Saturday, October 30, 2010
Grips for the Crosman 150 Part 2
It's important to do this sooner rather than later. If you contour the grip to shape, then try to recess the screw head, you risk tearing out the wood. By cutting the counterbore first, any tear out will be sanded off during the normal grip shaping. As usual, a forstner bit was employed to cut the flat-bottomed hole.
Test fit. The original CR150 grips are too small for my hands--especially at the heel, so I left some excess wood for fitting.
I'll add another piece of wood in the back as a filler a bit further down the road.
Gonna shoot for some symmetry this time around. Locked both grips together and sanded the bottom of both sides as one piece.
And made the area at the backstrap a uniform curve as well
Worked the heel down a bit to get it closer to final size.
Then went back to the belt sander and started making rooster tails of rosewood.
Used a charcoal dust mask and eye protection. Remember that exotic hardwoods can cause serious allergic respiratory reactions in some people.
The belt sander was great for quickly getting the grip contours roughed out. I just winged this and compared sides as I worked away.
More shaping with a sanding drum.
It's starting to look like a grip.
More to come.
Thursday, October 28, 2010
Still Messing With the Benjamin 3030
I’ve been busy with my visiting family but I did mess around a bit more with the Benjamin 3030.
There’s about 1/8” of slack between the point where the cartridge is contacted by the piercing pin and the hammer. Thus the valve opens up a lot more than I think is needed.
So I made a rubber spacer…
Installed.
It still pierced the CO2 cart, but not as much.
However the spacer slid and got between the hammer and the trigger (you can see the indent).
There’s a hardened steel insert in the hammer that the trigger engages. I only got a few more shots over the paltry 10 I was getting though so I pronounced it a failure, at least for now.
Then I thought about the hammer spring. Right is the “original” but probably not stock hammer spring. Center is the replacement I dug up, and left is an even weaker replacement I found in my big box of springs. I may need to make an even weaker one.
I also added an o-ring to the valve where it contacts the tube. I doubt that’s why there’s a groove there but I noticed that the valve was sliding back and forth a but as the hole in the tube that the screw sits in was larger in diameter than the head of the screw. Obviously the solution is to make a screw with a larger head…
Anyway I managed to get 20 shots with the weaker spring. Which is not a success, but lets me know that I’m on the right track. I think if I keep the valve from moving altogether I may see a slight increase as well. I think the hammer hits the valve, knocks open the seal, but then the entire valve body rebounds and bounces a but, preventing the seal from closing in a timely fashion. Or I could be wrong, which is likely. I also suspect that gas is leaking around the barrel, through the valve body and into the space between the hammer and the valve body, as well as the shot tube – sometimes the bbs bounce out of the loading port, but I don’t know if it’s the rebound or a gas leak.
The goal is the advertised “up to” 30 shots, so if I could just get it up around 25 I’d be happy. I still need to run it across the chronograph but it’s been raining for a week.
Tuesday, October 26, 2010
Grips for the Crosman 150 Part 1.5
Top edge of each grip is sanded flat on the belt.
Put the grip on the frame, pushed that flat edged against the gas tube then pressed it down hard. The small protruding boss of the trigger pivot pin left a slight mark on each side. Drilled a small hole for the boss at each mark then spotted and through drilled for the grip screws. Yeah, I'm glossing over, but I've done a bunch of grip posts and everyone is probably asleep by now.
A couple #6-32 screws and the grips are on.
Has a certain BSA 240 Magnum look to it right now. That'll pass. With the grips on, I traced around the frame then went to a drum sander.
Sanded up to, then just slightly beyond the traced lines.
Only fitting the top of the backstrap and most of the frontstrap for now. Not sure yet how much excess to leave at the heel.
Not quite committed. There's still enough extra wood to provide possibilities.
Already looks better than the original grips.
More soon.
Friday, October 22, 2010
Just some of this and that
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.
Tuesday, October 19, 2010
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.