Carroll Dividing head, Threads ?

[lathe nut]

Hey all, a fellow stopped by the house which is a part time scrap dealer like me, he said that had some machinist stuff wanted to know if I wanted anything before he made the scrap load, to my shock there was a 6" Carroll dividing head with all the plates, tailstock , in excellent condition, missing the chuck and the holding dog only, kept my excitement in check and asked how much he wanted for it, he said if you would give me ten dollars would be a lot more than it would bring, of course I said yes, had another bucket with mill cutter, bits and lot more things, I got it all for twenty, where I am stumped I need to put a chuck on the dividing head, it took it complete apart cleaned and painted it but the treads have set me back, looks like it is one and three quatre threads (1 3/4") looks like seven or possible even 7.5, T.P.I. does anyone know what the correct answer is, guess they were common on Carroll but uncommon to everyone else, thanks for the help in advance, Joe ?

 

[RM-MN]

This might not answer your question but this is a question asked by a member on "The Hobby Machinist" back in 2014.



"I've got a nice Carroll dividing head. I want to mount a 3 jaw chuck on it. does anyone know where a fella can get a threaded chuck backplate for one? This is a 1 3/4 inch by 6 TPI thread unique to Carroll products. Ive been hunting E-bay and the like without luck."



With this in mind, check your threads again and see if it really is 6 TPI.
Here's a thread on Practical Machinist, again from 2014 that discusses the possible answer to your question.

https://www.practicalmachinist.com/...1-3-4-6-tpi-for-carroll-dividing-head.293430/

 

[djc]

Please do not take this the wrong way, but if you are asking about the spindle thread, why not include a picture of the spindle nose?

Even better would be to include a picture of the spindle nose with a ruler touching it, ensuring the zero mark on the ruler is aligned with one of the thread peaks.

You could draw a one inch line on a piece of paper and divide it into six (parallel line division). Hold that piece of paper against the spindle and see if your marks align with the thread peaks. If they do not, try with another line divided into 7. To confirm or deny your 7 1/2 tpi theory you can divide a 2" long line into 15 pieces.

 

[morsetaper2]

There are two Carroll div head brochures over on vintagemachinery.org

Every thread nose dividing head in either brochure was listed as either a 1-3/4 x 6tpi or 2-5/16 x 6tpi threaded nose. I'd say you probably have a 6tpi nose as other have said as well. There is a hole chart there as well that you can download.

 

[awake]

I'm sorry to say that it will be impossible to find anything for this DH, so your best course of action is to send it to me for disposal.

Okay, I thought it was worth a try ... !

Years ago I got a dividing head that (as best I can tell from the pictures) looked somewhat similar - though I am 99.9% mine is an import knock-off unit. I don't recall what the spindle thread was, but I wound up making a backing plate to attach an otherwise-unrelated chuck. As I recall, it wasn't an overly difficult job.

 

[lathe nut]

I did get a metric thread gauge, it is showing 4MM, I measure across the threads, possible 39 or 4, not been able to find much out about it, was looking for a back plate 6" to fit a 3 jaw chuck, maybe you guys across the pond might know if they are gettable, I am surprised that a I though was an American made dividing head had a metric spindle unless the head was really built overseas, like what would I really know about that, what I do know is I have a restored head with all the tooling and all the plates and am back to zero, thanks for any help in advance, Joe

 

[morsetaper2]

I did get a metric thread gauge, it is showing 4MM, I measure across the threads, possible 39 or 4, not been able to find much out about it, was looking for a back plate 6" to fit a 3 jaw chuck, maybe you guys across the pond might know if they are gettable, I am surprised that a I though was an American made dividing head had a metric spindle unless the head was really built overseas, like what would I really know about that, what I do know is I have a restored head with all the tooling and all the plates and am back to zero, thanks for any help in advance, Joe

I find it oddly strange you are coming up w/ a metric spindle on a Carroll DH. What leads you to believe it is a Carroll DH? The number in your first picture does not match up w/ anything in the Carroll catalogs on vintagemachinery.org. Is there a Carroll logo on the DH - didn't see anything in your pictures?

 

[awake]

4mm is very close to 6 tpi (note morsetaper2's comment above) - have you tried a 6 tpi thread gauge?

 

[morsetaper2]

Restoration of a Carroll dividing head over on OWWM.org. Plus photos of another.

https://owwm.org/viewtopic.php?f=77&t=231620

 

[lathe nut]

awake, I tried them it is most defiantly a 4MM, maybe at some point in its life it decided it did not want to be like his friends, I did talk to a machine shop, and they will cut me some 1 1/2X8 thread.​

morsetaper2, see that my total tear down clean and paint is done, never gave much thought about the threads, that is my only issue at this time.​

 

[awake]

Always good to check - I've been "bit" a time or two ...