Things have worked themselves out and I will continue posting on the bigger brakes.
I went into work this moring with a 50 pound packet under my arm, well it was breaking my arms actually. I left tonight with slightly under 32 pounds.
I rough machined the rotors leaving only a slight cleanup cut on them.
The back side is machined to the stock 2 inch wide braking surface, I actually left 2.1 inches to be sure.
The front side or the side the hat is bolted to is 2 1/4 stock to clear the caliper and I left an extra 12 inch for bolting but I can trim that down later.
Each rotor lost about 8.5 pounds. They started at 24.86 pounds each and came out at 15.8. This is the initial machining.
I will try this weekend to drill a pattern on the rotors. I will actually figure out tomorrow what I will weight if I drill about 240 holes at 1/4 inch each.
Anyone know what a hole 1/4 inch by .265 doesn't weight???

Anyway in these pictures the surface facing up is the back side of the rotor, it is .1 inches wider then stock. The side down on the carpet is 1/2 inch wider then stock for bolting the hat to the disc.

I made this hat before seeing the disc and afterwards thought it looked way too small. I am scrapping it and remaking new 10 inch ones.
This hat fell right into the hole I bored in the disc

This is the stock rotor beside the new 14 inch.


This is a machined rotor beside the stock one.


This is the machined rotor with the 8 inch standard size hat sitting in the middle
The hat is way too small for this size of rotor and I will move up to 10 inch


Another closeup of the machined rotor
This is the back side, not the side that the hat bolts to



Once the hat and rotor are bolted together and I plan on 18 screws per rotor along with a slight press fit of the hat into the disc for centering I then put the two piece, hopefully now one and remachine all surfaces on the disc for finish and truing it up with the hat. I left an honest .010 for this purpose.

 

Pardon my stupidity, but how/where are the bolts going?? I don't see any holes, or a flange left for them...
what angle do they go into the hub???

I familiar with stock setups, similar to the stock vette setups..but this???

GENE

 

Glad it worked out.

For comparison: How heavy is a stock rotor?

 

Gene the part that is down against the rug is wider then the part sticking up. The new 10 inch hat will rest on this ledge, actually it will press lightly only this ledge for centering and 18 bolt holes will be drilled and taped. I have very fancy button bolts that my son has.
The hat shown is way too small and I decided the first time I saw the rotors that they were scrap.
The new hats and rotors will be bolted together to look like the stock setup.
I will anodize the hats gold for looks.
Contary to what some might think I planned for these rotors before ordering the wheels. The wheels run me over $600 each and I needed them to clear these massive rotors.
I am not just filling in the empty rim. I planned it before ordering the rims

 

My stock rotors have not been weighed in the last 10 years so I don't know. I would have to carry one into work to get a accurate weight. I don't know how good my bathroom scales are.

They lie about my weight all the time

 

Norval, why not machine the rotors like wilwood does some of theirs? As in, drill the holes and in between the holes machine out a chunk, that would save even more weight. Soemthing lik this, would be a lot of work.

 

I think its because he's putting a lot more bolts in it than the wilwood.

 

Already thought of that but today I borrowed a very large lathe and just hogged out the unwanted material. Cutting the tabs like that takes a mill , a dividing head and some time.
I would like to do that too but today I just wanted to cut those ugly big casting down.
I would like to do it just like in the picture.

 

Yes, but when are you going to get some real calipers and some real brake pads? Organic is all fine and good for one stop. Why not have that one stop be a little better? Sure there will be an improvement by having the larger rotors, but go all the way. Someone with stock sized rotors and good pads could probably have better braking, and that is the goal, right?

What are you going to do about the rear? The brakes might be a bit too heavily front biased if left stock.

 

Forget calipers other then a weight penelty I feel stock calipers are fine. Pads?? I have run racing pads for short terms and still have them in the shop gathering dust. Performance Friction metalic pads and after 3 hard stops they really start to work but for that one panic stop with normal temperature brakes a organic pad will work better.
Good racing pads need heat and repeated stops. They also eat rotors. At $511 for a pair of rotors I don't want anything nibbling at them.
I do not race, dona't need metalic pads, don't need new calipers that cost a fortune just to loose some weight.
I a one stop panic stop my orgainc will match any metalic. ONE PANIC STOP
The rears? I don't run a proportioning valve and will count of the brake caliper piston size and the large rotors to do the biasing.
I have run for years without any porportioning valve and consider that a big improvement by itself.

 

That's looking really good, Norval. They look a lot more like rotors now, rather than metal pizzas or something. The weight is certainly coming off. Oh, btw, a .25 diam x .265 piece of steel weighs .004 lbs so 240 holes would weigh .96 lbs. Isn't that through just one surface? So for both surfaces that would total 1.92 lbs. Also, I measured a rotor and hat that I have here and it is using 8 fasteners that are .25 diameter so I think 1/4" hardware to attach the hat is more that sufficient, especially if you are using more than 8.

 

Just weighed a front rotor 17.5 lbs

 

Thanks, Dan. So Norval is at 15.8 lbs right now plus whatever the hat and bolts will weigh. Sounds like if the hat is aluminum and he drills a few hundred holes in the rotor he may actually end up at about the same as a stock rotor. That would be pretty cool!

 

NOT to change the subject, buy why is there the differance between the front and rear stock rotors, that 1/8 inch differance in the mounting flange thickness, so they do NOT interchange....drove me crazy finding out, it's subtle...but they will not interchange....dumb move on someone's part....seems like...

GENE

 

Yeh gene.... I just bought a whole set of rotors from NAPA to replenish stock and they all look identical. Guess I'll have to name them to tell them apart.

 

Because the rears have the drum for the parking brake?

 

That's the funny thing, the fronts have that also, a smooth machined inside surface, the only visible difference on the rears is the extra 2 holes for adjusting that start wheel.

 

Norval, have you modified your calipers to accept the dual-pin pads? I recently received a full set of Hawk HPplus pads (single-pin) from VBP and they had instructions for drilling the normal calipers to accept dual-pin pads. Not even sure if there's a performance advantage, but it might be worth looking at if you haven't done it yet...

I can scan the directions if you want.

 

Thanks Burners for the calculations and no it is 120 holes per side or a total of 240.

My hats are going to be 10 inch and 18 1/4 inch bolts works out right. The dividing head stops in 20 degree increments so 18 x 20 equals 360 degrees.
Actually the way I am going to do it is with a computer printout giving the location of the taped holes and the 1/4 inch rotor holes.
You just use the digital readout and dial in the various co ordinates.
Should make a very accurate set of holes.
Now that is 240 holes plus 18 times 2 == alot of drilling.

 

I won't drill the calipers. The single pin sits in a boss raised above the caliper. A dual pin would rquire drilling the caliper itself.
The pads are held in the caliper by front and back edges.
Also getting pads from the local supply house is not a problem.
I can't see how a dual pin would work with normal pads. The complete pad is one the rotor and no room for another pin.