Saturday, January 2, 2010

Benjamin Model 132 Pistol Disassembly, Part 1

Happy New Year! I finally had a bit of time to buckle down and tear apart some airguns.

I picked up the lower pistol, a later Benjamin 137 (.177 cal) earlier in the year. Unfortunately it works fine. The upper pistol, a pre-1952 (according to Fletcher's "The Saint Louis & Benjamin Air Rifle Co.'s") Benjamin 132 was purchased in November and happily doesn't work at all! So I'm going to tear into it.

Just a few comparisons. Besides the use of plastic grips on the 137 and some differences in screws, the sight on the earlier pistol is a one piece brass affair, where the later sight is a steel stamping.

The markings on the breech cap are different.

The 137 has the model info on the right side.

The later pistol's barrel seems to protrude beyond the muzzle plug, where the earlier's is flush. Enough of such mundane matters, on to the fun stuff!

The lever hinge pin lock screw.


Punching out the lever hinge pin.

Notice the groove that the screw tip locks into.

I pulled the lever free.

I pulled out the muzzle plug.

A disgusting mess.

I lined up the link coupling pin with the hole to remove it but it wouldn't press out.

Because it's offset...hmmm...

So I used a small diameter pin punch to push it out. A reminder never to force anything.

With that I pulled out the pump plunger assembly.

With the worst wiped off...It doesn't look too bad.

I could not for the life of me loosen this screw...I'll touch on this later.

I unscrewed the pump rod from the link coupling.

And the felt oiler comes off.
On to part two shortly...

Monday, December 28, 2009

Finishing Up the Haenel 311

So, here I go, taking it apart again...So I took some more notes applicable to both the 310 and the 311...

The lesson I've learned: Insert a pin (not a punch, it's too long) to hold the auto safety spring in place so it doesn't spring inside the housing.

As I said, the set screw seems too tall. Perhaps that's keeping it from cocking reliably?

The hole is full of burrs.

So I drilled it out and a bit deeper.

Much better.

I took some time to understand exactly how to reassemble the safety...notice the ball protruding inside. First I inserted the ball and the rubber "spring".

Then I put the end cap on. I have to insert the safety with the flat aligned down.

Here we go...the suspense is killing me...

Notice the pin that retains the end cap is not in place.

The safety pushed home.

Then rotated to pick up the ear on the automatic safety link. The pin was then inserted to hold the cap as well as the safety in position.

I figured I should write down what the two trigger adjustment screws do. A is a screw adjusted spring loaded plunger on the trigger. B is a screw that determines sear engagement.

Location of the screws.

The only obvious problem beyond that setscrew was that the trigger guard screw wasn't, um, screwing in.

Threads are stripped.

Thankfully the threads in the trigger housing were fine.

Rather than spend a half hour making a screw...I found a longer one in my big box of screws.
Would this solve the problem?

Nope...Neither of those two small problems were causing the larger problem of the gun randomly not cocking.

At rest, the cocking lever is centered in the slot...

When I pull it with a bias to the left, it rotates obviously. Just a small amount but you guessed it...if I pull it straight back it catches. If I ride the left side of the slot it doesn't. I don't see why it would matter but it seems to be the problem. I shot repeatedly without it failing to catch. We'll see if that's all it was over time. I can't see how to tighten things up without a huge amount of work, so I'm calling this done. I learned a lot about the Haenels and now it's time to move other damaged, beat up, ugly and abused airguns.

Sunday, December 27, 2009

Haenel 311 Sight and a Small Problem After Reassembling the Rifle

I had disassembled the Haenel 311 sight a while back and finally found the time to reassemble it. There was a lot of slop in the sight...

The flat plate that covers the guts had a serious dish.

Here's a view after a quick rub on the surface plate against some sandpaper. I worked it until that center section was flat.

I pressed the knobs back in with their balls and springs.

Clean and ready for reassembly...

Except that the sight had a problem in that the piece that holds the iris was too thick now. Which makes no sense as I didn't take any material off of the housing...but it explains why the plate was dished...

So I lapped it until it worked can see there's no visible gap.

Anyway, the rifle was sold to me with the problem that it wouldn't cock I reassembled it not finding anything obviously wrong.

Just as on the 310, the surfaces that the spring contacted were rough.

So more lapping against sandpaper on the surface plate (a separate plate than the one I use for measurements, thank you very much...)

Still a few gouges but mostly flat...

Then I polished them.

I aligned the piston seal screw lockscrew hole...

It seems to stick up a bit proud compared to the 310...hmmm....

Anyway I reassembled it easily and it seemed to work fine...until I there were several times when it wouldn't catch. It seems to happen I have to take it apart again.