Crosman 600 Restoration - Part 1 of 3

[WyoMan]

This was put on the internet about a year ago, so if you’ve seen it already then disregard... although I’ve added a few new photos. Search engines can at least find it here so maybe it will be more helpful.

References:
http://stevespages.com/pdf/crosman_factory_service_manual_all.pdf
http://anotherairgunblog.blogspot.com/2010/02/crosman-model-600-disassembly-part-1.html

I purchased three CR 600 basket case guns that were beat up and didn’t hold gas. They were pretty cheap, and that’s good, because the all-in cost wasn’t. The plan was to get at least one or two working guns from the best parts. There aren’t very many “before” pictures because I wasn’t sure if the project was going to pan out. But, here we go…

All three guns were disassembled and the best two of the three frames were taken to be ceramic coated (fellow member breakfastchef gave me some ideas on this). Then I started working on the internals. First thing I needed was a valve removal tool:


This tool was just a 6 point 13mm socket that was ground as a "spanner". It will reach down the front of the tube to unscrew the front part of the valve. The valve body seal gets squeezed by the front and back halves. It seals to the tube by the extrusion. A couple turns will free the front half. The back is retained by threaded sleeves (inside threads) that are removed with a 6-32 screw.

Some photos of the disassembly are missing, but I did do more camera work when it was put back together... here’s the old valve parts with hammer and cam ring:


It’s easy to see why it didn’t seal - the valve body seal (113 o-ring) was hard, brittle plastic. It cracked when I backed it off the threads. The rest of the parts don’t look so bad.

Here are some "old school" mods to a valve that is older than the mods. Increasing the valve volume by cutting a couple threads and boring the inside by one drill size:


And a shaped valve stem with everything polished:


Then I polished the hammer, replaced the internal o-ring (size 014), and dry lubed the interior. I’m using cast urethane o-rings for the wear resistance and the CO2 impermeability. They’re a little more money but I’ll spend the nickel here:


Valve and hammer finished:


On to the cam group next... helps to have some spare parts available:


I selected the best cam / ring combination…the best meaning the smoothest movement thru the twist. Here’s how they will look inside the frame:

For proper cycling, the alignment of the feed arm in the “up” and “down” position is what matters.

Next was a thorough cleaning of the tube – inside and out:


Here’s the frame back from the coating shop.


They tell me that the ceramic thickness is about .0005”. It’s hard and it can crack, but it’s a thin coat... less headaches getting things to fit. It was a pretty good job overall with a flat black satin finish. There were about 12 different “blacks” to choose from...if you can imagine that:

Ready to assemble... Part 2

Part 2:  http://www.gatewaytoairguns.org/GTA/index.php?topic=121810.0
Part 3:  http://www.gatewaytoairguns.org/GTA/index.php?topic=121811.0

Wyo