Frame question. Kimber aluminum frame pins and pin hole play?

[kdogg]

I have a couple of these aluminum framed Kimbers and the other day while fitting a new MSH to one, I noticed the pin holes, the hammer pin hole to be more specific, seems to be worn slightly. I have play in the hammer pin. It's not very much, just enough that is is noticeable.


When I say play, if you run the pin threw the frame, the pin then has front to back and up and down play in the hole.


The gun still works 100% though. Should I be concerned? What does someone do in this case? Will Kimber take care of it? The gun has several thousand rounds threw it but no where near the 25K Kimber claims to have tested them to.

[niemi24s]

Should I be concerned?Your description doesn't really give much of an idea of how much play there really is but, FWIW, there can be as much as 0.004" of play and still be within Army Ordnance specifications.

Regards

[10851Man]

Kdogg,

I have a brand new (steel frame) Sig 1911 here that was sent to me for evaluation and it has visible movement in both the hammer and sear pin holes. I don't like that at all, but the gun does function perfectly.

First thing you need to do is measure the diameter of the hammer and sear pins and their holes. The ordnance spec on the hammer pin (IIRC) is about .156" +or- .002" and the sear pin is .108" +or- .002" respectively.

I keep the 'oversize' hammer and sear pins from Cylinder & Slide in stock. Their title is a bit misleading as they are only made to the 'high limit' of ordnance spec; around .1575" on the hammer piin and .1105" on the sear pin.

The pins are very easy to make if you have access to a lathe and the raw material. Any competent gunsmith could do this. The countersink under both pins is 60° IIRC. I have .111", 112", 113" and .114" reamers in stock for the sear pin holes. If I find one worn, I ream it to the first true oversize and fit the new pin to the sear. Reamers are available from many of the large tool and machinist supply firms, as they are not a 'gunsmith specific' piece.

Seldom do I find the holes truly 'worn' (read: egg-shaped) and in most cases, you will find a 'low limit' (.106") sear pin in a 'high limit' (.110") frame hole.

Hope this helps...Robert

[niemi24s]

And, FWIW, Army Odnance blueprints for all the 1911 parts are available in our Tech Issues section - just in case you want to have something to compare any measurements to.

[kdogg]

I have the tools to measure the holes, I'll do it when I'm home. Right now I'm in the car driving back to Michigan from West Virginia.

Anyway, yes egg shaped might be a good description. The hammer pin hole, if I insert the hammer pin and look at the pin/hole from the right side of the frame there is a visible grapping in the back bottom portion of the pin hole if that makes sense. Between the pin and the frame. It's like the pin had pushed back and down into the frame a little. Maybe from the shock of the gun recoiling when being fired? Again doesn't look major.

I'll measure from different sides of the hole and see if it's different from different angles.

[kdogg]

I guess it's not really out of spec. The hammer pin is .156 on the money, every time I measure and the hole it .157~.158 depending which angle I measure from.

That was the one I was worried most about.

One of those over sized pins will take up the slack correct if I decide to get one anyway or should I just not worry about it?

[10851Man]

I would go with the oversize hammer and sear pins from Cylinder & Slide. The hammer pin is about .1575" and the sear pin is approximately .1105" in diameter...Robert

[niemi24s]

Hi Robert:I would go with the oversize hammer and sear pins from Cylinder & Slide. The hammer pin is about .1575" and the sear pin is approximately .1105" in diameter...RobertDid you ever run across any pins that were too oversized - wouldn't go through the holes in the hammer or sear?

[10851Man]

Yes, but only with the TiN Coated C&S Oversize Pins....In that case, I ream hammer and sear to accept the pins...Robert

[kdogg]

Just remember reaming isn't really a good option on a aluminum alloy frame unless you have it refinished too, when you ream the holes, you take off the hardened surface the pins ride on, exposing the softer metal underneath.

The I think a .1575 hammer pin would fit without issue. Most of my measurements were .1576~1580 anyway.

[kdogg]

I need to order some items from Brownells anyway, will these work?

http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=16420&title=1911%20AUTO%20PIN%20SET

I'm confused as if it actually contains over sized pins though. I looked on Wilson's page and those two sets are ALL I see listed, nothings listed on it's own as over sized pins in a set of two.

Brownells doesn't carry the over sized C&S sets either.

[10851Man]

I agree...Never mess with aluminum frames here. I have only seen one in my lifetime!!!!...Robert

[kdogg]

I agree...Never mess with aluminum frames here. I have only seen one in my lifetime!!!!...Robert

They make nice carry guns, that's for sure. Really light weight and nice.

[niemi24s]

I'm confused as if it actually contains over sized pins though.
It probably doesn't.

My rule of thumb is that unless the manufacturer provides a dimension which exceeds the maximum Ordnance spec, the word "oversized" in the ad means nothing more than "at the upper tolerance limit" - not over it.

Also note the "ground to maximum diameter" in the Brownells ad you posted.

The word oversized (and undersized) is abused a lot by aftermarket 1911 part makers.

Regards