F.A.M.E concept, different approach

[SynRodSteve]

First, I want to give props to 22synrodn(Mrod Forum) for his work on the F.A.M.E mod, which I've done in my 25 Marauder.  It works AMAZINGLY well.  I took his idea of getting the hammer up off the tube and came up with the design below.

I am working on a custom hammer with 4 nylon tipped set screws as my 'points of contact' between airtube and hammer.  I am not done machining it but I inserted what I have into the air tube this morning and I think this is going to be awesome.  I also did the FAME mod and it REALLY works amazing, but I wanted something that I didn't have to mess with re-setting (the lug screw washer) any time I removed the hammer (even though it is not really difficult).  I will be testing this new hammer this week

This is the hammer, with the lug hole on top.  The green 'dots' are 10-32 set screws that protrude barely above the surface of the top front of the hammer .  The two holes adjacent to the lug hole (at 40 deg each off center) are access holes for adjusting the bottom rear setscrews.  The theory is that these contact points will have much less friction, and also keep the hammer aligned in the bore.



Here's the bottom of the hammer, set screws are bottom rear.



I've only machined one side of the hammer slot...still need to finish it up tomorrow.  I believe this hammer will be heavier than my stock one as I cannot machine the same length of the cutout due to interference with the set screw and access holes.  Are there any issues with that?



Small hole in counter bore holds a 'tang' on the spring and keeps the spring adjusting nut from turning while adjusting spring tension.  The nut on the other end also has a hole to catch 'tang' at that end

[Hobbyman2007]

Nice work, the heavier hammer has two things that it will change . One is the dwell time of the valve opening , which is ok for shooting heavier lead or if you have a longer barrel . The other is lock time from trigger pull to valve opening ( micro seconds ) which should t really be noticeable . You can theoretically reduce the preload on the hammer spring to reduce the dwell if you're finding you're using more air . Don't forget to use an SSG .

[Taso1000]

Steve,

I don't have a marauder or have ever had one apart in front of me.  From your pictures it looks like because the hammer is short it wants to tumble in the tube.  I've been looking at your hammer and I came up with an idea.

Could you mount outrigger like guides on the front or rear of the hammer to keep it from cocking/tumbling in the bore?

I have attached pictures of a failed attempt at lightening a B51 hammer, please ignore my hack job lol, but the pictures show a trailing support I intentionally left.

Taso

[SynRodSteve]

Hobbyman.  I do have a DIY SSG also based on 22synrodn's design and it works great. Taso1000...the hammer won't tumble as the cocking lug rides in a slot in the air tube.

[SynRodSteve]

The results are in.  Cocking is INCREDIBLY smooth with this hammer/nylon tipped setscrew combo.  Absolutely ZERO binding or sticking or galling in the air tube...just like butter.  Having said that, I don't think it is markedly 'better' than 22synrodn's FAME mod.  Advantages I see are not needing to 'adjust' lug washer any time hammer is removed (not really a big deal) and no need to machine material from the breach for washer clearance.  Disadvantages I see are simply the effort required to machine the hammer.  We'll see how the nylon tips wear but I'm assuming it will not be a problem.

My string results were NOT as good as with FAME but I believe that is a result of a heavy hammer.  I was not able to machine the 'slot' as long as OEM due to interference with the setscrew holes, therefore, there is more material left on the hammer than OEM.  I assumed I would need to address this but wanted to see results before I removed any more material.  I used the same spring settings as with FAME, but used more air and got less shots.  I'm going to get a scale and drill holes in my hammer (probably in rear face) to get it close to OEM weight and see what that does.

I'm very pleased with the way it came out but like always, will still be tweaking it

Here's the finished hammer:


Trying to show the tip protrusion above the hammer diameter.  I just eyeballed it and fit in airtube until I got as little 'play' as possible while still allowing for smooth sliding of hammer in tube. My hammer is about .015 smaller than the air tube (1.060 airtube, 1.045 hammer)

[aPpYe]

Hi there.  I am really interested in this concept.  I am interested in doing it on a Discovery, however.  A F.A.D.E. mod!  I was also thinking of perhaps going a bit more ghetto by not tapping the holes.  The idea would be to cut some lengths out of some round stock and stuff them in the holes, grinding them down (trial and error) until I get the lengths I need, and shimming them back up (perhaps with bits of paper?) if I go too short. Maybe going short would be a good idea as I could shim with a soft rubber to provide some degree of tension on the tube.   I could go the other way and use some very slightly long, high durometer polyurethane stock for the lengths themselves, also providing tension.  Thoughts?

