Needle and thread size for larger leather

[CHT]

Hi:

We are building some new things that, at one point are thicker.  When we sew 3 pieces of veg tan together it comes to about 22 - 24 ounces of leather.  We have been breaking needles and wondered if we should be moving up in size and thread?

This is on a Juki 1508, using Schmetz size  21 needles and Superior Thread 92 size bonded nylon.

Anyone have input and thoughts?

Thank you

Chuck

[Ferg]

In my humble opinion, you need to use no less than 138 thread and probably 207 for that thickness of leather.

Needle size accordingly.

Ferg

[Rahere]

How big is the thing? It sounds like a case where reversion to hand-sewing with the parts glued and drilled is the only way to avoid using thread that's so thick wear will be an issue - although kevlar thread is available.

[CHT]

Thank you Ferg, makes sense.  We re timed the machine and then stitches looked better but needle failure.  So larger makes sense.  

Thank you Rahere for the thought.  We need to stay with machines for now.  138 is not a whole lot thicker than 92 so will give that a try.