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Air Gun Home Forum Index » Airgun Smithing » help with washers    View previous topic :: View next topic  help with washers   Posted: Sat Nov 14, 2009 8:04 pm sniper Silver Status Member Joined: 28 Nov 2008 Posts: 3752 Location: Star, Idaho i'm finally tackling fixing my gamo 440 .177. the barrel washers are so worn i have excessive side to side play. needless to say it doesn't group anymore. in trying to take out the set screw myself i broke off two easy-outs. they aren't that easy the grind marks at the screw are from an attempt tim made to take it out.he failed. i found a shop in my area that does tap extraction and the owner said he'd look at it. going on the pretense he can remove it and give me the correct new screw, what type of washers do i need? it's my understaning the factory washers are plastic?? how do i measure for them? do i measure the next size up from the existing? i figured i'd post to give me some lead time in case this guy tells me something different from any of you (slavia/rsterne). this is a 1992 model and we go waaay back. i have no idea how many rodents i've bagged with this thing but it always loved crosman destoyers. it has a macarri spring and of course GRT trigger with added tru-glo sights. thanks Last edited by sniper on Sun Nov 15, 2009 1:09 am; edited 1 time in total _________________ I believe in gun control, If there's a gun around I want to be controlling it.......   Posted: Sat Nov 14, 2009 10:20 pm Mark5043 Silver Status Member Joined: 12 Apr 2009 Posts: 1379 I take it there is not enough left of the set screw head to notch it out with a dremel tool,plus cut off disc and back it out with a screwdriver...... I have done some crazy small screw extractions this way.For some reason when I click on your pictures,they won't load on my computer,so I can't really see what your working with here.   Posted: Sat Nov 14, 2009 11:30 pm sniper Silver Status Member Joined: 28 Nov 2008 Posts: 3752 Location: Star, Idaho Mark5043 wrote: I take it there is not enough left of the set screw head to notch it out with a dremel tool,plus cut off disc and back it out with a screwdriver...... that's what tim tried. _________________ I believe in gun control, If there's a gun around I want to be controlling it.......   Posted: Sun Nov 15, 2009 1:08 am sniper Silver Status Member Joined: 28 Nov 2008 Posts: 3752 Location: Star, Idaho i uploaded 2 pics......... are both there?? my cpu is on the verge of flying down the TRAP range. _________________ I believe in gun control, If there's a gun around I want to be controlling it.......   Posted: Sun Nov 15, 2009 1:27 am Mark5043 Silver Status Member Joined: 12 Apr 2009 Posts: 1379 Yeah, they are there,but my computer still won't load them from the postimage site,so I can't see an enlarged pic.Looks like their server is overloaded,or maybe my computer is a POS,and I need to throw it out the freakin window,and into the swimming pool.. From what I can see though it looks like the head of the set screw is gone,and the shaft of the screw is flush with the surrounding metal?if that is the case you may,like you said have to take it in for a tap extraction.you can do it yourself though.Just get a carbide drill bit the same size as the screw shaft.of course you'll most likely "Roach" the threads,but you should be able to use a self tapping screw a size larger,with like washers or bushings.Maybe someone else can chime in for an alternate solution?   Posted: Sun Nov 15, 2009 1:55 am kanyon Silver Status Member Joined: 09 Aug 2008 Posts: 1582 Location: New Zealand Drill a hole right though it..as big as you can go with out hitting the thread.. put the action in the frezzer...the screw will shrink more/faster than the steel around it being smaller....use the tang of a file to turn it....DON'T hit the tang in as it will exspand the screw and bined it up.... OR Drill it out and retap for the next size...if possable....You can get fine steps by going between metric and inch threads..   