Sheldon Spindle Taper Size?

Rex · Jan 19, 2019

Was looking forward to first attempt turning between centers, installed new 5 MT dead center in the 11" Sheldon TS 56P and was disappointed in the result. All literature I see indicates spindle taper to be 5MT, dimensions of this dead center are a couple thousands away from published 5 MT numbers. Spindle ID at end is @ 1.617. What to do?

johnoder · Jan 19, 2019

Ditch non fitting item (you would need the FACTORY bushing the lathe was sold with, which held the same size center the tail stock used)

Put chuck back on

Chuck up steel

Using compound, put on a 60 degree included point

Rest "tail" of "dog" on a jaw

You are now turning between centers

MILO74 · Jan 19, 2019

https://www.practicalmachinist.com/vb/general/morse-taper-198460/

Rex · Jan 19, 2019

OK, may be stuck with that workaround, but why does the original Sheldon catalog list the tailstock as #3 & headstock as #5 if it isn't? Alas 5 newly purchased dogs all straight tails in anticipation of using existing drive plate on spindle.

Milland · Jan 19, 2019

Rex said:
OK, may be stuck with that workaround, but why does the original Sheldon catalog list the tailstock as #3 & headstock as #5 if it isn't? Alas 5 newly purchased dogs all straight tails in anticipation of using existing drive plate on spindle.

Go here: Machine taper - Wikipedia then to Sizes, where you'll find that there were short variants of the 1-5 series to allow headstocks to maintain a larger through hole.

If the taper mate blues up to match on the section that's engaged, you could cut the current center, repoint in the spindle, and use that for your center. It won't be as hard as the carbide insert, but since there's no relative motion at the headstock you can get away with it.

iwananew10K · Jan 19, 2019

it IS 5MT...BUT is a "short" 5MT...same taper angle,but a different gage line.

your 5MT fits the taper as far as the angle but is too large to fit all the way in.

strokersix · Jan 19, 2019

I thought the Sheldon short MT5 was to leave a SMALLER through hole and thereby more material left in the spindle nose for rigidity. My thought anyway.

Illinoyance · Jan 19, 2019

Listen to John Oder. Better yet, turn a piece of round so there is a shoulder on it. Flip it around so the shoulder is against the chuck jaws, then do what John said. You don't want your center pushing back into the chuck.

Limy Sami · Jan 20, 2019

Rex said:
Alas 5 newly purchased dogs all straight tails in anticipation of using existing drive plate on spindle.

Drill and tap the front face of the lathe chuck to take a driving peg.

Rex · Jan 20, 2019

Milland said:
If the taper mate blues up to match on the section that's engaged, you could cut the current center, repoint in the spindle, and use that for your center. It won't be as hard as the carbide insert, but since there's no relative motion at the headstock you can get away with it.

Might try this. How far should the point project from the spindle thread?

iwananew10K · Jan 20, 2019

if you want the proper sleeve Miller Machine and Fabrication will make you one...his site is off right now but will be back soon per him.

What Milland said works too, just buy the really cheap MT5 centers, they will cut pretty easy,cut down to desired stick out and repoint as needed and toss them in the bin when they get too short....it really does pay to repoint them in-situ....even if you buy the proper sleeve buy the cheap MT3 ones to put in the sleeve and repoint them when you use them.

Rex · Jan 20, 2019

morse tapter sleeves

iwananew10K · Jan 20, 2019

Those standard sleeves will produce exactly the same result as you have now, and if you cut one down so it doesn't stick out, when you stick a MT center in it won't go "all the way" in.

NO standard sleeve or center will work without modification.

I can uderstand wanting to use the drive plates, saves sometimes needed room, I can't recommend Miller enough, he does solid work.

All you need to do is ask for a sleeve with a 1.625" big end as deep as you spindle taper with the angle of a 5MT and accepts MT3 centers....less than 200 bucks as I recall.

Ps- if you want a 5C adapter JFK has the Sheldon specs on file and will make one for you.

Milland · Jan 20, 2019

Rex said:
Might try this. How far should the point project from the spindle thread?

That's a matter for you to decide. Check out your drive plate (or whatever you'll be using), figure out how far you'd like the point to stick beyond that, and go for it. Usually the carbide insert centers aren't as hard as the full-steel dead centers, which is why I suggested cutting the one you have.

On the suggestion that having a stub Morse allows a smaller spindle bore for stiffness, I sorta agree from a "common sense" standpoint, but what I wrote was from Wikipedia, which is never wrong. Never. Do not question the Wiki, you will be found...

Rex · Jan 20, 2019

Drive plate will be a backing plate from a wrecked 6" 6 jaw chuck modified for the purpose, I'll get measurements using the new set of expanding arbors & dogs.

jhruska · Jan 20, 2019

Sleeve dimensions:
Length 3.830"
d 1.433"
D 1.623"
This sleeve fits the spindle of my 1953 11" Sheldon - tapered roller bearings in headstock.
Extends past the spindle nose around 0.090"
Dimensioned with digital calipers.
John

4GSR · Jan 20, 2019

I've chased this one many times over the years with the two Sheldon lathes I have.
If there was such a thing, it would be called a Morse 4-3/4 taper. It has the same taper as a No. 5 MT, at face of spindle, it is 1.625" diameter or there abouts. The collet adapter, measures 1.630" at the big end at the flange.
Don't try to use a spindle adapter from a South Bend lathe, they are not the same taper. Ask me how I know this.

Ken

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