Singer 31-15 capabilities

[Radardog]

On 2/13/2018 at 12:16 PM, Wizcrafts said:

I own a first generation Singer 31-15 from the early 1920s and I can tell you without hesitation that is cannot handle #138 thread in its shuttle. In fact, I am limited to a max of #69 thread. It sews about 1/4 inch of compressed soft material and is best used as a tailoring and alterations machine for cloth and linings. The take-up links and needlebar mounts are not strong enough to withstand the pounding that sewing veg-tan leather would place on them.

A much later generation of the 31-15 can probably sew with #138 thread. I know some folks who use later builds to sew chaps and shoe uppers.

My 31-15 with a added servo motor sews 2 pieces of 8-9oz leather with no problem using 138 thread.  The machine has to be set up properly with  proper needles DBX1 system number 22 or23 needles with a leather point.

[Wizcrafts]

1 hour ago, Radardog said:

My 31-15 with a added servo motor sews 2 pieces of 8-9oz leather with no problem using 138 thread.  The machine has to be set up properly with  proper needles DBX1 system number 22 or23 needles with a leather point.

Then your 31-15 is obviously a newer model that doesn't have the shuttle pinned to its shaft. My only timing option is bending the shuttle driver arms. Fortunately, I only bought the machine for tailoring cloth or sewing very thin wallet interiors.