I just started a thread a few minutes ago about possibly purchasing a new Lilja barrel from a fellow member here. Well here's what happened.
Barrel dialed in through the headstock, thread shank cut, threads cut to a point where the action almost goes all the way on with a slight tight spot at the very end. I'm making one last pass without even advancing the compound. As soon as the threading tool hits the metal it's obvious that the timing of the lead screw is off. By the time I realized it and hit the emergency stop 1/2 of my perfect threads just got the their tops cut off. Didn't hear anything break, didn't hear any weird noises, nothing. Immediately i though maybe I read the thread dial wrong so I turned the machine on, engaged it on the same mark I was using all along, turned the machine off and manually put the cutting tool next the the remaining good threads. Something happened and i was about a third of a thread off now. I never touched the head stock gear change levers, and I always engage on the same number "1" when threading barrels. After realizing that the timing was off I backed everything away from the work and turned the machine on and engaged the half-nuts. The lead screw isn't turning continuously. After about 30 seconds of checking gear engagement the lead screw stops turning for good. No matter what I do with the levers the lead screw isn't moving. I'm a little pissed at this moment as my 2 month old "gunsmithing" lathe is not only a 3000lb paper weight but it just cost me $430 and probably will end up costing me a very good customer. After a beer and a cool down I walked back into my shop and decided to start investigating. I remembered when I first turned this lathe on and tested all the feeds that the clutch on the feed rod clutched out a couple times while putting a load on the carriage wheel. I investigated and didn't see any type of overload clutch set-up on the lead screw. I decided to take the gear box cover off and hopefully figure out whats wrong with this thing. Got the cover off and nothing is damaged inside, oil looked brand new, everything was silky smooth. I noticed the keyed shaft that operates the lead screw turns all the way through the gear box and rotates a collar which is inline with the actual lead screw but at that junction where the collar meets the actual lead screw outside the gear box the interlock seems to stop. After more investigating it appears that the lead screw has a hole drilled and tapped that lines up with a hole in the collar that's attached to the gears inside the gearbox. It looks to me like this is the only thing tying these two assemblies together. It about the size of a 1/4" set screw and it appears it has a "tit" on the end of it that engages the collar on the gearbox. Where is it?? If it broke then there should still be the threaded part of this "shear" screw in the flange attached to the lead screw. It's simply gone, and it appears that it was never even there. Id say that the little bit of threading i did on this barrel and the minimal threading done before this was accomplished by the friction locking these two parts together. Friction from the pre-load adjustment on the lead screw I'm guessing. I've got a broken lathe that I just spent a ton of money on, a damaged barrel that's not usable on this customers gun, a customer that's probably gonna walk cause he won't wanna wait another 3 months for another barrel, and a shop that's out of commission till my new lathe is fixed, or in my opinion is assembled properly. I should've kept the Southbend and had it re-built. I'm kicking myself in the ass!!!!
Barrel dialed in through the headstock, thread shank cut, threads cut to a point where the action almost goes all the way on with a slight tight spot at the very end. I'm making one last pass without even advancing the compound. As soon as the threading tool hits the metal it's obvious that the timing of the lead screw is off. By the time I realized it and hit the emergency stop 1/2 of my perfect threads just got the their tops cut off. Didn't hear anything break, didn't hear any weird noises, nothing. Immediately i though maybe I read the thread dial wrong so I turned the machine on, engaged it on the same mark I was using all along, turned the machine off and manually put the cutting tool next the the remaining good threads. Something happened and i was about a third of a thread off now. I never touched the head stock gear change levers, and I always engage on the same number "1" when threading barrels. After realizing that the timing was off I backed everything away from the work and turned the machine on and engaged the half-nuts. The lead screw isn't turning continuously. After about 30 seconds of checking gear engagement the lead screw stops turning for good. No matter what I do with the levers the lead screw isn't moving. I'm a little pissed at this moment as my 2 month old "gunsmithing" lathe is not only a 3000lb paper weight but it just cost me $430 and probably will end up costing me a very good customer. After a beer and a cool down I walked back into my shop and decided to start investigating. I remembered when I first turned this lathe on and tested all the feeds that the clutch on the feed rod clutched out a couple times while putting a load on the carriage wheel. I investigated and didn't see any type of overload clutch set-up on the lead screw. I decided to take the gear box cover off and hopefully figure out whats wrong with this thing. Got the cover off and nothing is damaged inside, oil looked brand new, everything was silky smooth. I noticed the keyed shaft that operates the lead screw turns all the way through the gear box and rotates a collar which is inline with the actual lead screw but at that junction where the collar meets the actual lead screw outside the gear box the interlock seems to stop. After more investigating it appears that the lead screw has a hole drilled and tapped that lines up with a hole in the collar that's attached to the gears inside the gearbox. It looks to me like this is the only thing tying these two assemblies together. It about the size of a 1/4" set screw and it appears it has a "tit" on the end of it that engages the collar on the gearbox. Where is it?? If it broke then there should still be the threaded part of this "shear" screw in the flange attached to the lead screw. It's simply gone, and it appears that it was never even there. Id say that the little bit of threading i did on this barrel and the minimal threading done before this was accomplished by the friction locking these two parts together. Friction from the pre-load adjustment on the lead screw I'm guessing. I've got a broken lathe that I just spent a ton of money on, a damaged barrel that's not usable on this customers gun, a customer that's probably gonna walk cause he won't wanna wait another 3 months for another barrel, and a shop that's out of commission till my new lathe is fixed, or in my opinion is assembled properly. I should've kept the Southbend and had it re-built. I'm kicking myself in the ass!!!!