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4130 fab shop for an alt bracket

rjcthree

Well Known Member
As I look at the reality of having to have an alternator bracket fabricated, I realized that between COVID and retirements, I no longer have resources or access to get that done easily. I’m going to need a simple bracket from 4130 bent and drilled and normalized ( maybe not in that order), bonus would be cad or zinc plated. I’m guessing this isn’t going to be cheap as a one off, it needs to correct. Does anyone have any hints or provide that service? Thanks in advance.
 
Why does it need to be steel? Aluminum would be fine if it's sized appropriately. That way you can make it longer to pick up the next bolt boss to the rear to help with alignment and make it stronger too. Here's the one I made 20 years ago from billet 6061-T6. You can use the free SolidWorks through EAA, design your own, and have it made via hundreds of internet job shops.
20201015_153618.jpg
 
As I look at the reality of having to have an alternator bracket fabricated, I realized that between COVID and retirements, I no longer have resources or access to get that done easily. I’m going to need a simple bracket from 4130 bent

Mild steel will do fine for that. I have made them from two pieces of mild steel 1/4" thick angle welded together. It was easier than trying to bend a thick piece of steel and get the geometry correct.

Some alternators will not sit directly below the case mount holes and you might need to add an extension to the weldment one way or the other.
 
Mild steel will do fine for that. I have made them from two pieces of mild steel 1/4" thick angle welded together. It was easier than trying to bend a thick piece of steel and get the geometry correct.

Some alternators will not sit directly below the case mount holes and you might need to add an extension to the weldment one way or the other.

+1

I made one for my 6 and used either 3/16 or 1/4" mild steel. The one that Van's supplied for my old ND without a boss, was 1/8", and I didn't feel it would be sturdy enough. I also welded instead of bending. Plenty strong for this application. 4130 would add some strength with thinner sizes, but in this case it is way easier to just upsize the stock than to deal with 4130.

Larry
 
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Someone on another thread mentioned a generic adjustable alternator mount. You might search VAF to try to find that thread.
 
I usually make my own for my airplanes. Anything from a simple piece of angle iron with a piece of tube welded to one leg, to a more sophisticated cradle weldment. The Rocket has the later, with an adjuster arm scavenged from one of my old Pontiac GTO engines. All mild steel, all painted with rattle can - no problems.
 
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