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tigger

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  1. tigger

    Cutting half inch thread.

    No one was insisting on a sloppy fit bodge that was out of true, once again the sort of precision you seem to think is absolutely necessary is not required, set production tolerances are more than good enough and these can be easily be achieved by any reasonably competent home machinist using the methods described.
  2. tigger

    Cutting half inch thread.

    Er... no the threads need clearance, reason one, a precise thread may not fit if any muck is present as in a combat situation, reason two the expansion of two dissimilar metals due to heating, as I'm sure you know aluminium is prone to galling if clearances are on the tight side especially if butted up against steel, you don't want a moderator you cannot easily remove, again the sort of thread precision you are advocating is neither needed nor desirable the silencer butted up against a register is all that is required.
  3. tigger

    Cutting half inch thread.

    You seem to be making a mountain out of a molehill, we are talking airguns here! Utter thread precision is simply not necessary in this case. Just about every threaded barrel I've ever seen has an undercut at the rear of the thread so the silencer registers up against the concentrically finished flat behind the thread, a certain amount of play in the threads is actually desirable especially on a firearm as this allows the silencer to be removed when fouling occurs, in fact a long time ago I remember having a batch of 9mm barrels from the long defunct Stirling arms company that needed threading for moderators I set up an old Herbert capstan and one of the apprentices did the lot without a hitch, and as a former auto setter I can tell you the bolts we produced were concentric and precise enough to go into jet engines and nuclear power plants!
  4. tigger

    Cutting half inch thread.

    Coventry diehead? thousands of capstan and auto setters can't be wrong can they?
  5. tigger

    Cutting half inch thread.

    As above, first of all you'd need to get the end of the barrel turned down to half an inch, (to thread 1/2 UNF) getting this done without a lathe would be nigh on impossible, I'd have to disagree about the thread cutting though, a split die held in a floating tailstock holder would have no problem in cutting a concentric thread, the loading would be directly down the barrel not at ninety degrees as with a chaser or form tool held in the toolpost .
  6. With the attitude and frankly ignorance most people in this country have to guns and shooting the last thing any government would want is even the tiniest amount of bad PR with the sport. Guns, the press and public attitudes in this regard are a potential toxic mix in Britain. I thought that was obvious to most of us who do shoot and own guns.
  7. Nice to hear that the government cut lottery funding to all shooting sports five years ago. It probably heard the word "guns" and thought bad things. Peter Wilson was sponsored by a wealthy Arab businessman who himself was a former Olympian, so well done to all involved an excellent result despite official disinterest and disapproval.
  8. tigger

    Project 97K

    Nice! I've recently just finished restoring a BSF S60, your article has inspired me I'll have to dig out the photo's!
  9. tigger

    Wiehrauch 95

    The main aim should be accuracy and smoothness legal power should not be a problem with this gun, check out some of the tuning tips in the technical section.
  10. tigger

    FEINWERKBAU SPORT ( MK 3?)

    I suspect your gun is one of the last versions produced six or seven years after this advert first appeared, I recall seeing some of the supposedly last production run in my local gunshop, (1992?) the barrel weight was bigger than the one in the advert, this was I believe an attempt to add some weight in the vain hope of taking on guns such as the HW77/80 and Original 45 which by this time were dominating the springer class in field target shooting. I also remember being surprised at the very bland stocks fitted to these guns, prior to this most had nicely figured beech.
  11. tigger

    FEINWERKBAU SPORT ( MK 3?)

    Not sure if FWB allocated different marks to the various minor design changes they made to the Sport, but the first guns had nicely figured and finished stocks and plastic trigger blades, the next incarnation had an aluminium trigger blade and and the chequering was to a lower standard, and the final and short lived production version had a very plain stock and the Dan Dare style muzzle grip glued onto the end of the barrel as you've described it's probably the rarest of the breed, the Sport had been overtaken by many of it's competitors by this stage, I dont know what they were thinking when they stuck that thing on! It does nothing for the handling and near perfect balance, I can't remember if the barrel still has the dovetails pressed into the muzzle , so fitting the original style foresight might not be possible.
  12. tigger

    Machining Polyurethane in the lathe

    If that's the case couldn't you use a viton O ring instead? Very easy to splice if needed and far more durable and chemically stable than polyurethane.
  13. tigger

    Machining Polyurethane in the lathe

    Some pictures. ( I hope!) Note the file on the bed of the lathe, this is what I use for final finishing. Finish the seal to size installed on the piston, securing a new seal without doing this will almost certainly result in it being slightly oversize after you've screwed it onto the piston face. The seal is held on with a tapered collar and screw, Diana airguns use this sort of arrangement, very secure and seal won't rotate in use. I made this one for a BSF S60, I did a few other 26mm seals at the same time all slightly varying in size to see what worked best, around .010-012 of "crush" seems to be optimal with this particular design.
  14. tigger

    Machining Polyurethane in the lathe

    Positive rake for me when machining polyurethane, you need a shearing action anything else will push the material aside, cutting to close tolerances and with a good finish is also difficult, I tend to get the seal to within 20-30 thou and then finish to size by wrapping some 180 wet and dry around an old file and "grind" the seal to the exact dimensions by hand, it goes without saying of course but be very careful doing this and make sure the file has a handle, for parting off braze a stanley knife blade onto an old toolbit, present the blade to the work in the style of a guillotine blade so it cuts rather than shears, and finally freezing the material does work but you do have to work quickly. Moniter closely any seals you make when in use, this material does seem more prone to burning around the transfer port area that PTFE or nylon 66.
  15. tigger

    Piston head weighting

    No, you are just as likely to loose power and make the gun harsher to shoot, it's a question of getting a balance of piston weight, spring power and swept volume, the latter largely determines the potential power the particular gun will produce, trying to bump the muzzle energy up by altering one thing often upsets something else, usually accuracy.
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