saltydecimator 482 Posted October 14, 2015 Report Share Posted October 14, 2015 ok, tried t odo a 13" gun but could never get to run birdshot with the ports not ridiculously massive....so ive turned down barrel in lathe and have the tromix shorty gas piston replacement, but im still confused as how to deal with the gas tube problem.... some folks seem to beat the ridges out? others make new tubes? im sure its simple buuuuuut Quote Link to post Share on other sites
saltydecimator 482 Posted October 14, 2015 Author Report Share Posted October 14, 2015 while lookin for pics of shortened gas tubes, i came acroos this, pretty interesting!! Quote Link to post Share on other sites
TonyRumore 1,332 Posted October 14, 2015 Report Share Posted October 14, 2015 We sell the tubes that go with the short pistons. Tony Rumore Tromix 2 Quote Link to post Share on other sites
dariman3 6 Posted October 15, 2015 Report Share Posted October 15, 2015 while lookin for pics of shortened gas tubes, i came acroos this, pretty interesting!! Custom built PSL by a board member on akforum.net. Want to try doing one of these someday. Quote Link to post Share on other sites
saltydecimator 482 Posted October 16, 2015 Author Report Share Posted October 16, 2015 Well my current plan is to heat up old tube and blast the ridges out so the new fatter dia. Bolt extension can pass through Quote Link to post Share on other sites
evlblkwpnz 3,418 Posted October 17, 2015 Report Share Posted October 17, 2015 (edited) You can easily waste a ton of time on it and still end up with something that will not work well or look good. Just get the Tromix tube and focus your time and efforts on more important aspects of the build. Edited October 17, 2015 by evlblkwpnz 1 Quote Link to post Share on other sites
G O B 3,516 Posted October 19, 2015 Report Share Posted October 19, 2015 If you must do it yourself, try using a sucession of ball bearings and knocking them thru with a BFH and punch. Anneal the part before starting and between each size of bearing. This will keep it from cracking as you stretch the metal. Always knock the bearing thru cold. Temper after reaching the desired size. Quote Link to post Share on other sites
gunfun 3,931 Posted October 19, 2015 Report Share Posted October 19, 2015 I think that would run a good chance of growing the thing lengthwise, or buckling the end as you push the bearing through. Also keeping the bearing or mandril, or whatever centered would be the big difficulty. Typically the weakest spot will deform, and all the force will go that way. IMO, just buy the tromix one. Quote Link to post Share on other sites
Heartbreaker 1,085 Posted October 20, 2015 Report Share Posted October 20, 2015 while lookin for pics of shortened gas tubes, i came acroos this, pretty interesting!! Ah, the Russian bottle-opener stock! Purpose-built for those huge bottles of vodka! Quote Link to post Share on other sites
G O B 3,516 Posted October 20, 2015 Report Share Posted October 20, 2015 I would buy the piece from Tony, but some times a guy just HAS to try! Quote Link to post Share on other sites
saltydecimator 482 Posted October 23, 2015 Author Report Share Posted October 23, 2015 Got some correct id tubing. I'm gonna try and build my own. Quote Link to post Share on other sites
gunfun 3,931 Posted October 25, 2015 Report Share Posted October 25, 2015 Pics or.... 1 Quote Link to post Share on other sites
saltydecimator 482 Posted October 29, 2015 Author Report Share Posted October 29, 2015 Has some dang machine marks though. I gotta read up on how to work with the slop 1 Quote Link to post Share on other sites
gunfun 3,931 Posted October 29, 2015 Report Share Posted October 29, 2015 It's not a bug, it's a feature. Annular fluting for faster cooling. 1 Quote Link to post Share on other sites
G O B 3,516 Posted October 29, 2015 Report Share Posted October 29, 2015 It's for a Russian gun. It is supposed to have rough machine marks wherever it will have no effect on function. 1 Quote Link to post Share on other sites
evlblkwpnz 3,418 Posted October 30, 2015 Report Share Posted October 30, 2015 (edited) Has some dang machine marks though. I gotta read up on how to work with the slop Back your cross slide out a few turns and then go back into the workpiece. Do the same with your compound slide. If you run either back out at all then you have to do it again. Just pay attention to where you are before you back out in terms of the dial (can't remember what it is called, one more cup of coffee please, lol). You may be able to adjust the gibs to make it a little tighter (I have no clue exactly what you are working with and I am under the assumption it is a well worn lathe). I hope this helps. Edited October 30, 2015 by evlblkwpnz Quote Link to post Share on other sites
Goose 95 Posted November 16, 2015 Report Share Posted November 16, 2015 Slop like the backlash in the dials? If so take evil's advice, the machine I use at school has about 50 thousands before actual tool movement happens. Just pay attention to what number you were at on the previous cut Quote Link to post Share on other sites
evlblkwpnz 3,418 Posted November 19, 2015 Report Share Posted November 19, 2015 Slop like the backlash in the dials? If so take evil's advice, the machine I use at school has about 50 thousands before actual tool movement happens. Just pay attention to what number you were at on the previous cutI bought a new lathe last year and it had slop from day one. I adjusted the gibs a little to reduce transverse movement, but no matter how I am doing it, if I run away from the piece or headstock at all I go out further and then back into it. +1, the dials are your friend. 2 Quote Link to post Share on other sites
saltydecimator 482 Posted November 20, 2015 Author Report Share Posted November 20, 2015 gotcha... and prob using dull crappy taiwan( ) bits isnt helping.... more like scraping off the metal vs cutting it! anyways, im gonna confuse things more by suggesting that the barrel stub can be used to turn into the gas tube! seriously folks, mic it! (mayeb this is already common knowledge?!?!?!) Quote Link to post Share on other sites
Goose 95 Posted November 24, 2015 Report Share Posted November 24, 2015 (edited) I've been messing with my tailstock(that's what she said) for a couple of weeks now(3 days a week, couple of hours each) and finally have it down under a thousandth from one end of my 29 inch blank to the other. I pray to God that someone in another class doesn't start tapering their barrel before I do and throw it out for me. Our machines are well maintained but are still about 50 years old with hard student/learning curve usage. Carbide is my friend. As for using barrel scrap, never occurred to me, I don't have measuring stuff handy, or any stubs to play with(that's what she said) but I'll take your word for it, not a bad thought. And your scrapping comment reminded me of a video someone was telling me about the other day where they watched a guy octagon a barrel on his lathe. He had a custom ground bit, the machine was off and the barrel was locked in place, and he just traversed his bit across the length of the barrel until he'd created a flat, indexed 90 or 180 degrees and did it again. I'd forgotten about it, I want to see it, I'm gonna go look for it now. Edited November 24, 2015 by Goose Quote Link to post Share on other sites
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