Dividing head de-crustification

[PeterT]

I'm glad you mentioned this about hardening over time. On some surfaces that's OK, on others a bad thing.

 

[ChazzC]

I'd love to find a light grease or spray lubricant that could be applied to internal or external parts that would last 20 years or so without becoming a problem of its own.

Boshield T-9?

 

[trlvn]

As usual, it took far too long for me to recognize that there was a simple answer. I mentioned before that the spring-loaded pin didn't have a way to stay in the retracted position. When I needed to crank the handle multiple turns, I had to keep pulling the handle out or it would snag on the sector arms or even lock into a hole.

I had dreamed up a couple of solutions involving springs and knobs and whatnot. I actually started working on one when I happened to look yet again at the existing threaded hole in the handle. Duh!! This time, the handle happened to be turned so that I could see the longitudinal groove milled in the inner piece. I already knew that there was a slot milled around the circumference so that an inserted pin would hold the pin in the retracted position like I want. The two slots meet up.

All I need is basically a dog-point screw. With it, I just need to pull the handle back and twist slightly to lock the pin in the retracted position. Twist again and I can lower the pin into the next hold. Feel really dumb for not inspecting earlier. My only defense is that everything was quite rusted when I got it. Nothing but crud was visible in the hole. For a long time, I thought this hole was for lubrication--like the others on the dividing head.

Anyway, the handle functions properly now.

Craig
(Brass FTW!)

 

[CWret]

Much better than making a spring gizzmo!

 

[buckbrush]

I use car bumper wax on my machined and ground surfaces on my tools and machines. I think it is Meguires?

All the Brown and Sharpe type dividing heads I have used have a Brown and Sharpe taper in the spindle, usually a 9 B&S, little ones have a #7 B&S.

 

[trlvn]

All the Brown and Sharpe type dividing heads I have used have a Brown and Sharpe taper in the spindle, usually a 9 B&S, little ones have a #7 B&S.

Yeah, I finally figured out that it really is a Brown & Sharpe #10 taper. After I got the crud cleaned out, I could see that the Morse taper sleeve I was using for testing was not engaged at the small end.

Anybody have a spare B&S #10 centre? I did more than a little online searching and there seem to be few options available. One was a 'ground to order' type of shop. No prices listed but I suspect they'd want more than I paid for the entire dividing head.

Craig

 

[That-Guy]

@trlvn I've got a question about this head for you. Do you recall what the spindle threads are? Because, and I really hope I'm wrong, they measure out at 55 degrees... making them....whitworth [style] threads!?!?!?! They also measure at 2.280" / 57.912mm, so that's different. Who built these things?

 

[trlvn]

@trlvn I've got a question about this head for you. Do you recall what the spindle threads are? Because, and I really hope I'm wrong, they measure out at 55 degrees... making them....whitworth [style] threads!?!?!?! They also measure at 2.280" / 57.912mm, so that's different. Who built these things?

I thought it was 2-1/4 inch diameter by 4-1/2 threads per inch. I remember checking the threads with a 60 degree 4.5 tpi gauge and I thought it fit properly. I'd expected it to be 2-1/4 by 8 tpi. I remember it was 4.5 tpi because that is not a thread pitch that my lathe is listed as being capable of. However, since the lathe will do 9 tpi, I though it could also do 4.5 by substituting one of the gears in the train.

Can you not make use of the backing plate that was with it?

Craig