strain screw shim

[zeke]

Has anyone ever found a shim (basically a thin washer) that fits the strain screw? Then ya could adjust out the strain screw without altering it, and still be able to tighten it down? Easy to reverse. An x frame trigger pin shim comes very close, but slightly to large an outside diameter and slightly too small an inner diameter.

Any comments?

 

[kev74]

I don't see why it wouldn't work. The head of the screw migh stick out further than you'd like. But if thhat's not an issue, it shouldn't be a problem.

 

[StrawHat]

Why is it needed? The strain screw is to be tight in its seat.

Kevin

 

[Jeppo]

Fired primer with the anvil removed.

 

[DWalt]

The standard fix, if needed, is to use a fired primer cup (no anvil) over the screw tip.

 

[zeke]

Why is it needed? The strain screw is to be tight in its seat.

Kevin

the idea being to lesson the spring tension slightly, while keeping the strain screw tightly screwed down. With shims you can adjust the amount of tension, unlike using a primer cup between the strain screw tip and the spring.

 

[Protocall_Design]

Coat the screw with blue or purple Loctite after cleaning with solvent. Coat the threads on the frame with Loctite. Screw together, mop up the excess with a paper towel and Q tips. After it sets, you can adjust it and it will stay where you put it.

 

[series guy]

A great way to use the strain screw to adjust trigger pull is to replace the factory screw with McMaster number 95235A507. It has thread locker built in and will stay where you put it. This way there are no modifications to your gun. I put the factory strain screw along with the factory rebound spring in a small ziplock bag along with the serial number and model number of the gun. This stays in my safe and can be reinstalled if the gun is sold.

 

[zeke]

Coat the screw with blue or purple Loctite after cleaning with solvent. Coat the threads on the frame with Loctite. Screw together, mop up the excess with a paper towel and Q tips. After it sets, you can adjust it and it will stay where you put it.

My confidence in breaking a properly set up screw head loctite joint is lacking.

 

[scooter123]

I've been using shims for this for over 15 years. Unfortunately you can't purchase these shims, in my case I made them from basic shim stock. If you don't have a shim punch block and punches what you will have to do is clamp the shim stock between two pieces of steel (vice grips and 1/4 inch steel) and drill a hole of the correct size for the strain screw thru the shim stock. Shift the steel as many times as possible so you can drill out a bunch of holes. Once you have a bunch of holes then the fun begins, you take a pair of scissors and hand cut each shim to the diameter required.

Note, the above is how I did the first shim. Then I got smart and used the punch and die set at work to make up a batch in 0.005, 0.010, and 0.015 thicknesses. Below is an example of what I used. They are not cheap. Note Wholesale Tool is about 2 miles from my house and they are good people to work with. BTW, they are sort of the Harbor Freight of industrial tool supply so they are mostly chinesium but it's pretty high quality chinesium. The SKU for that particular part is SKU: 0704-9982


https://www.mscdirect.com/product/details/48424501

 

[Protocall_Design]

My confidence in breaking a properly set up screw head loctite joint is lacking.

My confidence is very high. I've been doing this for 30 years with no problems. The set screws with a patch of threadlocker don't hold very well. One drop of Loctite isn't enough. You have to clean the male and female threads well with solvent, let it evaporate, then coat both threads. All the voids between the male and female thread have to be filled for it to work right.

 

[zeke]

I've been using shims for this for over 15 years. Unfortunately you can't purchase these shims, in my case I made them from basic shim stock. If you don't have a shim punch block and punches what you will have to do is clamp the shim stock between two pieces of steel (vice grips and 1/4 inch steel) and drill a hole of the correct size for the strain screw thru the shim stock. Shift the steel as many times as possible so you can drill out a bunch of holes. Once you have a bunch of holes then the fun begins, you take a pair of scissors and hand cut each shim to the diameter required.

