On the K model you won't be able to put casters on them. I've tried to source industrial casters with a long enough stem. Found some but when you try to move it they bend. It's a waste of time, effort and money because of the 3 point legs. Beyond that it is always going to be unstable even if you could find casters. The three legged configuration is deadly for tipping over if the wheels don't spin right.
Casters do however work on the Landis L models with square base.
The best way to move a K are the following:.
1. Put a pipe under one of the legs and do a leveraged slide. The longer and thicker the pipe the better. Very effective to move on a flat surface.
2. Grizzley tools sells a rolling tool stand wheel set. Great to move the K around the shop.
3. Use a powered winch or hand crank come along to get them up a trailer ramp. My best recommendation to move them by trailer. Harbor freight. Go slow and adjust the legs as needed to slide up the ramp. They slide down the ramp by themselves.
4. Make your own platform with 4 wheels. I believe 32" x 32" should work. But I think mine is 30" x 34". But not really sure. Need two people or some set blocks to raise it to put it on a platform.
5. Dolly. Good luck with that. There are some specialized Dolly's that lean back with four wheels but they are expensive but a joy to use on these machines. Use a Costco dolly and 50-50 chance you will hurt, maim or kill yourself.
I'm moving these by myself all the time using a combination of the above.
Other advice:. Leave the chainstitch where it is. Nobody really wants to buy them.