I figure it won't be too exceedingly difficult to find the right length as there is more than ten thousandths difference in diameter to work with between the striker and the tube.

I had some questions about your design, as I have never seen a Marauder I wasn't quite sure what I was looking at in your pictures.  First, you state that you are only using 4 points of contact.  I realize that it would create some additional friction, but wouldn't having EIGHT (4 on the front, 4 on the back, all 90 degrees from one another) create a more perfectly centered striker?  Or maybe SIX (3 on the front, 3 on the back, 120 degrees from one another)?  An advantage of having six would allow you to have access holes all the way around...

Also, the third picture you have in your first post confuses me because the two nylon tips are diagonal from one another, going from the front to the back of the striker.   Why is this?

Thanks for your time...

[SynRodSteve]

I've found no need for more contact points, and wanted the minimum possible.  All you need to do is keep the hammer off the air tube and this design does that. Not that more would hurt, but they're not needed.  The reason they are at 40 Deg off center is because the marauder has a slot machined into both the top and bottom of the air tube so you can't put one at 12 and 6.   40 deg was just a random pick to get it away from the slots.   Also, if you had 4 and they were all equal 'degrees' apart, there would be no way to access the allen head to adjust them once you had a set screw in the opposing side of the thru hole.   In the third picture, you are looking at the side of the hammer so you're seeing the front and rear nylon tips that are really more on TOP in the front, and BOTTOM on the rear.  If you look closely in that third pic, on the left end of the hammer you can see the cocking lug hole, which on the marauder is at 12:00 on the rear of the hammer.  The nylon tips are roughly at 10 and 2 on the front, and 4 and 8 on the bottom.

[Motorhead]

Very well executed design to get a lower drag assembly. You got some machining skills brother !

As more modern PCP's come to market from around the globe a very substantial trend is appearing ...
LIGHT hammers of very short stroke thrown at valve by quite stout springs having zero preload present.
This lack of preload & stout hammer spring the hammer Does Not Bounce and has the same effect as SSG fitted actions.
Outside of Big Bore guns the use and need for heavy hammers is that of old school design & application.

You may want to try using some 7075 or equivalent grade aluminum for the body of hammer and get weight going the other direction and do some testing .... in some instances Less is More 

have fun ... looking good !!

[SynRodSteve]

Thanks Motörhead. I was wondering about aluminum. Sure would be easier to machine.  The heavier hammer definitely affected my air consumption in a negative way. I haven't run any strings since taking some weight out of it. I'll get to that later this week.

[PBguns]

Yep....I am a LW hammer convert. 7075 is your friend here.
On my .25 I found with my lighter poppet spring really liked being married to a 17g-19g hammer.
 I tried a few different weights (25g & 33g).

I was truly surprised at my results.

[aPpYe]

Hey it worked!  After breaking a drill bit against that hardened steel hammer, I figured out how to properly drill a hole and put eight of them in there, 1/8" deep and 1/16" diameter, all 90 degrees from one another in a sort of "X" pattern, both front and back.  Once the holes were drilled, I put some 3/16" long, 1/16" diameter rod stock in, and started filing them down slowly until the hammer moved freely.  I did them two at a time on each opposing end of the X, as I wanted to make sure I could have the material protruding as evenly as possible on each side ...  After about an hour or so of filing and trial and error, I got the hammer sliding in the tube smooth and free.  The cool part is that I can't hear any metal to metal contact when sliding the hammer.  It is riding on the plastic pins all the way around.  It also feels nice and snug in there when trying to wiggle it around against the tube.

