After installing some new parts, I experienced very stiff operation of Ambi Thumb safety on my Springfield Armory Garrison/.45. that I think I got resolved with some online help.
I bought my 1911 mostly as a range gun, but also to learn how they work. Recently, I purchased a Wilson Combat Bullet Proof Deluxe Sear, A-2 (Item #314) and Ultralight Skeletonized Hammer (Item
#337B ), as a trigger group upgrade to the factory SA MIM parts. It helped that the parts were on sale at 25% off (I got both parts for $64 plus shipping), and I have had good luck with previous WC orders. Previous to this, my local smith (Brandon Bunker) had installed my WC BP Ambi safety and FO sight. While I am for sure not a gunsmith, this time I decided to try and have a go at fitting the sear and hammer myself, to save some money and as a skill development exercise for me.
While the parts went in with no issue, after installing the sear and hammer, using the Ambi Safety was quite a chore. The axle would insert, but it was very hard to get in, and very very stiff to engage and disengage, with a slight "hitch" to the upward movement. I spent a couple days thinking about why this was so. I even removed all the new parts, and reinstalled them one at a time (I got pretty good at taking it apart and putting it together). I ended up realizing the primary issue was the left hand TS piece interacting with the new sear. Although they looked very close to the original parts, there was something just slightly off going on.
Finally after looking around for good online sources of instruction, I happened on this video by Jason Burton of Heirloom Precision, who explained the process he used to fit a Thumb Safety. The process Jason described of fitting on the axle was exactly what I was experiencing:
I examined the sear lug of the left hand part of my thumb safety. Sure enough, I saw some uneven wear there, indicating incorrect contact with the sear, and the cause of the stiff operation, as per the video. I placed the part in my block, and used my Grobet USA 6" #4 file to take a few few strokes (4 maybe), keeping the file parallel to the opposite side of the sear lug. I reinserted the part into the gun. It was better but still a little stiff, so I removed it and took a few more file passes (2 maybe). I polished where I filed with a little Flitz held on a finger, to give it a bit of a shine. After final assembly, it worked much better, up and down, and the hitch was almost gone.
The rotation of the TS went from "Almost Impossible with Two Fingers" to "stiff but manageable with a thumb". I think I could have removed some more material, but I decided to leave it as is for now, and go shoot it. I am assuming the metal will wear in even more, and hopefully result in a crisp operation after a few hundred more rounds, but it is much, much better than I started.
The location of where I filed on the part is circled in red, below. The orientation angle of the file, at left, is the angle I filed at (file rotated 90 degrees, obviously.) I filed straight across the surface, holding the part steady in my block.
Some other things I noticed: The right hand piece of the WC TS "catches" into a small teeny hex screw. The screw head actually rests in a slot, so removal of the right hand piece means you rotate it up all the way, so the screws reaches the slot milled there. Very clever. The two pieces also join in two keyed slots, on both ends. It appears to be a very secure design. (Bear in mind this is literally the first TS on a 1911 I've ever seen close up or taken apart, so I have very little for reference.)
Anyway, it was an interesting couple of days working this out, so I thought I would share in case it helped someone out with the same issue.
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Originally Posted by RJ
After installing some new parts, I experienced very stiff operation of Ambi Thumb safety on my Springfield Armory Garrison/.45. that I think I got resolved with some online help.
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