M3 Cap Head Lengths and Substitutions


I am in the process of building an i3 MK2 clone from the budget build article. There are many sizes of M3 cap head bolts. Buying these individually is somewhat costly as you either end up buying small quantities, or spending less per unit on large quantities - but have lots left over. I see a few kits that have various sizes - but not all are a 100% match.

My question is: How substitutable are these fasteners with each other? Will an M12 work in place of an M10? Thanks for your help!



Hi spacha,

The short answer is “yes”. However, be prepared to cut down some of those screws as some places require clearance. I’m in the States, so getting metric hardware is very expensive compared to imperial. I wound up buying enough for 3-4 printers and I use the extras for all sorts of other projects. The price of the hardware wasn’t that bad, it was the shipping!




I’m in the same boat. I can order all the stuff I need on Amazon. But I would be buying packs of 100. The price per unit isn’t bad - I just would be buying a lot of extra. I guess I just need to build more printers! Thanks!



M12 & M10 are different diameters so no they are NOT interchangeable… going between Imperial (USA) & metric can sometimes be done e.g. 0Ba & M6, its close but not exact.

As for length you can always buy longer & cut to fit.



As there are no M12 or M10 screws in the build, I assumed he meant M3x12 and M3x10.



on the mk2 2pcs of 360mm M10 threaded rods are used with nuts.

maybe this help