Is there a better way to make elliptic holes in a proto PCB?

[eeng67]

Hi,

I have a personal project that needs a pot.

The pot I have has mounting tabs that don't fit in the proto PCB holes. Moreover, to make the pins fit, I had to "join" 2 pair of PCB holes.

I ground the PCB a bit with the Dremel engraving tool, then I drilled through the remaining material. Finished the job with a small file by hand. The final result was so-so and I deemed it good enough.

I don't have access to a drill press, nor to a router.

I am wondering if there is a better way to do than. Would you have any useful tips for me?

 

[ronsimpson]

Today I used a file to make the pins smaller. Not good but worked.

 

[rjenkinsgb]

Use a small drill bit part way through the material and "rock" the drill in the plane of the wanted slot. It will mill quite a bit away. Drill an intermediate hole first if needed, then do that in each hole to join them.

Just take your time so you don't snap the bit.

I use that technique for cutting large holes in panels & boxes etc., starting with a row of holes just inside the required cutout line

 

[eeng67]

Use a small drill bit part way through the material and "rock" the drill in the plane of the wanted slot. It will mill quite a bit away. Drill an intermediate hole first if needed, then do that in each hole to join them....

Well, that is more or less what I did.

I have tried in the past to drill a tiny hole between two 0.1" holes and wasn't very successful. That is why I removed some of the PCB material off first with the Dremel.

I guess one can get better at it with experience.

Next time I'll probably enlarge the existing hole(s) with a 1.5 mm drill bit and file off part of the pins/tabs.

 

[rjenkinsgb]

I have tried in the past to drill a tiny hole between two 0.1" holes and wasn't very successful

Jab it with a knife tip, then rotate the knife to cut a small centre mark so the drill does not skip.