Of course, I didn't think to look up the actual material I was using until after I was done.  I used this fluorescent modeling stock I came across for the pins, which turned out to be is acrylic.  Apparently this is not really intended for wear or friction resistance.  No big deal though.  I am still waiting on parts to put this gun back together anyway.  I have not yet had the chance to actually shoot with this mod ...  I will order some 1/16" stock later today, perhaps acetal or nylon.  Any thoughts on what the best material would be for this?  I see you use nylon.

I can see how supporting only at the top front and bottom back reduces friction when cocking ... The hammer wants to go in those directions when pulling the bolt back due to the pressure on and location of the cocking lug.  Reduced cocking effort is only half of what attracted me to this mod in the first place though.

In the F.A.M.E. thread, he mentions that his ES and SD numbers dropped considerably as well.  This is where I am thinking it would be better to try and center the hammer all the way around.  It is for this reason that I went with eight pins instead of four.  That being said, the most pronounced galling I see on my old tube is actually at the top, just above the valve pin, at the end of the hammer travel.

[SynRodSteve]

Where did you place them relative to the cocking lug?  I don't think you can have any directly on top or bottom due to the air tube slots.  I believe I will see comparable ES improvements with my F.I.F.H (Fame Inspired Floating Hammer) as the F.A.M.E.  I have only run strings prior to machining more material off my hammer to reduce weight to OEM specs.  I haven't had a chance to run it since reducing the hammer weight but I expect great results.

[aPpYe]

Where did you place them relative to the cocking lug?  I don't think you can have any directly on top or bottom due to the air tube slots.  I believe I will see comparable ES improvements with my F.I.F.H (Fame Inspired Floating Hammer) as the F.A.M.E.  I have only run strings prior to machining more material off my hammer to reduce weight to OEM specs.  I haven't had a chance to run it since reducing the hammer weight but I expect great results.

I have them in an "X" formation.  Basically all at 45 degrees away from the top and sides, all 90 degrees from one another.  They are all about an eighth of an inch from the ends.   It's gonna be a solid week (at least) before I can shoot it though, and the gun will be so different than it was before (full length disco tube vs 2250 tube, ported valve, transfer port and barrel, marauder poppet, hammer mods) that it will be difficult to to tell if it did anything really.  I am really looking forwards to trying it out though.

... So what made you choose nylon over something else?  I was considering acetal as well...

[SynRodSteve]

Are you putting this in a marauder?  I don't see how having the buttons at 12 and 6 will work, given the air tube slot.  I believe the tips on the set screws are like acetal etc.  I don't think there are a lot of choices for nylon tipped setscrews.  Having said that, they work great and are easily adjusted.  They are not soft at all and glide nicely on the tube.

[Taso1000]

Gentlemen,

What about molybdenum impregnated nylon for your pins/pillars?  That is the material Scott (Motorhead) uses for his lightweight hammers. 

Taso

[Motorhead]

Issue to be aware of with M-rods is as the upper receiver is tightened against velocity adjuster / end cap and then the rear trigger assembly screw on the bottom ... Tubes are commonly made slightly oval when both are snugged up.
* If the hammer fits too tight it will start to hang up as it's draw rearward cocking action.

Just some FYI ...
Scott

[aPpYe]

Are you putting this in a marauder?  I don't see how having the buttons at 12 and 6 will work, given the air tube slot.  I believe the tips on the set screws are like acetal etc.  I don't think there are a lot of choices for nylon tipped setscrews.  Having said that, they work great and are easily adjusted.  They are not soft at all and glide nicely on the tube.

Lol ... like I said, an X formation.  Think 1:30, 4:30, 7:30 and 10:30, as if I drew an "X" in there to mark the positions...  This gun started life as a CCS 2400kt, but is now more or less a Discovery.  The design does not allow for the fine adjustment yours does, but does allow for eight pins.  I would think you could go with eight pins as well, just at different angles, and to tell you the truth, I was thinking of going with more of a bias towards the top and bottom, say 1, 5, 7 and 11 ...

Gentlemen,

What about molybdenum impregnated nylon for your pins/pillars?  That is the material Scott (Motorhead) uses for his lightweight hammers. 

