Sheldon lathe guys

I am looking at a picture of what appears to be a very nice model Sheldon lathe:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item%67850540&category 72
The picture makes it appear as if the compound can be positioned anywhere along the cross slide. In the 9th photo down you can see a dovetail and what appears to be a gib. Is this actually a gib to adjust the cross slide or is it a clamp to position the compound along on top of the cross slide.
I was never sure how they worked and would like to know. (have never actually seen one)
Bill D
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I would tend to agree. I've never seen a setup like this before.
I think that in this photo one can see one of the two vertical clamping screws that tighten the clamp that holds the compound to the slide:
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http://www.reliableiam.com/OCTB3/b78j.jpg
It's the one at the extreme rear, right corner of the flat base for the compound. The other one is hidden. I think the thing that you say might be a gib is actually the clamp, which would be gib-shaped and visible in that 9th photo. The difference is it's not tapered, and tightens by pulling upwards.
Jim
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jim rozen wrote:

Thanks Jim
Yes, I had spotted that little fellow and imagined that there might also be a third screw in the center but there is yet another photo that dispels that. (I think) In any case that setup provides such superb wedging action that the two screws are plenty to lock that well enough to stop a freight train. (^:
Seems to be a quality machine! Love that 60 speed gear box as well.
Tks again! Bill
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Bill wrote:

Yup, the Sheldon R-series lathes are quite sophisticated. This is not a feature exclusinve to the Sheldon, however. The machine in question is a pre-1968 R-series, with the open QC gearbox and keyed leadscrew. The post-1968 machines had an 80-speed, closed oil-bath QC box and a separate carriage feed shaft, so the leadscrew would only be used for threading. I see the oil pump handle, so this model also has the apron running in an oil bath. The post-68 machines had multiplate clutches instead of gears to connect the carriage and crossfeed drives. These clutches could be adjusted to deliver just the feed force required, so they would slip in the case of a crash. This machine looks like it probably has that, too. Note the screw heads in the middle of the feed advance handles' shafts. I don't see the auto cutoff that the later machines had, though. The handles had detents that were connected by linkages inside the apron, so when the carriage hit the micrometer stop, or the cross slide brought trip lugs into contact with the cutoff button, the feed handle dropped out of the detent.
The design of the R-series lathes were the just about the most advanced available at the time. The headstock is belt driven, and the drive pulley runs on it's own, coaxial, bearing set, NOT running over the spindle as so many other machines did. This was to prevent vibration of the spindle. The reduction gears are on the motor, to keep the gear vibration out of the spindle. The headstock is lubricated by an ingenious system that uses the bull gear to throw oil up into a trough hanging below the top cover of the headstock. Oil holes drip oil to all the places that need to be lubed. (Funny thing, they specify way oil in the headstock, but gear oil on the ways!) The late R15 also had a pop-out threading dial, so that the leadscrew sould not be worn by ANYTHING touching it, except when threading. You swapped the dial for a blank plug that was stored in the side of the apron. I could go on for several thousand more words describing all the neat engineering features I discovered while overhauling mine!

What you see there is the clamp that locks the compound swivel base in position. 2 socket head bolts pull it up to clamp the swivel to the cross-slide. The cross slide uses a tapered gib that is positioned by opposing bolts from the back of the carriage.
I have a 1972 Sheldon R15-6 (15 swing x 42" between centers), D1-6 spindle). It is an incredible machine. Mine had severe bed wear, but I have fixed up the bed and now am finishing up the crossslide. I bought it because of the 2.25" spindle through hole, and the high speed (either 1250 or 2500 RPM depending on whether the dual-speed motor option is installed). That makes it possible to use it as a completely general purpose lathe, many other 15" machines will not do high speed, so you need a small machine, too. I want to only have one good one. Note this is a roughly 3500 Lb machine. I cannot lift the tailstock myself. Even the upper HALF of the tailstock is at the limit of what I can move without lifting gear! The headstock is the size of a V-8 engine block!
Jon
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Thanks Jon. That's a winner of a response. I have no need for another lathe but I so admire the Sheldon that I do an ebay search on them daily. (Must be nuts!)
Thanks again Bill
Jon Elson wrote:

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Thanks Jon -
I was beginning to think I missed something in the words.
I have a Sheldon 11x44 myself and don't see anything unique.
The knobs are larger and generally all is scaled up.
The Buck is a standard production chuck. Nice.
Martin
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Eastburn wrote:

The 11" Sheldon is a fairly pedestrian lathe. It is in no way comparable to the R series, especially the post-1968 R's. 80 threading feeds and 80 different cutting feeds should give a hint. The 80-speed QC box is so innovative they have a raft of patents on it. Getting 80 different ratios in a 10 x 10 x 6" box is quite a trick.
The headstock and apron are quite innovative, too. Any lathe that has FOUR separate oil-bath gearboxes (requiring a DIFFERENT lube in each one, too, wouldn't you know!) has got to be a bit different.
You might take a look at my site on the machine, at http://jelinux.pico-systems.com/sheldon.html
for some of the story. By the way, I am finally done spotting and scraping, and am putting the machine all the way back together! It only took 22 months to fix all the wear! I still have a few small things to fix, like the bolts that held the DRO onto the cross slide were rusted out. 3 came out easy, but one has a stub seized hard in the crossslide. I may have to just chisel it off.
Jon
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YOu sound a bit to smart to be I get 48 threads in mine from 4 to 225 IIRC. There are many 11" types from smaller than mine to twice as heavy. No comparison - I didn't see anything new to speak of - just bigger. I have a qc-box back gearing, end lever gearing and gear drive in 2 axis.
I remember yours and the overloaded side yard - nice recovery.
Martin
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