Singer 31-47 Thread Size

[leatherman13]

Hello all,

I haven't posted in a while, but I've definitely been on the forums researching. I've been reading a LOT of forum threads about sewing machines and understand what is necessary as far as walking foot, servo motor, etc. Unfortunately, the cash outlay necessary is out my league, at least for now. I have been hand stitching all of my work and now have a client who would like some tote bags and I thought it was time to finally get a sewing machine to help. I have a small home machine which I do a lot of thin deerskin bags for the same client and I knew it wasn't going to help. I scoured the Bay and craigslist and found a lady selling a Singer 31-47. I checked ISMACS, and it was in the 31 family and is for heavy fabrics and leather. I picked it up for $250. It has the original table and clutch motor. I've done a s much reading as I can find, but my question is, after much digression, what is the biggest thread size that I can run through this machine? The lady I bought it from said her husband did upholstery work and the thread that came with it is size EE, which is 69? I'd like to go to at least 92 or even 138 but cannot find any information regarding thread sizes for my machine. If anyone can help it would be appreciated.

[Wizcrafts]

I have a very similar machine; a 31-15. Despite my best efforts, the largest thread size that clears the shuttle and bobbin case without snapping or binding is #69. I tried opening up the shuttle to clear #92, but it caused skipped stitches from the excess slack in the hook to shuttle driver positioning. Mind you, my 31-15 is first generation; 1920s. Your 31-47 may be newer and may allow thicker thread to pass around the bobbin case.

Don't push it if you hear a distinct snap as the thread goes around the bobbin case. That is the beginning of the danger zone.

[cdthayer]

To give you a comparison, I run Bonded Polyester T-92 & V-92 thread top and bottom with a Size 18 needle in my 1939 Singer 31-15 treadle, and have never had a problem with thread damage or breakage. I’ve never used any other thread size in it, and have sewn off & on with it for a year and a half. The material that I’m sewing ranges from thin to medium-thickness vinyl, and thick woven fabrics. Very little thin leather.

The slow speed of my treadle application probably makes a difference for me. I’ve never run my machine on a power stand, so I don’t know what it would do at higher speeds.

I don’t know how much different the hook assembly might be between Wizcraft’s machine and mine, but mine is over a decade newer machine.

CD in Oklahoma

[leatherman13]

Thanks for the information Wizcrafts. I checked my serial number and it is a 1933 model. Slightly newer than your 31-15 so I might try #92. If not, I'll settle in with #69 and get to work. Thank you!

cdthayer - I'm going to try the #92 and hope for good results. I will be trying to feather the clutch and keep everything slow so maybe I won't break thread or burn it. I still need to work on getting a servo motor. Thanks for the information!