SpudFiles

Another Gun Show, another classic Crosman joins the menagerie

Not holding air, missing iron sights and with a cracked butt pad but otherwise in good shape.

Interesting "Valve train" on this one:



At first I thought the trigger/hammer mechanism was broken but it turns out that unlike most similar airguns that use a hammer to strike a valve open, the trigger on this one holds a "blow off" valve shut and it's the pressure that opens it.

1) and 4) is the chamber body, with the check valve 2) being held shut by spring 3). Air from the pump comes from the left of the image.

5) is a cup shaped piston that slips over the nipple on the right of chamber 4) keeping it sealed as long as the trigger keeps part 9) in place, locking it through rod 7).

When the trigger is pulled, 5) is free to move to the left of the image through cylinder 6), allowing the chamber to dump through the transfer port into the barrel.

Parts diagram for completeness' sake:



Should make an interesting Winter project, the question is whether I keep it as-is or manufacture a new chamber and valve setup that is more efficient...

I'd vote for internal upgrade, and a small cleanup operation on the outside. Old guns shouldn't look too new, but a little TLC never hurts.

Talking about Crosman guns, a gun store nearby has an interesting 2240 on display. Didn't have the chance to look at it very well, but it looked pretty standard to me, and a small piece of text next to it claimed that it had 15ft/lb, does that sound feasible? The name of the builder also rang a bell

Will get some pictures when I visit again.

Nice find! The 1400 is an interesting and good looking piece with very decent power potential for a pumper. Looking at doing a new tube and poppet style valve for mine when I "get round to it". Some of them have nice grain on the stocks hiding under the factory finish...




@ Lab...15ftlb from a 2240 would be far from stock...who built it?

@ Lab...15ftlb from a 2240 would be far from stock...who built it?

I did some searching, and I believe it must be a 2240 built by Quackenbush. Can't find any other 2240 rebuilders

Gippeto wrote:Nice find! The 1400 is an interesting and good looking piece with very decent power potential for a pumper. Looking at doing a new tube and poppet style valve for mine when I "get round to it".

Here's what I have in mind off the top of my head, a slightly unbalanced spool that would have much more flow, allowing the transfer ports to be opened up too. The o-ring on the pump end of the spool would be floating to act as a check valve for the pump.



I would also replace the pump head with a floating o-ring. I might lay if of for a couple of months though as this will clearly push it past 500 fps and I hope to have my PAL by early 2019.

Some of them have nice grain on the stocks hiding under the factory finish...

That looks to be the case with mine too.

Lab...15ftlb from a 2240 would be far from stock...who built it?

With a standard barrel length, 15 ft lbs would imply it's a bigger caliber than 0.22"...

edit: I failed to take into account the fact that pump remains pressurized, meaning that as drawn the spool would not be balanced.

It would have to look something like this:



That or introduce a bleed valve for the pump head.

How will it open if it's balanced? Isn't the unbalanced version better?

I think this valve is better. It is easier to do, it opens faster than the usual opener. The master who made this valve has a very good opinion of him

wyz2285 wrote:How will it open if it's balanced? Isn't the unbalanced version better?

Of course it needs to be slightly unbalanced in order to open (note in the diagram that the spool o-ring diameters are different), but by adding a spool element you can greatly increase the diameter of the opening without a corresponding increase of trigger pressure. Reviews of this model note that the more you pump it, the harder the trigger is to pull and I would want to avoid that.

I think this valve is better. It is easier to do, it opens faster than the usual opener. The master who made this valve has a very good opinion of him

What model is that from? I think it's more useful for a multi-shot, while this pumper is intended to dump the whole chamber every time.

.

I think this valve is better. It is easier to do, it opens faster than the usual opener. The master who made this valve has a very good opinion of him

What model is that from? I think it's more useful for a multi-shot, while this pumper is intended to dump the whole chamber every time.[/quote]
Yes, the master uses it for the semi-automatic, here is the link, only this is the Russian-language forum http://forum.guns.ru/forummessage/30/2001501.html

Ah yes, the Huben. Some discussion here.

Some more thoughts on how I would make this in practice.



The idea is that air from the pump goes through the threads on the endcap and a floating o-ring acts as a check valve.

edit: I made a drawing to scale in the meantime and due to the chamber retaining bolt it looks like a more conventional check valve is going to be required.

Revised design:



Finally got some time on the lathe, turning operations done on the one piece chamber body seen here with the original:



Milling and drilling to follow.

It looks excellent. I have not analyzed the drawings, but I'll do it, but it's luxury!

Revised design as I got the dimensions wrong enough on the first one that it couldn't be salvaged:



One piece chamber waiting for porting:

On the left goes the air pump yes? and go through the small channel?
Another question. How much pressure do you have to shoot, under normal conditions?
The first question was already answered by the drawings. I would just like to know the pressure.