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  1. dave048

    Circular runout normal to datum axis

    Thanks guys, exactly what I thought. Sorry about the 1987 date I didn't think it mattered but just in case I threw it in at the last minute with out verifing. The interrupted surface is gaps between bolthole bosses. Powerhound, if you get a flight safety alert on one of your favorite...
  2. dave048

    Circular runout normal to datum axis

    We have a barrel shaped part about 20 inches in diameter with a one inch wide flange around the perimeter perpendicular to the barrel axis. The GD&T callout on the flange is circular runout (not total) to the axis of the barrel. In other words perpendicular runout. The shop has been checking...
  3. dave048

    twisting rotorblades

    You might try Hexcel in Washington state.
  4. dave048

    twisting rotorblades

    You might try Hexcel in Washington State. Thats all the info I have. Is this for aerial firefighting use?
  5. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    israelkk- Thanks for the post but changing the type of plate process is not an option. This is an overhaul facility. The OEM sets the plate process type. Electrodeposited cadmium plate combined with carburized surfaces is very common in aerospace gearing. The process is very mature. There is a...
  6. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    swall- thanks for the post I am very interested in the "infant mortality". Is there a paper that explains that condition? This condition seems to explain some of what we have experienced. Also is there some work that explains how the 23 hours bake was selected in QQ-P-416? Maybe something that...
  7. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    Thanks, TVP. This is a overhaul facility. What I was wondering is what would happen to the gears. But it's probably too hard to say. Apparently they won't crack under normal usage but we are not sure whether they have experienced heavy loads. Then the question is What now? Do we suggest...
  8. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    Thanks TVP. I have one other question that could could cost someone thier job (fortunately not me)and a lot of money. I know that the bake is to prevent embrittlement and to prevent a decrease in ductility caused by the plating process. The question is; What would happen to a cadmium plated...
  9. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    Aerospace parts are routinely core hardened then carburized. The carburized surface is the only surface that reaches 62 Rc. Many are Cadmium plated too.
  10. dave048

    AMS QQ-P-416 history of bake times, carburized parts

    I have a pinion gear made out of 9310. It is carburized and final tempered at 300 deg F (Rc62). Currently the post plate hydrogen embrittlement bake in AMS-QQ-P-416 for this type of part says 23 hours at 275F. I have evidence that this used to be 12 hours. Is that true? and further back in time...
  11. dave048

    twisting rotorblades

    OK, OK there is 14 degrees of twist. My "facts" came from the fact that I see the blades every day and they looked straight. To me 14 degrees in 26 feet looked straight. We have racks of those blades around here so I went out and looked and then I checked the B/P. You can see the twist if you...
  12. dave048

    twisting rotorblades

    Mike is correct there is no twist in helicopter rotor blades, main or tail. Perhaps you are thinking of propellers? Also ours only have a hollow metal core made from a flattened tube with composite for the rest. Dave
  13. dave048

    Tolerancing Dispute

    Perhaps the misunderstanding about which dim to put on top persists because the standard has changed. The older standard (I don't remember the version# but it was some time ago) used to specify that for ID dims the smaller number goes on top and the larger on bottom. Now, the larger number is...
  14. dave048

    EDM to repair NDT indications

    I am interested in the replys to this question. This is not a common repair procedure in aerospace applications. In fact in 30 years of engineering I have never heard of anyone doing this. The only repair I have used is removing material to a depth necesary by mechanical means(grinding). EDM of...
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