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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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#102 ·
I just completed these modifications tonight. I took off some of the radius on the hammer, changed the angle, polished the sear and hammer. I added aset screw in the trigger guard to prevent overtravel. I could support the entire weight of the gun with a scope on the trigger before. Now the weight of the receiver along with the scope is enough to break the trigger (barrel removed). Wow!!! Thanks for all the valuable information here. Matt
 
#103 · (Edited)
Well I'm just a retard, and pretty new at the 10/22 deal, but this thread gave me the confidence to play with my hammer.
Worst case scenario, I buy a new hammer........

I did look at the drawings closely and tried to follow the jig picture, but my old milton vise wouldn't do, so I used a calibrated eyeball;) .

I used a squinty eye, a razor for a straightedge, my carbon fiber knee vise to support the hammer on while I worked gently with a triangle file.......them polished with jeweler's rouge.
After going from 4-5 lbs inconsistent factory, to 3ish pounds that wouldn't take a 6" drop, back to 5 lbs I wound up finished.

Kids, I now have a consistent 28oz (RCBS spring scale) trigger that has taken half a dozen drops from 8-10" without going off unwanted. The trigger may not break like polished glass to a benchrest guy, but it feels great to me. No grit, just smooth takeup then click.

I am one happy camper:t !!!

If I get a new scope, I'll take the scope off and do about a dozen drops from 12" just to be sure, but I think its good to go!!

Hotdamn I like this forum!! (please do not follow my example..... use proper tools, and know what you are doing before attempting trigger engagement modifications. AT THE VERY LEAST-know how to check your weapon for safe function before beginning!!!!!!). I wouldn't have dicked with mine if I didn't know how to tell if it wasn't safe!
 
#104 ·
sobrbiker883 said:
Well I'm just a retard, and pretty new at the 10/22 deal, but this thread gave me the confidence to play with my hammer.
Worst case scenario, I buy a new hammer........

I did look at the drawings closely and tried to follow the jig picture, but my old milton vise wouldn't do, so I used a calibrated eyeball;) .

I used a squinty eye, a razor for a straightedge, my carbon fiber knee vise to support the hammer on while I worked gently with a triangle file.......them polished with jeweler's rouge.
After going from 4-5 lbs inconsistent factory, to 3ish pounds that wouldn't take a 6" drop, back to 5 lbs I wound up finished.

Kids, I now have a consistent 28oz (RCBS spring scale) trigger that has taken half a dozen drops from 8-10" without going off unwanted. The trigger may not break like polished glass to a benchrest guy, but it feels great to me. No grit, just smooth takeup then click.

I am one happy camper:t !!!

If I get a new scope, I'll take the scope off and do about a dozen drops from 12" just to be sure, but I think its good to go!!

Hotdamn I like this forum!! (please do not follow my example..... use proper tools, and know what you are doing before attempting trigger engagement modifications. AT THE VERY LEAST-know how to check your weapon for safe function before beginning!!!!!!). I wouldn't have dicked with mine if I didn't know how to tell if it wasn't safe!
posts like this was my entire reason for chasing down these angles, and posting this technique.....

i really feel that these little rifles are a "gateway" gun for "tinkerin"...i know i get in alot more hours of tinkerin, and have just as much fun from it, as i do shooting the results.... there is alot of satisfaction in doin something like this for yourself, in my opinion.....

a side benefit of this is you now have a very good understanding of the internal workings of a basic semi auto trigger...as well as basic metal working..

thx for the post, and keep us posted on it
cletus
 
#105 ·
That is so very true. sobrbiker... when I started doing all this stuff I knew nothing about working on guns. If I needed a trigger job I took a gun to a smith. NOW I am confident enough to at least try to work on any gun I own. Currently the only ones that I hesitate on are 1911's and that is mostly because I don't have all the right tools to do all of the complicated and precise measuring. Now THOSE guns are complicated! I can certainly see why the old ones were loose and rattlecans... it made sure they would shoot.

Cletus was actually the guy that got me to try heat treating. The first time I used a small file. When the tail shattered like glass, I thought 'uh-oh... I have messed up now'. Come to find out that is exactly what it was supposed to do, so I actually did it right. So I tried it again, then I tempered it in the oven and voila'... it was great.

