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Set screws for aluminum plate

phaxtris said:
Stainless fasteners and aluminum are often used together because they are both corrosion resistant to external elements, quite often the reason aluminum was chosen in the first place,
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That might be true in theory but in actual practice, I've seen different.

When Alum Bud wheels became fashionable on 18 wheelers all sorts of oxide corrosion became evident after a year or two of use, Usually took a very big sledge hammer to break an alum rim from the hub and that was after the air wrench guys took the threads off the studs...so we all started carrying a jar of some sort of salve to stop the corrosion , Copper Coat was the preferred brand to carry....workd excellent....then the govmt with its powers of deductions decided that using an anti seize on stud threads & wheel nuts was verbotten totally. Now even the air wrench guys at the tire shops wouldnt even use WD40 on the studs...so now SS lug nuts became the thing to have...but damned if they didn't eat the lug nut engagement area out of the alum bud wheels ....so you boys arent the only ones fighting this oxide thing....and if the truckers cant find a solution good luck to the rest of us.
 
historicalarms said:
But damned if they didn't eat the lug nut engagement area out of the alum bud wheels .
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Theory In practice, plated nuts would have been less of a problem

All of the corrosion you witnessed is a result of galvanic corrosion, accelerated by the conductive salt spray encountered on the road

The copper antisieze you used clearly helped to be somewhat of an insulator, at least better than metal on metal with salt spray everywhere
 
Just my .02 c but would it be possible to source aluminum screws ? I know I've seen a selection at home depot and at my work, that or cheap titanium from somewhere like Ali express?

I know is metric, but just to give an idea
metric titanium set screw

or there is the cadmium (example)
 
curmudgeon said:
I came across a few suppliers of aluminium set screws, but no online prices. Are they prohibitively expensive to buy or make?
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The threaded rod is easy enough to get , but I'd hate to spend the time making 650 screws with them, even with just a flat head slot cut :P
 
phaxtris said:

Nylon threaded rod is available
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plastic is what got me in trouble in the first place. Grainger has refunded the entire order yesterday... Some have asked if the plugs will sit for years in some cases. The answer to that is yes. I think mainly the accessible holes will be used more. I see a source for aluminum setscrews in USA, but no prices without calling them. I will look further today.

Another option is to C-bore the hoes about 1/8 deep at 0.53 dia. I would then make plugs on the 3D printer (green). I have red plugs for all the reamed holes. I can print 650 of in about 3 days for less than the cost of a spool. At issue is removing some thread engagement (still leaves over 0.800 of thread.. I would have to chamfer all the holes again, not a Biggy.

Anyway... for today, I am still making a BIG pile of swarf. I finished second side on one of the housings ... ending at 5:00 am this morning. Just getting up now for my shift, and cutting # 2.
 
If it's just plug do you really need to have more than a few threads in, it only needs to stop junk from filling in the holes right? A plug 2 -3 threads thick would accomplish that goal I would think
 
Kind of low tech but maybe you could blank off entire areas with something like an adhesive vinyl & just trim it local to your part/work. It would help protect your entire surface. Just be aware they make different flavors of adhesive & you don't want permanent. Auto paint suppliers also have fully adhesive lower tack masking sheets but not sure how if impervious to coolant etc.

 
 
To think abut this in a different way, let's stand back and ask what's the problem you want to solve? Swarf getting in the holes, correct?

How about something that doesn't let swarf in the holes but doesn't need to thread into the holes? How about if it is plastic so it won't corrode?

I don't know all of your constraints but how about plastic tape? I have a couple rolls in my tickle trunk that essentially look like 2" wide rolls of electrical tape except the adhesive isn't gummy like electrical tape. One roll is from U-Line, no P/N and the other is a sample of Type 471 that the 3M rep gave me.

Link: 3M 471 They claim it's good for masking and withstands processes like anodizing, and electroplating and removes clean. Available at U-Line: 3M 471 at U-Line

Less costly alternative: U-Line Alternative Tape

I picture you cover the whole plate then open areas that you need free to fixture parts and when it starts looking used up you replace the tape. You might still have to plug a few holes but way fewer than the whole plate. When you want to clean up swarf just sweep it out like the tape wasn't there.

For the holes that get used a lot or are inconvenient for a given setup or if you still want a plug in each hole you might find something interesting in the Essentra Catalog. I see that Digikey stocks the MPP series of flexible pull plugs in thermoplastic rubber. P/N MPP10A is for 3/8" threads and costs $0.22 ea in Qty 1000. Current stock is 7,932 pc.

Here's a photo:
MFG_MPPxxAseries.jpg


Essentra have other things like low rise domes that snap into holes and Digikey has other manufacturers too, here's a Heyco domed cap:

MFG_62MPS0375.jpg


Any of that useful?

D:cool:
 
PeterT said:
There are silicone plugs used for powder coating blanking off threads. I'm sure they are way cheaper with the right supplier, picture just to give you idea. Im sure you can get proper seal/fit but question is do they need to be flush/below or proud is ok?

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They're usually tapered and easy to insert tightly since they compress. Likely ideal and cheap
 
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Arbutus said:
FWIW, I have had zero issues when using stainless 316 tooling pins in my Saunders tooling plate. These are threaded M6 and get moved occasionally. No corrosion at all.

The unused holes are plugged with 1/4" LDPE rubber plugs for easy cleanup. The plugs are also available on the SMW site. Or on Amazon: https://www.amazon.com/dexierp-Protection-Force-Thread-Plastic/dp/B08H8FDBS9?th=
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I am leaning this way. I will make green plugs out of PLA to represent threads. I have red plugs already to represent reamed holes.

My plate is slightly different form Saunders, as I wanted full dowel engagement instead of perhaps 0.25. Saunders used the holes as both thread and dowel all on a 0.8-0.9 thick plate. I gave them the opportunity to quote a system for my machine. They cam in at about over 6K USD for a 4 plate modular system. It would not have been tailored exactly to my machine. So 6K USD = 8800 CAD with tax buy not including shipping and brokerage fees.
 
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