Exact diameter of a 17mm round pcb

[Machinist Joe]

Im planning on machining a heatsink with a pressfit for a 17mm round pcb, but I don't know the exact size to make the pressfit.

Can somebody with a caliper take a measurement of the diameter of one?

Or better, if somebody has a flashlight that uses one, take a measurement of the inner diameter of that hole?

Thanks guys!

 

[rocket689]

Every "17mm" pcb that I have come across is not a repeatable measurement.
What I usually do is machine the step per the actual pcb.

If not, I will make it exactly 17mm or slightly larger.
Then the pcb's "tabs" can be filed to fit. :beer:

 

[JLSE]

Most boards that I use are 17mm +/- .3mm or so. A sanding disk and dremel work well
or as suggested above machine to fit.

If its going to be a standard size for a kit, id go with 17 and the excess can be taken
off the PCB by the builder..

If the hole is slightly small the fraction of difference usually snaps off, and the PCB
just goes where its told

 

[LarryDFW]

Machinist Joe;

I measured several different 17mm circuit boards.

They varied from 17.0 to 17.1mm on my dial caliper.

I would like to see your heatsink when you finish it,

since I use 17mm circuit boards in lots of my lights & lasers.

LarryDFW

 

[Machinist Joe]

Thanks for the input guys. It actually wont be just a heatsink it will probably be a fully machined laser body. It will use a "pill" with a 17mm hole bored out on one side and a pressfit diode mount on this inside. This will make it so I can use a 17mm driver or a blank 17 mm board with the drivers on the inside, the pill will then screw into the barrel, and the focus adapter will then screw over the top of the barrel to focus and defocus the laser. I should soon have some 3d renders of the entire thing. I doubt I will do a run of them, because machining it will be a PITA.

Anybody have suggestions for a cheap and easy way to hold the switch in the tailcap? Ive seen the threaded rings but was wondering if there was an easier way.

 

[cilegray]

As for holding the switch in tailcap, a tight fit will usually do as it'll have the batteries holding it in when activated...
Could always use a tiny dot of superglue for a semiperm fix

 

[JLSE]

As for holding the switch in tailcap, a tight fit will usually do as it'll have the batteries holding it in when activated...
Could always use a tiny dot of superglue for a semiperm fix

I agree with a tight fit, but would advise against any Cyanoacrylate based adhesives
anywhere near a laser. Not only can the fumes fog your optics, but can also impede
electrical connections, as well as ruin a finish via a white foggy residue that has
to be sanded off..

Your best friend as far as adhesive goes is 2 part 5min epoxy for a secure fit.
Should the need arise that the switch needs to be pulled, you can just burn it out
and reapply with the new switch.

 

[cilegray]

Epoxy is a little permanant for my taste especially for something that can fail like the switch. Its not gonna fume anywhere near a module...and btw, you can prevent them fumes with the use of an accelerator that insta-cures CA glue crystal clear.

 

[BShanahan14rulz]

Eh, if you can make a threaded retaining ring, that's probably the easiest and most reversible way. Plus, it ensures constant pressure which may affect the water resistance of the light if you are using a switch cover.

One option might be to make the pill out of brass, or somehow have a brass ring that the driver press-fits into. That way, worst case the driver is too big and has to be sanded, or it is too small and has to be soldered.

Alternatively, RHD (I think) found some flux that allows you to solder to aluminum and made a post about it somewhere here on LPF.

 

[Netscott]

I agree with a tight fit, but would advise against any Cyanoacrylate based adhesives
anywhere near a laser. Not only can the fumes fog your optics, but can also impede
electrical connections, as well as ruin a finish via a white foggy residue that has
to be sanded off..

Your best friend as far as adhesive goes is 2 part 5min epoxy for a secure fit.
Should the need arise that the switch needs to be pulled, you can just burn it out
and reapply with the new switch.

OP, sorry to butt-in but a quick message to wannaburn here (seeing as he just posted in this thread today):

wannaburn,

There may be something wrong with your e-mail. Can you verify that you are receiving my messages? I've sent you three messages since the 9th concerning my order with no response from you. The last message I received from you was on the 7th.

Thanks,

-Scott