I think you will find 3/4'' plate is way too thick & the mount wont work as 3/4'' will stop it fitting on the disk, if I remember right the OEM Performance machine caliper bracket was only about 3/8'' thick, then centered on the disk using shim washers

 

Pete's right, 3/4" will problematic with how that caliper is designed to mount, 3/8" is what all the stuff I had for that design was. You could make it work maybe but it'll take some machining and creative engineering.

 

So the 3/4 was a fail. I didn’t have the equipment to machine it properly. I have some 3/8 6061 on the way. I live in Hawaii where supplies are limited so should arrive in the mail hopefully tomorrow. I tried to keep it as simple as possible because of my lack of tools. Holes are arbitrary until The bracket is cut and fits nicely. I like the bottom mount look so I’ve decided to go with that. Any recommendations on a bushing for the axle?

 

I went 3/4" for the axle hole, will save you some headaches with the spacer game and getting the bracket rigid enough to not flex or misalign on you but I can make my own spacers to fit.

I did a cardboard mockup using a spare rotor, did a little spacing to get the calipers to sit exactly where I wanted then did some tracing. My working print is stashed, this is the mock up collecting spider webs in the garage rafters .

 

You're good to go, as 3/8" or 10mm is sufficient for this purpose. That's the thickness I use on the 6061-T6 rear disc brake adapters I make for British sports cars.

I don't know that you need a bushing if your goal is merely to avoid wear at the hole for the axle. The bolt holes that affix my adapters to the axle flange do not wear, and they get used hard by the racers who've mounted them. Almost all of the force exerted by the caliper is radial (with a small amount being centrifugal, as the rotor tries to tug the caliper toward the outer edge of the disc), so it gets transferred to the stay attaching the bracket to the frame dropout.

That said, a bushing with a shoulder does look nice--and of course can help establish precise lateral position. Here is a bushing page from McMaster. It might be that the usual suspects sell replacements, and you could drill the hole to fit whichever one you choose.

 

I’ve been on vacation for the last month so happy to be back home working on the shovel again. Almost done with the rear bracket. Still need To drill my hole for the brake stay and do some more polishing. It fits perfect on the rotor. Minor flaws here and there but over all I’m happy with it. Not bad for an amateur I’d say

 

Where you going to mount the anchor strap ?

 

Here. Wiill this work? Your scaring me🤪🤪🤪 I set it up for a bottom mount

 

I'd like a little more meat with my **** tendencies but it should be fine. I'm kinda of an overkill builder cause I tend to be a bit hard on things occasionally

 

makes sense! I should’ve beefed it up more on the brake stay side. At this point I just want to get this b**** on the road. I guess if I start having problems I’ll just make a better one 😂 or I could weld a support bracket that runs from side to side behind the caliper 🤔🤔🤔