It’s a two piece safety that really shouldn’t need smithing, just remove the old single and replace with the two piece.
Replace the left side, then lock in the right by slipping it into place so it matches up with the left.
It’s held in place by tension.
I’ve done a few and none needed very much if any filing or fitting.
Here’s a DIY video...
https://www.youtube.com/watch?v=j8jFgdA0R2Y
I have done one in the past and it was a simple remove old and put in the new.
However on the Para Ord. P13 the safety part which engages the sear is a lot smaller than the Wilson Ambi. As such the Wilson will go in but not rotate.
Needs a steady hand to file or grind to the correct size.
On a 1911 a safety is a fit part. While some drop in, don’t expect it to. It’s not a hard job to do yourself provided you have the proper tools. A small file is usually all you need, but a marker can help also.
One thing you might encounter is if you have a fit grip safety. When you fit a grip safety you blend the frame which usually means you have to blend the thumb safety also.
If a safety just drops in without fitting then chances are it isn’t right.
There is not a lot of error room from fitting properly to being too loose ( IE unsafe)... so in my world ( only been working on 1911’s since late 70’s) ALL safeties should require fitting rather than relying on luck of “ oh it dropped right in and works”
LMK if can’t find someone on your side of town
There are several areas where a thumb safety would/should need a bit of filing/fit work. The sear engagement is the most obvious/critical. if you go too far there, you will ruin a $$ part, and/or make the gun unsafe.
As mentioned, if you are unfamiliar with the inner workings of a 1911, it's probably a job best left to a 1911 smith. However, if you can detail-strip a 1911, and have a decent understanding of how all the parts work together, then fitting a thumb safety is typically a DIY-able job. You just need to understand the mechanics, tolerances, and potential interference areas. The correct tools (files, stones, armorer's block, etc.) and good lighting/magnification also helps...as does a steady hand.
I still need some recommendations for a gunsmith to install a ambi safety on a Para Ordnance P13.
I have since learned:
1 - That a drop in safety is generally made for single stack magazine guns.
2 - That double stack magazine guns are not so easy to install a drop in safety and require fitting.