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Discussion Starter · #1 ·
So a good buddy of mine decided he'd build me a steel midplate for a st-10. Started out as a 12" square plate that was 1.25" thick and 40lbs give or take.

Now at its correct in size and weight it is about 10ish. From my understanding this mid plate does double duty supporting the main bearing better and not allowing the mainshaft to move on shock loading, but also act as a girdle for case flex. In a 4000lb car running 11's with slicks, it should be a good test ;)

now we saved the a-cad file to duplicate this plate, given there is interest we could make a couple others. Thinking they might be a aircraft grade aluminum vs steel, little easier to work with.

IMG_2273.jpg
 

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Boldly procrastrinating
66 El Camino 57 Chevy pickup 2004 Tahoe
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looks good. Nothing like guys creating their own solutions.

So that's a piece of steel plate , not cast iron?
 

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Hi,

About the steel plates. I'm actually making them again, but I'm backed up with the steel plates for the Muncies. The billet 6061 T6 plates are also being done for both the Muncie and ST10. I plan to have them both done by May.

You may want to measure your plate. This may appear to be an easy part to make but it is not. I'm sure when you do it manually you can probably hold better tolerances because you need to check them during the process. I use machines that have QC probes in process to maintain the accuracy and make corrections.

That being said, from the original Borg Warner prints, they allowed .004 flatness overall from .498 - .502. and you could not vary more than .002 in 1 inch of surface travel. The bore had to be perpendicular to the plate within .0005. If you exceed these dimensions you can wipe out your extension housing bushing as well as destroy your pilot needles.

Surprisingly the factory diecast plates were extremely accurate. There is a video on measuring plates here:

 

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So a good buddy of mine decided he'd build me a steel midplate for a st-10. Started out as a 12" square plate that was 1.25" thick and 40lbs give or take.

Now at its correct in size and weight it is about 10ish. From my understanding this mid plate does double duty supporting the main bearing better and not allowing the mainshaft to move on shock loading, but also act as a girdle for case flex. In a 4000lb car running 11's with slicks, it should be a good test ;)

now we saved the a-cad file to duplicate this plate, given there is interest we could make a couple others. Thinking they might be a aircraft grade aluminum vs steel, little easier to work with.

View attachment 412497
Good day. Are these mid plates still available? I’m in Calgary and in need of one myself.
 

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Discussion Starter · #9 ·
Good day. Are these mid plates still available? I’m in Calgary and in need of one myself.
sorry all sold out of steel and aluminum one. I could talk to buddy and see if he still have the program cad file. Cost would be high though for a 1 off.
 

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