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Stoning the Hammer

267K views 279 replies 112 participants last post by  Toomany22s 
#1 · (Edited)
To improve feel and lighten your trigger pull, grinding/Stoning the the angle on the area of engagement of the hammer is one way to achieve a smoother - crisper trigger. Best of all it can be done yourself for free (if you already have the tools). The tools you will need are stones, vise and a 1/8" drill bit.

In short: Slide the .125" drill bit through the pivot hole of the hammer then set the hammer in a vise so that the drill rod is sitting on both of the vise jaws. When tightening the vise set the bottom of the sear notch in the hammer level with the top of the jaws. Then remove any material of the engagement area that rises above the the vise by stoning or grinding.

This is how the setup should look:


In this pic note that the bottom of the notch is at the top of the vise jaw (red line) to help achieve this you can insert a razor blade in the notch and push down if the notch is too high.


cletus hungwell said:
I do my rough work w/ either a cheap, super course stone, or just use metal cutting sanding belts (i have plenty of those).... when i get down close, i bring it in to final size w/ a medium india, the buff w/ the paper wheel and compound.....

the paper wheel is the slotted paper buffing wheel sold/used by those knife sharpeners at the gunshows...... great product!!!.....firmer than hardest felt, cheap.....you can get them from texas knifemakers supply, jantz supply, or any of the knifemaker's supply houses........ it comes as a "kit" w/ 2 wheels, one is fine gritted, and w/ lube to cut heat, the other is the buff...it comes w/ le homiedou cr51 rouge....good stuff for alot of gun work......will put the "slick and shiny" on most any metal part, if you've got the skills.....

if you don't want to buy the paper wheel setup, just go up through the fine white arkansas stones...it will be fine for your finish!....
Here are some before and after pics, the difference is not very much.



How it works...
cletus hungwell said:
Changing the angle will reduce pull force required..... the extreme negative angle required to keep the hammer from slipping off the sear when it's dancin on it's pin during cycling is what makes the pull so heavy on the stock guns.......if you take a group out of a gun, you can watch the hammer being cammed to the rear as you pull the trigger...... what changing the angle does is reduce the amount of trigger pull force used to cam the hammer backwards against it's spring......the tighter the fit of hammer/sear to their pins, the less negative angle required......

of course, the combination of the two is what you'd go for when you're lookin for precision over reliability.... it's a balancing act, determined by your intended purpose of the group......

cletus
Why it works...
cletus hungwell said:
the angle is determined by a straight line running from the center of the pivot hole to the BASE of the sear notch....that line is 0deg.....

as most pivot holes i've checked have all been .218", that puts the center @ .109" from the edge of the hole....

(using a .125" rod in the pivot hole of the hammer) my math shows this will give a 3.9 degree angle......use the trig function on a scientific calculator to figure these....

it seems to me that the minimum angle needed will be determined by the amount of slack of the hammer/sear on their pins....the tighter the fit, the less angle needed... i do not have any hard numbers on slack vs angle at this time though......


cletus hungwell said:
any pivoting part's 0deg angle has to be a straight line from the center of the pivot point straight out through the edge..... this is the angle that allows sear movement w/o the hammer moving....... we have to add some negative to make up for the slack in the pins/parts.... to get this, we use a 2nd line, a negative angle intersecting the 0deg at the base of the notch......as this line extends past the base of the notch, the material climbs out over the sear nose, and creates the effect of the springs forcing the sear deeper into the notch....... the amount of angle, and the depth of the notch are selected based on intended purposes of the gun/group.....
Some angles to experiment with...
cletus hungwell said:
or, to get the desired angle, use .004" over center per deg....

0deg=.109", or 7/64's
1deg=.113", or a #33 drill shank
2deg=.117", a #32 is .116", add .001 shim under it!
3deg=.121", a #31 is .120, so, add a thou of shim stock....
4deg=.125"

these are approx figures...shim between the pin and the vise to get additional angle adjustments......

later
cletus
cletus hungwell said:
i'm really amazed, and thankfull to all here, for all the help and knowledge so freely shared.... and, i get a special kick out of pitchin in an idea from time to time.....
I couldn't have said it better myself and Thanks to You cletus for helping me understand this whole "sear notch -angle - engagement" thing.

These quotes were taken and edited from the "My Hammer Grinding Jig" by batmanacw and hijacked by cletus, Markbo, J57ltr, a few others and myself :hide:

If you try this method Please post your results!!!

