Updates and More IZH 61 Sight Stuff

Nick's time crunch has been going around. I've been busy making things--just not airgun things. Co-worker Rich needed some adapters for his new Chris King 15mm through-axle hub, good customer Kyle needed bolts for a 38 year old 3TTT Italian stem for a restoration, one of my pocket knives wants rosewood handle scales...

Here's the workbench as of last night: pocket knife scales on the left, a screwy Daisy 790, a rod to become a centering indicator, Gamo V3, Tau CO2 cap to possibly be converted to a bulk-fill, Stronglight chainrings that need milled to retrofit to a Campagnolo Victory crankset, aluminum angle to be milled to soft jaws for the vise... There's more, but this is enough for now.

The Gamo V3 is from blog reader Michael. It's a lead-ball (BB sized) repeater. It's got a strange, intermittent problem. The first shot dribbles out the barrel, then subsequent shots seem just fine. Haven't, as of yet, ascertained whether it's valve related (doesn't appear to be) or if it's in the hammer/striker assembly. I'll have to get back to this one in a while.

Since the Taig had the milling adapter set up, I squared up the vise jaws and scratched one project off.

Here's the Daisy 790. It works as is--thanks to a trigger from long-time Daisy repair guy Jim Coplen. Jim isn't online yet, so call him at 507-281-2314. He's in Minnesota, so don't call him at 3AM.

The Daisy 790 is the same gun as the Smith & Wesson 79G.

But mine has a really weird problem. There's an alignment issue that a past owner tried to correct. The loading trough has been drilled out to 5/16" and the bolt body ground away on the sides. The bolt fits off center to the left--and aligns correctly with the breech--but the oversize trough is a challenge with tiny .177 cal pellets. Not sure what I'm going to do with this one yet. Maybe just shoot it as is. Anyway, this was also moved to the back burner.

...Which brings me back to the IZH 61. The upgraded diopter sights are great, but after adding an anti-glare tube to the front sight, I wanted one for the rear sight as well. After looking at the rear sight unit, I think there's enough thread depth in the block for both an anti-glare tube and the aperture, too.

Started with a piece of 5/8" diameter aluminum rod.

Turned down an end to 8.95mm.

Technically speaking, hex dies aren't for cutting new thread--they're for "chasing" or cleaning up existing threads that are dirty or damaged. Round, adjustable dies are for cutting new threads--except I didn't have one on hand in M9 x 1mm. Since I was just cutting soft aluminum, I think the hex die will be fine. The die holder for the Taig lathe, however, is designed to hold 1" round dies. I had to get a bit creative to hold the hex and mounted up the milling adapter and used the milling vise as a holder.

This set up held the die perpendicular to the round stock. I was able to position the die then start the thread by hand turning the lathe jaws.

After cutting the thread, I spotted with a center drill and through drilled.

More very soon.

Jeffrey Corton’s Diana Seal Tool

As you can probably tell, I’m in the midst of Holiday craft selling insanity and haven’t had time to play with the Rochesters or any other airguns lately.

A while ago I received the following pictures from Jeffrey Corton showing his extremely simple (as in, "why didn't I think of that?"), no machining required version of the seal tool I made for the Diana pistol piston seals. Also scroll down to the bottom for a nice solution to the Crosman model 38 valve tool as well…

All pictures and text by Jeffrey Corton, thanks a bunch Jeff!

1. Parts: seal, electrical end cap (large end diameter slightly larger than piston crown), O-ring, 2" socket extension and socket (slightly wider than the electrical end cap).

2. Work seal over small end of cap.

3. Set end cap inside O-Ring. Press seal using extension/socket down to O-Ring. O-ring is simply present to prevent seal from sliding off the end cap.

4. Final position of seal and end cap.

5. Place end cap over piston crown.

6. Using extension and socket, press seal over end cap and onto piston. Picture has seal already installed and one set to go.

7. Seal pressed in place.

8. Remove extension/socket and end cap should be free.

9. Tada, mission complete.

As promised, a bonus for the Crosman Model 38 valve:

"Don't have a cool lathe like you, so I had to figure out another way to unscrew the Crosman 38T Valve. So: snap ring pliers. See attached pic. I just used the 90-degree attachment, didn't even attach the ends to the plier handles. Just set them in place and twisto-presto. Easy peasy lemon squeezy."

Thanks again Jeff!

Insane Weights for the Aeron

My wife was shooting the Aeron B96 a few weeks ago and found it to be a bit too heavy. Removing the weight was helpful, but now it's too light at the muzzle. I wondered if there was a compromise.



The factory supplied steel weight is 24.5mm in diameter, 24mm long, and weighs 78 grams.

Before she shot it, I was actually using it with two 78g weights attached. The weights slide onto an 8mm diameter rod and secure with a single M5 setscrew. The weight(s) can be located anywhere on the rod and fixed to achieve the balance characteristics that the shooter wants. A slightly heavy muzzle is often preferred.

I cut a piece of 7/8" diameter aluminum rod to make some new (light weight!) weights.

Faced off the end then skim cut to get a nice finish.

Center drilled.

Then gradually through drilled.

5/16" is pretty close to 8mm. Turned out to be an OK fit.

With a parting tool, I cut off a 24mm long cylinder. There's 0.250" rod in the drill chuck to catch the piece as it's cut through.

Another view. Was pretty liberal with the cutting fluid.

Here's the piece "caught".

Cut two more weights--each 12mm long. At this point, the quick part of the project took a turn and became an exercise in machining. Sometimes, easy is too easy. I wanted the two smaller weights to equal each other exactly and I wanted them together to weigh as much as the single large weight. Why? Why indeed. It's for an airgun. What else can I say?

After deburring, it was a matter of weighing and facing and weighing and...Until they were very, very close.

Found center lines on each, and spotted, drilled, tapped M5 x 0.8mm for setscrews.

Started the threading in the drill press for alignment, finished by hand with a plug tap. After sorting through the bin of M5 setscrews, I finalized the weights--with the deburring tool. They were that close. The largest weighs 20.6 grams. The two smaller, half that, at 10.3 grams each.

Since this was already pushing the absurd for a couple aluminum tubes, I hand-stamped the weights into each piece then gave them a brushed satin finish.

Installed.

Gapped,

or scrunched together.





This just might be the project that clearly shows just how far wrong I've gone. And the weights are closer than a tenth of a gram.

Rochester Disassembly, Part 3, Valves #2-#5

So left confused by the fact that the valve was soldered to the tube on the first Rochester, I disassembled the other 4 rifles…

Rochester #2. This is the 2nd best one.

The butt stock is actually in better shape.

Receiver.

Missing screws in the barrel band though.

And those are unlike the screws used in the other ones.

Roll pin instead of a solid pin.

Different pump head. Just a little grease…

Pump head.

The nut that retains the hammer spring is different.

Nut, spring and hammer sleeve.

All the other Rochesters had this type of nut, and only one nut.

The valve on this one is soldered to the tube as well.

You can see the smearing of solder on the brass.

So I took apart another Rochester, #3. It’s also soldered but has a brass ring as well. Not sure why.

The 4th valve wasn’t soldered, as far as I could tell. However mechanical means would not unscrew it. It seems to have a cement-like substance between the halves. Probably need heat anyway.

And the fifth valve is soldered to the tube.

Here’s the valve from Rochester #1 again, just so the valves are all on one page.

So four out of five valve assemblies are soldered to the tube. Next up it to make a vise block that snugly fits the valve body and a wrench that fits the tube (somewhat like a barrel vise and wrench), then use a propane torch to heat up the join and see if I can unscrew the halves. Sounds like fun…