my Pfaff 34 needle thread raffling up

[amateursewing]

I was doing some leather work, quite heavy leather bikers jeans on my Pfaff 34 industrial treadle with a size 35 polyester thread, on double leather layers the machine sews fine but on triple layers the needle thread was constantly ravelling up at the needle point, as thought it was not being pulled by the hook underneath around the shuttle, I tightened up the upper tension alot but it doesnt help, my Singer 20 U machine did it PERFECTLY, albeit a bit hard on some sections but no needle thread reavelling at all, what do you think could be wrong here? I am a bit disappointed with the Pfaff 34 as this was a saddlers machine but it wont sew three layers of leather whereas my Singer 20U (a much lighter strength machine) did it fine. thanks - I was using leather DPX5needles size 16 in the Pfaff 34. and DPx5 size 16 in the Singer 20U.

amateursewing 

Edited May 22, 2016 by amateursewing