Vintage bolt

[gml1998]

I am currently reconditioning an old Grinnell vise. It is missing 2 stove bolts that hold the jaws to the vise. They are 5/16 by 16 tpi. 1 inch long. All 5/16 bolts today are 18 tpi. If anyone has something like this I would be happy to purchase a few. I couldn't find anything on the Internet.

 

[JZiggy]

Years ago I had a machinist make some bolts like this for some old English vises. I highly doubt there will be anything to source off the shelf.

 

[Cleave]

Check ebay? Is it Whitworth? Even if you have to get a hex bolt and file the top to fit the counter sink and hacksaw a slot in the top.
I got a couple Whitworth bolts on ebay once.

 

[RoninB4]

Odd thread but lots of older items had "unique" thread designations before standardizations were in place. If you can't locate them off the shelf I'm sure you know a competent machinist can cut/make these.

 

[2oolhound]

It does look whitworth as peaks and valleys are round. 5/16 W is 18 tpi tho. 3/8 W is 16 tpi. Here is a chart

If it is Whitworth and a good chance it is, taps and dies are still easy to find new or used. Bolts should be too but I've never tried finding any. Most guys into British motorcycles or old cars will have lots of spares and used bolts around if you know of any in your area.

 

[leg17]

Is Grinnell made in Providence?
Brown and Sharpe is/was in Providence.
B & S had many proprietary thread pitches.
(Having trouble digging them up but I'll keep trying)
Maybe Grinnell bought the screws from Brown & Sharpe.

 

[micromind]

Looks like Acme threads, see if you can find anything with those threads.