Looking at a Singer 111w151.  It's an old army parachute-repair type machine.  It's needle feed.  Takes 20 and 22 needles.  Size 22 is good for 138 thread.  Has a 1/2 HP clutch motor.  Manual says 7/16 clearance under presser foot.  Is this OK for veg tanned leather glue sandwich with combined thickness of 8-10 oz? Assuming the 111W is OK for dress-belt type work, what changes could be made to increase the capability of this basic machine?  Add a thread lubricator?  Change to pulley?  In th