Thursday, April 28, 2016
MMM Mondail Roger BB Pistol
Since parts are difficult, if not impossible to come by, workarounds have to be done.
Air gun leaks in two places:
The reader should refer to Nicholas Carter’s blog pages as to how to disassemble and reassemble the gun. He has great pictures and good commentary.
First, let’s deal with the Piercing pin area.
Since original seals are hard to come by, I used one from Walther Makarov pistol.
The green end seal is from a Makarov.
This seal requires the center hole to be slightly enlarged to fit snuggly around piercing pin. Also, a little sanding to reduce the outer circumference is needed for a good fit. (I’ve read where some put pipe tape around the threads of the collar. I did not)
Secondly, let’s move to the valve assembly area.
The original seal was virtually gone.
The stem is pushed out.
The little O-ring in the base discarded. Its function of sealing the back stem inside the cap is not needed.
The cap is ground down to remove any lip. Again, not needed since original valve seal is unobtainable.
Clean the valve stem. Notice the vent opening.
I made a valve seal from 1/8th Urethane/Polyurethane sheet. (Red)
Cut out a 1” X 1” section from the sheet
The center hole was drilled out to fit around the large part of the valve stem. I used a #3 0.213 drill bit.
(place the collar back onto the valve stem, insert into the drilled hole and circumscribe the outside diameter using an ultra fine point Sharpie.)
This outside circumference including the black ring was trimmed using an Exacto knife.
Do not cut inside the black ring. Trim the outside only enough to allow the seal to fit into the cup cavity.
It is necessary that this seal is a flush fit to the sealing ring inside the valve body.
Assembly the valve stem, seal and cup.Notice how the seal comes up to the vent on the shaft.This is a critically important assembly step.
I drilled a 7/32nd shaft into a dowel. This tool helped to push the seal around the stem and into the cup.
Notice how the valve stem is almost flush with the end of the cup.
Disassemble one last time.
Put a small drop of metal Epoxy into the small hole. This is going to hold the valve stem in place and seal up that end of the cup. (This is why the little O-ring was no longer necessary.)
Reinsert the valve stem to the original depth. Don’t worry about a little dome of epoxy. The spring will fit over it.
Let cure the appropriate amount of time.
Insert the seal flush with the edge of the vent and level. Do not worry if cup was not ground level.
Insert valve stem assembly into air valve housing.
Try blowing into the piercing pin and moving the hammer. Even if properly sealed, a very small amount of air escape may be notice. The CO2 will supply far greater pressure to fit the seal.
If not, disassemble and reseat the seal again. It took me three tries to get it right.
Reassemble gun. (I had significant trouble getting the barrel out. I took a Dremel tool and ground off the painted surface from the tip and a little more so that the barrel would slide into the housing. The set screw is all that is needed for a firm fit.)
This is very important!
Place the gun in the Open position. This takes the pressure off the hammer.
Pierce a CO2 cylinder. A slight hissing will occur until the neck of the cylinder is sealed by the end seal. Then, the valve assembly will jolt into its sealed and ready position.
Load BBs. And remember, this is not a pure repeater. Each shot requires the gun to be pointed up to drop a BB into the loading chamber.
Saturday, April 9, 2016
Monday, April 4, 2016
Hey, remember me? Yeah, I used to blog about air guns before I ran out of space and money, as well as all the air guns available in the valley... Well my buddy Kent came across this Model 130 in a barn and it needed resealing so here I am again. I previously covered the earlier version of the 130 so it will be neat to see the differences.
In good shape but it appears some shade-tree mechanic has been at the innards…
That does not bode well…
That hole should be for adjusting hammer spring tension, but only on guns with a knock-open valve, on this model I suspect it’s what they had on hand?
A lot of scratched around the roll pin…
The bolt screw hole had a burr on it that prevented it from coming out until I deburred it.
It looks like they tried to use a tire patch to seal the transfer port. Not the best idea.
This is going to be a pain. The other 130 had an o-ring instead of a pump cup. I’ll have to try and press the brass ring out and modify a 1377 pump cup. Or I’ll machine a new one…
Roll pins only come out one way. Well they come out both ways but one does less damage.
A nice oval piece of spring keeps the trigger from slopping around.
The mechanic inserted a flat piece of rubber between the hammer and the blow off valve because he had no idea how the gun worked.
Notice the dents on the valve spacer.
Now to clean and reseal, hopefully soon.
Sunday, February 28, 2016
This doesn't break any new ground either, but its just such a nice little gun, I
There's still a plan kicking around to make a new trigger. Mentioned before that the trigger really needs another 1/2" or so of set-back. Guess that'll also entail a new trigger guard.
Still on a sling kick, the slender 22mm (7/8") sling mounts from the HW35E finally found the right home. They look exactly right on the old girl.
Even the front barrel band was a good fit.
Finding the right 7/8" sling was the hardest part. This isn't exactly the place for a two point black nylon Magpul. A trip to Dick's Gun Room did the trick. They had a nice selection of leather slings taken off trade-in rifles.
Digging through the options yielded an old 7/8" George Lawrence Co. #5 military sling. A few minutes with some Sno-Seal leather conditioner, pure beeswax, and a heat gun on low had it looking like a million bucks.
Thanks for checking in.