Add bling to my 392

[jon.k]

It isn't the best shooter, but neither am I. Here's how I added a billet lever to my 392 -- mostly in pictures. This is a '97 gun that lived un-lubed until I bought it last year.

First disassembly. The roll pins were tight, it was not easy to push them out. Bought a new, cheap set of pin punches, and the roll pins are much harder than the punches.




The current lever arm had a bit of play in the pivot. You can see the hole is ovalized.



These aren't the most accurate calipers, plus I'm rushing to beat the camera timer on my phone, but I'd say the hole was about 5 thou too long in one dimension. I could wiggle it as I pumped when the lever was open about 30-45 degrees.




Then I removed the forearm from the lever. I drill through to the other side, then push the pins out.



My cheap new pin punches are too short. I have to use a hardened finish nail to give them the final push.



I consider myself poor, so I only bought the billet lever, an adjustable piston head, plus a new link pin and rivet for this project. So I need to retrieve the link from the old pump arm, which will mean grinding away this rivet and replacing it with the new one sitting on top.



Only after I remove the old link do I see that my plan won't work. The new rivet is 0.25", but the hole in the lever link is 0.28" thanks to an undersize rivet with hardened bushing around it. Checking back here I found a couple posts where TimmyMac notes this upgrade, but I had thought I read I could reuse my link. so the project goes on hold while I wait for the new link to arrive. I bought a new front plug too, since I'm already spending more money. The old rivet I remove by grinding off the ends with a dremel and a cutoff disk. I still destroy the lever arm by grinding away too much surrounding metal and then warping it while pounding out the rivet. I see why TimmyMac says this is a bad design, and I'm glad I'm not trying to salvage the lever.

The new link is also beefier. It is 0.12" thick; mine is only 0.11" thick. As a result the new link doesn't fit in the slot in the base of the piston, which measures 0.118". I later use a warding file to open up the slot in the piston 0.004". the metal is soft, it only takes about 10 minutes, so not a disaster.



I'm glad I took this picture, I referred to it about 6 times to be sure to orient the link correctly before closing the new rivet in. I don't want to wait for a new rivet to ship!




TimmyMac suggests annealing the end of the piston before cutting the threads. You can see I've already cut the piston head off with my dremel. the cup looked OK; a little hard, a little nicked up around the edges, but still functional.




I have a cheap chinese tap and die set for coarse SAE and metric thread pitches that uses round dies, but I need 1/4 x 28, and the hardware store only has hexagonal dies. I'm too cheap to buy another die holder, so I improvise with a scrap piece of hard maple flooring. It sits on a set of really soft jaws I am using to hold the piston in the tiny clamp-on vise.



The hardwood flooring die holder worked just fine. These threads look good. I harden them a little with a water quench and heat treat for strength, then coat with secret sauce to keep rust off it.




I buck the rivet with a ball-peen hammer until it is as flush with the lever as possible; first the small side, then the large side.




Then I assemble the piston, and check it for length, and refit it about 8 times trying to get the length perfect. The difference between too much slack and too over-centered is about 1/2 turn of the piston head, or about 1/64" of length. I set it so the cup contacts the valve when the lever is 3/4" away from the pump tube, which feels a tiny bit loose but it does still hold the forearm up with no pumps. the old piston head is laying on the bench above the main subject.



Here's what the front-end looks like now, with billet lever and steel front plug. I got a new primary pivot from the hardware store; it is a wee bit longer than the original, but I leave it alone.




Finally I get to take it to the woods and re-sight in the scope! The new front plug does look sleek, I guess it was worth $25. didn't realize how autumnal the world is until I looked down at the ground.

[BenjiHunter]

Nice job!

[White Eagle]

Nice job!

+1!

[jon.k]

Thanks guys!

[Tater]

Very nice job Jon. Good tutorial pics too.

[avator]

Thank you.. I have a '68 blue streak that could use this as well as a couple 140s.
BTW... it's not very often you see one of these with a scope and a williams peep on it.

[jon.k]

Thank you.. I have a '68 blue streak that could use this as well as a couple 140s.
BTW... it's not very often you see one of these with a scope and a williams peep on it.

I think the total parts breakdown was:
$40     standard billet lever
$15     lever link
$15     stainless piston head
$25     steel front plug
$4       round rivet (keyed is $6)
$3       link pivot
$0.35  primary pivot
---------
$102.35

The front plug was an afterthought, but as you can see a wise shopper would have bought the steroid parts kit for $99 and come out ahead without having to cut up the old piston and mangle the old lever.


Yeah, I say I'm too poor to send the thing to Mac1, but then I buy it pants AND suspenders!

The gun came without a rear sight, so I put the peep on when it arrived. Then a while later this vintage Swift 3-9 x 40 scope came up for cheap on the yellow classifieds, and I had never even looked through a scope, so I threw down for a set of used rings and the IA mount from Mac1.

These pumpers can do magic with a scope -- they take a a cheap $25 scope and by the time you get it on the gun it is a $100 scope.

[K.O.]

Nice job and tutorial...

I have been on the dark side lately but the Benji and Crosman pumpers will always be my favorites...

[Airhunter177]

Great looking 392!

[longhunter]

nice job . I plan on doing that to my 392P, this winter.