Title pretty much says it all. Also, new member here - this is my first post. I've been doing a LOT of reading about the Singer 31-15 machines just via the search results but I'm not finding exactly what I'm looking for, hence this post. I acquired a 1925 Singer 31-15 with K-leg table and clutch motor from a friend who is a professional cosplay fabricator. He'd originally gotten this machine for free himself when the prop department for the Lyric Opera of Chicago was upgrading a lot of their equipment. I guess they were giving away old machines like this so he took this, thinking he'd use it to sew leather. He wanted a machine with a walking foot though and one came up at a good price right after he got this old machine so the 31-15 has just sat in his living room and was never used. It was in fact serviced right before he acquired it, so other than requiring an oiling, it should be good to go. I do know from reading some of the posts that the earlier model 31-15 machines apparently won't take heavier-weight sewing threads nor will they sew thick leathers. I'm not intending to use this to sew thick veg-tan leather, but instead thinner chrome-tan leathers, or very thin stuff like deer skin, some chrome-tan elk and bison I have, and possibly some thinner veg-tan like some goat leather I have that is 3-4 ounce if I recall correctly. I see this machine being used more for stitching on things like trucker-type wallets and pocket books, as well as carrying bags and pouches that are more made from supple leathers. My thicker leather work I would still be hand-stitching since I think big stitches and thick thread look better on things like archery quivers and the like, especially when those are made with 5-7 or heavier leather. I know that's beyond the capability of this machine. I'm already planning on swapping out the clutch motor for a servo motor, but I'd also like to know what other parts I should look at changing if I want to use this primarily as a lightweight leather sewing machine as well as something for sewing heavier cloth fabrics along the weight range of stuff like denim, cotton duck, or lighter cordura fabrics. Obviously for leather I'll want to use synthetic thread so what is the largest I can run in this machine? Is there anything I should look at to determine if this machine has been modified to sew thicker thread or use larger needles? I can certainly take some photos and post them here if it helps anyone help me determine whether everything is stock on the machine or not. I have a printed copy of the original Singer manual that was tucked in the drawer of the table along with a couple extra bobbins, several needles and some other random parts. Is there a source for a more modern/contemporary manual for operation of these old machines? I understand a lot of information, especially about sewing leather seems to be predicated on later model year machines and that ones like this from the 1920s may be rather limited in what they can do along those lines. It still seems like it SHOULD be capable of at least sewing minor, thinner leathers like what I've described above. As I said in the beginning though, I did not pay ANYTHING for this machine so it's fine with me if I spend some money on upgrades like the motor and if there are other things I can install to make this a better machine for what I want to use it for. Any suggestions/additional information would be greatly appreciated. Thanks in advance!