View Full Version : making bolts for head on mill?

11-11-2004, 07:53 PM
I need to replace the "head clamping bolts" on my mill. I have one original bolt (it is broken), the rest are home made. Previous owner cut off the heads of some regular bolts and welded on a piece of flat bar to get the needed square head.

Looking for suggestion on material and how you folks would make the new bolts. Lagun get $24 a piece for the original bolts.

11-11-2004, 08:02 PM
If they are square head because they fit in a tee slot, they could be turned and threaded (and heads milled) from cold finished heat treated 4140. Also known as ASTM A193 B7. 3 feet of this from McMaster Carr will cost less than 40 bucks in the 1 1/2" dia. size.


Paul Alciatore
11-11-2004, 08:09 PM
If you need a square head, why not use setup studs and just make the heads as nuts (or buy them) and Loctite them on.

Good quality setup studs are readily available in a variety of sizes and the Tee nuts may work for the heads. A little grinding may be needed to size them. Both of these should be as strong as a grade 5 bolt.

Paul A.

11-11-2004, 08:34 PM
Not sure just what design you need, but MSC www.mscdirect.com (http://www.mscdirect.com) and probably others sell bolts with T-nut heads. Also quite an assortment of other setup stuff that might be adapted. I'd explore Paul's idea, myself, before trying to carve a whole bolt from solid stock.

Forrest Addy
11-11-2004, 08:35 PM
Use heat treated 180 KSI square head T-slot bolts and modify the heads if you need to. You don't want mickey mouse poorly fitting bolts in this application. Bad bolts will mar the load face of the T slot.

B-7 really isn't stout enough for this application wihout reheat-treatment. If you do make them don't allow any undercut in the head-body intersection. If anything leave at least a 1/32" radius.

11-11-2004, 09:02 PM
I may go the 4140 route. The problem with using a separate nut is the thickness. The heads are not very tall. so only a couple of threads would be engaged.

11-11-2004, 09:13 PM
They make square head setup studs and they still make square head bolts,maybe look for them.

11-11-2004, 09:29 PM
Thanks, I will check with a supplier next week and see what I can find.

11-03-2005, 01:01 PM
Forrest, I ordered the T-slot bolts that you suggested this morning. I figure I may need to modify one side of the tee to fit the circular slot.

And yes, it took nearly a year to get back to this project due a family emergency that came up that week.