doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com 1883 Colt Trigger plate screw

I have an 1883 Colt S x S that I am restoring. Currently my biggest challenge is the trigger plate screw, it is seriously buggered up and I don't know the best way to removing it? Any suggestions?

Best to start with a long soak with a GOOD penetrating oil. It sounds like the screw will have to be replaced, but you don't want to make matters worse by breaking it or damaging surrounding metal. If you can get it out, you might be able to save the screw by TIG welding the head and recutting a new slot after dressing down. Also, it sure helps to have the old screw if you need to have a gunsmith or machinist make a new one.

A picture might help, as we don't know whether the screw slot can be used at all, once the threads are soaked. Patience is a virtue here. I've had some extremely stuck screws suddenly come out easily after several months of repeated soaking. While soaking, you could try tapping it with a brass drift to help the penetrant soak in. You could also alternate soaking and heating with a soldering iron. The abrupt change in temperature between the male and female threads can break the bond of rust, corrosion, etc. Did I say that patience is a virtue here? Rushing with dry rusted threads leads to galling, then you're screwed... pun intended. Gun screws are usually small, so things like E-Z Outs aren't likely to be any help.

If any screw slot remains, carefully clamping the action in a drill press vise and using a properly fitting bit in the chuck is a good way of maintaining firm downward pressure while turning the chuck counterclockwise BY HAND.

If that fails because the screw slot is too buggered, sometimes you can carefully cut the slot a bit deeper with a steady hand and a Dremel cut-off wheel. Going too deep into the screw head increases the chance of twisting the head off. Alternately, a small sharp chisel can be used to rotate the head counterclockwise by repeated tapping, but there is the risk of damaging surrounding metal, so it's kind of a last resort.

My all time favorite penetrating oil is Cabot's Tasgon. You likely won't find any because it was discontinued in 1983 due to creosote content. I only use it for more expensive things and things that can't be replaced. I don't even consider Kroil to be a penetrating oil as it has failed getting into threads for me so many times. I don't think it is any better than straight kerosene. I use my remaining supply on things that aren't real stuck, or as an assembly lube. Many folks swear by it... I think they need to get out more. I've had good luck with ZEP 45, pure oil of wintergreen, Burlite, and the 50-50 ATF/ acetone mix. I've tried everything I could get my hands on and most were disappointing.

Do you have a drill press or mill at your disposal? I use one of my mills, a tight fitting screw driver bit and a whole bunch of downward pressure on the quill, that almost always works.

I have used that procedure myself. It may take a few minutes to set up, but it paid off. I don't have a mill, but did it with a drill press.

WOW, a lot of very good advice. I do have a drill press but not a mill. I can send pics but I'm not very good at uploading the pics.
This is a very tired Colt, and it was used a lot. The screw is severely buggered. I've got time and am a patient person. I definitely don't want to do any further harm to it. I will continue to soak it and wait. The techniques you all mentioned at jarring the screw loose will come sometime down the road.

If the screw slot is chewed up but appears to have a chance at removal with a screw driver bit in a mill or DP, take some time to file the tip of the bit to sink into the slot as best as possible.
Then when giving it a try, place a small amt of valve grinding compound on the tip of the bit.
It will help the bit grab in the screw slot a little more than w/o it.
Use heavy hand pressure downward on the quill when trying to remove it. Sometimes very slightly turning the chuck/w bit engaged back and forth will help loosen things.

For heat, I place a brass (or steel) rod onto the head of the screw, Hold with pliers at the other end and heat the rod w/a propane torch. The heat travels down (and up!) the rod to heat up the screw.
A poor quality screwdriver blade can also be used. It will/can fit right down into the screw slot to transfer the heat.
Remove any handle from it especially plastic ones so you don't get a smoldering plastic while doing this.
Re-usable of course for this purpose,,it wasn't any good as a screwdriver anyway.

I like the valves grinding compound idea. Never thought of that. As for heat, I have usually heated whatever the screw is screwed into if possible. Heating causes expansion and would we not want the female part to expand more than the male part? Of course, most of the time I am not dealing with gun parts and precise heat location is not always viable, so everything gets hot.

All good information. Examining the wretched screw slot again, I'm thinking a very angry person, with a short fuse, attacked the screw with poor equipment and a heavy hand. But considering this gun is at least 125 years old, who knows what the real story is. Anyway, I'm here to bring peace back into its life and work slowly towards a solution. If I send a picture to someone more tech savvy than me, could they upload the picture so you all can see what I'm up against?

Hi Carl, It maybe that you'll just have to drill it out and make a new one. I can help if that is the case.