Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. BrainFailure

    4140 as spring steel?

    Oops. Sorry I thought you were talking about a helical spring. Try going to McMaster.com and type in "Blue Spring Steel" in the search field. It will give you a lot of choices for 1095 springs steel (UTS = 1215 Mpa).
  2. BrainFailure

    4140 as spring steel?

    Brashear: How are you calculating your applied stress? If you are using a spring hand book then you are getting shear stress. Material properies are given in tensile stress. To convert from tensile to shear multiply by 0.58. 7075 will definately not work. At the max stress you are...
  3. BrainFailure

    7075 vs 7068 Fatigue Data

    Thanks TVP!! $600 is quite a steep price. Probly worth it but I know I couldn't convince my boss.
  4. BrainFailure

    7075 vs 7068 Fatigue Data

    I have always wondered if 7068 would perform better at high cycle fatigue, but until recently I could not find any information. Here is what I found: http://www.kaiseraluminum.com/wp-content/themes/kac/files/alloy-7068-rod-and-bar.pdf The only problem is that this test had a static stress...
  5. BrainFailure

    AA 6082 & 6060 fatigue data

    I checked my Atlas of Fatigue Curves by Boyer and it came up blank. Sorry.
  6. BrainFailure

    Aluminum Sheet - 2024 T3 vs T4

    What specific Properties are you interested in? I am not an experpert but it looks like the ultimate strength is almost identical: http://www.grantadesign.com/userarea/Mil/mil5.htm
  7. BrainFailure

    Profile Bearing Length Ratio, tp, ASME B46.1

    Howdy: An engineer that no longer works at my company put a spec for Profile Bearing Length Ratio on a print at my company that I am not clear on. Is this a bad spec or do I just lack the education to interpret it? Here is the spec: tp = 50% TO 70% AT DEPTH P = .25 Rtm, RELATIVE TO REFERANCE...
  8. BrainFailure

    Switch Contact Design Help

    Just kidding. I found three hall effect sensor manufacturers with chip scale packages, and every single sensor in a chip scale package sleeps for 50ms in between readings. My the pulse train I am trying to catch has a pulse width of 350 us so this will not work at all. How frustrating!
  9. BrainFailure

    Switch Contact Design Help

    Wow. The Allegro A1172 is a hall effect sensor that is .015 X .078 X .078 inch. That is incy winchy! I think I can make this work. I will have to put it on a flex pcb.
  10. BrainFailure

    Switch Contact Design Help

    The problem with the hall effect sensor is that it would have to fit in an envelope of about .025 X .070 inch. Thats smaller than the typical SMD resistor.
  11. BrainFailure

    Switch Contact Design Help

    Howdy: Not sure if this is the right forum. I am working on a product with a motor that has an encoder and a gearhead. The encoder is an incremental type so I need some kind of sensor to signal every time the output shaft reaches a specific angle. Unfortunatly this sensor must fit around a...
  12. BrainFailure

    Nitrile Seal Problem

    MatkenMD: At first we wanted to avoid making a new seal mold, but we ended up doing exactly what you suggested. The seal manufacturer is remaking the mold to give us the 13% squeeze that we originally asked for. Here is another update: After trying synthetic oil, we actually still had a...
  13. BrainFailure

    Nitrile Seal Problem

    Here is a follow up: I talked to a few seal experts and they are saying that non-synthetic (patroleum-based) hydraulic oil can contain small amounts of plasticizer which can cause nitrile to shrink a small amount. For most applications 3% shrink is not a problem but for my application it is...
  14. BrainFailure

    Nitrile Seal Problem

    Ted: I had the same thought. Unfortunatly the assembly manager already threw out the oil that was in the failed units. I am currently soaking seals in new oil and it appears to have no effect. Unfortunately I am not sure if it really is having no effect or if it just takes 3 months for the...
  15. BrainFailure

    Nitrile Seal Problem

    BTW thanks everyone for your responses. Bud: Cure date on the batch I currently have failures from is 4th quarter 2008. Ted: The seals are shipped in clear bags but as soon as we get them we store them in dark bags. Another thing to consider is that the seals are nice and stretchy before they...
  16. BrainFailure

    Nitrile Seal Problem

    Isrealkk: Thats a good thought, but in this case my squeeze is like 3%. Plus remember its a cup seal so the material doesn't actually squeeze, it flexes.
  17. BrainFailure

    Nitrile Seal Problem

    Ted: No and No. Also note that it is not an oring, its a custom double cup seal (cross section looks like an "N"). I did some research and I found that in 2006 we switched from Viton to Nitrile to save money. I wouldn't think that this would cause a problem because the other seals have...
  18. BrainFailure

    Nitrile Seal Problem

    Howdy: My company builds hydraulic dampers for prosthetic knees. I am having a problem with nitrile seals (60A durometer) that are shrinking about 3% over a period of about 2-4 months. When we build the dampers we 100% inspect them. We are having units that pass when they are built, but...

Part and Inventory Search

Back
Top