I have sewn many a car seat, snowmobile seats, motorcycle seats with a Singer 31-15, which I much prefered over my Juki walking foot. I have just purchased a 111w151 to do a camper interior.It will need parts and work, first. If someone is doing a few projects, then sure what he has will work, I think. Upon inspection of my machine yesterday, I saw and then realized the problem with the foot that was encountered. It is not typical. Also, the bobbin is a very tight fit, so I could see the request on that. Waywak had the regular everyday feet, but I did not realize the configuration of the 111w151 foot, as that machine is at my shop, and my computer is at home. I did not intentionally give out false information. I was not implying a home owner machine would do the job, as I know that it never would!
When using a straight stitch machine, and you have to jump over multiple layers, stop the machine and hand spin the wheel over the lump so that you do not break the needle. Singer Co., in the past, has been very helpful to me, they even sent me a bound copy of "historical records" full manual and repair book for my 31-15, which I should never have sold when I moved. So, ok, I should have examined my machine before I posted a reply, you DO know more than me, so I'll leave future replies up to the expert. The previous owner handed me a manual, but I later saw that it was for the 111w155 not 151. I intend to call Singer today so see if they can get me the correct paperwork I will need to restore the machine. I look forward to learning from this site.