Alternatives to M3.5 screws


I’m currently building the IE edition of MPCNC, but I’m having serious problems getting hands on a set of M3.5 bolts. This is a very rare dimension here in Europe. I have tried multiple stores, and have even tried special shops that sells “every type of bolts in the universe” and they didn’t have them in store, but was able to get them for $1.5 for one screw, and $1.5 for a nut. That’s almost $150…

The best solution I have found so far is HobbyKing which selles stuff for RC cars, but they only have M3.5 25mm length and have approx 4-8 weeks shipping time.

Does anyone know where I can get these screws at a fair price in Norway or other parts if Europe?

The M3.5 screws and nuts seem to be new to me.

I build my mpcnc (IE edition) with M4 screws some time ago. I also rebuild my corners today and reused my M4 screws. I don’t know where to assemble M3.5.

Thank you for the reply! I didn’t even think about using M4 screws. If the design hasn’t changed since you build your mahcine, it will probably work here as well. I’ll give it a try!

Im building my MPCNC at the moment and I did not find any M3.5 here in Sweden. I also went for the M4 and drilled up the holes where it was needed.


Hi ErikFromNorway,

I have just finished building the machine and had the same problem, but I found a place eventualy. There are places in the middleassembly you will need the M3.5’s. You can get them here:
Ole (from Denmark)

Hi Ole,

NICE! Thank you very much for the tip! RS-Online actually has a Norwegian site as well, so I have just ordered a set of 100xM3.5 screws at the same price as 2 screws at the specialist shop here in Oslo :slight_smile:


I got mine from Modelfixings


What are the flat-to-flat size on your nut?
Mine are 7mm, and new IE design are made for 8mm nuts.

Are there some of you that find M4 8mm wide nuts ?

Same problem here :frowning: At RS web I can buy M3.5 screws, but they dont have the nylock nuts. Are them critical? or I can use the regular nuts? Or is it better to drill the holes to use M4 screws and nylock nuts? Is not dangerous drilling the holes, so they became so close to the edge of some parts, and the part is weaker?

Thanks for any information about this issue. Im still collecting all the hardware and parts, and dont know what exactly to do.

EDIT: I also thought about using M3 screws and nylock nuts, instead of the M3.5, so I dont have to drill anything and the printed parts stay as the originals.

I used M3.5 with M3.5 regular nuts. To compensate for the missing nylock nuts, I used Loctite Threadlock (blue, medium strength). I’m pretty sure this will be enough.

Thanks for the idea Erik! I´ll do the same i think :slight_smile: