PT 1911 countersink slidestop radius DIY technique

Discussion in 'Gunsmithing Forum' started by cuba, Apr 26, 2010.

  1. cuba

    cuba New Member

    PT 1911 counter sink and radius slide stop pin end
    I started this thread to help the DIY type person that would like having this treatment done to their 1911 for what ever reasons you may have be it cosmetic or practicality.

    The major concern I had before countersinking my frame was the weakening of the frame, I did my home work and research concerning the countersinking of the frame which for some has been a legitimate point of contention.

    I've always thought that the protruding slide stop looked unfinished, but understood the purpose for it and after seeing some custom 1911's with the countersunk slide stop I though it gave it that finish look that I perceived was missing.

    I looked at the Nighthawk countersink profile, the Kimber profile, The Les Bear profile, Ed brown profile, the Valtro Jardin Custome profile and the Wilson profile though more profound I liked better for a couple reasons, one was that the countersink was wider which I felt spread the removal of metal in a more tapered manner which would weaken the frame less for instance if you file a V grove 2/32"deep on a piece of steel 5/32" and apply a fulcrum pressure it would probably break in half, but if you spread the 2/32" in a tapered manner it would bend but not break in two. Also making the countersinking 3/8" would make it easier to push the pin out, as well as to line up when assembling.

    I was concerned about the profile of the slide stop pin whether to leave it flat and slightly relieve the edge like the Nighthawk or round it off with a complete radius like Wilson's which is what is needed to easily assemble the slide but did not know exactly how to achieve the radius, when it came to me how an electric pencil sharpener worked and I figured a clever way to achieve this by using a hex head driver on the end of a drill covered with emery cloth (photo attached on post #1).I knew that the constant rotation of the emery cloth would create a perfect radius.

    I hope that this tutorial will helped some one that has wanted this treatment on their 1911.
    When enhancing your 1911 with a countersink slide stop pin most people find that producing a perfect radius on the pins end is very difficult, but I have found a technique that simplifies the process.

    You need to under stand that it is critical not to change the remaining diameter of the pin or frames shaft, also you don’t want to over heat the pin and change the tensile strength of the pin.

    First remove the slide from the frame and slip the stop pin through the hole on the frame, with a sharpie marker shade all the protruding section of the pin, if you have a black pistol use a silver color sharpie.

    Now take the pin out and on a grinding wheel start to grind the tip of the pin applying light pressure so as not to over heat the pin, as you start getting to the end of the marked portion check it with the frame, the idea hear is to leave the pin slightly longer then flush about 1/32” to 3/64” because you will need this extra material once you start to rough shape the radius on the grinding wheel, I would wrap a piece of masking tape about 1/8” below the end of the pin to assure that I don’t change any of the remaining diameter of the pin. Start rotating the pin around the grinding wheel in a continuous motion making sure not to grind where you’ve taped, when you have roughly radius the point of the pin you will end up with a slight point, which later on you will remove, that’s why you left the pin slightly longer to begin with.

    Third you will need a 7/32” or 3/16” hex head screw driver tip and a small piece ¾” x ¾”of plumber’s emery cloth. Install the 7/32” or 3/16” driver tip to a hand held drill and place the piece of emery cloth on top of the driver and hold it down with your rough slide stop pin and run the drill at a high rpm while pushing the stop pin down into the driver, it works like an electric pencil sharpener and will produce a perfect polished radius and while applying pressure and pushing the stop pin down, will remove the extra length that was left slightly longer and pointed.

    Now for cutting the countersink on the frame I installed a new cobalt 3/8" twist drill bit with a 118 degree profile tip on a hand held variable speed drill motor and centered it on top of the frame slide stop hole and drilled at a slow rpm keep the drill straight and only go as deep as the width of the bit 3/8” just enough to remove a minimal amount of material to create a dimple which turned out to be about 1/16" deep excluding the tip of the bit that will fall into the original cavity of the frame hole about 1/16" now the point of an 118 degree x 3/8” drill bit is 1/8” long, so you see if you have half of it falling into the cavity hole you are only removing 1/16” of tapered steel, to visually judge what 1/16” is just look at a 1/16” drill bit, it almost looks like a needle.

    Now I thought about a ball cutter but I knew I did not have a drill press needed to keep it dead center and that if I used it with a hand held variable speed drill there would be no way to keep it dead center, and I thought about a counter sinker but was afraid that the pointed guide spinning around the frame hole could make contact with the inside of the hole and increase the diameter of the hole and that’s something you absolutely do not want to do,

    So for me a new 3/8" bit would keep it dead center with out even touching the frame shaft.

    After I needed to smooth and polish the countersink area and what I used was a three inch piece of plumbers emery cloth which I rolled as tight as I could long ways and folded it in half and clamped the two ends onto my drills chuck and at a high rpm polished the inside of the dimple until it was perfect about 1 1/2 minutes make sure you plug the frame hole because you don’t want the emery cloth contouring to the frame hole and altering the diameter of the hole, what I used was a 13/64” drill bit and held it flush to the bottom of my dimple with my left hand while doing the polishing.

    One thing to remember if you have a black gun is to use some masking tape around the 3/8” dimple to prevent any swirl marks from the emery cloth mime is stainless and I was able to remove any swirl marks with a light rub of emery.

    Be aware that the 3/8” dimple will not have a 3/8” profound radius but more like a melted look since you’re doing everything by hand.

    I think that the 3/8” countersink even though it’s bigger you still have to work at it to push out the pin but it’s more practical for ease of take down. We tried using a 5/16” countersink on my sons SA mil spec and he uses the back of a pencil eraser for take down, I think any thing smaller than 3/8” you will be restricted to use a tool of some kind for take down.
  2. NGIB

    NGIB New Member

    I saw this same post on other national gun forums and it will be received here the same way it was received there - not necessary and it potentially weakens the frame. It's your gun - do what you want but I personally think it's a VERY bad idea. I doubt any of our resident gunsmiths (or JMB) would agree that this is a good idea...
    Last edited: Apr 26, 2010

  3. Ruzai

    Ruzai New Member

    The visual appeal of it may be wonderful and the feel of it on an indexed finger may be great, but the tensile strength of the steel that Taurus uses on their 1911s is average at best. The amount of metal removal is a big problem, since you are actually causing the slide stop lever to actually have less to apply pressure to on the countersunk side of the frame could ultimately cause major wear and issue with the frame especially in the case of your pistol having torque from the barrel link (often from a bad fitting link). Though YOU may not have problems with it doesnt mean they wont develop or be more apparent with someone else doing this job.
    Like NGIB said, its your pistol, do as you want but this is just my 2 cents.
    When Nighthawk, Kimber, or some other company offers this option that's fine, they have trained gunsmiths and engineers who are capible of doing this with barely any drawbacks, especially on a line of production guns.
    I really dont see a point to altering a design that works perfectly, the design always looked finished to me...
  4. DrumJunkie

    DrumJunkie New Member

    I don't think it has as much to do with inferior steer by Taurus. But it does bring to issue the removing of steel in an area that does not need removed to begin with. What's the plus side to this besides looking different? I am not at all comfortable with the idea of removing material from a frame all the while heating it up pretty good too in a place that really does not need to have that kind of change to the frame.

    Also..I see it right that this novel of a post was the OPs first?:confused:
  5. stalkingbear

    stalkingbear Well-Known Member

    I don't do that to any of my own personal pistols and cannot recommend doing it yourself to any pistol you care about. The idea of cosmetic VS lessened strength just isn't worth it.
  6. cpttango30

    cpttango30 New Member

    I am with NGIB and The Bear if the Bear says it is wrong I am sure 99.9% that it is wrong and shouldn't be done.

    I personally don't think it looks all that good to begin with.
  7. masterPsmith

    masterPsmith New Member

    This is something that poses no advantage of any kind. Removing metal from that area of the frame has the possibility of weakening the frame. I would never do it to mine and I have been doing 1911 work for over 40 years. Take it from there.......................