ENCLOSURES: Cutting Holes for a Battery Draw

I know I could probably pay Tayda to do this, but they don't always have the enclosures that I want, and part of me likes going down the hillbilly route with a hand drill and a file.

Here's my process for cutting out holes for battery draws.  It's actually pretty easy to do.  

STEP ONE:  MARK OUT

So first things first - make sure that you know where you plan on putting the foot switch and other parts, to make sure there's room for the battery draw.  

Use the battery draw as a guide to trace out the length / width etc, using a square.   

STEP TWO: DRILL THE OUTLINE

I use a small drill bit to get as close to the inside edge of the line as I can, trying to keep the holes quite close together.  I don't have a fancy pedestal drill, so this is all done with a regular battery powered hand drill.

STEP THREE: REPEAT, BUT BIGGER

Then I use a larger bit to drill around the smaller holes, and in some cases this breaks through the edges of the smaller holes, creating a bigger gap.

Once this is done, metal shears finish the job - it's usually doesn't take much effort at all.

STEP FOUR: GET BUSY WITH THE FILE

As the title suggests, time to get busy with the file.  Check progress as you file, because aluminium is quite soft and the file will do its work quickly.  Check the hole with the battery case occasionally, just to make sure you are on track.  Watch the corners too - most of the hole can be the right size, but if the corners aren't, it will not fit, leading you to remove more material than required.

STEP FIVE: DRILL MOUNTING HOLES

I like to drill the holes for the battery holder at this stage, using the case itself as a guide.

NEARLY THERE

After drilling out small pilot holes for pots and jacks etc, it's time for the stepped bit.  Keep an eye on the stepped drill bit, as they tend to clog and this can cause issues.  I find slow and steady drill speed with a little pressure works for me.

I also like to double check the size while drilling, using the components that will go on the enclosure, to make sure that I don't accidentally overshoot it.  

Hopefully it looks something like this when you're done.  I've given it a light sand and a wash in warm soapy water by this stage.