Members dmar836 Posted December 8, 2012 Members Report Posted December 8, 2012 That took about 2 minutes and removed much of the slack. I still have play at the hook and it is stitching well except for the stop-start thing even without turning the material. I was going slowly and then doing some hand turning of the wheel and felt/heard a slip. Flipped it up and the top thread was under the hook body. It couldn't slip off to form the knot as it was actually around the bottom of the hook. I can watch it stitch fine into air when I go slowly and keep tension on the loose thread ends. Any other reasons why the hook would be allowing the top thread, while pulling it around, to drop the bottom half of the loop under the hook body? There appears to be a need for some additional resistance from the top thread so that it stays longer at the end of the hook point. The take up arm is still moving down when the hook has turned more than half a rotaion. Seams like the take up arm moving up slightly earlier would provide the needed tension and help set the stitch earlier. Could I readjust the needle bar height and appropriate hook timing to allow for this? My needle bar had no mark so I'm wondering if the PO or I have that way off. Or maybe I'm beginning to show my ignorance of these machines again? Dave Quote
Members gottaknow Posted December 8, 2012 Members Report Posted December 8, 2012 The purpose of the take up lever is to "give" the hook enough slack to travel around the hook, pick up the bobbin thread, and then set the stitch at the top of the stroke. If your top and bottom shaft timing is off just one tooth, you'll have slack in the thread at the wrong time and it will "flop" anywhere it wants. If you turn the machine by hand and keep the slack out of the thread and it make a good stitch, your shaft timing is still off. The amount of stroke of the take-up lever is engineered to match the amount of thread it gives the hook. If the take-up lever is not coordinated with the hook, you'll have issues as you describe. There is no way the take-up can give your hook more thread than it requires. The order of timing the machine again is as follows. Take-up lever all the way up. I place my finger under it and push up as I turn the handwheel, making sure it's all the way up. Remember, one tooth off makes a big difference. Then refer to the timing mark on the lower shaft. It has to be exactly lined up. At this point, make sure your hook is down all the way. If your hook is too high, it can throw off your timing, making your needle bar too low if your set the point of the hook where it needs to be in the scarf of the needle. Turn the needle bar all the way down and then measure 3/32" rise. At this position, the point of the hook should be centered at the needle and 1/16" above the top of the eye. If your needle bar height is off, raise or lower it until it's where it needs to be. Check your latch opener adjustment as I've described earlier (if you can find it..heh) and make darn sure the threads pulling up clean. Trust me Dave, when you get your machine timed and set, you'll eliminate the issues you're having. I hate to sound redundant, but if you were my apprentice, I'd un-adjust everthing ten times until you could do it in your sleep. By the time we get done, you'll likely be able too. Regards, Eric Quote
Members gottaknow Posted December 8, 2012 Members Report Posted December 8, 2012 Btw, have I mentioned when you first start out, you should be holding your tail thread out the back of the foot until you've formed a few stitches? Quote
Members dmar836 Posted December 8, 2012 Members Report Posted December 8, 2012 You've mentioned it for sure and you'd be a great mentor. It is something subtle going on. The shaft timing is good. The hook and needle bar I have adjusted numerous times. This eve I reset the gears one at a time to see if shifting the set screws on the groove in the shafts helped. I did move the hook gear once before to allow extra adjustment but never strayed from the groove. Tonight I jjust changed which set screw lined up with the groove(and swapped screws) so that was probably 5 teeth. The needle bar couldn't be adjust to get it timed right so back the way it was. Really it sews fine, makes good stitches, and responds to thread tension adjustments appropriately. So I think it is subtle. I may have inadvertently jumped teeth when I had the hook out so I might mess with that too. I know I can get it! Dave Quote
Members dmar836 Posted December 8, 2012 Members Report Posted December 8, 2012 I played with timing and retarding helps a bit. I watched this am as I hand turned the wheel and it is happening at about 1/4 turn of the hook after it has picked up the top threaad. When I let go of the wheel the entire mechanism - hook to handwheel backtracks a bit. That is allowing the top thread on the hook to become slack and the bottom of the loop to fall down under the hook body. The to of the loop on the hook is picked back up and continues as it should. This ends up with the top thread around and under the hook body. Now I have to find what is physically making the machine spring sightly into reverse when forward pressure is relieved. I'm getting there! Quote
Members gottaknow Posted December 9, 2012 Members Report Posted December 9, 2012 Got it! Nicely done Dave. Regards, Eric Quote
Members dmar836 Posted December 9, 2012 Members Report Posted December 9, 2012 (edited) I wondered what could make it want to roll back a bit when I stopped sewing only when in certain places in the sewing cycle. I thought first the drive belt being old and stiff. Of course it dropped the loop around the hook even without the belt. I then thought it could be something spring loaded. Everything we have discussed was timed and working but the feed mech always sounded violent. You guessed it, the feed pressure was so great that when the pressor foot hit the material, it was so over clamping that the spring pressure was acting as a resistance to the following cycle - the ascending needle. The early hit, with its high spring pressure, gave enough resistance to "get past" that, unless I was constantly on it, would cause a slight relaxation backward. This was just at the stage where the point of the hook had reached maybe 90 degrees past catching the top thread when then backing off allowed the thread to partially fall - frequently getting under the hook. Now, with no excess back pressure, the hook stops cold and the top thread stays planted on the hook point regardless of location. I also centered the needle in the feed dog and spaced the needle bar from the pressor bar according to spec as well. I still have concerns with adjusting pressor foot height. Both are now lower than before. I adjusted the gib so that they are more equal. Is there just one overall height adjustment for both feet and then just the one gib screw to balance the pressor and walking feet heights relative to each other? All the help has been phenomenal! Dave Edited December 9, 2012 by dmar836 Quote
Members TSquared Posted December 9, 2012 Author Members Report Posted December 9, 2012 Dave, I need to move my feed dog to the left to center the needle. I tried to loosen the two little screws without success as I could not get them loose. Is there a different setting? Quote
Members dmar836 Posted December 9, 2012 Members Report Posted December 9, 2012 Hmmm, Is the needle not centered? Maybe Erin knows differently but I didn't think the feed dog was adjustable side to side. I would look first for a bent needle as that's easiest. Looking underneath at the fork that runs the feed dog and the associated shaft above, I see no adjustments but could be wrong - perhaps the screw on the end of that shaft is an eccentrc. I suppose the needle bar or needle bar frame could be bent from a hard stoppage? How far to the side of the hole is the needle? Dave Quote
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