What is it?

A friend sent a picture for me to identify. It's like a lathe dog but the wrong way round. The thread is on the vee side.

It has a countersunk hole on the other side. I guess it's some kind of clamp, but I've never seen anything like it.

One of these :

**LINK**

Actually it may be a nut splitter, a hardened wedge fits in the square hole.

Appears to be a pipe hanger

If it were stainless, it would possibly be a clamp off the regulator for a diving bottle. But it looks like its cast or malleable iron. So the tensile strength isn't huge. Still, my bet's on something along those lines

Nutcracker?

I like the nutcracker! and Neil's nut splitter. I had wondered if it was half of an old scaffolding connector, the type to allow for angle between the tube, but it's nothing like the 'modern' split pattern. Bill's hanger and Simon's clamp of a pressurised bottle seem plausible, too.

It looks like a double start thread, if it is, then faster locking would be more important than applied force.

I note, too, that the range of travel of the thread looks like the entire space inside the ring. So perhaps not a dedicated item. I discounted a puller due to the radius opposing the thread and the hole, and various other reasons.

Is the small hole theaded or plain?

As a diver there is no way on this earth I would have that as a clamp on a first stage and I'm certain that is not its function. I would go for a nut cracker. Again it is not strong enough to use as a splitter for metal nuts.

Colin

Scarfing clamp for gluing rods together to make gunwales for small boats and fishing net mouths - for instance.

Rik

Another vote for a nutcracker. Google for "screw-type nutcracker" and you will find many variations on this theme. Or build your own with instruction at http://www.instructables.com/id/Over-Engineered-Nutcracker/

Looks like a multi-start thread, If so, speed of operation was a consideration.

I took Mike's advice to Google and found some which similar, although nothing identical. There would appear to be a pad or (on some designs) a handle that makes use of the hole. My friend says he's been told it's a pecan nut cracker. I've never cracked those, so I don't know why it would be specific for this nut.

Many thanks, all.

I guess so too.

I think it may be a controlled cushing device, such as using a couple plates,with grain between, for preparation of samples for early moisture testers, or for compacting those ground samples into a standard sized pellet for use in the testing instrument. Early machines were far better than the farmer collecting a few grains and biting them between his/teeth as a test for readiness for combine harvesting.

Maybe a parallel pin pusher for removing or refitting them without banging a parallel pin punch against the pin.

Martin C