Speaking strictly from a machinists standpoint, I would approach this with extreme caution. As 2old stated, pipe threads are tapered. IF the bolt has a large enough OD and goes deep enough to engage enough full depth threads, then it might work. The fact that the calipers are aluminum makes this critical. I've already had to repair a Wilwood caliper for a guy that stripped his out. They are pretty soft.
Also, you will have to make sure that the bolt does not bottom out on the taper before it provides enough clamping force to seal the banjo.
This would be a very difficult setup to ensure safety. You would be better off, IMO, modifying the caliper to take a standard banjo, if that's the ony thing that will work.
Another option would be to find someone that does machine work and have them make a very short 1/8" pipe "L" fitting. This is entirely doable.
Last edited by Hotrod46; 02-12-2020 at 07:09 AM.