So if I understand this right, the main shaft on the BelAir Bantam is larger in diameter than the Singers, soooo you had to have the machine shop hone or bore the hand wheel out so it would fit.
If I've got this right I just might try to make a HC out of my SEWMOR 303. I just happen to have a spoked hand wheel that's a loosey goosey fit on the Singer shafts. Might not be too hard to hone it to fit.
Joe