Light bracket

[Chicken lights]

My centre light box needs fixing. The stainless has some cracks and broken areas. So I got this aluminum bracket bent up.

I’m thinking find the centres, measure out to mount the license plate. The license plate light is two holes, so measure out from the centre line and mark. Then figure out where to mount the two 4” round lights. Roughly how it’s pictured.

I’m curious how bad a 4 1/2” hole saw is going to wander.

Pretty basic, and not very exciting.

As always, just curious if there’s a better way to tackle this. Sometimes brainstorming out loud gets some interesting answers to debate

 

[YYCHM]

How are you going to cut the 4 1/2" hole?

 

[Chicken lights]

A 4 1/2” hole saw

 

[YYCHM]

A 4 1/2” hole saw

As in the ones with a pilot drill bit? Do you have a drill press?

 

[Chicken lights]

As in the ones with a pilot drill bit? Do you have a drill press?

Yes, the kind with a pilot drill bit.
Not a very good one, I have a little jobmate drill press I borrowed from a friend

 

[CalgaryPT]

A trick used by carpenters to enlarge a door knob hole that was drilled too small is to clamp a piece of sacrificial wood behind it. It gives the drill bit something to guide it and prevent the hole saw from wandering. You get a cleaner hole. Also, if possible, never use a hole saw vertically; the teeth biting in erratically cause it to jump. You'll get a cleaner hole if you feed the hole saw horizontally with a hand drill.

 

[Johnwa]

Another way is to use the holesaw to cut a 4 ½” hole in a piece of ½-¾” plywood and clamp that to the metal. Use the 4 ½ hole to guide the saw.

 

[Chicken lights]

Another way is to use the holesaw to cut a 4 ½” hole in a piece of ½-¾” plywood and clamp that to the metal. Use the 4 ½ hole to guide the saw.

Spell it out like I’m slow, please...

Locate the centre hole
Drill the centre hole
Put the drilled plywood on, around the holesaw

Then clamp the plywood to the bracket

Then drill the 4 1/2” hole?

 

[CalgaryPT]

Lots of vids if you Youtube "Enlarging a doorknob with a hole saw." But here's two examples:

I get that you are not enlarging a hole, but the principle is the same. You are using the wood to guide the hole saw and reduce wobble/chatter.