An Achilles Heel…..IZH46M

[Frank in Fairfield]

It feels like it Mike and the new piston seal was due.
I can tell the compression is much stronger.
Chronograph will tell.

[Airnut]

Nice!
Depending on your welder's skill and the filler alloy he used that repair might be stronger than a factory new part.

Yes and no. The weld filler metal will be stronger but welding cast steel has a tendency to make the base metal brittle within the heat effected zone.
Without knowing what recipe was used to make the steel you can only guess as to what filler metal to use.
We will see if it will pass the test of time.(fingers crossed)

[subscriber]

I just saw this thread for the first time.  Frank, please update us on how the repair is working. 

If the compression is too high and risks breaking the link again, compression can be adjusted via the thread on the piston, in quarter turn increments; like this: 

https://www.gatewaytoairguns.org/GTA/index.php?topic=153027.msg155687779#msg155687779

[Frank in Fairfield]

Actually, I guess the guy added some material to complete the weld.
Now, I think is an RCH too long and while the pistol cocks and some air is pumped into the valve, the cocking arm cannot reach complete battery.
I have to hold the cocking arm while depressing the trigger.
So, Venturi Arms won’t respond and I have a very expensive paper weight.
 

[subscriber]

Frank,

If you loosen the grub screw that locks the piston's thread used to set the compression, I am convinced you can get your pistol's function back, by shortening the piston's effective length by 0.5 mm (half a turn), because that has the same effect as shortening the link pin to pin spacing.

Try it.  You have nothing to lose.

Ebay has a pistol like yours with one bid on it at 400 bucks right now...

https://www.ebay.com/itm/135785391589?_skw=IZH+46M+linkage&itmmeta=01JVF7RDV9PA4RXDSD9G12ANMG&hash=item1f9d70a5e5:g:z6sAAOSwlOdoIj35&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1dS05SeChNeXxpwDN3kBE5YJaHUOchl9l9ONTLjj%2BU6Pl3sHQO5i123knWLwqE%2BWbXZUTZssgqWPlYPkAXA3zPh7iVT%2BjRdhXyq9yfV6klqSJ6XaV5tyQLtk%2FWrvpyIWf3uF085rJC9xR8Ns1ZAjpkgSXy%2FEGuitRPzy9tOE98rxeTdYaWv1B38YkKQo7y%2BUp4asFJx4anMuSYc8h0c983NQ2ksgjnBDyc4YtQKAm3b2URKSxuk5jHsb4o2vgsB3fw%3D%7Ctkp%3ABk9SR-Td4efbZQ

It also has this greedy offer:
https://www.ebay.com/itm/144704669173?_skw=IZH+46M+linkage+air+pistol&itmmeta=01JVF7S9MJEZAKFPEJ6237B5VS&hash=item21b11205f5:g:m9kAAOSwrdtjFNah&itmprp=enc%3AAQAKAAAA4FkggFvd1GGDu0w3yXCmi1eMCK%2FvIip3eOJDIm2JJ9xMyttARLfFoi9w2SF6%2BRca4V%2BHZNFwBoa%2B4aQ%2BuVPAiWYMngq%2BP0JQ8b7J8PgEb6DkaHD8JMGJVMdYUjJp6k4xk%2B8GrVRQNoPgkqG3qibJDlNEGrirw9fxb9zY%2FBv%2BWYWyqPk6bwmIkRg5gJFwUVupmNoiaBZpV0zoBs%2Frr%2BdkcKe3ssU5UAQ1hF0q8jkd4%2BI%2FESJUiFG4PtSZvBqC1OaH2ERICx5r1IlSYmu%2FJ5K%2BcSrmi8I1sNAWn9dgnnLSw%2Fut%7Ctkp%3ABk9SR8Ca5efbZQ

I think the broken part could be cut out of flat stock and finished with a drill press and a file, if you were motivated.

I wonder what would happen if you contacted Pyramyd Air about parts for the 46 M...

[Frank in Fairfield]

Grub screw?
In the back of the piston?
Pyramid Air & Air Venturi are the same people.
Maybe there is service station in Canada??

[subscriber]

Frank,

Below is a photo of the rear of my 46M piston ( posted at the link I provided above).   There, is half of the cocking mechanism hinge threaded into the rear of the piston.  The grub screw is clearly marked with a red arrow.  It enables the effective compression to be varied by 1/4 turn increments and then locked in that position so it does not drift in use.





If you pistol is so old that it lacks this adjustment and grub screw, then what I see as simple, isn't.  If your pistol has the compression adjustment feature, then your connecting rod pivot center to center distance is likely to be the same as mine at 110 mm.  The the attached STEP file may be useful for you, should you choose to make one from scratch, or have Prolabs or Xometry make one for you.  I called the part "connecting rod", as those companies don't make firearm parts; and you will lose the argument that airguns are not guns if you mention the full model number...

[Frank in Fairfield]

Thanks for your advice and photo.
Yes I have that screw.
After loosening turn the sleeve which way do you think?
Then tighten the grub..

[subscriber]

Thanks for your advice and photo.
Yes I have that screw.
After loosening turn the sleeve which way do you think?
Then tighten the grub..

Clockwise would shorten the piston.  As your connecting rod seems too long between pivots, shortening the effective length of the piston would be the right direction.

