Thursday, June 12, 2008

A Prototype Barrel Band for Derrick

Derrick wants some custom barrel bands, so I worked on a prototype for him today.

Milling the bores and profile on the Taig CNC mill.

I used the "sprue" technique to fixture the band.

The rough band.

Derrick wanted two setscrews 30 degrees each from the centerline. This meant setting it up 41 degrees and 45 minutes referenced off the flat side of the band. Time to pull out the trusty Starrett vernier protractor. I bought it many years ago at an estate sale that was coincedental to my birthday for $35.00. It must have been 1994 or 1995 depending on whether the sale was a Friday or a Saturday. But again, I digress.

I calculated the distance from the edge of that lug to the drill position and used an edge finder (once again) to find that reference edge.

The drill bit, she was not cutting. Why? because she is a left hand drill bit. Now labelled as such and squirreled away with the other left hand bits.

Now one hole was drilled.

The setup repeated and the other hole drilled.

The hole through the lug was drilled.

Tapping the setscrew holes.

All done. Those are the shortest setscrews I have. Now I have to mail it off to Derrick and see if it fits.

Tuesday, June 10, 2008

Diana Model 5 Disassembly, Part 1

I found the time today to tear into the neighbor's Diana model 5 (branded as a Winchester 353)

Two screws hold both the trigger guard and the grip/stock on the action.

One is significantly longer than the other.

The action separated from the grip.

The pin for the cocking link is removed. When I disassembled the Model 6M, the instructions said that the pin would just slip right out. On the 6 it didn't but on the 5 it was very loose, and somewhat worn as well. I'll replace it.

The pivot bolt lock screw was removed.

And the pivot screw removed, separating the barrel from the action.

Two stamped washers ride on either side in grooves.

The front sight screw was loosened and the sight drifted off of the barrel.

The screw is retained by an e-clip.

The trigger link spring was removed.

And the link pulled out. Just like on the Diana 6M.

The trigger pivot pin was pushed out.

And the trigger and spring removed.

Diana Model 5 Disassembly, Part 2

And on we go...

The piston link was pulled forward and out of the slot.

The piston link.

The trigger adjustment screw (with ball) and locking screw. The trigger screw has a setscrew inside that adjusts the position of the ball relative to the screw...

The sight was removed. One screw was missing. We'll see if I can make a replacement.

The action was clamped in the spring compressor and the locking screw removed.

A strap wrench was used to unscrew the cap, keeping light pressure against it with the compressor. Unlike the Diana 6, the cap on the 5 holds the spring in. So it has force bearing against it.

The cap unscrewed fully and the compressor was unscrewed.

A spacer (which is interesting, I would have thought the spring would have taken up the full length of the tube) and the cap.

Spring guide, spacer, cap and the spring. There was a serious lack of any lubrication.

The piston was pushed out. I'd like to say "carefully", but I ended up skinning one finger on the sharp tube slot edge. Don't they have deburring tools in Germany?

The piston seal was in rough shape.

I'll have to make a replacement.

The dovetail button on the end of the piston.

All taken apart, I'll get it back together later this week.

Sunday, June 8, 2008

Manu Arm vs Diana 5

The topic of plastic pistol "stocks" came up on the vintage airgun forum and both the Diana 5 and the Manu Arm pistol were discussed. Since I have examples of both, I thought a quick comparison would be interesting.

Top, Diana 5,branded as a Winchester 353. In very rough shape on loan from a neighbor. I'll probably be stripping and lubing soon for the blog. Bottom, Manu Arm pistol.

The Manu Arm is a good bit shorter and has a clamshell stock vs. the one piece that is on the Diana.

The Diana 5 is very similar to the Diana 6M I blogged about, with a screw on end cap retaining the spring. I haven't taken the Manu Arm apart yet, but it looks like the end cap is retained by a cross pin.

The Manu Arm rear sight is wobbly. They should have used two posts and one spring, rather than one post and two springs...The Diana 5 rear sight is exactly like the rear sight on the Diana 6

The front sight of the Manu Arm.

The Front Sight of the Diana 5

The stock Manu Arm insert makes it very hard to hit a small target.

A typical Diana front sight blade.

MANU ARM Cal 4.5 .177

So they are very different pistols. How's that for reporting?

Oh, As for velocities, although the Diana 5 is old and worn, both shoot comparably, 408 fps with crosman wadcutters in the Diana vs. 398 fps for the Manu Arm.