Accurate drilling tips

[Guybrush]

Hi all

I just wondered if anyone has any advice on drilling? I always find that when I drill the holes in an enclosure they always end up a little off-centre to what I was aiming for. This then leads to the decal not lining up completely accurately with the holes. I'm only talking about a few milimeter's of wander but it's annoying all the same.

Does anyone have any tips on how to get the holes exactly where you want them?

I'm currently using a cordless handheld drill so I assume that a pillar drill would make an imediate improvemnt. Unfortunately I just don't have the space (or funds) for such a big piece of equipment.

Any advice would be greatly appreciated.

Thanks

[sturgeo]

In the past i found that using a center punch, drilling a small pilot hole with a regular drill bit and then using a step drill to the desired size yielded the best results.

[m-Kresol]

I second sturgeos suggestions. Centre punch is a must. The smaller the pilot hole the better. You can still make adjustments then.

Also, as you feared, a drill press is super helpful. I use a regular drill (not cordless, but you know, one of those to drill into walls) and have bought a small stand for it. That's cheap, doesn't take up to much space and will ensure vertical drilling.

[stringsthings]

In the past i found that using a center punch, drilling a small pilot hole with a regular drill bit and then using a step drill to the desired size yielded the best results.

+1

The pilot hole is very important.  I've found that using a very small bit gives the best results.  If it drifts a bit, you can fix it before using the step bit.
Lately, I've started using my dremel drill press.  I just use a small regular drill bit for the pilot holes. ( as opposed to the super tiny pcb bits which break easily when drilling )
anything other than a pcb ... )

[EBRAddict]

Sometimes I drill consecutively larger pilot holes when I want a very accurate placement. I also adjust the angle of the drill press table to make sure the surface of the enclosure is perpendicular to the path of the drill bit.

[raulduke]

A Centre punch is first and this is essential IMO.

Then a small pilot hole (I start at 3mm).

Then scale up in bit size (2/3 of mm at a time) working your way up to the largest hole (usually the foot switch or DC conncetor).

Some cutting fluid/compound can also really help.

[jimilee]

I use a 1/8 pilot hole and a small hobby drill press. It's not terribly expensive, it came from harbor freight.


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[culturejam]

In the past i found that using a center punch, drilling a small pilot hole with a regular drill bit and then using a step drill to the desired size yielded the best results.

This is the correct answer.

[davent]

I'll just reiterate, but first make sure your layout it is acccurate. Center punch absolutely essential and start with a small, very small bit. I start with 1/16"/1.5mm bit as it fits inside the center punch dimple is not going to skate out as long as you're using quality, sharp drill bits. I'll then step up by 1/32" until i've drilled the 1/8"/3mm hole which is where my step bit starts.  A drill press is great but i had no problems during the years i was doing this with a hand drill.

1. Perfect layout
2. Excellent sharp drill bits
3. Center punch, and this needs to be done accurately, i use an optical center punch
4. Use a drill bit as small or smaller then the center punch dimple
5. Small steps until you reach your step bit start size

dave

[GermanCdn]

Couple more things you need to consider:

1. If you aren't using an automatic centre punch (i.e. using a hammer and nail punch), don't hit the punch too hard.  It doesn't take much to dent an aluminum enclosure.
2. Even if there's a drilling template available, I always use a small metal ruler to measure the centres of the pots/components before I populate the board and check it against the template.  I've used the wrong/out of date template before.....
3. Slightly overdrilling your holes gives you some play, and generally doesn't create stability issues on board mounted pots, as they rigidly act as a whole.
4. Pilot holes are a must, prevents bits from skating.

[darrenw6000]

Hi I know this too well but I went and got a spring loaded centre punch and the accuracy was noticeable straight off
I too did not want to buy a drill press so I found this



It keeps the enclosure nice and steady while you drill with the cordless...and I think it was only 20 quid

[matmosphere]

Last pedal I built I was in a rush. I taped it up measured and just used the stepping bit. Ended up working out perfectly. The masking tape was just enough to keep the bit from skidding around.

As germancdn suggested I always overdrill by a small amount and have never had an issue.

[cajone5]

Best results from the methods described above.  Accurate layout, center punch, pilot hole, step bit.  Drill press will make your life much easier.

[culturejam]

Another great tool is an X/Y table. With that and a laser-dot drill press, you pretty much can't go wrong unless the bits are dull.