2ndArmored Posted June 15, 2019 Report Share Posted June 15, 2019 The bolt of the M1 carbine is a lot easier to work on with a handy little tool designed just for that purpose. (No, I'm not in the wrong chat room.) Taking apart the Thompson's 55B rear sight looks uncomplicated, but I question putting it back together. I can't find any diagrams or videos regarding its composition. All I want to do is remove (and return) the ladder assembly from the base so I can dump the base into the bluing tank. To those who've had their sight restored (HA!) I request advice or admonitions. Do I need special tools for this job, or are the usual (pin punch sets, screwdrivers, etc.) sufficient? Link to comment Share on other sites More sharing options...
gijive Posted June 15, 2019 Report Share Posted June 15, 2019 The above picture shows the pin that needs to be removed. Drive it out with a quality punch otherwise you risk flattening the end and marring the finish. The pin is under tension from a spring and plunger housed in the long tube marked with the Lyman nomenclature. After many years of storage and cosmoline these pins are sometimes hard to drive out. One removed the plunger can be removed fairly easily. Sometimes the spring gets stuck in the tube from years of grease, be careful removing it. Once removed you can re-blue the base. 1 Link to comment Share on other sites More sharing options...
reconbob Posted June 15, 2019 Report Share Posted June 15, 2019 I don't want to rain on your parade, but good luck. You'll need it. I have done manyof these because so often we have to blue the sight base with the receiver so they match.The trouble is the long thin pin that serves as a hinge for the ladder, If you are really luckythe pin is undamaged and you will be able to drive it out and replace it without too muchtrouble. But this is a very long shot,,,this is what usually happens - - one or both ends of the pin have been flared because the pin is not hardened and the end can easily be flattened by being struck with a punch. You will not be able to drive the flared head thru the base. Pick the side that is not flared/damaged. If both ends are flared you will have to drive the pin one way to expose 1/4" of the pin so you can dress and remove the flare with files so you can then drive the pin out thru the base the other way. - the pin is usually bent. Not much but all it takes is a little to prevent the pin from easily replacing. What we do here is, after the pin is out we dress the ends and also the holes for the pin in the base with tiny round Swiss files until you can easily slide the pin back into position in the base. usually it will only go in with one end - there will be a :good" and a "bad" end so use the "good" end. - the pin is too long to drive out with standard punches. We use a starting punch, then a regular punch, then special drill rod we got specifically for this purpose which is slightly undersize to drive the pin all the way out. Once the pin is out and you have checked it for easy refitting you are over the hump.I'll add this - when we do work like this we keep time sheets by the minute and it is common forit to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feelbad if it takes a while. This is all hand work. There are no shortcuts. Bob 1 Link to comment Share on other sites More sharing options...
TD. Posted June 16, 2019 Report Share Posted June 16, 2019 Chuck & Bob,Great information. I recommend this thread be included in the reference section of the Board. All good stuff!!! Link to comment Share on other sites More sharing options...
2ndArmored Posted June 16, 2019 Author Report Share Posted June 16, 2019 I don't want to rain on your parade, but good luck. You'll need it. I have done manyof these because so often we have to blue the sight base with the receiver so they match.The trouble is the long thin pin that serves as a hinge for the ladder, If you are really luckythe pin is undamaged and you will be able to drive it out and replace it without too muchtrouble. But this is a very long shot,,,this is what usually happens - - one or both ends of the pin have been flared because the pin is not hardened and the end can easily be flattened by being struck with a punch. You will not be able to drive the flared head thru the base. Pick the side that is not flared/damaged. If both ends are flared you will have to drive the pin one way to expose 1/4" of the pin so you can dress and remove the flare with files so you can then drive the pin out thru the base the other way. - the pin is usually bent. Not much but all it takes is a little to prevent the pin from easily replacing. What we do here is, after the pin is out we dress the ends and also the holes for the pin in the base with tiny round Swiss files until you can easily slide the pin back into position in the base. usually it will only go in with one end - there will be a :good" and a "bad" end so use the "good" end. - the pin is too long to drive out with standard punches. We use a starting punch, then a regular punch, then special drill rod we got specifically for this purpose which is slightly undersize to drive the pin all the way out. Once the pin is out and you have checked it for easy refitting you are over the hump.I'll add this - when we do work like this we keep time sheets by the minute and it is common forit to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feelbad if it takes a while. This is all hand work. There are no shortcuts. Bob Holy cr@p - nothing is simple! Thanks for letting me learn from your experience. Forget it - I'll just use a sharpie and color it to match the receiver. Link to comment Share on other sites More sharing options...
