Flying EMT

Flying EMT

Active Member
I have one stainless steel brake disc that got warped a little bit somehow (I land on a 2 mile runway so rarely heat the brake up). I could surface cut it on a brake lathe, but was wondering is there a minimum thickness? Ben
 
Flying EMT said:
I have one stainless steel brake disc that got warped a little bit somehow (I land on a 2 mile runway so rarely heat the brake up). I could surface cut it on a brake lathe, but was wondering is there a minimum thickness? Ben
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Here is a screenshot from the Matco documentation, assuming you have these. I measured mine when I switched to the thicker disks and they were right at the minimum thickness. There is very little allowance for wear.
 

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The min thickness on my Cleveland 5” discs is .167”. If any place on the surface of the disc where the linings rub is below .167”, the disc should be replaced. Mine were getting close, so I just recently replaced them with new Rapco’s.
 
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Tom, the new discs are Rapco, I just want to do a skim cut on the one to get rid of a slight warp. (I only noticed the warp when pushing it in the hanger and hearing it) It measures .181 now so it should have plenty of meat to accomplish this. The ones I took off have no numbers visible so I don't know what they were. FYI the old ones measure .149 now. Ben
 
I find when airplane disks warp, they cup, like a tulip, not like car disks that actually get a high and a low spot.. if they don’t drag, or you don’t feel a pulsating, I would leave them alone.. they need all the thickness they can get..
 
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I’ve never heard of turning rotors on an airplane but I guess that doesn’t mean it can’t be done - being an experimental and all. I wouldn’t exceed the minimum thickness though and I would ask myself what caused it to warp in the first place. Typically heat. Cut ‘em thinner and they’re gonna run hotter. Think about if this is where you want to try to save some money would be my suggestion.
 
Scott Hersha said:
The min thickness on my Cleveland 5” discs is .167”. If any place on the surface of the disc where the linings rub is below .167”, the disc should be replaced. Mine were getting close, so I just recently replaced them with new Rapco’s.
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I just replaced one of mine because the grooving got bad. Tried to take it down to flat on the lathe, but had cleaned up very little by the time I got to .165" I was at 1100 hours, so not complaining. I am really surprised to see the .130" minimum dimension in the matco doc above. I don't see how two different manufacturers of basically the same setup have such different specs. It is NOT a small difference. Does anyone know why Matco accepts such a thinner disk? Generally you need a certain amount of mass in the rotor to absorb the heat from an anticipated max effort stop.
 
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