Ok, Ok, I know it's not what henry did, but he's not around to QC my FranenT WWI machine gun carrier project. So, here goes...
We are in the process of wiring up the headlights and I have painted and primed the heck out of all the frame, fender irons, headlight brankets and buckets, etc., and am going to presume that I am going to have a negative ground issue with them. So, what I'm thinking is to run a separate ground wire from the focus screws and twine them together with the headlight wires and end up at the terminal block on the firewall. I've got an extra screw location on the terminal block that I am not using and was thinking of running a ground wire to that terminal and connect the headlight ground wires to it to give me a good, solid ground. I could run a separate wire all the way from the ground strap on the battery to frame location up to my firewall, but there must be a closer location that would work just as well.
The engine with starter starts just find, so my engine is grounded well to the frame through the crankcase arms and front cup mount.
Can I use a bellhousing bolt or hogshead cover bolt or some other engine related bolt head? Or should I just run the long wire from the battery ground?
I'm using a wooden dash and firewall, so I've got to go somewhere metal. Presume I can just work the bare wire around to see what give me a complete ground, but was interested in what others think and suggest.
Each headlamp is a ground. There needs to be bare metal connection where the headlamp bolts to the fender mount, and where the fender mount attaches to the frame. You can use any part of the headlamp as a place to attach a ground wire. The headlamp / fender brace bolts that attach the mount to the frame is a great ground too. Any ground connection should be attached to the frame. No reason to run wires to the firewall area.
I understand the theory of the headlight arms and fender irons, but mentioned that I had already primed and painted the heck out of everything and to grind parts back down to bare metal to get a good contact, but open them up to rust and corrosion kinda seems like a significant trade off. So I was looking for some alternate sources for a ground that would not involve removing paint.
I'm a big fan of star washers, so if I need to use the headlight mounts, I may incorporate a star washer or two to help bite into bare metal.
You need only clean the paint off a hidden spot on each item. It won't corrode provided air and moisture are not able to get to it. If you feel the need to be anal retentive, just put a dab of grease on each of the ground paths. Otherwise you will be stringing unsightly extra wires all over the car, and marring up all that paint with star washers and wires flopping around everywhere.
I don't think you're going to have a problem. Try it out first, I think it will be o.k. If not, it should be an easy fix since you've proven the frame itself is well grounded.
There's your non-visible answer to your own question. Easiest too.
Usually just tightening the bolts provides enough ground connection. However, you might want to solder a wire to the headlight socket and connect it to the inside of the headlight bucket, just to make certain that the socket it well-grounded.
after putzing around with bad grounds. I used the Dremel, cleaned the paint and primer. added a star washer, put it all back together. Bo grounding issues any more. if using the internal stars they look like regular washers.
Got 'em working with no additional wires. Clean grounds and some star washers did the trick.