Cutting Hole In Dash?

I need to cut a 2 1/16" hole for an additional Temp gauge.
I really don't want to remove the dash as everything is done and new.
I have a nice new big variable speed 1/2" Drill. Should I just go at it with a hole saw and go slow? Obviously my worry is having the bit wander and not getting a perfect hole without scratches!
Whatd'aY'all think?

 

Like this? will cut thru dash? Home Depot is just down the road!
At under $20 it is $100 less than that SWAG knockout punch!!

 

I would strongly recommend using a 2-1/16" bi-metal hole saw for that purpose....here's an example:

https://www.amazon.com/HSS-BI-METAL-DEEP-HOLE-ARBOR/dp/B01DO4WE16/ref=sr_1_3?crid=3I57L2GHPJXHD&keywords=2-1/16+hole+saw&qid=1557428533&s=gateway&sprefix=2-1/16",aps,162&sr=8-3

First you would want to center punch and drill a small pilot hole for the hole saw's small central bit, then use the hole saw to cut the desired diameter opening.

 

I have those, just worried about doing it in the Jeep.

 

Needs a steady hand... I prefer to save these for a drill press.

The hole saw would be my choice if the rough edge can be concealed.

 

If using a bimetal hole saw, do yourself a favor and predrill the 1/4" center hole. Get a section of 1/4" round stock from the hardware store and use that in the hole saw as the centering rod. There's nothing worse than the holesaw grabbing, breaking the drill bit, and making a mess of the base metal as it walks 5" before you can stop it. The roundstock will bend a little if it needs to, but it won't break and make a disaster.

 

If your going to drill the dash, then a bi-metal holesaw. Do you consider an under-dash gauge mount so you don't have to cut the dash?
Oh, I see you've already got two gauges over on the left, nevermind!
-Donny

 

I did. but I thought it would look better in line with the other gauges. photo above.

 

These are fantastic, BTW. Maybe you know an electrician you can borrow one from.

 

I need to cut a 2 1/16" hole for an additional Temp gauge.
I really don't want to remove the dash as everything is done and new.
I have a nice new big variable speed 1/2" Drill. Should I just go at it with a hole saw and go slow? Obviously my worry is having the bit wander and not getting a perfect hole without scratches!
Whatd'aY'all think?

Ive been a Locksmith/ Installer and Cj5 Aficionado for many years. I have Bored thousand's of various size trade related holes in steel doors , 90 percent of the time with bi metal hole saws . Always center punch then bore a 3/16 " pilot hole before using a Hole saw in metal. The pilot used in a hole saw mandrel is typically 1/4 " & will always follow the 3/16" hole. The pilot used in a hole saw mandrel is designed mainly for boring into soft materials. I'm fairly certain the thing that home depot sells is a circle cutter , mostly for crafts ; wood & plastics. Depot also sells Bi metal Hole saws and mandrels. Good investment when working on our CJ's. Please take the other very skilled fabricator's advice. ( ITLKSEZ, Keys5a, maurywhurt and the other fellas ).... BTW, I just did the same installation , over a GM tilt steering wheel in my ' 75 CJ5. I had to 'L' head in at a angle ! .....Still ,the center punch & the beginning
3/16" pilot hole saved me, of course. Please see the pics. Good Luck & Take your Time .
------Lockman

 

I would do a test hole on a piece of scrap first.

 

+1 - the fly-cutter type needs a stationary axis. Hole saw or punch for cutting such a hole in situ.

 

I’ve cut many holes for gauges in metal, fiberglass and wood. Always used a hole saw. Cheapest and easiest way to do it. Mask off the area, drill the pilot hole to 1/4” turn the pilot bit around in the mandrel and have at it. Slow and steady with a nice sharp tool. Good luck and don’t over think it, you’ve got this.

 

Like ITLKSEZ says, I would use a 2" hole saw, a little under size, because they wander. Then tape the dash in the area over, drill a 1/4" hole first, then I turn the drill in the hole saw up side down so you are using the shank for center, that way it does not have a tendency to wander as much. I have had hole saws jump over and make a mess instead of a nice round hole. It also helps if you tip your drill a little and let it cut the hole slow and a little at a time. Works for me. Good luck

 

I am so lucky to have access to a Greenlee hydraulic knockout set at work that has dies from 3/8” holes up to 4” holes. A knockout punch set makes perfect holes. Buildflycrash if you were closer I’d gladly let you use it! But like said before I use a holesaw daily and the best way for a clean cut is always a pre-drilled hole for a guide. The pilot bit on the holesaw arbor will almost always wander a bit, even when new.

 

Just a couple days ago I cut the hole for my speedo (repop dash)...and used this type of cutter. dash was on the work bench with a chunk of wood behind it and using a hand drill... I would highly recommend NOT using this cutter in place...it was a serious pain in the A**...turned out nice but...wow...lotsa sweat and cursing
If cutting in place I would think a 2x4 as a brace between dash and firewall would be a great help