jfhspike

I'm a realtive newbie on working on my old machine. My 31-15 was working OK for a while, but now it's gotten to the point where it leaves loops on the bottom no matter how high I set the upper tension. It doesn't tend to form rats-nests, though -- just cute little tiny loops through which the bobbin thread passes in a straight line. (And reducing the lower tension to the point where the bobbin-case drops freely (which is too far, I know!) doesn't solve the problem, either. My thinking (such as it is) is that maybe it's just pulling out too much thread per stroke -- enough that during the "pull it tight" phase after the upper thread's been wrapped past the bobbin, it's just not getting pull up far enough to bury the crossing. While I don't have the entire process of stitch-formation clear in my head, I'll bet that some of you folks do, and can make a guess about what's wrong. I've looked at the needlbar timing (removed the feed dog to make it actually POSSIBLE to look at it!), and one thing that's not clear to me in the instructions is this: they say that as the shuttle crosses the needle, "the point of the shutle should be 1/16 inch above the eye of the needle." Is that 1/16 above the bottom of the eye, the middle, or the top? Would raising the needlebar (assuming that I could adjust the shuttle-timing to match) make for less thread being pulled out per stitch? Or am I on completely the wrong track? Thanks in advance. John

And just in case someone reads this in the future...when you get the disks in the right order, there's still a question of whether the spring-holding disk is cupped towards the SPRING and knurled nut, or towards the two disks and the machine. Answer? Towards the disks and machine. BTW, in a fit of cleanliness (and a desire to better see what I was doing when I was timing the needlebar), I decided to remove the needle plate. First screw...popped right out. Second screw...appeared to have been put in by a gorilla. PB Blaster, heat...nothing worked. I finally managed to drill out the top of the screw and get the needle plate off, and then come in from below to drill out what remained...which pretty much worked, except that there was still some old-screw stuck in the threads. So I tried to chase it with a 4-40 tap (it appears to be a 40-thread-per-inch screw, of some non-standard diameter a little larger than 4), which mostly worked...until the tap broke off. A bunch of pounding with a drift-punch and then a center punch broke up the tap (yay!), and drilling with a slightly larger drill managed to drive out the remaining bits of screw...leaving behind enough thread to get a good grip on the screw. SOMEtimes things actually go right! --John

I went and looked at things, and couldn't see how that pin would work...until I looked at the parts book and found that the disks were assembled in the wrong order. The correct order is machine, disk1, disk2, spring-holding-disk, spring, knurled nut On my machine, the order was machine, disk1, disk2, spring, spring-holding-disk, knurled nut It gave the same net pressure on the disks, but it meant that the spring-holding disk never got pressed by that little pin. Thanks for prompting me to go look carefully. You never know what you'll get with a used machine... --John

Thanks, Jeeperaz (and Kevin!). I'll probably just stitch together the electrical cord for now, while I wait on other bits and pieces, now that I know the loads are modest, etc. By the way, something very similar to that O-thane is available from McMaster-Carr, where I should have looked first. But they don't sell the connectors individually. --John

Thanks very much -- all useful information. I'll go ahead and do some minimal cleaning and then oil the thing and see whether I can get it to run nicely. (It runs pretty smoothly already). I'll try the drop test to adjust the bobbin tension. -John

Two more things... 1. The manual says "left twist thread should be used in this machine" Am I right in thinking that essentially all thread that I'm likely to buy is in fact left-twist thread? 2. I'll be using cones of thread. The Sailrite folks say that I should pull the thread from the top of the cone to add twist, so it looks like I need a thread stand. But can someone tell me how you route thread from the stand to the machine? If I just run it from the guide at the top of the stand to that first little "button" that it goes around, about 4" above the tension discs, I worry that it won't be leading to that thing from the right direction. Am I just being a worry-wart? ---John

I'm a complete amateur -- please forgive me if I use the wrong words. I sew a fair amount of boat stuff, but nothing leather. But you folks seem to really know your stuff, so I want to pick your collective brains. I just picked up a Singer 31-15 for $50 yesterday. (To be honest, the table and motor are worth that to me, so it's a no-lose deal!) The previous owner warned that he'd used it a lot a few years back, but tried it recently and couldn't get it to "hook" properly. Well, I've got a Pfaff 130, so I'm not scared of the innards, and I took apart the bobbin-holder parts, and cleaned out a few pounds of lint and other greasy stuff, shoved it back together, and managed to get it actually sewing (under hand power, since I was doing this on the workbench rather than in the sewing-table that it came with). Tension adjustment was a bit of a mess, though: the upper thread pulled through the material (some fairly tight webbing), and the bobbin-thread ended up pretty much straight. That was with the upper tension cranked down all the way. So...I lowered the bobbin tension (the screw was ALL the way in, and took some oomph to unscrew!) and managed to make it even things out a little, but the stitching seemed very loose; the lower tension had to be AWFULLY light to make it work. (Still tight enough that when I held the bobbin-case-assembly by the thread, it didn't drop, but it was close to dropping.) Of course, all this was with the needle that was on the machine already. Kinda rusty looking, kinda "popped" as it pushed through the webbing. Now I'm ready to actually check the timing, etc., using the manuals that others have pointed folks to on other 31-15 threads here on leatherworker.net (thanks, everyone!) But I have a few questions for you as I try to get this thing going right: I'm planning to sew stuff on the canvas cover for my boat. It's reasonably heavy duck -- not quite sunbrella-heavy, but close. Mostly it'll be simple seams -- the needle going through 2-4 layers of the stuff, although at hems, esp hem-corners, we might be talking about 8 or 9 layers. 1. In the interest of longevity (this cover's on the boat for 6 months at a time, outdoors, exposed to sunlight, albeit winter sun).. I'm hoping to use V-92 polyester thread;Sailrite says #18 or #20 needle. Can this machine use those sizes? 2. I know I'm supposed to use 16x87 series needles, but they seem to come in several kinds of points. (Am I right that one of these is "ball point"? Sounds like a Bic sewing needle!). Can you give me a hint of what point-kind I need? 3. When I lift the presser-foot, the tension discs don't seem to relieve the tension much. Any thoughts about how to adjust this/fix this? 4. Anyone got any suggestions about the tension? When I loosened the lower tension, I adjusted the upper tension and got things to work...well...OK. But I was still getting dropped stitches and stuff. Unless I hear from someone with suggestions about it, I'll wait until I've got new needles, etc., before pursuing this further. 5. The oiling holes seem to have some gurry in them --- do I need to clean out every bit of this? Or am I seeing something like felt that's meant to hold a bit of oil, and cleaning it out will only mean that I'm screwing things up? Misc. Does anyone know why things like thread and needles are called "notions"? Thanks in advance! --John