Good Luck & Thanks, MorlyKrupt
 
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#4 · (Edited)
cletus' disclamer

cletus hungwell said:
this is fine tuning info..... it's only good for just that.....fine tuning for YOUR application.......

i'll be the first to say that these have ALOT of safety issues that must be dealt w/ in some way...... some can be dealt with by making adjustments to the parts, some just have to be dealt with by using good technique/sense... and due to how variable these things are, only the person doing the actuall work can know what is and isn't "safe" w/ any particular set of parts... the same as only the shooter can control when a gun is loaded and what it points at

if you're lookin for "lawyer proof" action mods that can be done w/o any regard to safety, THESE AIN'T THEM!!!!!!!!!!!

THESE AIN'T FOR BEGINNERS!!!.... unless you use the good sense to practice extremely good firearms safety, and are prepared to deal w/ the problems if you've made a mistake......

these are toys.....and, there is no reason for anyone to get hurt over them...it just isn't worth it!....

if you have doubt about your setup or the ability to do the mods, you can always print off the info, and take it to your local gunsmith and discuss it w/ him.... discuss your safety and performance needs, and see what he says.. you never know...he may get a much better setup goin for ya, using the same mods but w/ better technique from many yrs of workin gun parts...

these little rifles seem to be "gateway" guns for alot of folks...whether as shooters, or to get your feet wet tinkerin..... parts are cheap, readily available, why not???...... this is wonderful, and is plenty of folks here to help us, but, YOU'VE got to make sure that you do safe and thorough testing of everthing before you place yours or someone else life/property at risk...

later
cletus
and another fine post from cletus! :t ...clicky here for full report
 
#9 ·
Yesterday at work I quickly fashoned a jig that mimics the setup in the top picture. I did this because I do not have a very precise vice at home. I stoned my hammer last night with good results. It lightened the pull considerably. Ill post a quick pic of the jig soon. Thanks for all the info you guys post.

Josh

BTW: Does the hammer need rehardening after this change?
 
#10 · (Edited)
#11 ·
This is the jig I made.







We had some ground stock that was going to the scrap bin because we switched to 420 SS for our dies. They begged to be rescued and put to use. It is just soft steel but I can always grind them flat again when needed. Where did you find a nice vice for that price? Hey that rhymes.

How do you get into the crook of the notch? I stoned what I could then wrapped a piece of 1000 grit wet/dry sand paper around a small swiss file.

Josh
 
#13 ·
jvett said:
This is the jig I made.







We had some ground stock that was going to the scrap bin because we switched to 420 SS for our dies. They begged to be rescued and put to use. It is just soft steel but I can always grind them flat again when needed. Where did you find a nice vice for that price? Hey that rhymes.

How do you get into the crook of the notch? I stoned what I could then wrapped a piece of 1000 grit wet/dry sand paper around a small swiss file.

Josh
thx for the info, josh!!!!.....

i REALLY like your jig for that!!...it should do alot of different jobs, if you can figure how to set it up!!!!

re: stones......i have a couple of triangle stones....a med india and a hard ark that i use alot.. the final finish of the surface will make a huge difference now, because you're actually feeling the sear slide across the hammer instead of jumping off it.... i have a hard paper buffing wheel i cut to a knife edge for getting up in corners like those....

thx for the eval!!....and, riskin your parts!!...lol...

later
cletus
 
#14 ·
This is exactly why

This is exactly the reason I began working on the adjustable parts= there is NO ONE SINGULAR recipe that will work for everyone, and if you follow these pictures, some of you will end up with a trigger that causes you problems, and some of you will end up with a great trigger, and some of you will end up with a trigger that will not engage. This is because of the differences in the pin locations from group to group. Heck, the pins aren't even straight from side to side in any group that I have ever indexed, nor are the sear holes in the same spot. I am not saying this is stupid or dangerous, I love learning about stuff, I am just saying it isn't going to work the same for everybody, and so please think about things as you do them, and take little itty bitty steps, creeping towards a pull that you like, don't just go thinking you can set it up like these pictures, go for the biggest number filed off shown, and think that it is necessarily going to work the same. :t
Now go have fun doing something you can be proud of when you get done, and enjoy your project! :t
 
#16 ·
hags said:
this seems like the best way to introduce creep into a trigger group, if not make it unsafe. I reduced the hammer notch area and not the angle to lighten my trigger pull and my trigger "break" is light, clean, and crisp.
So instead of making the angle wider, you narrowed the width of the notch? Sounds like it would be an easier job than changing the angle, are there any cons to lightening the trigger pull this way?
 
#17 · (Edited)
I need the Info...

hags said:
this seems like the best way to introduce creep into a trigger group, if not make it unsafe. I reduced the hammer notch area and not the angle to lighten my trigger pull and my trigger "break" is light, clean, and crisp.
How much did you remove from the "notch area" or the "radius"? And what is the new pull weight?

