burrs

Thanks, John, it's just what I need to modify a PCB prototype to increase some clearances, so it stops exploding every time I turn on the HV.

I recall seeing a similar tool that cut donuts, but can't find my way back to it. ...Jim Thompson

Another tool is a suitably small "jeweller's graver". As with a dremel, practice makes better (not perfect).

If a graver is run in the channel between two conductors, it can also widen/deepen the channel.

I've had a lot of practise, and I can do SOT-23 sort of resolution.

Some of my FR4 scraps are 2 oz, which is much harder to work with.

I have a couple of square feet of gold-plated 1 oz, which is beautiful for hacking circuits.

What sorts of inner-layer and surface-creep voltage gradients are you allowing? What actually failed?

They're called Island Cutters. You can see a few here

Cheers, Dave M

Jim Thomps> >

Den torsdag den 22. september 2016 kl. 22.26.17 UTC+2 skrev John Larkin:

with cnc and a V bit you can do the small stuff

Eagle can directly generate gcode for isolation milling

-Lasse

Whoa, those are way too large.

I can grab my Dremel and hack a piece of copperclad in seconds.

We had one of those PCB milling machines, but it was so much hassle that we got rid of it.

This was milled on our Tormach,

but that was a big deal, too.

A 0.020" island is too big??? How small do you need? The DT-502 model has ID of 0.020" and OD of 0.08".

Dave M

W>>

Thanks, Michael! ...Jim Thompson

Totally impractical unless you have some jig to hold the tool bit and the board firmly in perfect register, because these bits are highly prone to skip around over the work surface. They actually intended for cutting holes in wall tiles and to prevent skipping you have to go in initially at an angle. A PCB doesn't have enough depth for this technique.

To make a pad on a breadboard, you can super-glue or epoxy a small square of FR4 on top of the main FR4. Little circles would be cool, if I had some way to punch them.

Similarly, strips of FR4 make nice power bus bars on top of the main board.

Everything you say is very true, but I wasn't responding to your posts. My post was to answer the post by Jim Thompson, in which he was trying to remember what a tool used to cut "donuts" was called and where to find them. I didn't mean to imply that the island cutter was a tool that would be appropriate to use with a Dremel for finely detailed PCB work. Sorry, I didn't mean to create a dispute on tooling meant for a Dremel..

Dave M

Cursitor Doom wrote:

I used these cutters on several PCBs. They are very good if you use a drill press and clamp your work. With a drill press, you can adjust the amount of penetration. I would not recommend them for hand-held drills.

You're welcome.

This looks like it will work:

It looks like the Harbor Freight (no longer available) punch, which works well.

Ed

This looks like it will work:

It looks like the Harbor Freight (no longer available) punch, which works well.

Ed

That looks cool. FR4 wrecks edges, but I'd never punch 1000 of those so it would be OK. I think I'll get one.

I'm not allowed to use the good foot shear on FR4 at work. I have to use the old ugly rusty hand shear.