Support BladeForums! Paid memberships don't see ads! Hey guys, I rarely make it out of the shop talk area, but I find myself in need of some advice from you leather pros, especially anyone who used a tippmann boss. I got a really big leather order in and decided hand stitching was out if the question so I picked up a used tippmann. I know how moody they are but figured I could handle it. I feel like I've almost got it there but I keep having the same issue. It seems like a little loop from the top thread keeps getting hooked by the bobbin shuttle and jams up the whole works. Even if I have a good run, it happens sooner or later. Seems to happen no matter how the tension is adjusted could it be timing? I'm sewing pretty light leather, 2 pieces of 3-4 oz leather, having better luck with heavier thread, 277 but want to punch it down to 207 if I can. Any advise is appreciated. The loop I'm talking about is the blue thread in the photo.