What size screws do you use to secure the emitter to the heat-sink?
I usually just look into my parts bin and pre-drill whatever size I have on hand. Lately I've been looking high and low as my supply is wearing thin. I need to restock and like to get an idea what size you guys use.
I generally have 1.4mm (~3/64") x 3 to 8mm. For larger heat-sinks I use 2.3mm (~3/32") x 8mm and cut them down to size to suite my needs.
Do you guys just stock up on one size (one size fits all)? Do you use smaller screws for stars that are under 16mm dia.?
I’ve used a lot of regular #4-40 screws from Home Depot ($1 for 10), as they’re fairly wide and low profile, but I tend to use 20mm stars where you have lots of space. I tried screwing down a 16mm star once and that was a pain in the backside - I’d have to find really tiny low profile screws if I were to do it again.
Recently I’ve been working my way through a giant stash of hex head 4-40 screws I salvaged from a microscope filter wheel. That should last be probably about 20 years at this rate.
Oh, and if you want self-tapping, just buy any old screws and file/ dremel a slot length ways down the screw. I use taps for all my work, but if you’re going into aluminium you shouldn’t have any problems.
you know, I never even thought of using laptop screws until I saw this thread. I have a whole bag of the bleeding things, I’ll have to go rummage and see what’s in it
hard drives have some good 4x40 screws and some smaller self tapping ones also, but the laptop screw have the lowest profile heads, and seem to be very good steel compared to 4x40s at the hardware store (the head is less likely to deform when you put some good torque on them).
Ever since the toothpaste thread I have shy'd away from the pastes, glues, etc. Too many variables. If I am able to use mechanical fasteners in a certain application, then that would be my preferred choice.
I always use a 4-40 socket head cap screw. I buy them by the 100 at Fastenal but they are available about anywhere. We tap the holes but because aluminum can be fussy and clog up the tiny threads and taps, we drill for a 65% thread depth from the tap in place of our normal 75% thread depth. The 4-40 X 1/4" length seem to work well in most cases. We do add thermal grease under the pad.