Your attitude is great though... if you mess up, you can buy factory parts for quite cheap. If you ever just can't get it to work right and can't figure out why, this place has the combined knowledge go help you figure it out and get it fixed. You gotta love it!

Mark
 
#106 ·
Well, I redid my hammer, AGAIN. While I was thoroughly please with my 1.75lb trigger job, I found out that I had made my rifle illegal for Silhouette by going under 2lbs.
So, I just started over and after another eyeball angle and polish session, I have a happy 2.75# pull.

New question, should I take out the MAPP torch and heat it up then quench in chilled oil to harden the surface I just made or will a filed/stoned/polished surface hold up in the long run??
 
#107 ·
You will get different opinions on that, but the way I see it, is it going to hurt to reharden a working surface? I don't think so. You could even temper it by putting in the oven at 500° for a few hours after the quench.
 
#108 ·
spring for it

sobrbiker883 said:
Well, I redid my hammer, AGAIN. While I was thoroughly please with my 1.75lb trigger job, I found out that I had made my rifle illegal for Silhouette by going under 2lbs.
So, I just started over and after another eyeball angle and polish session, I have a happy 2.75# pull.

New question, should I take out the MAPP torch and heat it up then quench in chilled oil to harden the surface I just made or will a filed/stoned/polished surface hold up in the long run??
Why not use a heavier trigger spring?
 
#111 ·
i bought another trigger group just so i could play with one and see what happened. i have no shop whatsoever ,no vice, no this, no that. anyway i put some 220-b sandpaper on a straightedge and gave the hammer about 6 strokes,cleaned it up and tried it. it was a Lil lighter so i did it again.lighter still! so i polished every surface that contacts other parts, did the bobby pin trick, and i think its good TA go! BTW the only way i have to judge weight is by comparing it to another 10-22 i have that has an under 2 lb. pull. it is pretty close 2 1/2 -3? maybe ? THANK YOU FOR THE INFO!!! regards bill :bthumb: P.S. i do have a dremel
 
#112 ·
BTW the only way i have to judge weight is by comparing it to another 10-22 i have that has an under 2 lb. pull. it is pretty close 2 1/2 -3? maybe ?
Water weighs just about 8lbs/gallon, so a milk jug and a coat hanger will let you see how much weight you can pick up without tripping the hammer.......

Aint 10/22's fun? Unfortunately I play with mine more than I shoot it it seems............
 
#116 ·
2.63 pounds +/-.
That's using the logic that if 1 gal=8.33 lbs, then (8.33/8)X fluid ounces should = dry ounces, which divided by 16 would be dry pounds.........

Nice job for a 10/22 stock setup.

Like I said in a previous post mine was 1.75ish, but I redid it to 2.25ish, because I was thinking it was too light for silhouette rules. I've since realized a 10/22 in a thumbhole stock is in standard class anyway, and just needs a "safe" trigger.
Maybe I'll find another hammer and start over.........
 
#119 · (Edited)
Actually 4lbs isn't really that heavy of a pull. Try a box stock Remington 700, or a brand new AR15. Most AR15 with the usual production trigger groups run 8-11lbs........the 2 stage 4.5lb RRA match triggers to be NRA service rifle legal feel like a feather compared to stock trigger groups.

Now that I actually have a trigger pull guage I trust noone's "my trigger feel like its about Xlbs" statements (even my own I've made in the past!).......
 
This post has been deleted
#128 ·
I've done a couple using these directions. For a hunting rifle, it works very well, but for a target rifle I would suggest a skeeter hammer. They provide the lighest trigger pull with the modified factory parts. I don't have a trigger pull gage but I would guestamate the pull on my home brew hammers to be between #3-#4. You can get under #2 with a skeeter hammer. #2-#2.5 with a VQ, and #2.5-#3 with a PC. At least thats been my experience.

swampf0x
 
#130 ·
All I can say is WOW!!

I did the stone job on my hammer last night and it made a huge difference. Must have reduced the pull by half or more. Just what I needed now that I have a good barrel on it. There is a little creep in the trigger now, probably was there before, just didn't notice it due to the excessive pull. But it is worlds better now.

Thanks for sharing the info guys.

Ewald
 
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