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Thread: Original Model 35 .22

  1. #1
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    Original Model 35 .22

    I've just completed a refurbishment of my Original Model 35 air rifle. This was bought for me back in 1977 so its 41 years old and has sat unused for 35 years. I'd read so much about how difficult they were to put back together, because of the ball bearing trigger mechanism, that I have never attempted to take it apart before but armed with information from this site and others I thought I would give it a go. I used a sash clamp as a spring compressor but next time I will build something to hold the rifle and the sash clamp in place as it did have a tendency to try to move sideways under pressure.
    The main spring was broken in two places and I decided to go for the full TW Chambers ultra tune kit with the Titan OS1 spring. This comprises a delrin spring guide and top washer to allow the spring to rotate freely, a new leather washer, the Titan spring and moly grease and and lube to soak the leather washer. After a good clean of decades of gunk with carb cleaner I reassembled with the new parts. The main difficulty getting it back together is the amount of main spring preload also the trigger itself is awkward to fit as you have to compress the trigger spring to get the pin in and it is an awkward shape to clamp, I ended up running several turns of string around the trigger and rifle to tighten it up. The ball bearing trigger unit is not an issue if you put a dab of grease on each of the ball bearings to hold them in place before you slide it into place.
    I wasn't happy shooting it with the leather washer in, it was inconsistent and producing a lot of smoke and shooting at under 9 ftlbs. It maybe needed more time to run in or I maybe hadn't soaked it long enough but when I came across Vortek synthetic seals I ordered one from Tony Burton. I also measured the trigger spring and ordered a coupled of alternatives of similar length but lower diameter wire, to give a softer trigger pull.
    A couple of other issues I had to deal with were a split in the stock across the piston grip and also try to improve the scope rail as scopes have a tendency to slide backwards on it. I glued and screwed the stock together (one screw up from the bottom of the pistol grip and a longer screw in the back of the trigger guard) and drilled a 4mm dia hole in the scope rail. The stock is now solid and the scope does not slip anymore.
    With the leather washer replaced and a weaker spring in the trigger it's shooting as nicely as I can remember, at around 9.5 ftlbs with Bisley LRG pellets. It was always a very accurate air rifle and today I got a 5 shot group at 40 yards that I can cover with a 1p piece so I'm very pleased with how it's turned out.

  2. #2
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    How about some pictures ?

  3. #3
    Hsing-ee's Avatar
    Hsing-ee is offline may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
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    Nice one. I have one awaiting an overhaul, I was considering the synthetic seal and I think I will get one now. The transfer port might need sleeving down to get the best power though, the leather seal guns usually work with a wider port, so a synthetic will need a narrower one.

  4. #4
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    Quote Originally Posted by where's it gone View Post
    How about some pictures ?
    I was going to post some but I don't have permission to post attachments.

  5. #5
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    Quote Originally Posted by Hsing-ee View Post
    Nice one. I have one awaiting an overhaul, I was considering the synthetic seal and I think I will get one now. The transfer port might need sleeving down to get the best power though, the leather seal guns usually work with a wider port, so a synthetic will need a narrower one.
    How do you sleeve the transfer port?

  6. #6
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    I'm thinking it sounds like there's too much spring in there, going by what you said about clamping, wrapping and preload.
    Donald

  7. #7
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    Quote Originally Posted by Rutherford99 View Post
    How do you sleeve the transfer port?
    I have never done it, you will have to ask Shed Tuner or T20.

    I believe the method is to measure the diameter of your transfer port by sliding in the chuck ends of drill bits until you find on that fits. I am not 100% clear on measuring the length, but I would put something round and flat (washer maybe?) to block up the port from the inside with something behind it (disassembled of course) and then push the bit in until it stops, then mark off the length on the shank of the drill bit.

    So now you have the diameter and length.

    You then need to work out the static compression ratio which is the ratio of the transfer port volume to the swept volume of the cylinder. For a plastic sealed rifle I think this should be about 1:400 or something, but you will need to ask Shed or T about that. There are online programmes that will work out the volume of a cylinder for you quick as you like.

    You then get a length of brass tubing of the correct length and internal diameter and external diameter, degrease it and the transfer port, press it in with a smidge of superglue, and there you are.


    If you put 'transfer port' and 'sleeve' or 'TP and sleeve' or 'static compression ratio' into the search engine there are alot of posts on it.

  8. #8
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    Quote Originally Posted by thisisdonald View Post
    I'm thinking it sounds like there's too much spring in there, going by what you said about clamping, wrapping and preload.
    The Titan spring appeared to be the same length as the original spring, would cutting the spring down reduce the power? I'm open to any suggestions to improve it further.
    The wrapping with string was reference to the trigger itself which has a 6 * 17mm spring at the back which has to be compressed to locate the dowel pin and is very difficult to clamp because of the shape, it was a lot easier to get the dowel pin in place once I had put in a spring made of 1mm wire rather than the standard 1.3mm, also the trigger now feels a lot better to me with a lighter pull.

  9. #9
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    How much preload was there before you started compressing the mainspring? Titan springs are regarded as one of the stiffer springs out there, so maybe trimming it a little would allow you to keep the power with less of the preload or even gain some power. I think power will go up when the leather seal beds in
    Donald

  10. #10
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    Quote Originally Posted by thisisdonald View Post
    How much preload was there before you started compressing the mainspring? Titan springs are regarded as one of the stiffer springs out there, so maybe trimming it a little would allow you to keep the power with less of the preload or even gain some power. I think power will go up when the leather seal beds in
    I didn't measure but maybe 50 - 60mm, it's a synthetic seal and has had about 400 pellets through and power is consistent. I'm not sure now I want to change anything as it is so accurate and enjoyable to shoot. If I could get some more power out of it without ruining the feel it would be nice but at 9.5 ftlbs it's very accurate to 40 yards.

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