1911 mainspring housing - Please un-confuse me

[gunsrfun1]

I have a Colt Commander, and the plastic mainspring housing developed a crack (probably my fault), so I got another one from Colt. It's plastic, and has a dimple near the top where the mainspring will sit. Down at the bottom, there is a nub in the hole that the pin goes through, to lock the pin.
Seems pretty straightforward.
Except ... I also ordered a metal MSH from Springfield Armory, just in case I wanted a metal MSH. But it's very different, in that there is no dimple at the top. There is a hole that goes all the way through to the bottom, and there is no nub at the bottom for the pin to lock into.The pin just slides in and out without locking.
I have not actually tried to install the SA part in my gun, but I assume the SA part is obviously not right for my gun. Is that because the SA 1911's have that internal lock gizmo in the MSH?
Thanks

 

[entropy]

Plastic Mainspring housing?
You probably need actual M1911 internals for the metal one, which will be the mainspring cap, mainspring, mainspring retainer pin,and mainspring cap pin. These will be held in the frame by the mainspring housing pin. I don't know what the hell was in the Colt plastic one. but buy new, quality, parts for your SA housing.
Parts 25, 26, 28 and 30 are internal to the housing, and 29 is the mainspring housing retaining pin, in the schematic here:

https://www.gunpartscorp.com/gun-ma...lt/1911-govern-ser70/parts-list-ser-70?page=4

 

[cfullgraf]

The nub at the bottom that you can see in the mounting pin hole is an extension of the spring follower at the bottom of the main spring.

I'm not sure about the dimple at the top you are talking about.

I've been replacing a couple mainspring housings recently with arched mainspring housings. My preference. I purchased Ed Brown and John Mason housings and they fit perfectly replacing the Colt plastic housings re-using the Colt spring internals.

 

[mjsdwash]

unless somethings changed, that lock in the springfield housing is a pin to keep the spring captive, not any kind of safety, though you may be talking about something else.

 

[gunsrfun1]

Thank you all, THR to the rescue once again. I get it now. I am somewhat new to 1911 gunsmithing, so I was thinking that the original plastic Colt MSH was simply a piece of plastic, not knowing that the MSH contains other parts, as Entropy has pointed out with his diagram.
I just took a look at the new MSH that Colt sent me, and indeed the "dimple" at the top that I thought was part of the plastic molding appears indeed to be part #26, the mainspring cap, and of course the "nub" at the bottom is part #30, the mainspring retainer pin.
So apparently Colt sent me a complete MSH assembly with all the internals. And the SA MSH I bought is simply the MSH, without any internals.
So I now have an extra set of Colt internals, if I want to install them in the SA MSH.
Not sure if I will simply use the Colt replacement (they sent it to me at no cost, and I don't plan to remove it once I replace a sear spring), or use the SA MSH ($22).
Thanks again.

 

[cfullgraf]

So I now have an extra set of Colt internals, if I want to install them in the SA MSH.
Not sure if I will simply use the Colt replacement (they sent it to me at no cost, and I don't plan to remove it once I replace a sear spring), or use the SA MSH ($22).

I'd use the metal main spring housing versus the polymer one. It is just more durable. You will lose a little weight advantage with the metal main spring housing but it will be minimal and I suspect un-noticeable with the gun loaded.

And just think of the knowledge you will gain working on your M1911.

 

[Cemetery21]

IF you decide to swap parts to the metal housing, there are a few ways that don't need 3 hands. I have a finish nail driven into the side of a bench with about 1/2" of the head sticking out. Push the head of the mainspring cap against that to compress the mainspring a little. Use a small punch or straightened paper clip to push out the mainspring cap pin. Or it might fall out when the spring pressure is off. Don't lose it. Release pressure on the nail head (gently) and the internals will come out. Put all 3 pieces in the new housing in the same order, depress the mainspring cap as before and secure the cap with the little pin you didn't lose. Viola'.

 

[Walkalong]

I (Immediately upon purchase) replaced the plastic Mainspring Housing on my Kimber, and reused the three inner parts. (Spring, Mainspring Retainer, & Mainspring Cap [Part with the "dent"]). I used one with a "Magwell" bolted on. The whole assembly is of course held on by the Mainspring Housing Pin. I would have to go look through my box of replaced 1911 parts to see which one I bought. The old plastic one will be in the bag the replacement came in with a note as to where the new part is.

 

[crestoncowboy]

I'd likely use the metal one as well.

But to the "more durable " ......I don't know about all that. I think one could likely find a durable polymer frame made in the last 30-40 years to use as an example if they tried really hard.

On some of our old production machines that run 24/7 there is a worm gear That lifts and lowers a thousand or so pound table constantly. 10 gears per machine on 40 machines For years we changed that metal gear every 8-12 months when it stripped. Then one day the part became obsolete and we ordered the replacements. We were all livid when we recieved a blue polymer/nylon/ plastic lifting gear. No way that would work....... that was roughly 10 years ago. I don't recall ever having to change one of the new ones. Lol

 

[Walkalong]

According to my note, I replaced it with a Kimber Tactical mainspring housing. (Along with some Cylinder & Slide, Ed Brown, & Wilson parts)

 

[gunsrfun1]

Thank you all again, great information.

 

[CapnMac]

MSH on a 1911 is a relatively non load-bearing part. Its primary purpose, beyond completing the gripping surface, is to enclose the hammer spring. Which actually bears upon the bottom pin through the bottom back of the grip frame.

The housing could probably be made out of paper pulp within no wear issues. JMB designed the thing out of steel because, in JMB's day, steel and machining were pretty cheap.

A person could probably make one from sintered metal that would last as long as the rest of the arm. Machined metal is more reassuring to the mind, and pleasing to the eye.