Cincinnati diving head - Disassembly ?

Panza · Mar 22, 2015

I'm trying to take apart my new old Cincinnati dividing head due to a tight spot in one place on the worm gear (every 40th revolution).
I've taken it down the the main casting but how do I get the worm and gear out ?
Before that I need access to the worm gear to lock it in place to get the chuck off. That chuck has been on there for 50 years I bet.

john.k · Mar 22, 2015

I have an old Cincinnatti dividing head ,probably mid thirties,and the worm fits its shaft with a slow taper.The worm is cast iron,so be careful not to break pieces off it.In fact ,I think just about all the parts ,except small gears, are cast iron.Mine is completely knackered ,and was a waste of money.Regards John.

johnoder · Mar 22, 2015

May be of some help

Cinc DH Scans Photos by johnoder | Photobucket

ronf · Mar 22, 2015

Here is a you tube vidio of a B&S. That might help you.
https://www.youtube.com/watch?v=DXef8SfT8fw

Panza · Mar 22, 2015

I have the scans already. But thanks anyway.
The B&S head is quite different as you can see below.

What I think I know is that the spindle is supposed to be pulled out of the non-chuck side.
Doesn't help much when the chuck is stuck.

Here is how far I have come:

ronf · Mar 22, 2015

Well looking at the scan I would say your right and the spindle comes out the back. Can you hold the spindle with the spindle lock or by holding the spacer ring? After getting the chuck off and removing the spacer ring the chuck lock will have to be removed. The worm shaft will have to have the eccentric removed from the left side first, then the shaft might be pulled fron the head, i said might, I'm unable to tell for sure from the scan. As for the chuck grip a pipe in the jaws good and tight set the spindle lock and put a pipe wrench on the pipe and rap sharply with a hammer. After all you live in lillehammer.

mach2 · Mar 22, 2015

Panza, check this link to a manual. Not sure if it is the same as yours but might help. Vintagemachinery org also has sales brochure.

Cincinnati Milling Machine Co. - Publication Reprints - Cincinnati Universal Dividing Head and Accessories Parts List | VintageMachinery.org

Mine is a newer version and it has been a while since taking it apart but there is a definite order of assembly. You might want to study the exploded drawings and take your time. Oh, and avoid the hammer.

johnoder · Mar 22, 2015

Manual is later - anti friction bearings and NMTB spindle nose

Back to your oldie.....

Ring behind chuck is bolted to spindle. Hang onto it with pin spanner and take off chuck

Then unbolt the ring and take it off spindle

Take off the four bolts/screws on back and the cover/bearing housing they retain

Disengage worm (handle opposite side from crank - it turns the eccentric worm mounting)

Take out spindle

Reference is the reprint of the 1919 Edition of A Treatise On Milling and Milling Machines

Panza · Mar 23, 2015

Thanks John - So simple.. yet so difficult. I saw the exploded view manual was for a later head too. Quite different really.
I will have a look at the "Treatise".

I have tried the following methods for breaking the chuck free (none of them successful):
- Clamping stock in chuck and using huge wrench on it.
- Clamping hex-bar in spindle and having a go at it with an impact wrench.
- Clamping bar across chuck and hitting it with a big hammer.
The spindle clamp does not hold enough and the plate behind the chuck was not strong enough

If I could get access to the worm gear from the side I could put some wood in there to lock the spindle.

johnoder · Mar 23, 2015

You could try Loctiting in a tool with a big hex on it and a shank to fit spindle bore.

(make good sense to have rear bearing and its housing off first)

Tool could be bored out when spindle was out

Loctite used to advertise their #271 as having 3000 psi shear strength. Fairly easy to see a 2" long X 1" diameter would have enough area to resist 785 Lbs/Feet of torque if this was the actual case

ronf · Mar 23, 2015

They make freeze spray, try to freeze the threaded end on the spindle, then try your methods again. If you can remove the worm shaft you might get access to the inside. You need to remove the eccentric from the end of the worm shaft first.

Panza · Mar 25, 2015

Finally it let go!
I think the kroil worked it's way into the threads after a few days. I also took out the brake wedge and cleaned it.
That combined with a new bigger hex so that the jaws of the chuck had maximum contact with the chuck itself. Then the impact wrench again.
The casting that holds the worm came out first but I can't quite figure out how they got it in there in the first place.
Thanks for all the great ideas ! If I get some time I'll try do do a little "how to".

Panza · Apr 11, 2015

All the major parts cleaned and painted:

Panza · Feb 22, 2017

As a thank you for the help here is a little video of it all reassembled:

[486] · Feb 22, 2017

Did you happen to take other pictures of the spindle?
I've got one I've been thinking on converting over to an nmtb40 spindle. Someone had already taken a die grinder to it to fit 5c collets...

Panza · Feb 22, 2017

This is the best picture I have (native resolution).
The thrust bearing is sitting on top of the spindle.

Cincinnati-Spindle.jpg

kovalchick · Feb 8, 2020

Parts breakdown

Panza said:
This is the best picture I have (native resolution).
The thrust bearing is sitting on top of the spindle.

Cincinnati-Spindle.jpg

Here is mine disassembled

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Cincinnati diving head - Disassembly ?

Panza

Stainless

john.k

Diamond

johnoder

Diamond

ronf

Cast Iron

Panza

Stainless

ronf

Cast Iron

mach2

Stainless

johnoder

Diamond

Panza

Stainless

johnoder

Diamond

ronf

Cast Iron

Panza

Stainless

Panza

Stainless

Panza

Stainless

[486]

Hot Rolled

Panza

Stainless

kovalchick

Plastic

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