couldn't count
on the saddle wearing quickly into the bed like, say, the main
bearings on an engine wearing in to fit the crankshaft.
It doesn't sound like a way to get consistently high accuracy. But
then, L&S lathes were not toolroom machines.
Anyway, that's history.
It looks to me like the classic Lodge & Shipley
design (Fig. 37 in your book), which is the same as my SB only
I have the Lindsay Publications version, and there's no mention of Lodge and Shipley in it anywhere so far as I can tell, and page 37 deals with tapping wooden lead screw nuts in my copy.
Check the drawings on page 79 and see if we have the same version.
Mine is a PDF that I got somehwhere.
Aww I see...page 79, figure 37 yup looks like the same book after all.
--for some reason I thought you had said PAGE 37
If you haven't already, skip to page 85, and read the text accompanying fig 43, 44, and 45 which is what I had been referring to earlier.
Yeah, I read it. It sounds good, but....
reversed front-to-back. The four-way support described as the "ideal
form" in the book has, to my knowledge, long since been abandoned.
I never claimed that it's in wide usage....
That would be a scraping/aligning nightmare. Likewise, I don't think
Or that it wasn't a nightmare to recondition...I'm just saying that the author considered it to be superior...however, I'll have to add that indeed, it probably was superior, at least by his fairly logical explanation of the merits inherent in said design.
the L&S supported the carriage on two Vs and an assymetrical flat,
because wear would be uneven between the flat and the Vs and, again, a
nightmare to keep aligned. You'd be obviating one of the two big
advantages of V ways. With two flats you'd at least have more balanced
wear but that isn't what a L&S has.
My SB just has clearance where that screw-on plate shows in the photo
I only have three engine lathes, (the rest are second op or cnc chuckers machines) but the ones I do have are as you describe...a vee and flat for the carriage, another vee and flat for the tailstock.
The SB is two Vs for the saddle, and a vee and flat for the tailstock.
It looks like the L&S bed only without any contact between the flat
and the saddle.
Okay gotcha three vees and a flat on a South Bend......
Right.
--the little Prazi that's down here only has one, pretty sure none of the others have more than two.
http://www.lathes.co.uk/hobbymat/page3.html
===
Then there's this:
http://www.lathes.co.uk/manson/index.html
--seem to fetch a pretty good price...should I sell it ?
Omigosh, that's cute. Heck, I wouldn't sell it unless I really wanted
the money for something else. You could keep it under your bed. g
You know, there are many ways to make a lathe bed and to achieve
accuracy. I've had some long and interesting discussions about this,
particularly with engineers from Wasino, and especially concerning the
sub-micron-accuracy lathes they started building around 2000 (no real
US market for them).
IMO, and not as a lathe expert or an engineer, but as a hobbyist, it
matters far more how well it's executed than how it's configured. We
aren't going to wear a lathe in the way a Lodge & Shipley had to deal
with production. Hardinges used dovetails; American used round ways in
the '70s; Wasinos used box ways; and we've seen every combination of
Vs and flats you could imagine. I don't think it's something that most
of us have to worry about.
--
Ed Huntress