Clark only changes the angle on thier "drop in" hammers.

Yes, both the Clark and VQ hammer that I have on hand both have more creep then stock. On the contrary some see this as a safety feature as the sear will have to drag further along the engagement area before it breaks.

when I replaced my stock hammer with the Clark, the pull weight dropped from over 7pounds to around 3.5lbs. Creep and pretravel don't really bother me. But since its a big deal around here and since I have never shot a light pull trigger with out creep, I figured that I would try and reduce the amount of creep on the Clark hammer by reducing the radius or engagement area. I removed about .015" and as an added benefit the pull weight dropped another pound along with removing much creep. No problems as of yet.

The reason for this thread is to introduce an easy repeatable way for people who want reduced pull weight of stock hammers to experiment to find what fits them best. And if you go just a little to far? Well Skeeters adjustable hammers are always available from Hawkteck!

Remember remove only small amounts at one time and do lots of testing to make sure your gun is safe!
 
#18 ·
hags said:
this seems like the best way to introduce creep into a trigger group, if not make it unsafe. I reduced the hammer notch area and not the angle to lighten my trigger pull and my trigger "break" is light, clean, and crisp.
the stock hammer is designed to actuall hook under the nose of the sear...the reason you don't feel creep w/ it is it has to cam your hammer rearward to start movin, so you just jump past it

this method does make you able to notice the length of engagement, or "creep" as you are calling it because you're not havin to jump a hill to get things movin!!!.... however, i cannot see how this could in anyway make a group unsafe...

changing only the depth of engagement on the hammer moves the nose of the "hook" of the hammer from underneath the nose of the sear, up onto the sear's face.... so, only a very knife edge of the hammer is riding on the face of the sear..... i personally see this as more dangerous than changing the angle..... if you do it w/ a set screw ala Sawdust, you can allways "put some back" when you take it too far....

a combination of BOTH is what i use on my "bench" group, and it is well under 1lb pull.....but, on my "field" group, i only change the angle, not the depth...... i can't make my "field" group jump slip off under any circumstances i've tried, but it does have a longer length of pull than my "bench".... like the M1D's and M14/M21 system, it's a single stage trigger, it's gotta have some depth of engagement...but, it is glass smooth even, during the entire pull...no hitches/bumps, roll off, loading, etc..

but, if you're happy w/ what you've got, i guess that's what makes a horse race!!!!.....lol.....

later
cletus
 
#19 ·
hags said:
this seems like the best way to introduce creep into a trigger group, if not make it unsafe. I reduced the hammer notch area and not the angle to lighten my trigger pull and my trigger "break" is light, clean, and crisp.
My experimentation with factory hammers backs up Morly's advice but shows that reducing the depth of the hammer notch will allow the hammer to trip if the trigger is pulled while the safety is engaged. So if you care about a safe trigger system don't reduce the depth of the hammer notch.
 
#20 ·
nomo4me said:
My experimentation with factory hammers backs up Morly's advice but shows that reducing the depth of the hammer notch will allow the hammer to trip if the trigger is pulled while the safety is engaged. So if you care about a safe trigger system don't reduce the depth of the hammer notch.
hey nomo,
i think the safety is just about the only part on this little rifle that has to be hand fitted, even from the factory!...

if you've got one that's doin that, peen the edge of the leg of the sear where the safety slides under to stretch some steel down to engage the safety.... it doesn't take much metal to make a safe trigger! it doesn't have to be a perfect fit all the way under the sear! if you move too much metal, just adjust it w/ a file till you get the right fit.....

my personal standard for safeties is this...... pull the trigger w/ the safety on.... then, click off the safety and try the pull.... if it is ANY different AT ALL from a normal pull, it needs work!!..

another option is to trim the bottom of the sear leg a few, and drill/tap it for a set screw.....that would allow you to allways make your safety work properly....

fwiw, i never even use the safety on my "bench" group.....1st rule is never put your finger inside the trigger guard 'cept when getting final line up on a selected target..... i only insert mag/chamber rnd in the gun when i'm behind it, w/ it pointing into the backstop, and i block the bolt open and remove the mag when i'm through...

on my "field" group, i make sure i have the safety workin to my standards, plus i insist everyone follow the basic 4 of safety........ which includes keepin the finger out of the triggerguard except when lining up on target...

later
cletus

ps: really nice handles you're makin!!!.....i love the brass ones you made for skeeter!!!!....
 
#22 ·
nomo4me said:
I think nemohunter's handles are pretty nice myself :D

BTW, I've tried peening both the PC and Ruger factory sears with no luck. The steel was too hard.

