Drill bit Size for TO-18 pressing

Lamarr · Jun 26, 2015

Hey Guys,

Done a small search but can't seem to find the answer! for a to-18 (5.6mm) diode, what size hole (aperture?) would one want to drill on a custom made mount/heatsink? It would be the same size as in a regular diode mount/casing but I have never drilled one from scratch so don't know the correct drill bit size!

I was going to go for around 5.55 but I'm not totally sure!

Thanks in advance guys!

APEX1 · Jun 26, 2015

Probably not a good idea lol, send it to flaminpyro.. Trust me,, you wont be disappointed. His work is second to none and very easy on the wallet.

Pi R Squared · Jun 26, 2015

Lamarr said:
Hey Guys,

Done a small search but can't seem to find the answer! for a to-18 (5.6mm) diode, what size hole (aperture?) would one want to drill on a custom made mount/heatsink? It would be the same size as in a regular diode mount/casing but I have never drilled one from scratch so don't know the correct drill bit size!

I was going to go for around 5.55 but I'm not totally sure!

Thanks in advance guys!

I suggest you look at a diode or a photo of one as you seem to be unfamiliar with their shape. You will immediately see that you need more than one size drill bit. The can of the diode is 3.55mm +- 0.05, there is a tiny wider part at the base of the can that is 4.1 or 4.2mm, the base plate, the part where the heat is dissipated is 5.6mm +- 0.025.

Alan

APEX1 · Jun 27, 2015

Pi R Squared said:
I suggest you look at a diode or a photo of one as you seem to be unfamiliar with their shape. You will immediately see that you need more than one size drill bit. The can of the diode is 3.55mm +- 0.05, there is a tiny wider part at the base of the can that is 4.1 or 4.2mm, the base plate, the part where the heat is dissipated is 5.6mm +- 0.025.

Alan

This is probably the bets info you'll get, I was just looking up the measurements to copy and paste lol. No need to do it now.

Lamarr · Jun 27, 2015

Thanks for the replies, don't worry I'm perfectly aware of that, but from what i understand the 'can' of the diode doesn't need to be as snug fitting as the wider base? Hence the reason directed at that! I can easily select the correct drill bit for the can.

Lamarr · Jun 27, 2015

noobphaser215 said:
This is probably the bets info you'll get, I was just looking up the measurements to copy and paste lol. No need to do it now.

Unfortunately he only listed the measurements of the base/can of the diode (I have these already) but I need to know what size drill bit to use in order to create a tight seal with the base of the diode when I press it in!

Pi R Squared · Jun 27, 2015

It would be much easier to just press your diode in a standard 12mm module and drill a single hole for that.

Alan

Lamarr · Jun 27, 2015

I would definitely agree there Alan! The trouble is I am doing a very big project using about 50-100 300mw diodes being driven to kick out about 200mw...I was looking to make a combined heatsink/house(module) for ease plus better heat transference (I can use a thinner heatsink material with bigger surface area if I press the diodes into my own housing, was hoping to use about 5-6mm aluminium u channel)

If I buy housing for each diode, that's fine but it's another barrier to heat transference and I would need to get deeper material to act as a heatsink (as the standard 12mm housing dissipates the heat over a deeper area)

Hope that makes sense! so if anyone knows what size drill bit to use for the base of a TO-18 diode please let me know!

Pi R Squared · Jun 27, 2015

Hopefully one of the machinists here that make parts, heat sinks, and hosts for us will see this and comment.

Alan

Lamarr · Jun 27, 2015

Yes indeed would be a big help and save me wasting money on drill bits to find out!

I'm not looking to 'step on their turf' either, just doing a one off project!

I'm thinking 5.55mm would work as that's 0.025mm all the way round the perimeter.

Mohrenberg · Jun 27, 2015

5.53mm +/-0.02mm

......is the size of the 5.6mm modules we get made.

Lamarr · Jun 27, 2015

Thank you very much Mohrenberg!

APEX1 · Jun 27, 2015

DTR and several other members sell them in bulk or by piece as well

10fenny · Jul 1, 2015

send your idea to flaminpyro. He could probably machine you a big block of diode heat sink!

where are you from so we could better help you find a machinist?

Drill bit Size for TO-18 pressing

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