PK. Posted June 17, 2019 Report Share Posted June 17, 2019 The hole in the base is undersized on the left side; this is by design to provide a press fit to keep the pin in place when assembled. The hole on the right side and through the sight ladder is sized for a slip fit so the pin can be easily inserted while the sight is assembled.Always remove the pin left to right and reinstall from right to left. 1 Link to comment Share on other sites More sharing options...
bug Posted June 17, 2019 Report Share Posted June 17, 2019 The hole in the base is undersized on the left side; this is by design to provide a press fit to keep the pin in place when assembled. The hole on the right side and through the sight ladder is sized for a slip fit so the pin can be easily inserted while the sight is assembled.Always remove the pin left to right and reinstall from right to left. As viewed from rear? Link to comment Share on other sites More sharing options...
2ndArmored Posted June 17, 2019 Author Report Share Posted June 17, 2019 The hole in the base is undersized on the left side; this is by design to provide a press fit to keep the pin in place when assembled. The hole on the right side and through the sight ladder is sized for a slip fit so the pin can be easily inserted while the sight is assembled.Always remove the pin left to right and reinstall from right to left. As viewed from rear? As viewed by the shooter. The empty shells are ejected to the shooter's right. The mag release is on the shooter's left. This is similar to theater direction - "stage left" means as viewed by the actor. Because it is the actor who is on stage. It is the shooter who handles the weapon, so directions are relative to that person's perspective. Link to comment Share on other sites More sharing options...
2ndArmored Posted June 17, 2019 Author Report Share Posted June 17, 2019 The hole in the base is undersized on the left side; this is by design to provide a press fit to keep the pin in place when assembled. The hole on the right side and through the sight ladder is sized for a slip fit so the pin can be easily inserted while the sight is assembled.Always remove the pin left to right and reinstall from right to left. Aw, I was looking forward to an afternoon of hammer swinging, pin smashing, and cussing. Thanks for the directions (in every sense) Link to comment Share on other sites More sharing options...
2ndArmored Posted June 17, 2019 Author Report Share Posted June 17, 2019 I don't want to rain on your parade, but good luck. You'll need it. I have done manyof these because so often we have to blue the sight base with the receiver so they match.The trouble is the long thin pin that serves as a hinge for the ladder, If you are really luckythe pin is undamaged and you will be able to drive it out and replace it without too muchtrouble. But this is a very long shot,,,this is what usually happens - - one or both ends of the pin have been flared because the pin is not hardened and the end can easily be flattened by being struck with a punch. You will not be able to drive the flared head thru the base. Pick the side that is not flared/damaged. If both ends are flared you will have to drive the pin one way to expose 1/4" of the pin so you can dress and remove the flare with files so you can then drive the pin out thru the base the other way. - the pin is usually bent. Not much but all it takes is a little to prevent the pin from easily replacing. What we do here is, after the pin is out we dress the ends and also the holes for the pin in the base with tiny round Swiss files until you can easily slide the pin back into position in the base. usually it will only go in with one end - there will be a :good" and a "bad" end so use the "good" end. - the pin is too long to drive out with standard punches. We use a starting punch, then a regular punch, then special drill rod we got specifically for this purpose which is slightly undersize to drive the pin all the way out. Once the pin is out and you have checked it for easy refitting you are over the hump.I'll add this - when we do work like this we keep time sheets by the minute and it is common forit to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feelbad if it takes a while. This is all hand work. There are no shortcuts. Bob At the sacrifice of historical pedigree, could I just replace the original (i.e. bent, banged, beaten) pin with a modern replacement and save myself a lot of trouble? Link to comment Share on other sites More sharing options...
ElectricSharpie Posted June 18, 2019 Report Share Posted June 18, 2019 This is my first post here and I am happy to have access to all this great information! Ive been looking for this retaining pin for a while repro or original but cant seem to find one. Anyone have a lead on one ? Ive checked numbrich and apex with no luck. PKs post was great for knowing how to re-install the pin. Link to comment Share on other sites More sharing options...
PK. Posted June 18, 2019 Report Share Posted June 18, 2019 Direction is as viewed from the top rear of the gun, as it would be fired. The pin is not a "standard" diameter, for whatever reason they chose to make it .115". When i need to replace them i use gage pins for stock. Link to comment Share on other sites More sharing options...
reconbob Posted June 18, 2019 Report Share Posted June 18, 2019 Well, that makes a lot of sense - right to left out, left to right in. I was not able todetect a difference in the hole size with my gaga pins but now that I think about itthat's the direction I go in when checking fit before bluing. Thanks for unravelingthe mystery! Bob Link to comment Share on other sites More sharing options...
Motorcar Posted June 18, 2019 Report Share Posted June 18, 2019 PK said; Always remove the pin left to right and reinstall from right to left. I think you got it backwards Bob Link to comment Share on other sites More sharing options...
Bridgeport28A1 Posted June 18, 2019 Report Share Posted June 18, 2019 I alway remember that most USGI pins move in the same direction as M16 takedown pins. Link to comment Share on other sites More sharing options...
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