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  • Users: yates
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  1. yates

    Dual grade bolts mystery

    This is not pacific rim stuff. The bolt is of European manufacture. P and L superimposed is the trademark of 'Paul Lefevre' later Blanc Aero, now Lisi (see fastener quality act trade mark listings and MIL-HDBK 57) It is a hi-strength aerospace bolt class 8.8 but with UNC thread.
  2. yates

    Help for the metallugically impaired

    After considerable experience in using hand-held XRF mahines to distinguish between alloys used in our plant (Inconel 718, Waspaloy, multiphase alloys, titanium alloys, steels, CRES(A286) 15-5PH, 17-4PH, 13-8Mo) I can state the following : - The functionning principle of XRF machines precludes...
  3. yates

    Engine Main bearing bolt yielding help

    Does this thread get the record for most posts ? Who said fasteners were simple ?
  4. yates

    Making a brass alloy

    Heat it until it reaches the eutectic melting point. Sorry, I must have missed the point of the question, why would melting zinc & copper be any different from melting lead ?
  5. yates

    Equivalent Cadmium Plating Specification

    I believe the Douglas spec. you are looking for concerns low-embtittlement cad. plating by the fluoborate process. The process is described in NAS672. You may have somme difficulty finding someone to perform the process for you. It may be easier for you to get the part vacuum cad. plated (MIL C...
  6. yates

    Buying of Inconel 718 and X750

    Special metals will not normally supply small quantities. go rather to distributors (Perryman, Fry Steel in USA) or wire drawers dpending on diameter you neeed (Brown Europe in France)
  7. yates

    316 SS Fasteners vs. 404 SS Fasteners

    I would not have thought 316 SS to be sufficiently hard to self-tap into structural steel ?
  8. yates

    Measuring a turbine vane airfoil leading edge thickness

    Not quite sure what you're looking for, the actual leading edge radius or the throat passage on the shoulder behind the leading edge. Since you're talking about Turbine vanes (and not compressor blades) the smallest cross-sectional area of gas flow (throat) is paramount to achieving required...
  9. yates

    Iconel 718 Bolts

    Inco 718, although not the best alloy in marine applications (better suited to aerospace applications withh high temps) may have been specified for the bolt material as the alloy is very well known in fastener applications, so shear behavior, stress rupture and fatigue characteristics are all...
  10. yates

    Fatigue of A4-80 bolt

    Cory, The references mentioned in VDI 2230, are a bit ancient. The influence of structure, for example, on fatigue resistance of titanium alloys is much better understood now than in the seventies when titanium bolts were in their infancy. Gerhard Turlach, who is one of the authors...
  11. yates

    Fatigue of A4-80 bolt

    You don't say to what standard your bolkt was made. A4-80 sounds like an EN definition, which does not necessarily require either a rolled thread nor a forged head nor underhead radius cold rolling. Without these three items, an austenitic stainless steel bolt (which you appear to have) has...
  12. yates

    Converting BTU to Electrical Watts

    See http://en.wikipedia.org/wiki/British_thermal_unit. Since there are EIGHT different values for the BTU. When are you English-speaking guys ever going to get around to using the metric system ??
  13. yates

    un-explainable breaking fastener

    If the definition dates from 1969, then it is highly likely that the embrittlement relief was either not specified, or insufficient. Then again if the definition says 'passivate', there would be no embrittlement relief specified anyway !. I concur with all the others - sounds very much like...
  14. yates

    Reversing Fastener Head

    Lcubed has it right. I forgot to point out this oft neglected fact. I thought that if someone wanted to reverse the heads, it could only be to improve accessibility in order to tighten the nut (the correct way of tightening a nut/bolt combination). I can't really see any other valid reason for...
  15. yates

    Reversing Fastener Head

    There is asolutely no difference in a tension bolt application, provided the substrate holes are adapted (i.e.sufficient chamfer or diametral clearance to avoid interference between hole edge and bolt underhead fillet radius)
  16. yates

    Microseal for porous Al castings

    Would HIP (Hot isostatic pressing) be too expensive ?. This certainly gets rid of porosity.
  17. yates

    Max. hydrogen content to limit hydrogen cracking ?

    Four hour soak at 190 deg C is the standard embrittlement relief used for steels that have undergone electrolytic processes (eg. cad plate)
  18. yates

    Flywheel Energy Storage devices

    On flywheels as an energy storage device, despite what common sense might tell you, the lighter the material used, the more energy you can store in rotation (square-cube law) Also, needs some fantastic bearing technology and balancing due to the high rotational speeds (energy stored varies as...
  19. yates

    Traditional x,y,z axes orientation to North/South/East/West

    Ask the Australians, they may not have the same view. Have you ever seen an Aussie map of the World ? amazing !
  20. yates

    Water Analogies For Teaching Electricity

    Zekeman has it on the ball. No analogy between voltage/current/resistance and pressure drop/flow/diaphragm coeefficent is possible since the first is a linear law and the second a square law. Also diapragm coefficient or its equivalent in the case of bends etc. varies with flow-rate. The...

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