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View Full Version : Sheldon 13" lathe WM "walking stick" under drive rebuild



Bill Pace
07-16-2012, 11:20 PM
My latest rebuild effort - a 13" 'M' series Sheldon lathe from around 1958 with a somewhat unusual Worthington vari-speed under drive nicknamed " the walking stick". (the red handle under the gear box)

http://i22.photobucket.com/albums/b301/pace1980/Sheldon%2013x36%20lathe/Sheldonfinished003.jpg

On its introduction the 'walking stick' was ridiculed and Sheldon quickly retooled to make the Worthington with an electric motor gear driven vari-speed that pretty quickly became obsolete because the company that made the gear drive went out of business, leaving nothing compatible to replace it with when it malfunctioned.

http://i22.photobucket.com/albums/b301/pace1980/Sheldon%2013x36%20lathe/Sheldonfinished007.jpg

As with so many of these old lathes being drug out of basements, warehouses, corners, etc, this thing was rough! - it was not one for the inexperienced (I had Lane for guidance!) The under drive assembly rebuild alone could give a fella a heart attack! replacing 7 belts and 5 bearings -- but, that was the really intriguing thing about this lathe, getting it functioning as it was intended - and be doggoned if its not pretty darn neat. Pull up or push down on the 'walking stick' and the speed increases or decreases.

http://i22.photobucket.com/albums/b301/pace1980/Sheldon%2013x36%20lathe/SheldonClausing013.jpg

The spindle had to have the bearings replaced (of course!), the gear train and gear box was good, just needing a good cleaning and the needle bearings in the box replaced. The apron had the first major obstacle - the worm and gear was wiped out! and of course no replacement was to be had! So, Lane figured a way to make one...
http://bbs.homeshopmachinist.net/showthread.php?t=54672

Next big hurdle was the evidence that the lathe bed had been reground? or some how worked on?, the saddle had .025 strips of one of the plastics for spacers - unknown? (as did the tailstock) could we just replace them (they fell off when disassembled) or would more be involved? Long story short, replaced then with .025 rulon and was fine.

I again went the VFD route to power the 3ph motor, this time gambling on one of the Huangyang VFDs that are all over ebay and are quite a bit cheaper than Hitachis/Tecos etc. I was a bit nervous about one of these things, but having been using it now for a couple weeks its performing very well (3hp one for $120 shipped) This is the switch panel - 220v on/off toggle, fwd/off/rev toggle for the low voltage, and the potentiometer - the VFD is in the back left behind the spindle cover out of the way of chips.

http://i22.photobucket.com/albums/b301/pace1980/Sheldon%2013x36%20lathe/Sheldonfinished002.jpg

These, along with countless hours spent with this'n that repairs, cleaning, painting, adjusting, etc,etc -- as I said, one of these major rebuilds is not for the casual homeshopper. But this is my 5th lathe rebuild, along with a couple mills, and I dearly love to finish one out and see it brought back to being a useful/beautiful machine again.

rock_breaker
07-16-2012, 11:58 PM
Nice job, my first thought was "it's to clean to do any work" the varible speed drive has to be a different experience.

Thanks for the pictures etc.

Ray

Rosco-P
07-17-2012, 09:07 AM
Drive looks similar to the Sheldon U series 4 sp. underdrives. I'm guessing that the red handle controls a pair of variable pitch sheaves? Any documention on its function other than what might be a Lathes.uk?

Tamper84
07-17-2012, 10:21 AM
Looks great!!! Good job!!

flylo
07-17-2012, 10:48 AM
:D What a differerence WOW! I'm Impressed!. Great job!

Abaker
07-17-2012, 12:02 PM
I got to join the chorus.

I wonder why that drive was ridiculed. It seems to be a really elegant, easy to use design - complete with a spindle tachometer. Does the spindle speed go all the way to 2000 RPM? I second the request for more info on the walking stick drive - I'd really like to understand it better.

I'm glad you mentioned that thread where you guys fabricated a replacement for the apron worm. I have to make a complete drop leaver and set of tumbler gears for the feed box. One of my Sheldons is missing the left hand drop lever. Some brilliant fellow "fixed" it by substituting a completely different drop lever with a tumbler gear that DID NOT MESH with the other gears. Then ran it like that - Sheesh. So anyway, the small 16T gear on the drop leaver has an integral key like the worm and I was trying to figure out how to make that. Now I know - thanks.

Bill Pace
07-17-2012, 01:04 PM
OK, I dug thru my pics and found a couple that should help in picturing this drive, and I'll tell a bit more about what I learned.

