Saturday, November 21, 2009

Derrick's Two-Tone FWB 124

I did the work on my Feinwerkbau before I started writing for the blog. As a result, I have no notes and don't have many of the images that I'd like to have for a blog post. Specifically, I don't have a single "before" picture. If you can simply imagine "beat to all heck" you've got the right idea. I've put off writing this post largely because of that, but the 124 is such a classic rifle, Nick and I thought we needed something tangible here.

Complete with backstory: My very first air rifle was purchased used from a gun shop back in the mid to late 1980's, a Feinwerkbau 124D. Years--and many other air rifles later--I sent the FWB off my good friend, Jerry, on long-term loan. At the time, I really didn't care whether or not the rifle ever came back. Then, a year and a half ago, I lost all my field rifles in a burglary. Weihrauchs and Air Arms: gone. When Jerry heard the news, he immediately said he was returning the FWB. Insisted, in fact. I'd practically forgotten about it as I hadn't seen it in at least 15 years. Anyway, I was traveling and it would be a couple weeks before we could make the connection. In the interim, and partly to console myself over the loss of the guns, I bid on--and won--a handmade walnut stock offered on from S. Ionescue. Figured I'd dress up the old girl.

Then the rifle showed up.

The gun was cocked when I picked it up. Probably had been for a decade. The compression tube was missing about 30% of the blueing and rust had set in. Luckily, the barrel/breech block assembly cleaned up and looked OK. I was dejected at the thought of dropping this ugliness into a handmade stock. The cost for a re-blue was steep yet do-able, but would push the time frame back another month or more.

I test-fired the gun over the chrony and the pellet didn't even leave the breech. Absolutely no compression. The piston seal had disintegrated.

I disassembled the rifle (yep, no pics) and dug the remnants of the seal out of the compression tube. Wax like chunks. Note the moly on the seal. The gun had been tuned before it was given away. I've read about the FWB 124 seals deteriorating, but this was my first experience seeing one.

The mainspring had taken quite a set as well as some cant.

In my pile of airgun parts was a complete FWB 124 rebuild kit purchased from Beeman probably in about 1990. The spring on top is the one removed from the rifle. Lower is a new spring. Looks like the old spring is 1.5" shorter. Even with the FWB rebuild kit, I wasn't interested in installing a piston seal from at least 20 years ago that we now know will fail due to age. I ordered a Maccari spring and seal kit and waited.

With the gun in pieces, I tried to refinish and salvage the compression tube. Couldn't get a cold blue to look even halfway decent. Tried at least 3 brands. Finally gave up and thought about the 2-tone Beeman commemorative HW rifles from the early 90's. A call to a couple of my machinist friends got me the name of the best chroming shop in the area. Akron Plating is less than 10 blocks from my house.

I took the compression tube down and explained what it was and what it does and had it hard chromed. Not nickel chrome--that's for Harleys. More subdued, it's sort of a light gray satin finish.

They did a great job leaving the lettering clean and sharp.

Absolute relief when I picked it up. The chrome finish was flawless.

The Maccari Mongoose spring is on the bottom. Shorter than the FWB springs, yet it promises more power. I don't remember if I asked Maccari to set the spring before he shipped it to me. He offers to "set" springs for $1 each. It compresses the spring slightly and can make initial installation easier. It's most likely that I didn't ask, as I've got a brute of a spring compressor.

Touched up the safety and all the small pieces as needed with cold blue.

Looks like a lot going on, but it's a pretty straight forward gun to repair.

Spent a lot of time polishing everything. This is the cocking shoe.

Piston was especially smoothed at the rear where it can drag inside the tube.

Wanted to tighten the fit between the ID of the piston and the OD of the mainspring.

Cut and deburred a piece of sheetmetal.

Found a dowel that's about the same OD as the spring.

Formed the sheet around the dowel.

Worked slowly and carefully to avoid folding or wrinkling the sheet metal.

Trimmed to fit the slot for the cocking lever. This was a "try and see" approach.

Pretty much got it to shape.

Carefully pressed into place.

Installing the spring will finish seating the shim.

Today, most spring guns use a separate spring guide. On the 124, it was machined as the forward end of the trigger housing.

Another shot of the pison

The Maccari seal was a really tight press fit.

This is the power plant.

You can see how much longer it is than the compression tube. Remember that the fork tangs on the tube are almost 2" long and it gets even longer. A spring compressor is a must to fit all this into the tube under some modicum of control.

Flex-Honed the inside of the compression tube. The honing scratches the walls and creates a base for the moly grease to adhere.

Barrel, breech block, cocking lever assembly.

Top view. A FWB plate covers the screw holes from the open sight.

Assembled. I moly'd the compression chamber and the piston seal. The spring got a thin coat of Maccari Heavy Tar to damp any possible spring vibration.

The front sling swivel had to be removed to fit the action into the stock. Required tapping out the rivet for the cocking lever and bushing the sides with washers.

Stock arrived from Ionescue.

The pictures don't do it justice.

Schnaebeled forend.

The edge of the rollover cheek piece is sharp.

Actually, all the features are sharp and well-defined. Exceptional work.

Dropped the action into the stock. It was a very snug fit, but I don't recall doing any wood removal.

Found some stainless steel cap screws

Mounted a Leapers 3-9X40mm scope in a set of medium Accushot rings. I modified the rear scope ring to provide a ball-end scope stop to mate with the 124's cross-grooved receiver. It hasn't moved a bit. I should take the scope ring apart and do a separate blog as it's getting harder and harder to find suitable scope mounts for 124's.

Had a trigger shoe for a 124. The trigger on this rifle is the aluminum blade. I refinished it with Birchwood Casey Aluminum Black.

An old model RWS barrel weight/stabilizer finished off the muzzle. The gun is currently shooting RWS Hobby pellets in the low 860's. Apologies for the rather dis-jointed nature of this post. Wish I had pics of the gun before I started as well as shots of the disassembly procedure. I'm kicking around buying a Maccari trigger. If I order one, I may revisit a complete tear-down, but right now, the rifle is shooting better than new and it's hard to get excited about messing with that.

Tuesday, November 17, 2009

Haenel 310 Rear Sight Elevator

Now to get the rear sight working...

Here's my initial only change was to go with a smaller radius on the top.

I punched out the pin.

I did not lose the spring.

I milled a channel in a 14"x1/4"x1/2" piece of plastic. I'm not sure what type of plastic it is, probably UHMW. It is very slippery. So I had to take lots of light cuts.

I rummaged around in my tooling and found this tiny woodruff keyseat cutter, which worked fine for making the undercut slot.

Fits perfectly!

Then I milled some ears on the underside.

And used a 90 deg. vee cutter to make them into wedges. These mate with the vee cuts in the sight.

A small radius relief...

I was going to cut the serrations on the mill but decided it would be safer (slippery plastic...) to use a checkering file.

Not perfect but it looks fine.

Installed and works fine.

Here are some of the tiny cutters I have...