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.

Friday, December 25, 2009

Daisy 717 Repair Part 3 Final

Wow, only four seals in the old gun and it almost made me bang my head against the wall. The joy of damaged pneumatics.

Daisy got a new 717 barrel/valve assembly to me in only three days. Thanks Daisy! It arrived on Christmas Eve via first class USPS. I considered upgrading to the Lothar Walther barrel of the Model 747 but it was about $33 more dollars compared to the standard 717 barrel priced at only $17. Though, if you think about it, a Lothar Walther barrel for $50 is a good deal. Still, my 717 was broken and the outcome was unknown, so there wasn't much incentive to spend the extra coin.

Old barrel on top. There's a flat on the old barrel near the muzzle. New barrel has no flat yet retrofits just dandy.

A bit concerned when I saw the flakes of material in the leade. Was only some black paint flakes left from the masking. Came right off.

This is the original 717 valve seat. It was made for the early cone-shaped check valve. Daisy still uses this same casting but puts a small beveled edge on the hole. I didn't find any other differences in the valves.

Installed the new assembly and all seemed right in the world. The old stretched casting was indeed allowing the valve to move backward under pressure and leak through the breech slot in the compression tube.

A day later, I heard a tiny hiss as I charged the pistol. A much smaller leak than before but it was there.

I left a comment at the end of Part 2 to Bobby about making some shim washers...

Just cut them with a pair of snips from some thin scrap on the bench.

And installed them in the forward portion of the locater hole. The right side plate (Daisy's part number 717-10) has a protruding stud that fits into this hole. All the compressed air pushes against the stud. Like the original valve, the stud is apparently damaged slightly, too. Forced slightly backwards from an over extended pump assembly.

With the shims packed in the front of the hole, the valve is pushed slightly forward into the compression tube giving the o-ring more support. Talking about a few thousandths here. And that's all it took. Problem solved. I looked hard at the stud and really didn't find any obvious damage but it must be bent backwards ever so slightly. So there it is. I thought the gun had one problem with the check valve and the gun actually had three issues: bad check valve, stretched hole in the valve body and bent locater stud in the right side plate.

The gun chronographed consistently in the 360 fps range with .177 cal RWS Hobby pellets. After leaving the gun charged for 15 minutes, it clocked 362. If I do get another leak, I'll just stack one more shim in the hole. Ideally, the seal on the valve face would sit deeper inside the compression tube by another 0.050" or more. If so, the gun would likely never have developed the leaks that it did--even with the stretched holes in the valve.

I think the gun is a prime candidate for some custom grips. We'll see what happens.

Monday, December 21, 2009

Daisy 717 Repair Part 2

Before I get too far ahead, I installed the new foam wiper seal and the o-ring piston seal. Got 'em from Daisy a few weeks ago for a dollar.

One whole dollar nets you two o-rings and a foam ring of the correct size. I bought 3 kits just for the novelty of having spares.

Screwed the piston head back onto the body and reinstalled it into the compression tube.

Coated all the mating surfaces with moly...

and bolted it back together.

Back to the valve. Popped off the snap ring

The exploded valve. Original seals are on top. Replacements scavenged from various o-ring kits are below. The o-ring on the left for the body of the valve is a #012 And the small stem seal is a #005.


Put it all back together and it still leaked. Super. Just for kicks, I then installed the new style valve. As I expected, it leaked.

The pump assembly does not need to be disassembled to get the valve out of the 7XX guns. Just the three phillips head screws on the left side of the shroud need to be removed. Pull the grip frame off and it all comes apart. I can get the valve out now in under 60 seconds--blindfolded. Then I took the valve apart. Again.

Sure, no problem I'll just clean up the valve stem seal on the lathe.

Matched the angle and literally just dusted the surface with the cut.

Reassembled. With teflon tape this time, too--just for good measure. Yep. Leaked. Not to be outdone, I'll just add an o-ring to seal the valve...

Cut the stem seal down to fit a R-01 o-ring.

And gorilla glued it in place.

Like so. Reinstalled--Reassembled--Leaked. It slowly occurred to me that it maybe wasn't leaking from the valve after all. I held the barrel assembly in the compression tube with a tight fitting drift and cocked the gun. It held. Moved the drift slightly and it leaked. The o-ring on the face of the valve is allowing blow-by.

Removed the ring. Looks fine--actually it is fine. It's brand new from the one buck Daisy seal kit. Then I saw the problem.

If you look carefully at the round hole in the casting you'll notice that it's not actually round. It's oval shaped and allows the valve to sit too far back in the compression tube. Only talking about a couple hundredths here, but it's enough to allow air to leak past the o-ring very slowly. Sounds like it's coming out through the transfer port. But, no, it's leaking from just in front of the transfer port. Thought about shimming it, then just called it quits and called Daisy customer service. A new barrel/valve body assembly cost $17 bucks. Sold! Good news is that the new body will work correctly with the extra valve I have. And, yes, I ordered another check valve as a spare. Will it work? What else could go wrong? This is why I don't work on airguns for a living... Well, it's one reason....

Initially, I thought the gun had somehow been over-pressurized--maybe someone attempted multiple pump strokes to get more power. But Nick hit it on the head. A previous owner over-adjusted the piston stroke and it levered the valve backwards on the closing stroke. Yeah, I need a new part.

Note to 7XX owners: The lever should close with just a bit of resistance. The parts are soft. Be careful.