Just some of this and that

I see this is post #450. Not sure if it's any kind of milestone, but congrats to my friend Nick nonetheless.

I've been working on airguns here and there, but don't have much that I really consider noteworthy--mostly because it's stuff covered previously--or it's just rather mundane. Probably even mundane stuff previously covered. Oh well, gotta go with what you've got.

Number ONE

7/8" HSS double-ended ball mill. Need it for one of those "future" projects. Bought it a few weeks ago because it was the right price for what will likely be one-time use. Problem? I don't have a machine capable of using it unless it's single-ended. About an hour (and three cut-off wheels) later, I cut through it without somehow hurting myself. What a super deal.

Number DOS

Looked at some guns online again (this passes for research) and finally settled on what I want grip-wise for the old Crosman 150. As I've been meaning to make grips for this gun for four or five months, this is a positive step forward.



It's a Bolivian rosewood.

Number Thrice

Didn't like the glossy black Crosman grips on this one. But I wanted black grips. Those guys on the Crosman Forum are right. Truck bed liner, TBL as they call it, feels great.



Two coats and the grit in the finish feels much better than stock.

Number Four

Didn't care for the bolt handle on a beater Crosman 2040. Knurled a scrap of 0.250" diameter drill rod.



Turned down here and there for breech slot clearance.

Cut the #8-32 threads.

All blued up and installed. The sharp-eyed will notice that this is not the same gun pictured 5 or 6 images above. I sprayed these grips with TBL, too.

450 airgun posts! Thanks again to all our readers.

More good stuff in a few days.

Benjamin 3030 Reassembly, Part 1

Putting it back together…for now…

Drilling the exhaust seal.

Turning the OD.

Facing.

Boring for the screw.

Cut off, next to old seal.

Not too happy with the face.

Inserted a new o-ring in the valve body.

Reassembling, used a spent CO2 cart to push the innards in.

All together. It works…but not well. The valve is staying open far too long, leading to that dreaded “braaap” sound and only yielding 10 shots per cartridge.

I forgot the screen,maybe that’s the problem? Nope. Didn’t change how it behaved when I replaced it.

The barrel comes back pretty far to knock open the valve. Perhaps I’ll try a shim between the hammer and valve and see if reducing that depth helps.

Also the valve seat is worn, probably a good idea to clean it up.

The holes the piercing pin makes in the cartridges is pretty large, I think reducing the hammer strike will also limit that hole, which could be good or may not matter. It’s possible the pin is sticking in the cartridge as well.

The main spring has a rough end. Maybe it’s a replacement?

I substituted a shorter spring. It behaved exactly the same. So at least I know it isn’t that?

I’m wondering if an even shorter spring would be good as that’s how much preload there is – the bolt hole still isn’t visible in the slot. But I think that the valve face could be the culprit. We’ll see.

Recessing the Stock Screw on the Sportsman QB77

Shooting the QB77 the other evening and was annoyed by the stock nut on the bottom of the forend. It's exactly where I want to rest the gun on my offhand. This is, what, the third gun that I've altered this way? I blogged a similar fix on a Crosman 180, but the QB77 stock is shaped differently, and besides, I wanted another approach.

Shot the gun until empty of CO2. Removed the trigger shoe, safety lever, stock nut and "locating stud"--to use the old Crosman lingo for the part.

The QB locating stud is double threaded. M6 x 1mm at the valve end, M7 x 1mm at the nut.

The hole through the stock is about 5/16", and since the gun is made in China it's safe bet they used an 8mm bit.

Forstner bits

A 5/8" is close (or maybe even the same) to the diameter of the counterbore for the washer and stock nut.

Clamped the stock to the drill press table and aligned by guesstimation and pure, unadulterated luck.

Deepened the factory counterbore.

Ran the forstner bit at a fairly high speed to help prevent tear outs in the wood. The bit also needs to be nice and sharp for a clean cut.

Probably a good idea to treat the bare wood with something.

Looks like a pretty good match. After it dried, I gave it a good slathering of Danish oil.

Need to make a couple parts--a screw cup to fit into that counterbore as well as a new locating stud. Gonna use a piece of aluminum for the cup. Normally, I'd use steel and blue it, but polished aluminum will work since the stock sports an aluminum Morgan buttpad. Found a scrap of aluminum rod buried on the workbench.

Turned down one end to 0.621". Dang.

I wasn't paying attention and missed my (self-imposed) target diameter by 0.004". Flipped the piece around and turned the other end to 0.625".

Second time was the charm. Spotted for a through hole. Set the piece aside and switched to making the new stud.

I'm going to take advantage of the 8mm through hole in the stock. Since 5/16" is almost exactly 8mm, I cut the head off a long 5/16" bolt and faced the end.

Threaded one end M6 x 1mm to fit into the valve. Original stud is below. Cut the thread to length.

Cut down and faced to OAL. This is the gun stock end of the stud.

Spotted-n-drilled with a #19 bit about 3/4" deep.

Tapped M5 x 0.8mm. Cut a shoulder at the base of the M6 (valve end) thread. The shoulder was cut to 7.09mm diam.

Back to the aluminum screw cup. Through drilled.

Then drilled a countersink for the head of a M5 bolt.

Locating stud.



Installed. That shoulder is a nice tight fit in the hole through the gas tube --the valve won't ever shift backwards under gas pressure.

Another view. You can see the M5 x 0.8mm threads in the stud.

Sits just below the bottom of the counterbore in the stock. The new 5/16" diameter stud is a snug fit in the through hole. Much better fit than the stock stud.

Left the screw cup a few thou long for fitting to the contours of the forend. A bit of dykem layout fluid...

and the cup is pressed home. Used a scribe to trace around the cup where it stands proud.

Should have used the drill press and a tiny sanding drum, but it was 10PM and I didn't feel like going out to the garage. Yep, lazy. Used a cratex wheel in the Dremel. You can see the scribed line in the dykem.

Getting there. Marked the inside of the screw cup. No way are the stock contours symmetric, so the cup is actually directional.

Sanded to just below the line. A test fit showed a high spot here and there. The cup was gradually worked down until I was satisfied, then sanded out and polished.





Don't think the bolt head is finished to the same degree as the cup. I'll polish it and re-blue when/if I refinish the stock.

It blends well and matches the polished aluminum plates on the Morgan perfectly. Most importantly, my offhand is happy again.