[Frank in Fairfield]

Thanks.
I see another of your threads on the GTA right now talking about this same issue.

https://www.gatewaytoairguns.org/GTA/index.php?topic=153027.0

[subscriber]

That thread is from a few years ago, about the same topic.

I hope you get your air pistol sorted out, and then let us know.  It is possible that you will need more than one try to get the compression setting back to you liking.

[Frank in Fairfield]

Also the lever that rides under the barrel that opens the breach will not stay in the slot where it belongs.
That may be caused by the lengthy piston, too.

[Stinger177]

This is all very interesting to me as I have an older (2005) MP46M (NOT MP46) and the Match rifle version (2003) in an MP532. I have never, ever had a failure of any sort on either of them, nor have I ever felt the need to adjust the pistons. Both shoot at around upper 460-ish IIRC. 460 - 480 is a nice sweet spot for these guns for 10M shooting, which is what they were designed for.

 

[Stinger177]

Frank,


Ebay has a pistol like yours with one bid on it at 400 bucks right now...

https://www.ebay.com/itm/135785391589?_skw=IZH+46M+linkage&itmmeta=01JVF7RDV9PA4RXDSD9G12ANMG&hash=item1f9d70a5e5:g:z6sAAOSwlOdoIj35&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1dS05SeChNeXxpwDN3kBE5YJaHUOchl9l9ONTLjj%2BU6Pl3sHQO5i123knWLwqE%2BWbXZUTZssgqWPlYPkAXA3zPh7iVT%2BjRdhXyq9yfV6klqSJ6XaV5tyQLtk%2FWrvpyIWf3uF085rJC9xR8Ns1ZAjpkgSXy%2FEGuitRPzy9tOE98rxeTdYaWv1B38YkKQo7y%2BUp4asFJx4anMuSYc8h0c983NQ2ksgjnBDyc4YtQKAm3b2URKSxuk5jHsb4o2vgsB3fw%3D%7Ctkp%3ABk9SR-Td4efbZQ

That $400 listing is missing the palm shelf, and who knows what else in that case?

 

[subscriber]

Description states: 
“Shoots great is missing some pieces of the grip.”

That $400 listing is missing the palm shelf, and who knows what else in that case?

 

[Stinger177]

Description states: 
“Shoots great is missing some pieces of the grip.”

That $400 listing is missing the palm shelf, and who knows what else in that case?

 

Yes, the seller did state that parts are missing. I just always question that if that important part is missing, why?, and what else is missing?

If someone is so careless as to lose a very important part to the whole shooting ability of a gun......??

I will confess here that I bought a Webley Hurricane with the rare match grips, and yes, it was missing the palm shelf, but I knew that I can make a new palm shelf, and......the gun worked perfectly.

So, maybe that IZH46M is a perfectly performing pistol. Just that it's a pain to replace or make the palm shelf. To me, even being a woodworker, I could replace the shelf, but it's not worth the effort. My main concern is why, owning a fairly expensive match pistol, would someone not retain the missing part, unless they just have enough money to spend and throw away parts?

That's just me talking. Maybe that's a great buy, but not for me.

 

[subscriber]

Dennis, the answer is real simple.  The seller is not an individual owner, but an airgun shop on eBay.  They took in the pistol to resell, after getting it for cheap.  Their eBay reputation is 100 percent.  They would not want to sell a non-functional airgun as functional. Look at their other airguns for sale:

https://www.ebay.com/str/ctairguns?_trksid=p4429486.m3561.l170197

The fact that the palm swell is missing may be why it is offered for such a low price.

Even after removing wood form my 46M grip, my hand is s tight fit against the palm swell.  I might remove it because it is uncomfortable.  Then I or my estate may sell the pistol in a hurry without the palmswell.

[subscriber]

Frank,

I don't know what else to suggest, except perhaps experimenting with different compression adjustment settings.   Much shorter to start.  Perhaps the added length to your connecting rod was greater than assumed.  The fact that the mechanism that opens the breech is out of its track puzzles me. 

Adding a stiff new piston seal while diagnosing the trouble might be muddying the waters.

[Stinger177]

Dennis, the answer is real simple.  The seller is not an individual owner, but an airgun shop on eBay.  They took in the pistol to resell, after getting it for cheap.  Their eBay reputation is 100 percent.  They would not want to sell a non-functional airgun as functional. Look at their other airguns for sale:

https://www.ebay.com/str/ctairguns?_trksid=p4429486.m3561.l170197

The fact that the palm swell is missing may be why it is offered for such a low price.

Even after removing wood form my 46M grip, my hand is s tight fit against the palm swell.  I might remove it because it is uncomfortable.  Then I or my estate may sell the pistol in a hurry without the palmswell.

Well, however your 46M gets passed on, I hope you will keep all the parts together. Just a suggestion to retain its value.

On the other subject, you make a good point there. I immediately think that the gun is from a personal seller, rather than on consignment, or through an estate seller. therefore I jump to judgement. My bad.

Looking at that link you posted - The Walther LGV - I've never seen a barrel lock lever like that. Interesting.

 

[Frank in Fairfield]

Well, I took it apart again (several times, actually), I loosened the screw (#27) and shortened the piston two of the segments then put everything back together. It would not pump air. So I did it again and added one segment. It still won’t pump air.

So, I guess it will just sit until I find an airgun smith that has Baikal parts.

Thanks for all your advice..