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Hi,
I too have realized that rubber bushings are truly crap stuck in those bracket holes on one of my cars.
I have more cars to do, but I’m not a very ambitious person to tear apart things, for the entertainment or fun. As after doing the one differently, I realized that it can lead towards production work routine that I did good to avoid in my life.
I didn’t know that the polyurethane one’s would disintegrate.
I was under the impression that poly anything was a better material than the firm black rubber that goes in there. They do last a little while, several years, before going wonky! Too cheap keeps those things being bought!
I still buy them with other orders to save the shipping.
I went to put aluminum into one of my brackets and found out why they used firm rubber.
The holes in the bracket are “as casted.” This is a “sand casting” and not an “investment casting” that would have been more accurate dimensionally.
These bores are tapered and out of round.
The bores are not straight in-line with each other, either.
The rubber just holds the alternators bolt in a general location in relation to the engine block.
The base of the bracket is the only thing machined after casting.
It is roughly lined up to those arms that the bores with a fixture that is clamped on a different location for a more rigid setup.
The surface is cut in one pass and drilled all the one setup.
This machined flat and the holes in there for the mounting bolts are put in accurately, otherwise, the bracket would be all over the place. A casted surface has all kinds of possible various flaws for a locating surface as found in the rubber mounting holes.
I setup the bracket up on my mill, on that machined surface and line bored them straight.
The bores were made to a fixed dimension that gave me a good true surface along its length, this way, I could make my replacement bushings fit snugly and slip in by hand.
Now This, is where I changed up from going with aluminum to eliminate corrosion issues later on just, in case I cared to remove them.
I used solid Gray Rod PVC, made with with a shoulder flange, just like the rubber setup but maybe a little larger for more surface area against the alternator housing.
I don’t remember swiping the steel bushings out of the rubber ones. I have been know to save those out of other things, for other projects. Material is material, to me and Saves me from making up spacer shims in fixtures.
I did add steel washers under the head of the bolt and nut on each end to keep them from possibly deforming the plastic when tighten.
I’m curious about you finding aluminum bushings that are either crushable or made undersized to fit those odd bores.
The price of $10 each is a good gig, if you can get it into a high production order.
Did you have them made just for your bracket? If so, you did good, for one off’s!
I used plastic cause it is easier and faster to machine and it was way cheaper than aluminum bar stock that I want to keep laying around.
I buy remnants of both mostly and very cheaply I might add.
Plastics stores are more easily found as they are very connected to manufacturers of plastic specialty items.
They are in the Sacramento and S.F. Bay Area and I hit them on my way through, if I have time to waste along with a few dollars.
When they sell it to me, it has been already paid for by their previous customers orders.
It’s called “setup charges and overall material cost” including any types of residual scrap!
They even recycle the chips as long as they are kept segregated.
With all that said, they still have some plastics that are astronomically expensive, by the inch, for my pocketbook, that I’ll never stock!
PEEK is one that is getting more popular, but I’m not in need of that stuff that badly. When I Last priced it, about six years ago, it was about $15.00. In 1.5 inches of diameter. Exotic materials are coming out all the time.
I’m glad to hear you changed up the setup down there!
Phil
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