Brake Drum Micrometer?



Brake Drum Micrometer?

Postby 62BillT » June 28th, 2011, 1:58 pm

I've got this posted on another board (not CT) and I thought I would post it here as well.

I've been in the market for a Brake Drum Micrometer. I like the Ammco 8500's but they are pretty expensive new and used ones aren't real cheap either. Then a lot of used ones need to be Re-calibrated and that tool is about another $100.

I've decided to try to make my own out of a Dial Indicator that I bought. I'm going put an extension on it to equal the inside measurement of an 11 inch Brake Drum.

My question is, is the inside measurement of a brand new drum Exactly 11 inches?

I'm planning on having it set to about zero on a brand new drum, and I should therefore get a pretty accurate reading on a used drum.

I'm going to try to make it as accurate as I can.

Any input would be appreciated.

Thanks

Bill
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Re: Brake Drum Micrometer?

Postby Indycars » June 28th, 2011, 7:18 pm

Most dial indicator have a 1 inch travel. You will need some pre-load, so why not start with a total length 10.9 inches.

Do you have a brake lathe???
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Re: Brake Drum Micrometer?

Postby 62BillT » June 28th, 2011, 8:31 pm

Right, the Dial Indicator I have has a 1 inch travel.

No Brake Lathe, just want to get a more accurate idea on the condition of them, other than going by eye sight. I've got quite a few Brake Drums to check.

Bill
Although I really like Corvette's, the "62" in my name is for an Impala.

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Re: Brake Drum Micrometer?

Postby Indycars » June 29th, 2011, 7:33 am

I wouldn't worry about it being exactly 11", most drums are stamped with a Maximum Diameter. That number really determines the largest
SAFE diameter for that brake drum. Look over the drum, inside and out for this stamp, it might be abbreviated "Max 11.060"
Rick
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Re: Brake Drum Micrometer?

Postby grumpyvette » June 29th, 2011, 7:51 am

I think youll find an 11" drum is no where NEAR 11" inside
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