In order to attach to the printer I got 1/2" x 10-24 bolts with 1/4" shoulder and square nuts that I ground one of the flats for easy install by popping of the end cap and sliding the assembly on before tightening the bolts. I drilled the mount holes so the bolts would fit. I used 10-24 x 2" machine screws with a flat washer and nut for the base, coming up through the bottom (it's what I had on hand). The bolt through the top portion 10-24 also, but I had to shape the nut size larger to accommodate the bolt head. I used a nylon locking nut with a washer on the outside. The cardboard spoil barely touches the mount. I think I will make a 1/8" thickness sleeve for the spool holder to alleviate that.