wildstar87,
Sorry for the slow response. Okay, the little copper spacer disks measure about 6.90mm in diameter. They are also scrap from copper hole punchings, so the disks are not completely flat (no problem, just hammer each one flat and file each side). Well, the protruding Lumileds slug from a recently purchased Luxeon III had a slug with a diameter of 5.20mm, and the Seoul P4 has a slug with a diameter of 6.10mm. The Seoul P4 slug is slightly larger. It was harder to measure the diameter of the protruding slug on the Seoul P4 since the edge was less defines and the calipers slipped on me. I used a cheap chinese set of digital calipers for measurements. It is not a Mitutoyo by all means, but it is relatively accurate according to some previous measurements taken.
I have the older PQS heatsink, and I ended up offsetting the emitters. I originally used the Luxeon III in the little slots, then when I upgraded it to Seoul P4s last year, I had similar problems as yours. This heatsink does not have a raised rim, and it only has four holes, so it works to offset them.
Now, I checked out the PES2 heatsink in more detail. It was something that I planned on getting recently for another quad emitter mod. I believe that you are correct about the spacing! Check this out for a top view of the PES2 heatsink:
http://candlepowerforums.com/vb/showthread.php?t=122625
I have the older, thinner PQS from modamag for my quad emitter Mag mod, and I believe that he used similar measurements for the spacing between each depression. I measured my older heatsink, then guessed how his would be designed and used my friend SolidWorks to draw it up. I did not include any of the multiple through holes that are drilled in the actual PES2 heatsinks. I have a feeling that those holes will cause a bit of trouble with offsetting. The below picture shows what would happen if you would happen to offset the Seoul P4 emitters. The drawing shows my measurements for the Seoul P4 slugs (solid circles), and the measurements for the round slots from the older PQS (slightly larger than the Luxeon slug).
(click on image for a detailed and dimensioned drawing)
Modamag, I can remove this image if you are uncomfortable with it. Sorry if I did not asf for your permission. It can also be removed if too big (sorry). These dimensions used are from what I measured and observed, and are probably not exact enough for a copied product design anyways. The above idea is Modamag's creative design that is not to be copied and sold! I just want to be safe
.
Anyway, you will see that a 45 degree offset could work, but the slug will be overhanging a bit. I tried other angles, but those "tri" slots cause problems every time. I conclude that for these particular heatsinks, offsetting the emitters may cause you trouble.
I suppose you could use an end mill with your drill press and widen those round slots. There is a chance that the mill will make the slots deeper, so the Seoul P4 slug may not reach the bottom, unless you make the round slot 8mm in diameter so the entire emitter will fit in there and you will be trouble free.
The drill press is built to be kind of sloppy with tolerances, so an end mill may chatter a bit (I am used to a sloppy POS drill press, YMMV
). As long as you dive very slowly, you should be fine, though. Just cut a little material away, bring it back up, check your progress, then dive some more. I know that McMaster has some cheaper end mills that you could use. You are dealing with soft copper, so I doubt you would need a nice carbide bit with a fancy coating. I found some cheap end mills for $8 to $13 each. I found a four-flute mill (for a finer finish) for $11.42. It is also a cobalt bit (a plus) so you can use it for other tasks. The place has fast and cheap shipping (especially if you live a few states away from Ohio). A 5/16" bit would work good for you I believe. The diameter of the Seoul P4 is 8mm, and the 5/16" bit is 7.94mm. With a little chattering or vibration, the round slot may end up at the right size or slightly larger. The next sized bit, a 3/8" bit, may be too big (9.53mm), so you would have to center each emitter by eyeball.
When using the end mill, I guess that you have to securely clamp the heatsink in place, then line everything up my eyeball. You could toss the emitters in the finished slots (with no epoxy) then place the reflectors on the emitters to make sure everything is lined up. You may have to go back and remove more material from the sides, but I bet that things will line up easily, regardless of skill level (you have a drill press in the first place).
What do you think? I feel that if you invested in nice copper PES2 heatsink (I am jealous
), might as well spend a little more for a perfect fitting slots for the emitters. It seems like the least amount of work for the best appearance and performance. If you need help with the bit selection, PM me. I can give you the part # for the bit.
Finally, you will have problems with isolation of the emitters' slugs if you just slap epoxy under each emitter and apply pressure. We know that the slug of the Seoul P4 acts as a positive contact (an emergency contact when you break off the positive lead by accident), so if the slug happens to press against a high spot on the heatsink through the epoxy, you will get a short there. You will end up with shorted or failed emitters, or generally strange electrical behavior of the light. You may blow you Fatman or Shark driver, too. Well, I seen this post by NYLYTE a while back and I have used his method ever since. Here is the link:
http://www.candlepowerforums.com/vb/showthread.php?t=157064
With a LDPE deli container lid, and an extra hour to wait, you can have a well isolated emitter that still has good thermal contact with the heatsink. It worked for me on every Seoul P4 I used (and the same with Luxeons). If you can find a way to apply continuous pressure on the emitter as the initial layer of thermal epoxy cures, then you will end up with an even thinner layer. It is probably best to make sure both surfaces (emitter slug and heatsink) has a nice finish. I like to file the bottoms of my emitters.
BTW, what reflectors do you plan on using? I am just curious.
-Tony
. I worried that I said "20mm IMS" way too much...
