Accuracy in marking / drilling

[inf0]

Hey there!

I'm always trying to refine my skills and become better at every aspect of building while working on my DIY projects.

In this case , I would love to know some insight about maintaining accuracy when trying to mark and drill holes for pcb mounting or other components.

In the cases where I don't order the holes predrilled , I've always laid the pcb flat on the surface i'm trying to mount it on and marked with a marker then used a center punch to start the hole.

However , even the slightest of deviation can sometimes make the spacers a bit off.

Any general tips & tricks would be greatly appreciated !

 

[Script]

Here's how I do it. That entire thread is worth a read.
https://groupdiy.com/threads/mounting-pcb-in-project-box.41598/post-995818

 

[Gold]

Transfer punches are the right tool for the job. Search for Transfer Punch set.

 

[inf0]

Thank you for your input! I'll read up on them !

 

[ccaudle]

Transfer punches, or centering punches, come in a set of different diameters. They have a point in the center, you find the punch which matches the diameter of your hole, put the punch in the hole and tap it with a hammer, and it makes a dimple centered in the hole.
You need to either tape your template PCB down really tightly so it can't move, or drill the first hole, put in the mounting stud, bolt down the PCB, then punch the other holes. I can tell you from experience that if you don't the PCB will slip just a little after you punch the first hole, and you punch the later holes with a dimple nicely centered in a hole that is slightly off from the correct position.

 

[Script]

I can tell you from experience that if you don't the PCB will slip just a little after you punch the first hole, and you punch the later holes with a dimple nicely centered in a hole that is slightly off from the correct position.

Exactly. And that's why I use marker pen on all four standoffs at the same time to 'print' for accurate position first. No taping or bolting needed. Fast and easy.

 

[inf0]

Definitely going to buy a set ! Thanks!

 

[Rob Flinn]

I use some masking tape to temprarily stick the pcb to the panel it's being mounted to. I then use transfer punches to mark where the holes are. Sometimes I don't use the transfer punches & just use the pcb holes to guide the drill. Normally works quite well either way.

 

[Gold]

You need to either tape your template PCB down really tightly so it can't move, or drill the first hole, put in the mounting stud, bolt down the PCB, then punch the other holes. I can tell you from experience that if you don't the PCB will slip just a little after you punch the first hole, and you punch the later holes with a dimple nicely centered in a hole that is slightly off from the correct position.

The main issue I run into when using transfer punches is that the PCB is too thin to be able to get the punch securely centered in the hole. The point of the punch is longer than the PCB is thick. I usually put something under the PCB to raise it up enough to get the punch secured in the hole. Often I leave the punch in the first mark and use the next size down to mark the next hole. Then swap the correct size punch for the one in the second hole and use the undersized punch to make the next hole. Then repeat for the fourth hole.

 

[13engrsapper]

if it is too big for our CNC, I use our laser to mark it, or make a marking jig with the laser - then I spot drill all of the holes with a good sharp spot drill, then I go back and drill the actual holes. If the surface is normally non-markable with the laser you can tape over or paint over the areas to be marked.

 

[Gold]

To use a marker and a center punch I don’t try to make a dot in the middle if the mounting hole. I fill in the whole area of the hole. Then remove the PCB and eyeball the center of the marker circles. It’s not as accurate as using a transfer punch but as long as you leave a little play in the drilled holes it works fine.