m00se

Ok, I took the linkage out and checked that block as you suggested CowboyBob. It swivelled and felt like it had no slop in it at all. As I put it all together I realized that the "needle bar frame tapered stud" (#31) might have been more loose than it should have been. I now have about 1mm of play front to back and that's if I really tug on it. Now I have to figure out why the upper thread tension is so high even with the tension disk knob backed way out. It seems the cumulative tension on the thread at the needle is excessive. I'm not breaking thread (polyester 138) but it seems right on the upper limit of it's range. I wish there was a service manual for these machines. It would maybe make life a little easier. Thanks so much for your help guys. I suspect I'll be deburring and dremelling on this thing for a while!

It does seem like a lot Constabulary. I am only guessing about the amount, but I think it's at least 3-4mm. CowboyBob - I knew there had to be a way to adjust this. I'll see if I can notice any play in there. There is some play in those levers in my OP pic but it doesn't seem like too much to me. Maybe ~1mm. Thank you both very much for your help.

Hi, I've been lurking on this forum for several months and learning quite a bit. Thanks to all! About me: I used to manage production in a company that made tonneau covers for pick-em-up trucks, and we had a mix of Juki and Consew lockstitch machines. LU-563s and the RB-2s working 8-10 hour shifts daily for years. Loved those machines and maintained them religiously. This was back in the 90's...ahh the days they go by so fast don't they.. Fast forward to today: My brother in law has been a shoe repairman with his own very busy shop for almost 40 years now, and he finally got fed up enough trying to put zippers in to add a flat bed machine to supplement his Singer 29-4. So I hit Craiglist and found us a unit. This machine is 100% there and sews fine most of the time. I've been using his 92 nylon thread with it and adjusting it as I see the need. I had to clean up the slop in the needlebar but I still have one problem I can't seem to fix and my memory from back in the day just ain't what it used to be. Side-to-side play in the needlebar is perfect. It's the front to back play I can't seem to find an adjustment for. There's about 3/16th inch front-to-back play in there and the only thing I can think of is that the L-shaped link or the associated parts have worn or gone out of round enough to cause this. I don't see a way to adjust this with a set screw or bolt head anywhere. I suspect there has to be some way to do this but I also seem to recall having to replace the linkage pieces in the picture I included at one point on 1-2 machines. Any ideas? Thanks in advance! Here are the links I'm thinking might be the problem: