I noticed the rotors don’t seem to have a sonex part number. Does anybody have dimensions for them? In particular the thickness, so I can buy material.
Hi Bryan,
My new rotors are .245” thick and 4.494” diameter.
Best,
Paul
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Thanks Paul! I’m either going to try making a set on the lathe, or maybe the Bridgeport. I have a rotary table. The other thing I need to know is the bolt size. I think they were 1/4” but I’m not sure. I will need to buy tooling for the countersink.
Cotton’s law strikes again 
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ACV-B01-24
Machined Stainless Steel Brake Plate for Hydraulic Brake
ACV-B01-15
Alloy Steel Flat Heat Socket Cap Screw, 5/16"-18 Thread, 3 1/4" Length, Black Oxide
I used the countersink below to clean up the new discs I got from Sonex, but so far haven’t cut any new discs. MMC parts below, and my dxf file attached.
Rusty
brake disc.dxf (10.4 KB)
From McMaster-Carr I ordered the following:
Cobalt Steel Countersink
for Screws, 82 Degree, Uncoated, 3 Flutes, 3/4" Body Diameter
3285A482
each 43.62
Black-Oxide Alloy Steel Hex Drive Flat Head Screw
5/16"-18 Thread Size, 3-1/4" Long
91253A597
packs of 5 5.83
High-Strength Steel Nylon-Insert Locknut
Black-Oxide, 5/16"-18 Thread Size
97135A416
pack of 20 5.44
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Awesome, thanks Rusty! I think I’ll try to make some practice parts in aluminum, just to get the sequence down. Then stainless - and I may try titanium as well.
I worked all that out a few years ago, but wouldn’t have posted it while they were still selling them.
Note that the bolts I got from MMC are maybe 1/8" shorter than the ones I got from Sonex, but I do recall that there was some extra on their bolts. I’ll be changing my discs and pucks in April during the annual. I’ve worn well into the tapered bolt heads.
Rusty
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I mostly need a set for myself, but may do a little production run to fill the gap in the community. Assuming nobody buys the company and restarts production, I wouldn’t want to compete.
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