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1928A1 Ejector Threading?


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Hi everyone! Haven't been on this board in a long time. Been working myself to death on mandatory OT. Anyway, I was wondering if anyone knew what the thread size was for a 1928A1 ejector??? Got to clean up some boogered threads and want to make sure I get the correct thread tap.

TIA,

Vic

Edited by m2hbvic
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Thanks bob241 and reconbob for the info. Never heard of 14-24 threads before. Good thing I asked you guys before I started spending money on the wrong tap. After searching around on the internet, I had assumed that it was 1/4-24 threads, which just so happened to be the threading that Harley Davidson used on some of their engine parts (cam cover?, oil pump?, etc.) back in the early days.

 

BTW, does anyone make thread repair inserts (Helicoil brand?) in this older 14-24 thread size???

TIA,

Vic

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I would not drill out the receiver for helicoils or keensert types of thread repairs. How bad is it? Pictures?

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Hi giantpanda4. It's bad enough in my opinion. When I bought it years ago, the flat locking tab part of the ejector assembly on the outside surface of the receiver was already broken off flush and it looked like someone had tried to peen the edges of the threaded piece and the receiver surface to keep the ejector from rotating out of its correct clocking position. Fast forward to the present and I decide to install a new ejector. Anyway, I decided to try and drill a small hole, on center, into the ejector, with a tiny drill bar, slip-fit guide bushing, and a tungsten carbide bit, and try and use an easy-out extractor to screw it out. No luck. Seemed like the ejector was siezed. Applied KROIL to both ends of the ejector a few times over the course of a few weeks. Still wouldn't budge. Seemed like the peening was holding it in tight. Started to continue drilling the hole deeper to try and get a better bite with the easy-out. Still no luck. Carefully tried grinding away most of the body of the ejector with a tiny tungsten carbide rotary mill file to try and relieve some tension on the threads. Still no luck. Ended up drilling the rest of the way through with the carbide bit. Ended up being slightly off center or off-angle by the time the drill broke through the other end of the ejector itself. Was able to pry out/unscrew what was left of the threaded ejector shank. Threads are visible on one side of the hole, and not so much on the opposite side of the hole. I'll have to see how the threads clean up when I get the thread tap that I ordered and run it in what's left of the original threads and hope the replacement ejector threads all the way in and clocks correctly. I'll try and post some pictures this weekend when I'm not working and have more time.

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  • 2 weeks later...
Hi M2hb, you probably won't find #14-24 helicoils. And it would involve drilling quite a bit larger hole in your receiver. I would borrow-or-buy the #14-tap, clean up the hole and new ejector with electronic-cleaner, coat the ejector threads with red Loktite and screw it in. If it comes loose someday, go ahead and thread the receiver 1/4-28 and build a custom ejector from a 1/4-28 bolt silver-soldered to an original arm.. Phil
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"First, do no harm" -to the receiver, if at all possible.

As long as there are some existing threads for alignment and strength, I'd use release agent on the ejector, and JB Weld, Brownell's Steel Bed, or some similar metal reinforced epoxy to create the missing threads. I've repaired some rather high stress parts with this method, and so far not one has failed.

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Thanks anjong-ni and mnshooter for the repair suggestions. I was hoping to keep the repair all solid and metal-to-metal by using a helicoil but that's not looking possible if nobody makes it in the odd thread size. I may just have to use the epoxy method after all. I may use some CB-200 glue, what I call "the glue from hell", that we use at work on aircraft to bond threaded nut plates to the structure instead of using rivets. It is some tough as nails quick setting polyester based glue. Smells toxic as hell when applied, but it holds/bonds just about anything after it cures to 75% strength in about 2 hours. It even holds up to the heat in the jet engine bays. Wish me luck. TIA.

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Vic,

I am curious what you will do if the CB-200 glue plan you outlined above works, but 3 years from now the end of the ejector breaks off. Or your plan does not work because the ejector is not screwed in far enough or too far or slightly at the wrong angle, etc. Is there a release agent for CB-200 glue? Or is this basically a one-shot deal once the ejector is installed via the CB-200 glue.

 

Good luck!

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I completely agree!

 

If you cannot post pics - PM me and I will post for you!

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Hi All,

 

Late to the show. Victor machinery Exchange has the 14-24 taps for $10.50 + shipping is normally a good starting place for tools.

 

https://www.victornet.com/subdepartments/Special-Pitch-Taps-up-to-1/2-inch/1260.html

 

Personally I'm rather fond of these old firearms. I'd set up the gun carefully in a quality knee mill (Bridgeport, Sharp, etc) to support tooling to put the tap in at the correct angle. Everyone's skill is different.

 

If the threads are replace rather than repaired, I'm sure everyone realizes those threads are timed with the ejector so the tab ends up in the correct location.

 

Enjoy,

 

Grasshopper

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