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  1. durablack2

    Making drawing and taking measurements

    I would trace the edges on paper, make the model, then print out a drawing 1:1 to confirm your model is the same. This will work to a certain level of accuracy. Looks like this is extruded material then sliced to width. The the mesh section at the top with the smaller holes is welded in...
  2. durablack2

    two proximity sensors, One LED light for system status

    Hey guys, I am looking to use two proximity sensors to indicate position of two devices (open and closed). Each device will have it's own proximity sensor. I would like to use ONE LED light to know the status of the system (open = green, closed = red, 1 open 1 closed = red) When the devices...
  3. durablack2

    spring mounting design differences

    Thanks Tug. We will be mating to metal in both areas, combined with relatively low cycle numbers so I'm not too worried about wear, but I am worried about a spring cracking or failing prematurely. Seems type B will be the best method for us for durability and cost.
  4. durablack2

    spring mounting design differences

    @Desertfox - thank you - i do not think rotating will be a problem but we will test to make sure no issues. I am not quite sure how we would go about clamping this end though due to how it is used and installed.. Hmm.. hopefully not an issue @btrueblood - I was not 100% clear - the rod will...
  5. durablack2

    spring mounting design differences

    Good point - we have limited space so that's just going to hurt us it seems.
  6. durablack2

    spring mounting design differences

    I am curious if there would be any noticeable difference in feel or longevity of two different spring mounting systems. On one end of the system we will have a moveable, range limited rod that mates up with a compression spring. The opposite end of the spring will mate to a fixed surface. The...
  7. durablack2

    compression spring force and active coils

    Makes perfect sense! Thank you Ed. Knew there was some fundamental thing I was missing..
  8. durablack2

    compression spring force and active coils

    If you have two compression springs and everything is the same except number of active coils, which will take more force to compress? The one with more coils or one with less coils? Take for example: Spring 1= 6 inch long, 1in outer diameter, 0.1" wire diameter, 10 active coils - compress 2...
  9. durablack2

    Weld Repair of Castings and heat treatment

    Thanks Bob for the in depth answer from your experience. We design and buy parts from many different overseas foundries which means we pretty much need to accept their workflows. Seems the best and safest method is to require welding to be done after heat treating which will also work fine for...
  10. durablack2

    Weld Repair of Castings and heat treatment

    Should weld repairs be conducted before or after initial heat treatment after casting? I am seeing mixed messages from sources I find online and from different regulatory agencies and it is not really defined in the ASTM standards I am reading. I am mainly looking at ASTM A27 and A148 but...
  11. durablack2

    Machining /CNC

    Couldn't you cast it and machine the outside down? Does the inside surface roughness matter to you?
  12. durablack2

    Hot Dip Galvanizing reduces strength by 20%?

    Thanks everyone. Perhaps the 'tempering' effect due to high temp at which galvanizing is done at (as blacksmith mentioned) is what has caused a strength reduction in the past on this particular part (150ksi tensile and about 5/8" diameter. My boss has a lot of experience and is usually right...
  13. durablack2

    Hot Dip Galvanizing reduces strength by 20%?

    Any basis in this claim? I am aware HD Galvanizing can cause hydrogen embrittlement but does it reduce overall strength of 'smaller' steel parts by 20%? By 'smaller' I mean 1/2" to 1" diameter rod or bolts.
  14. durablack2

    Quality management program

    I work for a small company with about 5 QC personnel. We have a homegrown access program that our QC dept uses but would like to get something off the shelf to replace it so that we do not have to spend time upkeeping it. We design parts and have them made by factories overseas (we are not a...
  15. durablack2

    HOW TO MODEL THIS BEND

    Thanks for the responses everyone. Sbaugh, it does look like it could be welded when looking at the pics I posted previously, but in hand it is clear those marks are tooling marks. This pic might be a little better. I think Handleman has it, the die is definitely doing more than just...
  16. durablack2

    HOW TO MODEL THIS BEND

    I need to model this bend (circled red in attachment) properly in Solidworks but am unable to figure out how to do so using the sheet metal tools. I don't really think it's possible to get what i need using basic extrude / cut tools either. Anyone want to take a stab at it or point me to some...
  17. durablack2

    Degradation of natural rubber vs. epdm due to sunlight and ozone

    Thanks to you GrahamBennet as well. Adding carbon black seems to be a good solution to our problem. Hopefully it will not drive up cost very much (doesn't seem like it would).
  18. durablack2

    Degradation of natural rubber vs. epdm due to sunlight and ozone

    Thanks TugBoatEng for the insight. It is probably most important that the core maintains mechanical properties after several years. It would be nice for the outside to maintain it's appearance but i don't think anyone will complain about surface cracking after it is installed in a loading dock...
  19. durablack2

    Degradation of natural rubber vs. epdm due to sunlight and ozone

    We could do that but the cost will still be higher than just natural rubber (but probably not as high as epdm). These are molded rubber bumpers so companies buy them because they look more professional compared to using d-profile extruded rubber. So I'm wondering how the surface finish will...
  20. durablack2

    Degradation of natural rubber vs. epdm due to sunlight and ozone

    We are currently selecting material for a rubber bumper that will be used in loading docks. I am looking to find sources that show degradation of natural rubber (or SBR) vs EPDM due to sunlight, weather, ozone, etc. I know natural rubber is rated as 'poor' in these categories whereas epdm is the...
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