I haven't wrapped around a bolt for a spaced coil, but I imagine it would work for your purposes, fifty, if you are having trouble.
For whatever odd reason, just using a coil jig but only the bottom half (not using that top part to "wind" the wire, I am able to get a pretty even, spaced coil, just by twisting the wire myself. It's some odd gift I seem to have that I actually shouldn't. I actually
prefer to wind that way, and if I want a contact coil, I just squish it together at the end, and it's about as even as a machine would do (at least in my eyes). I sort of assume it has something to do with knitting and crocheting from the age of about 4, when my grandma taught me those skills.... Good knitting has a lot to do with even tension, and I've knit things that look machine made. My sis is similarly equipped only she makes
complicated stuff (she likes to count stitches, I very much do not) but I've made a ton of blankets that I then embroider stuff in felt using colorful embroidery
threads. It's a lot of fun
With that said, you can wrap on
anything that helps you, just try to figure out (about) what diameter it is.
Anna