1911 Disconnector Recommendations

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DT Guy

New member
So today at the range, my SIG Nightmare Carry shot with its usual aplomb, but a field strip to clean it showed this afterwards:



Looks like the disconnector failed in a particularly MIM sort of way to my eyes; that eroded/crumbled look isn't what you'd expect from a tool steel part.

Since SIG will only fix it if I pay the $55 shipping, in spite of the obvious failure of their part, I'll be dropping a barstock disco in; any favorites?

A quick search found some positive comments about the EGW ballhead part, and EGW makes quality stuff; any reason NOT to use that, or is there something better on the market?

Larry
 
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Scorch

New member
Ah, yes! Good old MIM parts. Get an Ed Brown if you want a stronger one, or just about anybody else's if you just want a replacement that works.
 
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dahermit

New member
Looks like the disconnector failed in a particularly MIM sort of way to my eyes; that eroded/crumbled look isn't what you'd expect from a tool steel part.
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It looks exactly like a tool steel part that was not heat treated (not drawn to a soft enough state, left too brittle, or was fired too long at too high and temperature and the grains grew), correctly.

If a machined part breaks, it is because, "all steel things eventually break."
Id a MIM part breaks, it is because, "that is what can be expected from MIM parts."
 
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ShootistPRS

New member
If a machined part breaks it is because it was incorrectly engineered or incorrectly manufactured. Steel can be made to fit an application so its useful life is "absolute". Aluminum and its alloys begin to fail the first time stress is placed on the part. That's why aircraft aluminum parts have a life expectancy in "cycles". The same should be considered when aluminum alloys are used in guns.
 
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DT Guy

New member
Well, I've seen grain growth in tool steel; this is far too large a grain size for any furnace-based tool steel I've ever seen. It actually looks like a polystyrene cooler with a corner chipped off.

As far as 'eventually' breaks, I'm not sure a tool steel disconnector, correctly machined and heat treated, would be expected to 'eventually' fail at 2k rounds, would it?


Larry
 
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dahermit

New member
As far as 'eventually' breaks, I'm not sure a tool steel disconnector, correctly machined and heat treated, would be expected to 'eventually' fail at 2k rounds, would it?
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The key words might be, "correctly heat treated". Then change your statement to:
"As far as 'eventually' breaks, I'm not sure an MIM steel disconnector, correctly machined and heat treated, would be expected to 'eventually' fail at 2k rounds, would it?"
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Seems that MIM parts that are installed in jet engines and other high stress applications work alright, now don't they.
 
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weaselfire

New member
It's not the fact that it's MIM that caused a failure but, if you don't want MIM, don't buy guns with MIM parts or replace them with other options. Beyond that, if you don't want to send it for warranty, buy a replacement and fit it yourself. All the major names are decent, pick what meets your needs.

Jeff

Sent from my XT1254 using Tapatalk
 
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DT Guy

New member
I'm surprised at the pro-MIM attitude, to be honest. A part failed (a low-stress, relatively minor part) in a rather unusual manner, and the part is MIM.

While I don't consider it proof of causality, I do find it suggestive; yet others seem certain it was NOT related to the part being an MIM one. Hmmm.

I'd like to see photos of tool steel disco failures; it might help with determining the extent to which the manufacturing process played a part.


Larry
 
4

44 AMP

Staff
Since SIG will only fix it if I pay the $55 shipping, in spite of the obvious failure of their part,..
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This is the part I find surprising. Apparently SIG has changed their policy in the last few years, as a friend of mine bought a USED SIG at a gun show about half a dozen years ago, admitting he didn't do his usual pre-purchase inspection. The gun had serious issues, which he thought might have been the result of a previous owner's "gunsmithing".

He contacted SIG, and they immediately sent him a prepaid shipping label. Fixed the gun and sent it back to him, all on their dime.

So, either they've changed their policy, or there's something about your specific situation that negates the policy, or maybe you just talked to the wrong person at SIG. I don't see where it could hurt to talk to other people there, maybe the night higher up level?

I do agree it is not right to have to spend that much to get a minor repair done for free.
 
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g.willikers

New member
Like weaselfire said, the disconnector is such an easy part to replace, why do anything else.
They're not even expensive, not nearly as much as shipping yours to Sig.
 
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DT Guy

New member
44Amp,

I agree. Checking their website, it is what they state in their warranty section, and they stuck to it, even after I challenged (politely) them on it.

Disappointing, but lesson learned..

Larry
 
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PACraftsman

New member
Will Sig just send you a replacement part. Even if you don't want to use it because of replacing it ahead of time, you can have it on hand.
 
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laytonj1

New member
Seems that MIM parts that are installed in jet engines and other high stress applications work alright, now don't they.
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I don't know, do they?? What is their life cycle and failure rate? Are they subjected to the same type of forces as an extractor or slide stop? Are they constructed to the same standards as a gun part? Is the composition the same? Seems like a silly comparison to me.

Jim
 
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dahermit

New member
I don't know, do they?? What is their life cycle and failure rate? Are they subjected to the same type of forces as an extractor or slide stop? Are they constructed to the same standards as a gun part? Is the composition the same? Seems like a silly comparison to me.
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Just to get even "sillier", it is notable that some connecting rods on automobiles are also made using MIM...something that takes far more stress and strain that a disconnector for a 1911 ever would. To dismiss MIM as resulting in inferior parts is a bigger "silly". :rolleyes:
 
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Don P

New member
Just to get even "sillier", it is notable that some connecting rods on automobiles are also made using MIM...something that takes far more stress and strain that a disconnector for a 1911 ever would. To dismiss MIM as resulting in inferior parts is a bigger "silly".
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I concur. Has anyone proven without doubt that the part is MIM?? How about folks posting pictures on AR bolts that have broken. Parts whether MIM or machined for steel stock WILL fail from time to time. MIM has come a long way in the manufacturing process and quality has followed suit.
 
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DT Guy

New member
It's MIM; most of the gun's internals are MIM, with very evident molding marks. They appear to be of high quality, although the disco failing in ~2K rounds doesn't seem to support that.


Larry
 
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Unclenick

Staff
Is that because MIM turntable spindles started snapping off? ;)

I wouldn't be surprised if aircraft parts get x-ray inspection to eliminate any with faults that would cause a failure like that. I feel equally confident gun parts don't get x-ray inspection.

My wife did some work for an automobile maker trying to qualify a MIM shop to do some transmission parts for them, but the photos of the sectioned sample pieces were distressing. Apparently doing good MIM parts takes skills and abilities that are not to be found just anywhere that has the equipment. The shop had designed the mold, the automobile maker's engineers had come back with a number of suggestions to change and improve the mold and the sectioned sample proved that the mold wasn't working as it was. Eventually the shop dropped out of trying to qualify as they found the automobile maker just too picky and difficult to accommodate and decided work that difficult wasn't worth investing their time in.

So, maybe that shop made the disconnector or maybe it's a fluke. In any case, Ed Brown or EGW are both quality sources of parts, IME, and I wouldn't hesitate to use either.
 
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DT Guy

New member
Since this occurred, I've been told SIG MIM is sourced from India, and their supplier is considered to be less than state-of-the-art.

No idea if it's true, but this failure was disconcerting. I've not minded MIM in the past, and not had any failures to change my opinion, but this was a relatively new, relatively low-stress part that failed in (IMHO, at least) an unusual way.

And with Donna Summer gone (44Amp!), I've decided to get my 'disco' from EGW, which is a machined tool steel part.

My biggest beef throughout all this, though, isn't how the part failed, but how SIG handled it; enough to put me off their products going forward.

Larry
 
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