Jump to content

Lyman Sight Dis/Assembly


Recommended Posts

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

Lyman Sight.jpg

 

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.

  • Upvote 1
Link to comment
Share on other sites

I don't want to rain on your parade, but good luck. You'll need it. I have done many

of 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 lucky

the pin is undamaged and you will be able to drive it out and replace it without too much

trouble. 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 for

it to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feel

bad if it takes a while. This is all hand work. There are no shortcuts.

 

Bob

  • Upvote 1
Link to comment
Share on other sites

I don't want to rain on your parade, but good luck. You'll need it. I have done many

of 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 lucky

the pin is undamaged and you will be able to drive it out and replace it without too much

trouble. 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 for

it to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feel

bad 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. :blink:

Link to comment
Share on other sites

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.

  • Upvote 1
Link to comment
Share on other sites

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

 

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

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

I don't want to rain on your parade, but good luck. You'll need it. I have done many

of 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 lucky

the pin is undamaged and you will be able to drive it out and replace it without too much

trouble. 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 for

it to require 20-30 minutes to get the pin out, and dress it so it will go back in. So don't feel

bad 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

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

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

Well, that makes a lot of sense - right to left out, left to right in. I was not able to

detect a difference in the hole size with my gaga pins but now that I think about it

that's the direction I go in when checking fit before bluing. Thanks for unraveling

the mystery!

 

Bob

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...