Crosman hammer binding...

[antithesis]

I'll make this as brief as possible. If I wanted to reduce the abusive galling and scraping that is apparently taking place on my 80 dollar pcp tube (disco style, crosman 7/8",) firstly I bored a pocket for a bearing button to reduce friction along the top and reduce lateral wiggle....now after that, I want to avoid doing it again if I can, so could it help if I soften the radius around the rear edge of the hammer so that there is less corner to dig in at the bottom, or should I go the full nine and make bearings in back too?

Even with cobalt and carbide, this was no easy hole to drill....

[KnifeMaker]

For mine, I put two holes in top front (Pockets) 1 o:clock and 2 o:clock.  In rear Two more at 5 o:clock and 7 o:clock in the rear of the hammer. These are blind holes and drilled with 1/8" micro grain carbide end mills at highest rpm. They cut the hardest hammer material like butter. (Best done in milling machine or good drill press with well seated vise).


I then simply pres in nylon or Teflon bearing rod.  I believe this is called and written here on the GTA as the F.I.R.T.H. System.


MIke/Knife

[JPSAXNC]

I radius both the front and back edges of the hammer. But be careful not to remove to much material front the front edge of the hammer, or the sear might not hold the hammer. Another thing Iv'e done is to reduce the vale sealing area, so the valve can open easier, and I can use a lighter hammer spring to avoid galling the tube.

[antithesis]

I radius both the front and back edges of the hammer. But be careful not to remove to much material front the front edge of the hammer, or the sear might not hold the hammer. Another thing Iv'e done is to reduce the vale sealing area, so the valve can open easier, and I can use a lighter hammer spring to avoid galling the tube.

Reduce it? How you do that sleeve it?

[antithesis]

This particular hammer is notched for the rear screw, so I had to come pretty far back ..I made a 3/16 or so hole right behind that and kinda turned down a 1/4 delrin rod down to got the pocket and left a 1/4 head so it will span the slot.

With the clearance notch there is no 11 and 1 o clock in front...only solution I could figure for now

[PoolDoc]

I radius both the front and back edges of the hammer. But be careful not to remove to much material front the front edge of the hammer, or the sear might not hold the hammer. Another thing Iv'e done is to reduce the vale sealing area, so the valve can open easier, and I can use a lighter hammer spring to avoid galling the tube.

Reduce it? How you do that sleeve it?

I believe he means to reduce the OD of the poppet. That should allow easier opening because there is less force being applied to hold it shut.

[antithesis]

I radius both the front and back edges of the hammer. But be careful not to remove to much material front the front edge of the hammer, or the sear might not hold the hammer. Another thing Iv'e done is to reduce the vale sealing area, so the valve can open easier, and I can use a lighter hammer spring to avoid galling the tube.

Reduce it? How you do that sleeve it?

I believe he means to reduce the OD of the poppet. That should allow easier opening because there is less force being applied to hold it shut.

I think that would improve flow but closing force is determined by the size of the throat ... though dwell time can be improved, and again the flow around the poppet

[mackeral5]

how large of a throat are you running?  An observation I've made over the years is that many folks run excessively large throats for their energy levels.  Myself included.  I have several QB valves that are no longer in use because early on I thought bigger was always better.......

If the throat area minus stem is greater than transfer +10% or so the throat is too big and requiring more hammer spring than truly necessary to build equal power....

[antithesis]

how large of a throat are you running?  An observation I've made over the years is that many folks run excessively large throats for their energy levels.  Myself included.  I have several QB valves that are no longer in use because early on I thought bigger was always better.......

If the throat area minus stem is greater than transfer +10% or so the throat is too big and requiring more hammer spring than truly necessary to build equal power....

If you are asking me, I never measured but it's a magnum airpower valve body, so I think standard diameter

[bear air]

Following along on this one. I had issues with this in my Fortitude and hopefully I have mine solved but it never hurts to hear how other people are solving similar issues.

[antithesis]

Following along on this one. I had issues with this in my Fortitude and hopefully I have mine solved but it never hurts to hear how other people are solving similar issues.

I screwed up drilling the pockets so I am turning down the back half and finding something to sleeve the whole back with....with I had filled nylon

[mackeral5]

how large of a throat are you running?  An observation I've made over the years is that many folks run excessively large throats for their energy levels.  Myself included.  I have several QB valves that are no longer in use because early on I thought bigger was always better.......

If the throat area minus stem is greater than transfer +10% or so the throat is too big and requiring more hammer spring than truly necessary to build equal power....

If you are asking me, I never measured but it's a magnum airpower valve body, so I think standard diameter

That's a fairly easy valve to open, I'm surprised you are using enough hammer spring to encounter this binding issue--could there be another problem causing it? 

[antithesis]

how large of a throat are you running?  An observation I've made over the years is that many folks run excessively large throats for their energy levels.  Myself included.  I have several QB valves that are no longer in use because early on I thought bigger was always better.......

If the throat area minus stem is greater than transfer +10% or so the throat is too big and requiring more hammer spring than truly necessary to build equal power....

If you are asking me, I never measured but it's a magnum airpower valve body, so I think standard diameter

That's a fairly easy valve to open, I'm surprised you are using enough hammer spring to encounter this binding issue--could there be another problem causing it?

It's partly cuz I'm using a dead blow hammer, which needs a tiny bit more oomph to get it there, and since I got a small air capacity I run higher pressure....bit mainly I think it's that softer stainless tube against a crazy hard sharp cornered hammer

[antithesis]

Since I messed up and am now sleeving the back half completely I could use some recommendations as to what to use like moly filled nylon or phosphor bronze or the like

[nervoustrigger]

Yes, MDS nylon is pretty much ideal if you can get it bonded properly.  Epoxy alone probably won’t work though.  Drill for 3 pins at approx 120deg apart and that would probably do the trick.  The pins could be cutoffs from tiny brad nails, for example. 

[antithesis]

Yes, MDS nylon is pretty much ideal if you can get it bonded properly.  Epoxy alone probably won’t work though.  Drill for 3 pins at approx 120deg apart and that would probably do the trick.  The pins could be cutoffs from tiny brad nails, for example.

I could definitely make that work, know a good source, or maybe someone who  possibly got a maybe inch or two bar laying around, maybe I'll ask Motorhead idk