On used plates you need to lap first to get the step wear down flat, on new plates they do a good job from the factory making them flat and true( never checked but will from now on). Re-nitrate to a low heat to have it harden down about 3-4 thou deep after lapping. That low heat 99% will not warp the plate and no need for a touch up on re lapping after nitrating. All the plate are dial cheeked for warpage and if necessary the will be re lapped very lightly.5 thou at most... But never had a warped plate yet coming out of the nitrating process...

But at the same time i will start checking the new plate from Mazda for warpage.. you never know...

At the same time everybody has there own take on lapping or lapping with nitrating. But i can guaranty you that lapping a used plate 2-3 thou deep and checking the hardness with a dial indicator. it a much softer material with out the nitrating. Thus making sense that wear will occur more rapidly in a plate with out nitrating than with...

Hope that helps...

Hot damn this sounds like a good deal

Here are the Rockwell readings..

New Mazda plate from the factory no miles on it. RC 38-39

Used plate after lapping /Grinding 2-3 thow deep. RC 21-23

Used plate after lapping/grinding with re-nitride. RC 40

Hope that this helps...

Wow! That is a significant change.

I may have a set for you to resurface in a few months when I tear the engine in my car down to install the new 9.5:1 rotors. I didn't know about this and lapped the irons myself (although I didn't remove any 0.002-0.003", more like 0.0005"). I am sure they will need it again by then if the hardness is that much different(with 10,000 miles on the clock). I should have known that there was some reason that everyone didn't just do the lapping themselves....

I will let you know if they show appreciable wear (I don't want this engine to fail anytime soon).

Still Running that 420.00$$ per 13b special for RCC members.....

Thats a good deal!

Hi could you tell me what the RMS (Surface finish)is after the final lapping?
Thanks.

Just finished up a set of plates for a customer 3 rotor...

Enjoy
http://img130.imageshack.us/img130/7600/beforedg.jpghttp://img130.imageshack.us/img130/b...jpg/1/w800.png



http://img3.imageshack.us/img3/464/work009.jpghttp://img3.imageshack.us/img3/work009.jpg/1/w800.png
http://img694.imageshack.us/img694/21/work005.jpghttp://img694.imageshack.us/img694/w...jpg/1/w800.png
http://img3.imageshack.us/img3/4963/work013.jpghttp://img3.imageshack.us/img3/work013.jpg/1/w800.png
http://img694.imageshack.us/img694/8536/work015.jpghttp://img694.imageshack.us/img694/w...jpg/1/w800.png

The cost for me to have these done went up, so i'm pasing the savings on.

480.00 for a 13b
640.00 for a 20b

..

61 rms

It has nothing to do with them failing bolts/fittings.. They get blasted and re zinc plated..

Reconditioned plates... REMAN :)

That's some nice, thorough work there. Whats the turn-around time for the service?

Probably gets them done in batches.

I know we did a huge number of fasteners/pipes/studs etc. up here last year and by the time we gathered crap between my builder myself and few other guys the price to plate the items was almost halved due to the volume.

But yeah I imagine the dipstick tube/rear iron coolant tube are a biatch to remove :)

Sure about that number? We had some plates ground a while back and took some measurements of re-ground used and brand new OE plates. We found a new set of OE plate to be about 12 Ra (micro-inches) on average. Our guy got the used plates to an average of 8 Ra.

The rough correlation between the RMS and Ra is around 11%. So our measurements for the stock plate would roughly be 13 RMS.

They look to good to be as bad as your measurement would suggest.