Clausing 8520 Drawbar?

[Finster]

What metal is a 8520 drawbar made out of? I bought a new drawbar (way overpriced) from Clausing and it sucks. I give up and I'm just going to make a new one. I figure I'll just turn one on the lathe and cut the threads.

 

[woodchucker]

any metal will do. Mild steel, SS, even alum, the purpose of the draw bar is to pull it and hold it in the taper. The taper does the work, the draw bar just prevents it from moving out.

 

[Finster]

any metal will do. Mild steel, SS, even alum, the purpose of the draw bar is to pull it and hold it in the taper. The taper does the work, the draw bar just prevents it from moving out.

Thanks. I guess I could just use some all thread then.

 

[Rustrp]

What metal is a 8520 drawbar made out of? I bought a new drawbar (way overpriced) from Clausing and it sucks. I give up and I'm just going to make a new one. I figure I'll just turn one on the lathe and cut the threads.

I might suggest a 1035, 1044/45 or something specific for bolt manufacturing an A182 or A193.

In regards to what they are made of, it seems most manufactures are never to open on detailing specific alloy of parts and pieces. e.g. Extracting from Bridgeport that their drawbar is an import took a little effort.

 

[woodchucker]

Thanks. I guess I could just use some all thread then.

I would not use all thread, Use something that fits in the bore (self centers), that way you don't have to find the female threads, the draw bar will find it for you.
That means the bar is larger than the threads by a small amount.

 

[12bolts]

Sleeving the all thread with some thin tubing/conduit might work.

Cheers Phil

 

[Bob Korves]

Softer steels will not last as long in an application like a drawbar. Beautifully machined from fine steel and hardened, they last for a long, long time. They are not really more effective, and softer steel adapts to the hardened collet threads better. It depends on what you are looking for in a drawbar and how much money, effort, and/or time you are willing to put into one, and how often you are willing to make or buy a new one...

 

[Rustrp]

Thanks. I guess I could just use some all thread then.

Now, if you're serious about the all thread I would suggest ordering some 1040 or grade 8 from McMaster Carr, good price and next day delivery. Well, maybe not for you but they ship quick.

PS. While you're at it throw in a 3/8" Coupling nut, which costs double the 3' of rod and puts you out the door @ $22.oo plus tax and freight. I'm just guessing the thread is 3/8"-16, but I think I saw it on a spec somewhere.

 

[12bolts]

If finding suitable steel for the whole drawbar is difficult, or as Bob says, "money/effort/time", I guess another alternative would be to use any old piece of suitable dia steel and drill and tap each end for a piece of suitable thread.

Cheers Phil

 

[kd4gij]

BP drawbars are not that hard and considered consumables. You would rather strip the DB than the collet.