Just a quick post tonight.
The other day, I was taking apart a Crosman 2240 pistol and I thought the stupid tiny #4-48 breech screw should be replaced. I went to my spare parts and found I was down to two. Used to buy these screws right from Crosman, but with the Daisy/GAMO buyout, I think that option is now gone.
With all the Crosman CO2 guns around here, figured I'd better come up with a new source.
Let's face it, #4-48 just isn't a common fastener size. Crosman was essentially forced to use such a fine thread due to the thin gas tube wall thickness. To make it even harder to source, Crosman spec'd a low profile head--pretty much guaranteeing that this is a custom fastener. These just don't exist at the local hardware store/home center.
Let's face it, #4-48 just isn't a common fastener size. Crosman was essentially forced to use such a fine thread due to the thin gas tube wall thickness. To make it even harder to source, Crosman spec'd a low profile head--pretty much guaranteeing that this is a custom fastener. These just don't exist at the local hardware store/home center.
That micro 0.050" hex wrench is icing on the cake for a bad experience. Over torquing the tiny fastener--or wrench-- is pretty much inevitable.
Yeah, I pretty much hate this fastener. I usually treat these screws as single use. I'd much rather burn the dollar they cost than have to remove a stripped, stuck screw in a gun.
In an effort to solve my shortage and not have to think about this again--at least for the forseeable future--I bought a 25 pack of #4-48 BUTTON HEAD CAP SCREWS from McMaster-Carr.
Of course, the button head is a bit too wide in diameter to fit into the counterbore in the Crosman breech.
Here's the button head vs. the low profile socket head.
The button head is about 0.208" diameter vs. 0.180" of the original Crosman spec.
Made one of my fancy thread holders.
And a #4 nylon washer for standoff.
The Taig lathe makes short work of problems like this.
In a few seconds, the head diameter was reduced to a functional size. Don't need to hit the 0.180" diameter to the exact decimal. As long as the head fits the counterbore recess of the breech, it'll work.
Since I was still feeling all fancy from making the thread holder, I blackened the head and called it good.
As a marginal benefit, the button head fastener takes the next larger 1/16" hex wrench. The (.0125") larger wrench size feels gigantic in comparison.
No lathe? I just chucked one of these screws in a DeWalt cordless drill and reduced the head size with a small file in a little over 3 minutes.
More soon.
2 comments:
I picked up a few of those in my last order from Crosman a few years ago, but never have liked that easily stripped out head. That's a good tip on the McMaster source, will need to give that some consideration "just in case". So far I've not heard if Crosman's sticking to their old model of supplying parts for their guns, or if they've gone the way of Daisy with "parts only available in the form of a new gun purchase". :-D Gone are the days you could contact Daisy for a parts list then send in the funds to receive something like a rebuild kit for a Daisy 880 (something I did back in the early 80's, wore that 880 out twice that way). Crosman has always been better at parts supply and I've a decent stash of some of the more commonly required bits and bobs for their CO2 and pump pistols. Haven't worked up the courage to call and see if I can place an order since the take over.
Genial! soluciones rápidas a problemas fastidiosos!!!
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