Using brass bushings to get power to heated bed?

It may be a crazy but has anyone got any thoughts on using a brass bushing on each linear rail to get power to the heated bed? So run + in one rail and - in the other, brass bushing with wire attached to bed?

That way only a thermistor cable is needed, and if the cable fails print stops, but with the power cables if they get damaged things catch fire.

Is it an idea worth trying or am I nuts?

Edited 1 time(s). Last edit at 04/24/2013 07:06AM by lazzymonk.

The current is so high I think they would spark and tend to weld themselves. The sparks would probably destroy the MOSFET.

A simple solution is to use 26 way ribbon cable and polypropylene strip to enforce a minimum bend radius as described here: [hydraraptor.blogspot.co.uk]

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[www.hydraraptor.blogspot.com]

Most brass bushings are oil impregnated (some are carbon impregnated) to aid in lubrication. I would fear that the heat generated from the current and potential arcing would cause the oil to "boil" out from the bearings causing them to fail prematurely (source - welding too close to brass bushings).

Then there's also the safety risks. Two un-sheilded, very large conductors and high current are a recipe for sparks and pain. Probably won't kill you but still not a great idea to have exposed conductors.

The low voltage is not an issue as far as hurting yourself
12 volts would be way less of an issue than 24 volts and 24 volts is not that dangerous

But as was mentioned above, I doubt you would get good electrical contact through moving bushings and smooth rods
Those two items are not the best conductors

If you are worried about wires breaking, you are better off with some heavy gauge silicon jacket wires that have lots of small conductors inside.
You can bend that type of wire all day long and it does not stress
And it bends and forms into any shape easily

Hobby shops carry silicon jacket wire with 30+ small conductors inside
I use it in the high powered bike LED lights that I make
Some of the lights pull 7+ amps

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My projects are listed here - [www.el34world.com]

You could also get cable that is actually rated for the number of expected bend cycles. I think I have some rated for 1 or 1.5 million bends somewhere, but of course I forgot to dig that up when I was last wiring a heated bed...