Posted: Sun Nov 15, 2009 11:09 am Slavia Moderator Joined: 31 Mar 2008 Posts: 4382 Location: Waseca, Minnesota, USA Quote: Drill a hole right though it..as big as you can go with out hitting the thread.. put the action in the frezzer...the screw will shrink more/faster than the steel around it being smaller....use the tang of a file to turn it....DON'T hit the tang in as it will exspand the screw and bined it up.... OR Drill it out and retap for the next size...if possable....You can get fine steps by going between metric and inch threads.. That sounds about right. Some other thoughts: Put a few drops of a penetrating oil on it, and tap it for a few minutes to set up vibration so the oil will actually penetrate. Or, heat it with a torch and let it cool. Sometimes the expansion/contraction cycle will loosen things. If you're going to drill out the center of the screw for an extracting device, drill a small pilot hole half way through from both ends. If you try to drill from one side only you run the risk of going off center and destroying threads on the other side. Once you get a hole down the middle, use a drill larger than the screw shaft and go just deep enough to separate the screw head. Sometimes removing that tension at the head loosens the threaded end enough to extract. Regarding the screw - the barrel pivot screw also holds the locking plunger captive (that chisel pointed thing has a notch in it, and the pivot screw keeps it from flying out). If you wind up going with a larger diameter screw, you might have to deepen the notch so the plunger will slide. Let's say you find the perfect screw, but the head is too big. You can chuck it in a drill and spin it while grinding/shaping with a Dremel, bench grinder, belt sander, or the like. Regarding washers - to replace the plastic washers on my G1 I found a hardware store washer that almost fit. The O.D. was a little too big to fit in the recess in the breech block, so I found a screw that fit tight and clamped it with a nut. I then spun it in a drill while grinding down the O.D. with a Dremel. The washer's I.D. was too small to fit the pivot screw, so I went around and around with a little carbide cutter in the Dremel. It was also too thick, so I went to the hardware store with my calipers and sorted through the whole bin until I found the thinnest ones. Dropping it in muriatic acid (to remove the galvanizing) bought a few thousands, and the rest I ground out with a sharpening stone. (A few strokes on the stone, turn 90 degrees, and repeat.) As an alternative you might consider a shim stack of thin washers made from food cans, pellet tins, pallet banding, etc. A torrent of words your mother wouldn't like helps things go better, too. _________________ ¡Listo! ¡Apunte! ¡Fuego!   Posted: Sun Nov 15, 2009 11:37 am sniper Silver Status Member Joined: 28 Nov 2008 Posts: 3752 Location: Star, Idaho ok. i do see my vocabulary getting colorful with this one since i'm not too mechanically inclined. thanks guys. _________________ I believe in gun control, If there's a gun around I want to be controlling it.......   Posted: Sun Nov 15, 2009 12:08 pm Alstone Moderator & Site Supporter Joined: 01 Mar 2007 Posts: 4139 Location: Linconshire, ENGLAND It may sound a silly sugestion but could it be a left hand thread? As cocking the gun puts more pressure on the screw than closing the breach, and with the head on the left side this could be the case. Al _________________   Posted: Sun Nov 15, 2009 12:15 pm sniper Silver Status Member Joined: 28 Nov 2008 Posts: 3752 Location: Star, Idaho Alstone wrote: It may sound a silly sugestion but could it be a left hand thread? As cocking the gun puts more pressure on the screw than closing the breach, and with the head on the left side this could be the case. Al i wonder if gamo would answer that question. that would explain a lot Al. i just sent them an email. _________________ I believe in gun control, If there's a gun around I want to be controlling it....... help with washers     Air Gun Home Forum Index » Airgun Smithing You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum All times are GMT - 5 Hours   Page 1 of 1   All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First  Select a forum Main Forums----------------AirGunHome Q&AGeneral Air Gun Questions and TopicsPicture GalleryTarget Shooting: Casual, Fun and CompetitionHunting, Pest Control, Varminting People/Events/Airgun Issue Discussion----------------Introduce YourselfThe BS TopicClubs/Events/Regional/Political Airgun Issues Maintenance, Modification and Reviews----------------RiflesPistolsAntique, Collector and Novelty AirgunsBB GunsPellets/AmmoOpticsAccessoriesAirgun Smithing Buy, Sell or Trade Forums----------------For SaleWant to Buy   Note: If you are seeing "Please enter your username and password to log in." 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