Friday, January 8, 2010

Benjamin 312 Leather Seal Shenanigans

This is a boring and pointless post that only serves to show how much I have to learn about fixing airguns...

I decided to get clever and make the forming dies for the pump cup with a hole...

and a pilot...

Seems like a good idea as the hole will be perfectly centered.

Left to dry in the vise...

All torn up in the center. Did it twice and got the same result.

Decided that maybe the lack of a chamfer on the male die was the issue so I added one.

Still torn around the hole.

And again...

So I left only the merest hint of a pilot.

Tired of this yet?

Finally! But it's too damn short. I started using a female die with no center hole at all.

And shaving the leather thinner. I need to get some already thinner leather.

Too thin.

Last chance...I soaked this leather longer than the last and shaved it thinner but not as thin as the last time. It's long enough if a bit ragged.
I won't be spoiling the surprise to say that yes, this one works. And I didn't even show the 10 other failed attempts.
So what I learned is that the smaller the cup diameter the more the leather stresses. And that I need even more of a variety of leather thicknesses. BTW, here's a great post from the Classic Camp Stove forum on making small leather pump cups.
Did I mention this cup is available for less than $7.00 from JG Airguns? But what would be the fun in that?

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