2240 Power Adjuster / SSG ?

[WhatUPSbox?]

As far as tuning the "iron" sights, this is what I did a while back.
https://www.gatewaytoairguns.org/GTA/index.php?topic=172946

[Frank in Fairfield]

My 2300S came with a black power adjuster.
I bought a SS one from Dave.
I put the black one on my 2240XL..

[WobblyHand]

As far as tuning the "iron" sights, this is what I did a while back.
https://www.gatewaytoairguns.org/GTA/index.php?topic=172946

That's a good idea.  Don't know why, but sometimes I forget I can make things like that.  Thanks for the reminder!

[WobblyHand]

My 2300S came with a black power adjuster.
I bought a SS one from Dave.
I put the black one on my 2240XL..

Very nice looking airguns.

My interest is not in buying a SSG, but making one.  (Machining it.)  Been trying to make one from the diagrams in the SSG thread.  Not quite familiar with the ins and outs of a 2240, so a couple of the critical dimensions are elusive to me.  Slowly figuring it out.

[WobblyHand]

I was unhappy with the screw adjuster, it simply was too loose in the nut.  So I remade it.  Actually I made it twice.  I was single pointing the screw and it was close to being done.  I tried a test fit, and it didn't go.  I took off another thousandth of an inch.  Tried again.  Then I figured it out.  The thread was wrong, I had cut 32 TPI, but should have cut 24 TPI.  Oops.  Cut off the threaded section and started again - this time at 24 TPI to match the tapped hole in the nut!  For both of these attempts I used some 1/2" hex stock to start from.  That way I can do everything on the lathe.  This time I made the head thickness 0.200" instead of 0.250".  Also bored out a 0.250" section to fit the spring.  This means the spring is partially inside the adjuster.  The fit of the adjuster screw to the cap threads is much better with no slop.

The screw adjuster is good now.  I think I want to extend the back of the cap so there is less thread showing, so maybe make the cap about 1/8" longer.

The report is shorter now than with no SSG.  With the LDC all you hear is the hammer moving.  Pretty happy with this.  I need to edit my drawings so I can post them.

[WhatUPSbox?]

Nice!
I'm curious, how much do the moving parts weigh?

[WobblyHand]

Nice!
I'm curious, how much do the moving parts weigh?

The removable part, which includes the adjuster screw weighs 26.5 gm.  The moving parts weight 19.5 gm, guess that makes the adjuster nut weigh 7 gm.  I haven't weighed the cap.

[WhatUPSbox?]

Thanks. The hammer in mine was around 58 gm so about a 1/4 of the spring energy goes into the SSG moving mass. I think I'll try to make one (though not as pretty) and compare it with the simple power adjuster.

[WobblyHand]

There's quite a bit of mass in the stainless steel nuts.  They could be made of aluminum, or titanium to reduce the weight.  I was having difficulty making them narrow enough.  Need a way to hold them square after parting off, to clean up the parted face.  Regular nuts are much lighter.

[WhatUPSbox?]

Not sure what the down side is to SSG mass. Increases the required preload somewhat.

[WobblyHand]

Not sure what the down side is to SSG mass. Increases the required preload somewhat.

I remade the nuts in 6061 aluminum and figured out a way to make them a little it thinner.  They are 0.150" thick now.  Total moving weight is 13.2 gm now.  After knurling, the rod doesn't fit in my 1/2" collet, but it does fit in my 13mm ER40 collet.  I used the excess part of the knurling (made extra) to fill the back part of the collet and butted the 0.150" piece against it.  Then pushed it out so a little bit was exposed for turning.  This allowed me to get rid of the tiny bit left from parting and to flatten the nut.  Worked out ok.  I don't know how well they will hold up, being aluminum, although they are cushioned by the o-ring.  Probably won't last 10M cycles, though.

[Spacebus]

If you keep replacing the o ring why wouldn't they last indefinitely?

[WobblyHand]

If you keep replacing the o ring why wouldn't they last indefinitely?

Aluminum fatigue on the few engaged threads.  Practically, I'm going to run with it, until it dies.  Should be ok.