Stupid screws and LED question

906 Views 7 Replies 4 Participants Last post by jeffkrol, Mar 10, 2014

jeffkrol

Discussion Starter · Mar 10, 2014

I've decided to screw some new LED's onto aluminum barstock.
Most LED heatsinks you buy have 2 small screws, metric I assume..

Well I have a 2-56 tap and some #50 drill bits so I can drill and tap al I want using 2-56 screws which are a thinner shaft than the ones w/ the heat sinks but head is the same size so no problem there.
I looked for nylon washers to isolate the head from the LED base but I haven't had any luck w/ that yet..

One thing I found is nylon screws w/ a thermal rating of up to 150-ish F

Also found stainless steel..
The ones I have I assume are zinc plated..

Question is : Is any better than the others?.. In the high moisture env. and warmth of the LED's (My non-fan cooled can reach 120F on certain parts of the aluminum.. )..

Feelings about galv. corrosion w/ zinc and aluminum..

To make this really dull thread a bit more exciting.. anyone have any feelings re: using anodized vs non-anodized aluminum?

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1 - 8 of 8 Posts

GraphicGr8s

· #2 · Mar 10, 2014

Stainless for the win.

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jeffkrol

Discussion Starter · #3 · Mar 10, 2014

GraphicGr8s said:
Stainless for the win.

Yea that was the direction I was leaning to...
Means buying new screws..Local HW didn't carry ss that small..

I can't believe the redundant purchases I've done lately...

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GraphicGr8s

· #4 · Mar 10, 2014

Think how nice it would look with polished stainless instead of aluminum.

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Hoppy

· #5 · Mar 10, 2014

When I use screws to hold LEDs I use #4-40 screws, and they are still small enough that it generally takes a couple of taps to get through all of the holes. I would never even consider #2 screws for anything. I haven't tried, nor have I seen #4-40 nylon screws, but I would certainly use them if they are easy to buy. It doesn't take much to hold a LED in place, and those screws would eliminate the possibility of shorting out a LED.

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GraphicGr8s

· #6 · Mar 10, 2014

http://www.fastener-express.com/4-40-x-38-pan-sltd-machine-screws-nylon-Qty.-50-2.aspx

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Mark Allred

· #7 · Mar 10, 2014 (Edited by Moderator)

Hoppy said:
When I use screws to hold LEDs I use #4-40 screws, and they are still small enough that it generally takes a couple of taps to get through all of the holes. I would never even consider #2 screws for anything. I haven't tried, nor have I seen #4-40 nylon screws, but I would certainly use them if they are easy to buy. It doesn't take much to hold a LED in place, and those screws would eliminate the possibility of shorting out a LED.

X2. 4-40s are as small as I will go. Pretty easy to snap a tap off, even in aluminum. So buy two... when you break the first one, you will be more careful with the second!

GraphicGr8s said:
Think how nice it would look with polished stainless instead of aluminum.

Are you referring to the bar stock?
Stainless has horrible heat transfer numbers compared to aluminum.

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

It weighs 3 times as much also.

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jeffkrol

Discussion Starter · #8 · Mar 10, 2014

Mark Allred said:
X2. 4-40s are as small as I will go. Pretty easy to snap a tap off, even in aluminum. So buy two... when you break the first one, you will be more careful with the second!

Screws that come w/ some star puck heat sinks are about a 3......

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