After using my new mini-lathe to repair my cheap foreign made propane heater, I decided to use it for what I really bought it for – some amatuer gunsmithing. Enter my squirrel-b-gone device – a Crosman Pumpmaster Classic, more commonly known as the 1377. The Crosman 1377 is a fairly powerful (500 fps), extremely moddable, cheap air pistol that’s great for short range rodent elimination and lots of fun to shoot. My first order of business with the 1377 was smoothing out the trigger, which out of the box felt like the manufacturer had filled the gun with coarse sand before shipping. Now I’d like to make a replacement barrel band to allow me to thread the barrel for muzzle attachments.
First I needed to block out a piece of 6061 billet. The goal is to make the barrel band in one piece because I want everything as compact as possible so it will fit in my hunting bucket that I carry back and forth to my deer stand.
Next is the gruelling process of turning a square shape round. On a bigger lathe it would be a snap, but mine resembles a toy (though terrfically functional) so getting to this state took at least an hour and much cussing until I figured out I should be using the auto feed. What I didn’t get a chance to snap a picture of here was the brass mandrel I bolted to the face of the billet to allow me to turn it round in my three jawed chuck.
A few hours and several glasses of bourbon later and the square peg is now round. I messed up and cut an unecessary groove into the portion that fits into the pump tube, but it wasn’t my first and wouldn’t be my last screwup. I now turn the piece around and chuck up the tube plug so I can face the front.
Milling an outline on the face that looks more attractive than a rectangle. I messed up here too and gouged one side of one of the angled flats.
Rounding the nose on the lathe and doing some final finish work.
A little sanding.
Once again I skipped documenting a big step – cross drilling for the pin and milling the slot for the pump arm.
After all that I found the face of the band needed to be relieved a little so the pump arm could swing forward enough to allow the pump tube to fill correctly. I have no purpose-made power tool for this, so it’s time to break out the files.
The intended result has been achieved!
Trying my hand at cutting some threads.
After dressing threads with a needle file and touching up the blueing.
All that’s left is to figure out how to finish the aluminum and assemble her. At the moment I’m debating whether it’s worth the trouble to anodize it, or if some black satin spray paint wouldn’t do a lot to help hide my mistakes. 🙂 Decisions, decisions…