Sunday, June 6, 2010

The 1377 Project, MKII Piston, Part 3

Almost done.

The piston rod half.

The seal mounts.

Threading the other end.


Old vs New.

Drilling for a nylon insert.

Drilling the spanner holes. I first did 8 (old one had six and it was impossible to adjust)...

I had to shift it 45 deg. in the collet block to get eight holes. Next time I'll just use the rotary table.

Gluing in the nylon.

Nice nylon lock patch.

I drilled another set of 8 holes offset by 22.5 deg from the original ones.

Now I can always adjust it.

Just a 1/8" pin punch for the "wrench".

It works well but as I said I'm going to make a MkIII version that should control the squish of the piston cup better than the thin and soft aluminum. I had to use one of those brass shims to keep it from expanding the cup too much. But it doesn't draw vacuum anymore and should in theory work on any of the Crosman pumpers such as the 140, 101, etc...which is great.

More to come when I make the MkIII...


Orin said...


You are a true visionary. I see the stuff you make come together, piece by piece, and I am always amazed. It's like watching one of those "How It's Made" episodes. I especially liked the side-by-side comparison of the old and new pistons.

Do you draw out plans for everything you create, or just take some measurements and turn/mill on the fly?

- Orin

Nick Carter said...

Thanks Orin,
I didn't make any drawings for this project, just thought about it the last couple of weeks. But some stuff I absolutely do draw up as the tolerances are a bit tighter. Of course I wouldn't have had to make the MKIII (post tomorrow) if I had planned this out a bit more...