Tuesday, December 7, 2010
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.
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.
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.
Monday, December 6, 2010
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.
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…
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…