Note, the above is how I did the first shim. Then I got smart and used the punch and die set at work to make up a batch in 0.005, 0.010, and 0.015 thicknesses. Below is an example of what I used. They are not cheap. Note Wholesale Tool is about 2 miles from my house and they are good people to work with. BTW, they are sort of the Harbor Freight of industrial tool supply so they are mostly chinesium but it's pretty high quality chinesium. The SKU for that particular part is SKU: 0704-9982


https://www.mscdirect.com/product/details/48424501

Scooter123- Thanks it be appreciated. A little more than am willing to do, but very helpful. Recently when looking for trigger pin shims, found TriggerShims.com on an internet search. Was looking for trigger pin shims, as it seems they were no longer being offered from the usual source. He also offers a trigger pin shim for the M69 and "x", which has a slightly larger inner dia and almost fits the strain screw. He indicated he has hundreds of shims and will send him the dimensions i measured of strain screw (as best as i can measure)

Using dial calipers am measuring .218 for the screw head, .160 for the outer dia of the threads and .118 for the dia of the smooth shaft. Can i ask if these are close to the dimensions ya use?

thanks

 

[chief38]

You should really buy yourself a few new factory screws. Then shorten one to the length that gives you 100% reliability and also lightens the pull slightly. Fully tighten the new screw so it will not back out. IMHO, that is the proper way.

I like to replicate the rounded end as it is on the factory screw. Very easy to do this and while I am sure the screws have gotten more expensive, they can't be that much to be cost prohibitive. I would not personally use a washer and I am not a fan of locktite on the screw either - but that 's just my own opinion. I don't use locktite on any pistols or revolvers.

 

[zeke]

Any and all responses are sincerely appreciated. Thank You!

 

[bobbyd]

Buy another screw

Has anyone ever found a shim (basically a thin washer) that fits the strain screw? Then ya could adjust out the strain screw without altering it, and still be able to tighten it down? Easy to reverse. An x frame trigger pin shim comes very close, but slightly to large an outside diameter and slightly too small an inner diameter.

Any comments?

Strain screws are cheap and available Just file/grind a second screw to your specifications and you will have a more secure and repeatable alternative without messing with all of the rest of this shim complication.

 

[zeke]

Strain screws are cheap and available Just file/grind a second screw to your specifications and you will have a more secure and repeatable alternative without messing with all of the rest of this shim complication.

If shims were available, could set the "specification" and try it out for awhile, while maintaining the option of future adjustments. When determining the final set, could easily reverse it without keeping yet another inventory of oem parts.

While certainly not a gunsmith, have shortened strain screws before.

 

[DWalt]

Coat the screw with blue or purple Loctite after cleaning with solvent. Coat the threads on the frame with Loctite. Screw together, mop up the excess with a paper towel and Q tips. After it sets, you can adjust it and it will stay where you put it.

Clear nail polish works well for that purpose, paint it on the threads and let it dry first. It will keep the screw in place, but it will be stiff to turn but adjustable.

 

[Mike SC Hunter]

I have always used a pistol primer with the anvil removed.......Works and will stay in place forever.

 

[StrawHat]

the idea being to lesson the spring tension slightly, while keeping the strain screw tightly screwed down. With shims you can adjust the amount of tension, unlike using a primer cup between the strain screw tip and the spring.

As a S&W armorer, I am very familiar with all of the gimmicks used to mess up a perfectly good trigger action.

A good action job does not need reduced springs, backed out screws, or any of the other stuff that is done without thought to reliability or function.

Polishing three or four areas to reduce friction is really all that is necessary.

A smooth pull is what should be the goal.

Kevin

 

[steelslaver]

Smooth beats light. But, why shim the screw ? Turn it out and in to find where it is still reliable then count 1/4 turns till tight again. Measure length then remove .0065 of length from screw tip for every 1/4 turn then check for positive ignition. But, better to be a little on the heavy side than unreliable

You can buy 8-32 machine screws for gun at many Ace Hardware stores. Many of them have gun screw selections in the small divided boxes