What size are the threads on bar clamps?

[Wamsutta]

After all these years, one of my Jorgensen bar clamps finally had its wooden handle twist off. I'm not complaining because I've got about 30 years of use out of it. So I was thinking if I wanted to be a smart-***, I could weld a nut on there to replace the handle. I'm always tightening it more than hand tight anyway.

Right now I'm using 10 inch Wilde slip joint pliers to turn the threaded bar and those pliers are working beautifully. But I figure just in case I decide to weld a nut on there, I'd ask you guys what the thread size is. If I'm not mistaken, I think they're acme threads and I don't know if they make nuts for acme threads.

 

[The Cobbler]

if you're welding a nut on, you don;t need the threads . just drill a nut to slip over & weld er up!

 

[Wamsutta]

I still want to find out what the thread size is. One of those life long mysteries I've always wanted to solve.

 

[WWheeler]

How to tell acme thread pitch: https://www.packerfastener.com/technical/threads/acme.html

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[Wamsutta]

A 3/8 open end wrench fits over the threaded bar with a slight wiggle.

 

[The Cobbler]

they probably are acme, but there might not be much attention to specs other than TPI .

 

[Wamsutta]

OK - I got my reading glasses on and sharp pen. In the span of one inch, I counted 16 threads.

 

[The Cobbler]

looks like either 1/4 or 5/16 maybe . what's the OD ? https://westportcorp.com/blogs/thread-plug-gages/external-acme-thread-general-purpose-size-chart

 

[PCustoms]

if you're welding a nut on, you don;t need the threads . just drill a nut to slip over & weld er up!

Used to do this all the time with the HF 6" bar clamps. Whack the handle off, slip a nut (we used to buy bags of unplated just for this) over and hit it with a quick zap from MIG or TIG.

The operator had a torque gun to set a dozen or so clamps per fixture.

 

[Spareparts]

If you have a Metal by the Foot by you they have ACME nuts and the ACME threaded rod
at least here they do KC MO. area.

 

[MoonRise]

Ummm, just glue the handle back on with some appropriate adhesive?

Or 'weld' the handle back on with some JB-Weld.

Unless you want/need to use a wrench on a nut attached to the threaded rod of the clamp instead of the convenient handle.

In which case just find a big enough nut where the nut ID just fits over the OD of the threaded rod. Attach as you desire, welding can work.

Just beware of the most likely zinc plating on the clamp's threaded rod and possibly the nut you chose, it doesn't help with the welding process and the vaporized zinc fumes are not healthy to breath.

 

[Kscardsfan]

If you cross thread it bad enough it'll do the same thing as a weld for you.

 

[MovingAlong]

If you cross thread it bad enough it'll do the same thing as a weld for you.

I've peened over couple of threads with a cold chisel and then run the nuts down tight over them... seemed to hold pretty well too.

 

[MovingAlong]

... I think they're acme threads and I don't know if they make nuts for acme threads.

Believe they do, McMaster-Carr seems to have them.

 

[Kscardsfan]

I've peened over couple of threads with a cold chisel and then run the nuts down tight over them... seemed to hold pretty well too.

You mean tamper proofing? Yeah, I've done that to some signs etc. I got tired of people stealing from us.

 

[Wamsutta]

After all the measuring and mathematical calculations, I think they might be your typical 3/8"-16 machine threads.

 

[garfunkle24]

It should be fairly apparent if they're some kind of trapezoidal thread or a v thread. Are the crests of the threads a point or flat?