I'm becoming intrigued with Kenmores of this era (the 158 models) simply because they are rather mysterious. There just isn't a whole lot of information about them as compared to Singer models and I have yet to find a list of all the models AND all their features. There is a wide variety among the models even though they are all in the 158 line.
Kenmore 158.17800
This is a free arm with a super high shank, left homing needle, and a drop in bobbin
It has a number of built-in stitches and takes C-cams as well
It is easy to lock the feet onto the super high shank, you don't have to screw them on. It also has the extra high presser foot lift like most Kenmores of this era.
Only problem is that for some reason these feet are hard to find. You'd think for every one of these machines made there'd be a corresponding set of feet out there somewhere. But that doesn't seem to be the case, for whatever reason. The few original feet you can find - and even the reproductions - are pricey. Keep that in mind if you're considering one of these machines.
Super High Shank adaptor for low shank feet
To a certain extent, you can make do with low shank feet by purchasing this adaptor for about $15. It doesn't work with every low shank foot, but it will give you some more options. This is a low shank zigzag foot attached to the adaptor.
Then, there is the left-homing needle position on this machine which doesn't mean a whole lot for practical purposes EXCEPT that you have to have a special left position straight stitch foot. Happily, one was included with this machine.
Left homing straight stitch foot - a must with this machine
Besides being a free-arm, this model comes with a built-in buttonholer. Parts that originally came with the machine would be fitted on that gear behind the throat plate, but I don't have those parts. YET...
Built-in buttonhole feature - more parts needed!
Horizontal rotary hook/drop in Class 15 bobbin.
It also has a convenient quick release throat plate (ask the dummy who tried to unscrew it before I figured that it pops right out!)
And it sews nicely, with a 7mm stitch width. Nice, balanced tensions, no complaints.
Green is the bobbin side - nice tensions
Instead of showing how fast this machine sews (not that fast, maybe 880 spm) I thought I'd show how well it sews through very thick seams without stalling or skipping. Notice the presser bar lift, so you can get the 1/2" stack of fabric under the foot. This is SIXTEEN layers of stretch corduroy.
This machine is loaded with features, and would meet almost any sewing need from free-arm to buttonholes to stretch stitches galore. The only drawback is the unusual shank style which might limit the feet and accessories you are able to find for it.