A pamphlet I have from Sheldon (undated) shows the 13" M series lathes as having 3 drives - "E", "U", & "W" with the W (W for Worthington?) being the only variable speed, and even it doesnt show the handle, so the picture must have been after dropping the stick drive and replacing it with the Merkle-Korff gearmotor. John Knox over on the yahoo Sheldon site worked for Sheldon many years and seems to be a bottomless source of info on them. He said that when the 'stick' was introduced at a trade show it got poor reviews and this concerned the engineers so much that they went back to the drawing boards and came up with the gearmotor - and it was apparently well received.

From Lanes and I viewpoint we think its it a pretty darn neat and functional drive - although it is pretty complicated.

This pic gives a pretty good view of the stick - it moves 2 flat idler pulleys, one on front side of motor belts and the other on the underside, driving a short 3L belt connected to a long threaded shaft that is in turn connected to the arm that moves the variable sheaves. Being on the front and back of the belts makes it turn in both directions. The actuator arm for the sheaves was apparently later changed to be activated from the rear with the gearmotor.

Next pic is a close up of the threaded rod and the block it feeds (in the center with the grease nipple) - all the way to the right is fast and to the left is slow. Just underneath the threaded rod is another rod that has adjustable stops on the ends, when the travel reaches a stop it will 'kick or push' the stick from contact on the flat idlers, preventing over running the ends of the threaded rod. Whew! does that make sense?

abaker -- you see some horrible "repairs" on these things dont you? Hope the key repair works for you...

http://i22.photobucket.com/albums/b301/pace1980/frontofmotor.jpghttp://i22.photobucket.com/albums/b301/pace1980/vari-speedoveridemechanism.jpg

Peter S
07-17-2012, 03:13 PM
Bill,

You have transformed that lathe, great work. I particularly like the "powered" speed control - that's brilliant! A bit complicated compared to a hand wheel, but it looks like a winner to me.

Also interesting that it seems to have two expanding drives, I don't think I have seen that before, do they both work together to give a wider speed range (or perhaps one for forward, one for reverse to allow different speeds in either direction (sounds unlikely!)?

Abaker
07-17-2012, 04:16 PM
you see some horrible "repairs" on these things dont you?

Yes you do. I'm beginning to realize that the crashed, mangled and "fixed" tools are the ones that survived. They are too good for the scrappers, but still unusable so they sat in a corner and didn't get worn to a frazzle.




Hope the key repair works for you...

Thanks - it's a long way off both in terms of time and in skill. Have to do one of those 32/16 gear clusters as well.

wierdscience
07-17-2012, 10:28 PM
Looking good Bill,talk about 10 lbs of stuff crammed into a 5 lb box:)

lane
07-17-2012, 10:35 PM
Bill,

You have transformed that lathe, great work. I particularly like the "powered" speed control - that's brilliant! A bit complicated compared to a hand wheel, but it looks like a winner to me.

Also interesting that it seems to have two expanding drives, I don't think I have seen that before, do they both work together to give a wider speed range (or perhaps one for forward, one for reverse to allow different speeds in either direction (sounds unlikely!)?

As the speed changes the two pulleys work together as one open up the other moves in tighter ,and the belts ride up and down . With two similar pullets on the back side doing just the opposite. I still dont really understand why two variable pulleys . Looks like one whould have been enough, like a reeves drive.

Rosco-P
07-18-2012, 09:02 AM
As the speed changes the two pulleys work together as one open up the other moves in tighter ,and the belts ride up and down . With two similar pullets on the back side doing just the opposite. I still dont really understand why two variable pulleys . Looks like one whould have been enough, like a reeves drive.

Similar to the electrically shifted transmission in a Wade model 94 or 98 lathe. Several speed ranges selected by a rotary switch activating an electric shifting fork, variable speed within that range obtained by a pair of variable pitch pulleys also electrically driven.

Abaker
07-18-2012, 01:35 PM
If this is like my newer model L Sheldon the speed range in direct drive is about 250 - 1600. That's a pretty wide range to vary over fully automatically. They may have needed to use two pairs of vari-speed pulleys in succession to get that range with out any other step pulleys or a gearbox.

I really do like Sheldons they are great machines for their size.

Bill Pace
07-18-2012, 01:56 PM
That Sheldon pamphlet I mentioned shows

E drive 8 speed 50-1355rpm
U drive 8 speed 50-1200rpm
W drive variable 40-2000rpm

On my lathe using one of the laser tachs shows correct on the slow side at 40-50, but high side is only about 1400 -- which is plenty enough for me!

1200rpm
07-20-2012, 07:01 PM
oh man, i`m late to the party!

very nice! never seen a drive like that, pretty neat for sure.

great job bringing it back, looks like a sweetheart.

sooo... is it a keeper? :)