Drill & Tap Set Screw Question

[Fulgeo]

Hey guyz I am gearing up to start a project and I would like to use set screws to pin aluminum heat sinks into Mag D flashlights so as not to have to epoxy them into place. This will give me the ability to disassemble the lights if there is a failure. I am putting together about 10 lights for Christmas gifts this year. I plan to purchase a couple 3mm Drill and Tap sets. I will also be purchasing an inexpensive drill press. I plan on using 3mm x 3mm set screws. I was thinking about using steel or stainless steel set screws for this purpose. I need a little information on the following.

Do I need to worry about galvanic reaction between the aluminum flashlight body and the set screw(s)? Are the stainless steel set screws more desirable for this application? If there is an issue can the set screws be coated with a lubricant to protect against this issue. I really wanted to use a metal set screw and although I see some brass set screws out their they are harder to come by. Anyway thanks in advance for any insight you can provide.

 

[Anglepoise]

Over the years I have used thousands of SS set screws threaded into aluminum and have never yet had a problem when the installation was clean.
Now thing change fast around salt water and battery leakage etc.

A company in California called Pic Design have silver tipped set screws and these are fantastic when you do not want to damage the items you are 'setting'. Maglight use a pointed SS setscrew in their switch to make the switch stay in place as well as pass electric voltage.

 

[precisionworks]

galvanic reaction between the aluminum flashlight body and the set screw(s)

In this case, probably not. It boils down to the relative surface area of each of the reactive metals. For the light, the relative area of the light body is huge & the relative area of the SS set screw is tiny, which lessens any potential corrosion. Titanium set screws would be an even better choice.

 

[KowShak]

If you're worried about dissimilar metal corrosion, you can use a product called Duralac. It gets recommended for putting stainless rivets into aluminium masts, a marine environment is pretty harsh compared to the inside of a maglite!

 

[Fulgeo]

In this case, probably not. It boils down to the relative surface area of each of the reactive metals. For the light, the relative area of the light body is huge & the relative area of the SS set screw is tiny, which lessens any potential corrosion. Titanium set screws would be an even better choice.

I would be all over a Titanium set screw (or grub screw) but I can not find a source that sells them in small quantity or the desired 3mm diameter. If you know a source let me know. Thanks!

 

[LukeA]

If you're looking in the US, why 3mm and not 1/8th?

 

[precisionworks]

http://www.titaniummetals.co.uk/titanium_fasteners.html

http://mdmetric.com/titanium.htm

http://www.kingmarttitanium.com/boltscrew-2.html

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