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08-03-2016, 11:00 PM | #21 | |
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Re: Better ground with star washers?
Quote:
More seriously, when working on computer hardware from several different manufacturers I noted that they all used star washers and unpainted surfaces for ground connections which were very important for older mainframes. I use the same approach, but as my cars do not run in climate controlled computer rooms, I protect the connections with generous helpings of grease. My favourite grease for this is Vaseline, but I use what ever is at hand. |
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08-04-2016, 07:45 AM | #22 |
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Re: Better ground with star washers?
If you use star washers for ground contact then use zinc, cad or tin plated steel ones. Stainless steel has a passive invisible oxide layer on the surface and makes a lousy electrical contact. Ask any electroplater about the surface properties of SS.
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08-04-2016, 12:38 PM | #23 |
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Re: Better ground with star washers?
With skinny mechanics' wire, bent back at the end, Chief always pulled extra ground wires through the looms, especially on the head lights & tail lights.
Bill W.
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10-13-2016, 09:52 PM | #24 |
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Re: Better ground with star washers?
pgerhardt was right on the money with the star washers. Not only do they provide the best ground they keep things from moving around like the infamous point block.
HAPPY MOTORING, DUTIE |
10-13-2016, 10:02 PM | #25 | |
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Re: Better ground with star washers?
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08-02-2021, 05:06 AM | #26 |
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Re: Better ground with star washers?
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08-02-2021, 06:27 AM | #27 | |
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Re: Better ground with star washers?
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If someone is still worried, they can apply carbon conductive grease instead of dielectric, but we have been assembling with Permatex brand dielectric (-from NAPA) for years and have not experienced conductivity issues. We just remove the paint from the jointed areas and apply the grease as a rust prevention step. |
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08-02-2021, 09:24 AM | #28 |
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Re: Better ground with star washers?
A study has been done on this. The gist being that most star washers perform well, even when exposed to marine environments for extended periods.
https://www.nsrp.org/wp-content/uplo...ipbuilding.pdf Tom |
08-02-2021, 01:49 PM | #29 | |
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Re: Better ground with star washers?
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Interestingly enough, an ohmeter or resistance measurement is practically useless for this kind of thing, because in a low voltage high current system the amount of ohms resistance required to cause major problems is almost too low to measure accurately. So automobile engineers about 1915 devised the "voltage drop test", engine starters, charging systems, headlights and accessories, grounds and connections in particular are tested while they energized under load. Excessive resistance in a circuit can be inferred by the amount of voltage drop. The accepted figure is still 0.2 volts for the ground system. Zero would be best, but there will always be some. Even just a tiny bit of extra resistance - maybe a tenth of an ohm - will cut alternator capacity by about 30%. Interestingly maybe too much, while brass or copper studs, washers &c at the frame might seem to be a good idea at a major ground point, studies have shown dissimilar metal corrosion and fretting occurs. Good old plain steel washers and studs and ordinary hardware work the best over time. The "Star Washers" are most definitely a work around for the OEM, they work for their intended purpose to cut through the paint and primer down to bare metal and get the car out the door, and not outright fail within a reasonable time period. Somebody told me they aren't even used any longer by automakers. |
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08-02-2021, 02:20 PM | #30 |
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Re: Better ground with star washers?
For automotive wiring, a separate ground wire to each appliance is the most reliable. Not cheap and not always easy.
Star washers are extremely reliable if made from heat treated beryllium copper. Space ships and ICBM's use them. Examples taken from WW2 radio equipment that saw duty in the tropics, still appear as new today. Readily available and relatively cheap. |
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