Wednesday, January 12, 2011

A Spare Magazine for an Aeron B96 Part-2 Final

Back to the Aeron magazine.

Bolted a couple 1-2-3 blocks together and placed the original mag against the soon-to-be. This arrangement kept things relatively square while I marked the angle across the corner. The angle appears to be for ease of insertion into the mag carrier on the gun. Not shown: milled and finished the angle.

I set up the original mag in the milling vise and used it to set up the quarter round cut. The depth of this cut indicates the mag in the carrier. I used a depth micrometer set against the lower fixed jaw on the vise to position the work in the same location.

Used a 4mm end mill then test fit the mag in the gun. It was a good fit in the carrier. A bit tighter than the original.

Not exactly an epiphany, but I've been thinking a lot about how to mark off the pellet hole spacing on the mag. It occurred to me that I could simply remove the barrel...
and just use a transfer punch to mark directly though the breech.

Put some layout fluid on the face of the mag, then slid it home.

Lucked out and had a punch that fit the breech like it was made for it.

Tap, cycle the carrier manually. Tap, cycle the carrier...

Testing: Drilled some aluminum with various sizes of bits then tested .177 cal wadcutters in the holes. No real surprises here, but I settled on a #16 bit for final size.

A pointed indicator is used to locate the center of the hole...

then it's replaced with a bit and through drilled.

Then back to the indicator for the next hole. Slow, but it worked.

Opened the holes up to #16 (0.1770").





Used a #15 bit in a pin vise to chamfer the breech side of the mag to allow the pellet skirt to seat flush.

A small groove cut with a 1/4" ball mill marks the side to load.

Front view. Test firing was surprisingly uneventful. The darn thing functions and the pellets go into a little tiny single hole on the target--??? I am utterly astonished that this even cycles--let alone works. Oh, the bottom mag is the new one. I'm absolute proof as to the old saying about blind pigs and acorns.

Rochester Disassembly, Part 5

With the valve apart it’s time to make some changes.

01121101

The internal valve body threads are 27 tpi, as best I can figure. I was hoping I’d have a tap to clean the threads out but it was an odd diameter…

01121102

So I used a pipe tap as a scraping tool, following the wall around to clean off all the schmutz.

01121103

The plug was cleaned up with a thread file.

01121104

Now it screws together easily.

01121105

Whatever the old seal is, it has to go.

01121106

I made an arbor to hold the plug on the lathe. A rubber washer protects the inlet valve seat.

01121107

Parting tool set up to make an o-ring groove.

01121108

Turning the groove.

01121109

Test fitting an o-ring

01121110

Doesn’t screw quite all the way on, but that will be addressed…

01121111

Cleaned up the face of the plug while I was at it.

01121112

Like new!

01121113

I needed to bore a recess for the o-ring in the valve body.

01121114

Just enough to get down to the thread root.

01121115

Seems to go together snugly.

01121116

The solder filled a groove at the end of the threads on the valve body. I turned away the solder until I just hit the brass.

01121117

Test fitting it to the tube. Aligned, the gap is too large, but I suspected the threads in the tube needed more cleaning.

01121118

You can see that the slot and the setscrew hole need to be aligned.

01121119

After cleaning out the tube threads a bit more the gap is acceptable and similar to the assembled versions…

01121120

I also made two seals for the inlet and exhaust valves. They may be too thick (.125”) although the old ones are so deformed it’s hard to tell how proud they should be. I’ll try them like this and modify as necessary.

Next up is the pump plunger, then figuring out how to keep the tube aligned and sealed to the valve body without resorting to solder. Then reassembly…