The attachments for the Davis are a bit different than the usual, there is one style that slides on instead of the usual slide plate:
And one that bolts onto the bed of the machine:
The hem I saw online was done with the one that slides on, but for some reason mine was not fitting onto the machine so I tried the second kind. Let's just say it was not a fun afternoon, and the results were not pretty.
I whined a bit online, and a kind internet friend sent me a link to a video that helped a lot:
Especially interesting to see that even more experienced folks have to fiddle and fuss to get it started.
I also found this video:
I like how she started out, this doesn't work with hemmer feet that are attached, but I was able to use this technique to get it started with the Davis hemmer, then tighten it down on the bed of the machine.
So I made a 1/2 in. hem,
Then a 1 1/4 inch hem.
This was becoming kind of fun!
So now I wanted to try the hemmer foot on my 99K, since it was sitting there all threaded up. This is Singer 120855, a common low shank hemmer foot that fits on my 99K and my 66, and could go on my modern low shank machine also. I had to fiddle with a pin to get it fed in nicely, then work on keeping the right amount of fabric in the foot -- but after only a few tries I was pretty consistently getting this:
I was getting kind of giddy now, after feeling like a doofus trying to make a hem yesterday, here I was making nice hems! Hooray! So I had to try it on one more machine, my Singer 403a. This is a slant shank machine, and takes a different foot, 161195 for slant shank machines. The diameter is a tiny bit different, the 120855 makes a 5/64 inch hem. The one I have for the slant shank is 5/32, so bigger but still a small hem.
Starting out on the slant shank was a bit harder, mainly because this machine wants to SEW and it is hard to just do a stitch or two to get it going. But after fiddling a bit I had the same luck. I wanted to try it with something a bit stiffer that wasn't trying to fray like my cheap cotton, so I grabbed a scrap of ironing board cover fabric I had left from a project.
The fabric ruffled a bit from stretching as I put it through, I am sure I can adjust that with stitch length and being more careful not to stretch it as I feed it through. But yay, hemmers!
Singer also makes an adjustable hemmer I haven't played with yet, and I have hemmer feet for my White Family Rotary too. Lots of options to try still. But I learned it is super important to use fabric that is clean cut, and if it is too floppy a bit of spray starch would really help. Starting a stitch or two and then stopping and making sure the fabric is feeding correctly really helped, not too much or too little fabric or it gets all wonky. And holding onto the threads with a bit of pressure to start those first couple of stitches feeding through helped cut down on funky folds in the beginning.