Nomo4me
sorry!!...both of ya!!!...lol... hey, what can i say......wanna see my dr's note???.....lol.....

re: peening....... you're just not usin a big enough hammer!!!.... you can move that steel an amazing amount........i laid it down on it's side on my "anvil" w/ the left side up ...... i started "whupin" on that bottom corner where the safety slides under it, lol.... it did take some pretty deep blows from a fairly heavy hammer to move it........... as the part is case hardened only, it's completely soft through the core, so breaking it will take alot.... but you can chip off pieces of the hardened skin when peening wrong...........it makes the safety slide over farther prior to engageing by about .020", but not noticeable....

you may try using a series of center punch marks to get it "started"...then push that down to where you need it....

cletus
 
#23 ·
cletus hungwell said:
sorry!!...both of ya!!!...lol... hey, what can i say......wanna see my dr's note???.....lol.....

re: peening....... you're just not usin a big enough hammer!!!.... you can move that steel an amazing amount........i laid it down on it's side on my "anvil" w/ the left side up ...... i started "whupin" on that bottom corner where the safety slides under it, lol.... it did take some pretty deep blows from a fairly heavy hammer to move it........... as the part is case hardened only, it's completely soft through the core, so breaking it will take alot.... but you can chip off pieces of the hardened skin when peening wrong...........it makes the safety slide over farther prior to engageing by about .020", but not noticeable....

you may try using a series of center punch marks to get it "started"...then push that down to where you need it....

cletus
Cletus you are a more expert metalurgist than I and thus your courage to grab a bigger hammer :D
When I was a custom gunmaker I usually found that anytime I resorted to a lot of force to achieve a task I was significantly upping the odds that I would be replacing some customer's part out of my own pocket :rolleyes:
 
#24 ·
nomo4me said:
:D
When I was a custom gunmaker I usually found that anytime I resorted to a lot of force to achieve a task I was significantly upping the odds that I would be replacing some customer's part out of my own pocket :rolleyes:
i completely concurr w/ that one!!!! i only resort to "stretching" steel as a last resort, or a permanent one........ but, there are certain cases where that is the best, and factory used method!!!....

i'm sure you've had to straighten the cranes on some smith revolvers over the yrs that had been dropped w/ cylinder open..... and, stretched the crane longer to tighten the headspace on them....

i know the first time i had to "adjust" the sights on my fixed sight victory model smith&wesson, i was more than a bit hesitant!!!!.....lol..... it sure made the "screw stretching" fix for shortened strain screws on them alot easier to attempt!!

as this part is available very readily, and cheaply, i considered it a reasonable risk.... it worst comes to worst, and you break off part of it, just whack off the bad part, then drill/tap for a set screw..... a set screw w/ red loctite, or some oldfashioned peening/lock nut, should give you the safety you want, and will be more adaptable to other "revisions" that you may want to try in the tgroup....

keep us posted
later my friend
cletus
 
#25 ·
Revolver? That's the kind of door you walk through to enter the Ritz Carlton, right?
I was just a rifle and double bbl guy.

Nomo

cletus hungwell said:
i completely concurr w/ that one!!!! i only resort to "stretching" steel as a last resort, or a permanent one........ but, there are certain cases where that is the best, and factory used method!!!....

i'm sure you've had to straighten the cranes on some smith revolvers over the yrs that had been dropped w/ cylinder open..... and, stretched the crane longer to tighten the headspace on them....

i know the first time i had to "adjust" the sights on my fixed sight victory model smith&wesson, i was more than a bit hesitant!!!!.....lol..... it sure made the "screw stretching" fix for shortened strain screws on them alot easier to attempt!!

as this part is available very readily, and cheaply, i considered it a reasonable risk.... it worst comes to worst, and you break off part of it, just whack off the bad part, then drill/tap for a set screw..... a set screw w/ red loctite, or some oldfashioned peening/lock nut, should give you the safety you want, and will be more adaptable to other "revisions" that you may want to try in the tgroup....

keep us posted
later my friend
cletus
 
#26 ·
re: peening....... you're just not usin a big enough hammer!!!....


Cletus,

A trick I've used for many years for peening......


I took an old cold chisel about 3/4" and rounded over the sharpened edge and then polished it.

When using it with a metal bench block and hammer, you can precisely locate where you want to peen and stretch, moving the metal.

I used this method when making lockback knives and slipjoint folders, when the lockup was a little loose(locking bar) or out of allignment(stretched the spring a bit)

I elected to modify the chisel to have a rounded edge about the same radius as a 1/8 inch drill rod, so that the peening wasn't to abrupt.


Thomas Zinn
 
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