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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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#240 ·
Love my "new" trigger. It is very close to perfect. Just a quick question though: Did the standard triggers used to be better? I was out plinking with my dad the other day, and his 10/22 trigger was even better than mine! (Well, just as smooth and slightly lighter pull). Funny thing is, he has never done anything to his. In fact, I don't think he has ever cleaned his 10/22. I've had mine for 27 years, and he had his before I was born, so it's been a long time! (Looks dirty, but never malfunctions and shoots darn straight). Maybe it just wore smooth with time?
 
#241 ·
Matno...clean his gun and it will be even better :D

My ol' '72 vintage was pretty smooth before I ever decided to slick it up..now it's better..but it was decent from the get-go..but after about 25 years of shooting it was around 3 lbs..still had the abundant pre-travel..so it got a Adj. Sear and a hammer stoning...so in answer to your que I feel (and most guys do) the older triggers were better right out of the box...over the years I feel they got real bad and are at a all-time horrid.
 
#242 ·
I might offer to clean it for him, but really he should have more time to do it than I do! (He's a professor - so he gets school holidays off, and I've got a full time job plus 6 small kids in the house!) Besides, I already offered to clean up my brother's that he accidentally left at my house when he was in town last week.

This is encouraging though, since I'm looking to inherit two very old (but hardly used) 10/22s from my grandma. Haven't felt the triggers in years, but i think they're better than current offerings. Apparently nobody else in the family is interested in them. Can't have them yet because she thinks her gun cabinet would look silly if it were empty! But she lives close, and I can borrow them whenever I want. Someday, my boys are going to enjoy them!

Just added an overtravel screw to my trigger guard. Almost feels like more of an improvement than the stoning! Can't wait to try it out on a bench (if I can find a non-windy day!)
 
#243 ·
Hey guys I just did this and wow!!! I am in shock. Couple of things.....I put a .125 drill bit in the bottom hole and had to rotate the hammer to such a degree in my jig to lined up bottom of notch with jig top that the point was even with the jaws. I looked closely to make sure this mod hadn't been done by a previous owner and I could still see the hook so I knew it was stock. So I took the drill bit and put it in the second hole of the hammer and carefully lined up the bottom of the notch with the jig top and I had a very very tiny hook protruding up. Maybe >005" or something. So I took my medium arkansas wetstone and slowly cleaned up the hook till it was flush with the jig top. There may have been .001" left at top of jig and I stopped. After reassembly I cannot believe how much this changed!!! I haven't measured the pull but it has to be around 2- 2.5 lbs! It has cut it in half. Couple things............

Safety still works and I tried dropping the gun butt first on my carpeted floor from about 12" over and over again. The hammer held. After each series of drops I could flip off the safety and click the trigger. Can I safely assume this gun is just as safe with the safety engaged as it was originally? This will be a bench/plinking/hunting gun. So I still need safety as well as a good trigger to be important.
 
#244 ·
Well here is the results. My worries are for nothing. I went out last night and shot off around 100 rds. This mod has made this gun more fun to shoot. Safety works every time and my worries of the sear missing and going full auto were put to rest lol. It performed flawlessly! Thanks Morly!

I tried cleaning up the radius on the hammer in the past without touching the engagement surface at all (as was suggested by hags). I also polished everything inside the trigger group. I also drilled and tapped my sear to remove all pre travel plus the addition of a power custom trigger shoe for an over travel screw. While all these previous mods made a big difference in the trigger feel and got me around 4-5 lbs (with the exception of using hags method because I was too afraid of going too far so I never actually ended up removing much), Nothing has compared to actually removing the "hook" or changing the angle. This one thing has got me to a fine clean crisp feeling trigger that I will bet is around 2- 2.5 lbs.

I can now squeeze the trigger without making me flinch now.
 
#247 ·
Well here is the results. My worries are for nothing. I went out last night and shot off around 100 rds. This mod has made this gun more fun to shoot. Safety works every time and my worries of the sear missing and going full auto were put to rest lol. It performed flawlessly! Thanks Morly!

I can now squeeze the trigger without making me flinch now.
:bthumb: Gosh I miss this place :)
 
#245 ·
I'm glad you are happy with the results but to test for safety banging the stock on the floor should be done cocked and the safety already off.... not on. Make sure it's unloaded first... you wouldn't be the first to fire off an unexpected round! Yikes :eek:
 
#251 ·
How Cool.............

I pull up the last page in this post and find Chaser, Markbo, Batman and Morly all on the same page. :):bthumb:

Hello Guy's.............I don't get around these parts as often as I once did either. Good to see you guy's posting though.......brings me back!;)

Hope all is well with each of you.
 
