What Miriam said about the grease and such.
There is one thing (possibly 2) that the "Best Machine Singer ever made" doesn't do well.
1. FMQ
2. stretch knits (they didn't exist when these machines were made, and the best stretch knit machines seem to be able to go side to side and back and forth in a stitch. The slant-o-matic only goes side to side)
The dogs don't drop because the elevator plate moves up. Like Miriam, I have other machines that can do it, so I haven't bothered to try.
I have heard that you can't FMQ on it, but I'm not sure why. The manual shows all sorts of free motion embroidery and monogramming and darning, it's the same basic process.
a 66 / 99 / 201 can FMQ - they've got the horizontal bobbin (all to the left of the needle though)
a 301 can FMQ - it's got the slant needle.
it must be something about the combination of the two, or perhaps that the thread has to go "backwards" vs threading towards the bobbins on the other horizontal bobbin machines that FMQ...
Lots of people don't drop the dogs to FMQ, including Leah Day.
http://www.daystyledesigns.com/doiha...myfeeddogs.htm
If you're going to try it, I would not bother to raise the elevator plate, set stitch length to 0, and practice on something that doesn't matter. I've been making cat/dog blankets out of my practice sandwiches,...
I have 2 slant darning feet. One I like and one I don't. I have the singer one that came with the 431 (like your 401, but with an open arm, and it chain stitches) I like it, and one that lots of the sites sell (including sew-classic
http://shop.sew-classic.com/Singer-S...KED-P60417.htm). I don't like this one, I feel like I can't see what's going on with it. But it's possible you could do surgery on it like Leah Day does on the other "Generic" foot for the low shank machines.