Hoffmann-universal dividing head question

Markusfu · Mar 13, 2008

I'm hoping that someone with German dividing head knowledge can help out on this question. I have a Hoffman UTH 100 universal dividing head . It has a morse #3 taper in the spindle and the outside of the spindle has a strange taper and three holes for mounting a chuck. I'm thinking that this a very strange way for a high end tool to mount a chuck. Any ideas why this approach was used ??

thanks
Markus

aboard_epsilon · Mar 13, 2008

that's the same as mine ...

never took the chuck off mine ...

nothing about what type of chuck it is in the manual.

just listed as an optional extra ...three jaw chuck with backplate .

looks like a camlock to me

all the best..mark

alpha1 · Mar 13, 2008

Hi, Markus,

I have several German made divider which has the same flange as your
Hoffman, It is DIN type Camlock quite common in Europe, I guess you can fit some bison lathe chuck on it

Cheers,
Alpha1

rimcanyon · Mar 14, 2008

My Monarch 10EE uses a similar 3-pin camlock, and I have been wanting to find a dividing head that would allow me to move tooling between lathe and mill. Is it a D1-3 camlock spindle? If so, that would be good to know. The D1-3 has these measurements: pin diameter: 9/16", the tapered spindle is about 2" outside diameter at the end, and 2 1/16" outside dia. at the base.

-Dave

adh2000 · Mar 14, 2008

My Walter has the same nose and no its not D1-3 unfortunately. Its not really a camlock since there is no cam locking mechanism involved. If you look closely at the photo you see that the three pins stick through the flange and are exposed. On my tooling the pins are threaded, you have to start nuts on the back side of the flange as you put the chuck on the nose. Sort of a pain and not a really good design in my opinion. The centering taper is smaller than D1-3 but looks similar, like it might be D0-3 if that existed.

Alan

Erik · Mar 14, 2008

Spindle Noses

Hmm, looks like a standard DIN 55026 or 55027.

On both spindle noses you have studs with nuts.

On 55026 you have to remove the nut and on 55027
you just loosen the nut and turn a bayonet ring
(best, I think - at least easier).

And 55029 is the Camlock. The DIN 55026 or 27 kk3
(short-taper 3) is the of the same dimensions as Camlock D1-3".
(but the camlock has quite different studs)

Your dividing head has 3 holes and no bayonet ring, so it looks to me
like a DIN55026 kk3.

Cheers
Erik

AlfaGTA · Mar 14, 2008

rimcanyon said:
My Monarch 10EE uses a similar 3-pin camlock, and I have been wanting to find a dividing head that would allow me to move tooling between lathe and mill. Is it a D1-3 camlock spindle? If so, that would be good to know. The D1-3 has these measurements: pin diameter: 9/16", the tapered spindle is about 2" outside diameter at the end, and 2 1/16" outside dia. at the base.

-Dave

Dave:
If the above dividing head with its spindle taper has the same taper as the D1-3 (not sure we have figured that out yet) you could make selected D1-3 tooling (chucks) useable on that system by simply drilling and tapping for studs the back of the chuck spaced between the normal camlock pins. Then to use the chuck remove the pins and fit the studs and mount the chuck. Not the quickest, but would work and not affect the function or accuracy or the chuck when used on your Monarch.
Cheers Ross

Erik · Mar 14, 2008

Ross, why not screw out the camlock pins and make some threaded pins?
No need to make any holes. He could make the pins a tight fit in the chuck.

Cheers
Erik

wrench · Mar 14, 2008

That would pre-suppose that everything lined up well, which is probably not the case (Murphy's law). As for tight fit... I don't think it would be all that important, really. The bolts only serve to pull the chuck tight against the backplate. The accuracy/alignment comes from the taper. In fact, the pins on a D1-x camlock are quite wobbly to facilitate mounting, etc. But when the cam cinches up then everything "gets accurate".... we hope!

--Alan

Erik · Mar 14, 2008

Alan,
the thing about them being tight was only so they'd stay in
when the chuck was removed. :-)

Cheers
Erik

Markusfu · Mar 14, 2008

Hoffmann mounting

NO- it is not d1-3---- not even close. My original post was any idea why anyone in their right mind would want to put a chuck on a dividing head this way. It is very inconvenient to add or remove a chuck from this dividing head.

cheers
Markus

wrench · Mar 14, 2008

Actually, this is how a few CNC lathes have their chucks mounted though. I've seen it, but I don't understand it. Bolts extend through from the rear to the backplate of the chuck, pulling the chuck tight. I guess the throught is that CNC lathes don't really have many changes in usage paradigms or something.

Alan

xtremcycles · Mar 14, 2008

My small asian lathe have a similar taper called C-4 with 3 threaded stud for mounting like a camlock and it have a mt4 hole
the OD of the taper is around 2.125

wrench · Mar 14, 2008

The interesting thing here, however, is that it looks like the dividing head holes are not threaded. It seems like the intent was to put the bolts in from the rear and then into the chuck backing plate. There is a relief area in the casting's top to allow for a wrench to tighten the bolts too. And, finally, this would make sense if you were trying to mound a 3-jaw scroll chuck. Of course, this leads to the question of how you mount your 3 jaw chuck in your lathe arrangement.

xtremcycles · Mar 14, 2008

picture talk by itself

wrench · Mar 14, 2008

got it... I misunderstood your description.

Markusfu · Mar 15, 2008

hoffmann question- extremcycle

Extremcycle- do you find that this is a strange and inconvenient way to mount a chuck?

Markus

rimcanyon · Mar 15, 2008

you could make selected D1-3 tooling (chucks) useable on that system by simply drilling and tapping for studs

Ross, the idea is good. Now I need to keep my eyes open for DIN tapers. I think.

Markus, is your dividing head DIN 55026 or 55027? At least that would tell me what not to look for.

-Dave

IronFighter · Mar 15, 2008

Chuck Mounting

There is a list of spindle nose fittings here:

http://www.lathes.co.uk/latheparts/page8.html

Colin

Markusfu · Mar 15, 2008

hoffmann-

Rimcanyon- from what Eric states above in his list my Hoffman must be the 55026 because there is no camlock , simply a slight taper and then you must bolt the nuts to what ever studs are on your chuck.

Markus

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