Originally Posted by
sherrihepler
Which screw in bulb will fit it? Thank you.
Chances are that no one has the answer for you. There aren't that many of those machines that were sold and are still out there. You can probably purchase the manual for $10.00. You might be able to find one on the vintage Japanese sewing machine groups (Facebook, groups.io) for free. It will probably tell you which bulb fits it. I'm not sure about this machine, but the earlier MW machines were made by the Happy Company of Japan.
The other option would be trial and error. I assume that you know it's a screw socket. Just buy a couple of sizes with a coupon and toss the ones that don't fit. Return the ones that are unopened. Again, buy the cheap ones.
bk