Taso

That sounds like a good idea!  I am going to be going to mcmaster-carr to check out what they have...  I was thinking more along the lines of something impregnated with PTFE, but I don't know what is available.

Issue to be aware of with M-rods is as the upper receiver is tightened against velocity adjuster / end cap and then the rear trigger assembly screw on the bottom ... Tubes are commonly made slightly oval when both are snugged up.
* If the hammer fits too tight it will start to hang up as it's draw rearward cocking action.

Just some FYI ...
Scott

That's good to know.  I am doing this on a discovery, so the smaller diameter tube will likely mitigate this to some extent, but I would assume the effect is still present once the rear screws are snugged up...  More trial and error ahead I guess.  I suppose I could see how the hammer slides without the spring when otherwise fully assembled...

[SynRodSteve]

Ah....that makes sense.  I'm sure this will work very well.

[SynRodSteve]

Still working on a way to more easily make these.  In the meantime, I made this one.   I used a ball turning tool that I made several years ago to remove weight from the middle of the hammer (instead of the OEM type slot).  I got this one within a gram and a half (heavier) than OEM.  I'm going to look into using nylon set screws so that I can insert them in 4 places around the front and back of the hammer instead of my first attempt with only two on each end.  4 are not really NEEDED, but it can't hurt and will help even further in centering the hammer in the air tube.  With all nylon, I won't need to access them from the opposing side to adjust them, rather I can screw them in from the outside in on all four points.  I haven't put this one in to test yet but hopefully will tomorrow.

Making the arc'd cut in the center of the hammer on an arbor made for that purpose.


Finished cutting


Finished



The tool I used to make the arc

[aPpYe]

That's really cool! Definitely much more elegant than my comparative hack job.  The hammer will rest on the heads of your nylon bolts then?  I was really impressed with how it felt and sounded when I was done.  There was little to no slop and the hammer slid super smoothly.  Adjusting,  I found it easier to go with two opposing sides, getting them as smooth as possible (and even with each other) before moving on to others.  What angles did you choose?  I went with 90deg all the way around, diagonally 45deg from vertical.  I was thinking of narrowing it a bit though, biasing it toward vertical centering rather than horizontal, say at 1,5,7, and 11 o'clock, but I am not sure if that is a good idea or not... I have a new hammer on the way that I can mess with...

I was also thinking of doing this on a smaller scale with my SSG (original version) as well... dragging the spring guide in the gap adjuster is another source of friction...

Another idea would be to drill the holes slanted from your arc so they come out at the same spot they are in now, albeit at an angle.   This would allow you to continue to use your nylon-tipped metal bolts, adjusting from the inside again, and would theoretically reduce contact area even further as the hammer is then only resting on the squared corners of the bolts, though I do not know how things would wear this way ... you could turn the corners down a bit to increase contact area if it is an issue...  I think I am really splitting hairs at this point though.

Man I wish I had a real lathe! I have this little plastic and aluminum Chinese 6in1 lathe/milling/etc machine but it doesn't do metal very well.  Maybe I just need different tooling?  It is definitely not all that precise anyway.  It is why I am sticking with my rod/filing method, at least for now...

Very well executed design to get a lower drag assembly. You got some machining skills brother !

As more modern PCP's come to market from around the globe a very substantial trend is appearing ...
LIGHT hammers of very short stroke thrown at valve by quite stout springs having zero preload present.
This lack of preload & stout hammer spring the hammer Does Not Bounce and has the same effect as SSG fitted actions.
Outside of Big Bore guns the use and need for heavy hammers is that of old school design & application.

You may want to try using some 7075 or equivalent grade aluminum for the body of hammer and get weight going the other direction and do some testing .... in some instances Less is More 

have fun ... looking good !!

I have been pondering this as well.  Keep in mind that I am a comparative newbie, so my thoughts here may be off base.  Cocking effort aside, does it always to spell higher efficiency (tuning for the exact same FPE/FPS) to use a lighter hammer and a stouter spring?  I am thinking this might be so because less energy is required to push the hammer back, and the valve closes faster.  Is the logic sound here?