#252 ·
I miss all of the ol' Buddies...ya need to post more Gents and keep us right :bthumb::D
New Gen. here for sure...the good ol' boys are getting fewer. :(
 
#253 ·
You too Bruce! I can't speak for anyone else, but I just got tired of everyone doing exactly the same thing and calling it an "Ultimate". Nobody doing anything... just everyone buying the same A/M parts and installing them.

My other interests like ARs, varmint hunting and big bore revolvers kept me occupied, then I needed a refresh as I had a couple of .22 projects I wanted to finally complete. Lo and behold there are some very talented people posting about DIY work! Bedding, stocks, brass receivers... that is the sort of stuff that interests me.

Anyway, good to hear from you, Chaser, Morly, Vincent, Squasach, et al. Chaser has already had to reign me in once from getting snippy with someone I disagreed with. :D
 
#254 ·
I always check this thread when I see it's been updated. This thread opened my eyes and apparently also did the same for a slew of others. Spring is tough, catching up on all the winter stuff, then getting out on the bike as much as possible & shooting in-between.
 
#276 ·
Agree with Tom above for the most part.. polishing contact surfaces on ALL 3 parts is good! Just do NOT round off the edges.. think SHARP/CRISP! Polishing can/should be done on a very hard/very flat surface with high# grit wet/dry..1000 to 1200 for the final polish.
New MIM Hammer:
I just eyeball the "hook"(.02) of the hammer above the top flat as I tighten into my Vise.. and take that hook off with File/Coarse Stone... finish it/polish with Fine stone... then run the round part of the hammer across the stone or 400 gr. wet/dry about 10 times and then polish it.. done... wipe/spray clean then assemble/test and do it again if necessary.
Thanks for the reply. Do you know if the drill bit method works on the new style hammers as far as the geometry and repeatability?
 
#259 ·
I figured it was time to surface this great topic again.:bthumb:

I went through much of it to get best cross-section of information then went at it slowly.

First try was OK, safe and relatively smooth compared to original. Shot it fine.

Second try, getting quite good, still safe and added the overtravel screw, shot well, now we're getting somewhere.

Third try, NICE, safe to drop test and a just little mushy. Guess what :eek::AR15firin, getting some fails to reset and nice 2-3 shot bursts, Now just have to find a new old style hammer to start over. I will not be beat by this project and buy after market (yet!!)

Moral of the story - quit while you are ahead. :D
 
#269 ·
Overtravel adjustment was the problem...

I figured it was time to surface this great topic again.:bthumb:

I went through much of it to get best cross-section of information then went at it slowly.

First try was OK, safe and relatively smooth compared to original. Shot it fine.

Second try, getting quite good, still safe and added the overtravel screw, shot well, now we're getting somewhere.

Third try, NICE, safe to drop test and a just little mushy. Guess what :eek::AR15firin, getting some fails to reset and nice 2-3 shot bursts, Now just have to find a new old style hammer to start over. I will not be beat by this project and buy after market (yet!!)

Moral of the story - quit while you are ahead --or not;). :D
After taking advice from 'Shootsatsky' I backed off the overtravel screw 1/2 turn. :bthumb: Fixed it!!! Now my trigger is amazing and I did it myself for free(with lots of great help from this forum).
 
#260 ·
smong,

Before you give up on that hammer, check the 'hook' carefully as well as the edge on the sear to be sure they are square across, and that there is no rounding to the edges or burrs that can let the pieces slip when the bolt bounces.

Next, back off that over travel screw a half turn and check again. They can cause binding that can prevent a positive reset.

If those don't do it, you could try resetting the angle on the hammer, but you may already be thru the hardened surface and might have to treat it again.

Bob
 
#261 ·
144 thousand views and 160 replies. It lives! Actually I wish i never started this thread, the thought of all those old hammers being ruined is saddening. But at that time it seemed there was a never ending supply. Truely the best way to accomplish the best feel is to drill and tap the hammer and install a set screw that is adjustable. But stoning was cheap and easy. Fire on...:AR15firin
 
#262 ·
Im sure KIDD and VQ have had an up tick in business do to this thread. I tried to do it my self and got too greedy on the 3rd pass on one of the newer ones.

KIDD now has a couple of Benjamin's from me with upgrades to various OEM pieces.

KUDOS to those of you who stuck with it:bthumb:
 
#270 ·
Thank You, Morley!

First off thank you Morly, Cletus and the others that contributed to this thread and the others in the Action Reference Section.
I have done them this way since this was first posted. Haven't had any issues ruining hammers. Tried the set screw in the hammer, worked fine, but normally use this method. Count me as another one that is glad you posted this...........George
 
#271 ·
Thanks !

I was looking on-line to try and decide which trigger assembly to buy , and I found this site. I carefully followed the directions , and after the third reassembly - I have a trigger pull I like. It might not be " match grade " . but it is certainly a huge improvement. Saved enough $$$ to buy a couple bricks of ammo now that you can find it again. many thanks
 
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