Erma ELG 10 Winchester Rifle

[45flint]

that's brilliant flint.

One suggestion.. I chopped 2 coils of my mainspring - I figured it was too hard to cock, and maximum power wasn't really a concern. power did drop a foot pound or so, but cocking is now much easier, it's nicer to shoot, and wear and tear must be proportionately reduced also.

I wonder if this is not a good idea given breakages I have seen? Two incidents of frame breakage on the net. Not sure if anyone else has had a piston rod failure? I like to shoot my guns not just look at then. The reduced power may help preserve it? I tend to agree that power is not really that important here? But the other side, failures get reported, not normality, difficult to know if this is really a problem? Frame failure could have come from abuse or at least not careful handling? Have no idea if this piston rod is typical or more thin in design?

I think I read to make sure the cover screws are tight. I think that cover can certainly offer major support and if these screws did work loose with firing it could certainly be part of the issue?

[deejayuu]

Ours was bought with frame in two pieces. Do you have a link to other broken ones? Certainly agree on casing screws.
The frame and your photo of broken rod suggest, to me, basic design flaw producing right angle stress point.
P.S. on the bright side one just made 600 Euro

[45flint]

Ours was bought with frame in two pieces. Do you have a link to other broken ones? Certainly agree on casing screws.
The frame and your photo of broken rod suggest, to me, basic design flaw producing right angle stress point.
P.S. on the bright side one just made 600 Euro

Yes, I was reading it last night. I will look it up but it was a German Airgun Forum that was reviewing the Erma. It’s all in German, I had to copy each paragraph into Goggle Translation, which did a near perfect job. Will be back

The article is a great German review and mentions weakness: cites the next article on the breakage issue.
https://www.co2air.de/thema/27792-er...B10#post364337

You will notice his fix looks very much like yours.
https://www.co2air.de/thema/14525-wa...p-s-gefertigt/

[Shed tuner]

EASIER TO TRANSLATE THEW WHOLE SITE:

https://translate.google.com/transla...2%23post364337

[45flint]

EASIER TO TRANSLATE THEW WHOLE SITE:

https://translate.google.com/transla...2%23post364337

Thanks for that!

[45flint]

I was wondering if when I have mine apart with the piston repair why not epoxy some smaller metal plates right to that weak area. Less evasive and easy given my lack of machining ability. Any strengthening should be a plus?

[deejayuu]

If keeping a good one I'd consider filling the side frame voids completely with some form of modern adhesive/resin bond with fibre/carbon inclusion

[45flint]

If keeping a good one I'd consider filling the side frame voids completely with some form of modern adhesive/resin bond with fibre/carbon inclusion

Interesting thought, have to look at what’s available in this country. Almost seems foolish not to try something? Would seem a easy process and one that would never show? Whether that hurts collector value or not?

Ran across this UTube of using carbon fiber to reinforce a guitar neck. Could easily cut the carbon fiber sheets just as you cut your metal one? It may be stronger than metal in the end?

https://youtu.be/neUawpm9gsc

[45flint]

Getting ready to pull piston in the Erma and cleaned up the NOS piston from packing grease. I don’t know if this is common but the end cone looks to be welded on? Exactly the place the last one failed.

[dvd]

[QUOTE=45flint;7726694]Getting ready to pull piston in the Erma and cleaned up the NOS piston from packing grease. I don’t know if this is common but the end cone looks to be welded on? Exactly the place the last one failed.


The narrow parallel sided part of the piston rod going into the sear latching area of the piston rod is purposely rounded during the turning process, not welded.

Two reasons for this,

first is that it involves more manufacturing processes (cost) to fabricate them separately and then weld them together;

second reason is that it is faster to produce the stem and latching knob in a single turning process on one machine. What may look like a weld is a deliberate manufacturing process during turning of a single piece of metal (stem), where sharp 90 degree steps are avoided, leaving a bit more metal to strengthen the stem in the rear area adjacent to the sear latching knob.

I would think any breakages would be due to faulty hardening of the part or spring loads it is not designed for.

[45flint]

Making progress. Thanks much to DeeJayuu who shared with me all his wisdom on take down, without of which I’m sure I would have been lost. And of course thanks to Larry the collector that sold me the NOS piston! And without this forum all those dots would have never been connected.

Looks like a leather seal to me? Am I wrong, soaking in ND oil. Cleaning up all the parts to reassemble tomorrow. Using a automobile spring compressor similar to DeeJayuu. I could not get the barrel pins to release so I managed with the barrel on. The tensioning end of the compressor on the end of my wood vice instead of the rifle housing. Should be even more interesting tensioning to reassemble? Lol. I can see why a very well know US repairman offered to repair my piston if I sent it to him, but wanted no part of working on the rifle.



Looks like a leather seal? Now on new piston, that part was easy.

[45flint]

What an Odyssey in one thread , it’s back together and it works. Putting the spring back was a bit of a pain but got it done. From new purchase, to wall hanger, to working gun again in a month and a half. Even had a vacation in there. I guess this is how you learn about airguns. I feel I know the Erma pretty well now! I looked closely at the broken piston rod looks like it was not all together from the start? Bet it cracked during heat treatment? See pic.

[deejayuu]

Great result.! Delighted for you. Break is classic "beach marking" of crack propagation as you say.

[micky2]

Glad you got it back to working order again. bet you feel well pleased in doing so with it. l was sad to let mine go but l needed the money at the time. these are cracking little rifles.

[chieffool]

what a lovely gun.
Well done.

I have enjoyed every part of this thread so much I will be looking to find one of these for my own garden plinking collection.
So...
...if anyone knows of one available (and in virtually any condition - happy to take on a project)...
...PLEASE let me know!