Eron PV-1 clamp modifications

[cathead]

These Eron PV-1 clamps were well worn when I got them as they were galling badly and ceased to function well. Here is a photo
of the original clamp:


They are a nice looking clamp with a gripping hardened clamping surface that advances to the work at 20 degrees from vertical. They are tightened down
with an Allen key using a huge acme thread. There must be something wrong with the geometry because the acme threads were severely digging into
the cast iron moving part of the clamp as well as chewing up the top stationary part of the acme thread nut.

My choice was to scrap them or try to modify them somehow. The acme threads on the stationary part were severely damaged so I machined them
to a flat surface and fitted in a piece of steel and bolted it to the bottom of the channel using a 5/16 Allen bolt. Also, I machined a lip on the cast
part so that the bolt didn't have to take all the forces.
Here you can see the damaged threads threads on the top of the left part and the area on the bottom of the right hand part
that is showing a lot of wear. The dovetails themselves are still in great condition.


Here you can see the modifications made to the clamp. Also, I machined a square on the top of the nut. The mechanical advantage is a lot
better now as the Acme thread was about 8TPI and my threading modification has 24TPI. The work was somewhat difficult and I have three
more clamps to work on. Most of the machining involved working with the 20 degree angle so somewhat of a challenge.
All in all it was a worthwhile morning project. Hopefully I will be able to get the others done and be able to use them in some future project.

Thanks for reading along.

 

[markba633csi]

I can think of several times I could have used a couple of those

 

[woodchucker]

These Eron PV-1 clamps were well worn when I got them as they were galling badly and ceased to function well. Here is a photo
of the original clamp:

View attachment 399604
They are a nice looking clamp with a gripping hardened clamping surface that advances to the work at 20 degrees from vertical. They are tightened down
with an Allen key using a huge acme thread. There must be something wrong with the geometry because the acme threads were severely digging into
the cast iron moving part of the clamp as well as chewing up the top stationary part of the acme thread nut.

My choice was to scrap them or try to modify them somehow. The acme threads on the stationary part were severely damaged so I machined them
to a flat surface and fitted in a piece of steel and bolted it to the bottom of the channel using a 5/16 Allen bolt. Also, I machined a lip on the cast
part so that the bolt didn't have to take all the forces. View attachment 399608
Here you can see the damaged threads threads on the top of the left part and the area on the bottom of the right hand part
that is showing a lot of wear. The dovetails themselves are still in great condition.

View attachment 399609
Here you can see the modifications made to the clamp. Also, I machined a square on the top of the nut. The mechanical advantage is a lot
better now as the Acme thread was about 8TPI and my threading modification has 24TPI. The work was somewhat difficult and I have three
more clamps to work on. Most of the machining involved working with the 20 degree angle so somewhat of a challenge. View attachment 399612
All in all it was a worthwhile morning project. Hopefully I will be able to get the others done and be able to use them in some future project.

Thanks for reading along.

That's why Edge Precision made his own. He says the low profile and ones like this are not designed well. Check out his series on this... He's a little long winded, but he's amazingly bright, a fantastic engineer, CNC programmer, and I'm always impressed.

https://www.youtube.com/c/EdgePrecision/search?query=clamp

 

[cathead]

Thanks, Woodchucker! I added Edge Precision to my subscribe list so will be busy looking at his
stuff as days go by.

The reason these Eron clamps are poor design is that the "nuts" thread is only on the fixed side. This
causes a lot of side pressure on the screw forcing it into the cast iron on the movable part. As this
goes on, the top of the nut threads begins to fail ultimately rendering the clamp pretty much unusable.
Even though my advancing screw is much smaller, it has more mechanical advantage AND the downward
force is even on the threads. I would not have bothered with fixing these clamps if it wasn't for the nice
tight dovetails and hardened work face surface. Now that I have one modified, it will be a lot easier to
copy my newly made parts three more times and finish up the project.

 

[cathead]

This morning I was able to finish a second clamp. The other pair can sit on the shelf as I have had enough of it, at least
for now.


Anyhow, I had to show them off for anyone interested.

 

[cathead]

Today I finished up on the mill clamps giving them some cleanup and reworking and even a coat of paint. I have
to give a special thanks to my friend Craig who dragged them out of the dumpster at work.

 

[ConValSam]

Well done! Green paint job looks fantastic.