how to cut a perfect 4 5/8 hole for a gauge?
 

I have a couple of tachs and a GPS speedo that need a 4 5/8 hole cut for them and the margin for error is virtually non existent. The problem is nobody makes a 4 5/8 hole saw and to try and cut it free hand with a roto zip will just about be impossible with the tolerances it gives. What can I do. I am stumped. Surely someone here has done this before and knows the trick. The only hole saws I can find are 4 1/2 and 4 3/4 but no 4 5/8.

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

Go to Menards...or maybe Home Depot.....( i got mine at Menards thus the first suggestion) anyway in the section where they carry drills and wood working tools....they have an adjustable whole drill bit.....had a regular drill bt in the middle and an arm that can move side to side to make what ever hole you want up to 5" i think.....anyway that what i used to drill the holes for my monster gauges......i actually made them a tad smaller and followed up wid a hand file to fit them snug :)

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

use the rotozip drill a 1/8"hole in the ceter of where you want the hole drive a screw in the hole tie a string around the screw 1/2 the diameter of the hole - the width of the fence of the rotozip tie the other end of the string to the zip the string will keep you the distance from the center you want.

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

I prefer to just use a 4 1/2 and then a file or die grinder to GENTLY enlarge the whole for a nice tight fit. The single armed adjutable hole saw will do the trick but they take an experienced and controlled hand to use, they can easily destroy your dash and they like to twist and pop alot.

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

I've used the Rotozip with the hole cutting attachment, and it worked fine, and gave great results. You do have to be careful, and make sure you use the correct bit. As far as the adjustable hole saws go, the only one I've seen just goes up to 2 1/2". I've used hillbilly's method, and that works well too. The filing tends to be tedious though. Either way you do it, make sure to protect the area with a couple of layers of masking tape or something. Just in case. And mark the area to be cut with a template so you don't stray, and most important, Take your time:)

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

Yeah I guess a Roto-Zip would work well, I just can't bring myself to buyone it seems too much like a Martha Stewart homemaker tool. :evilb: :evilb:

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

I like that :)
Maybe if she had a Rotozip, she could have cut her way out of jail!

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

Depending upon the material you are cutting I bet you end up with a 4 5/8 hole with a 4.5 saw.

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

Its not far off when your done, just a little under ussualy. whole saws never cut the exact diameter that they are unless you put it in a drill press.

Re: how to cut a perfect 4 5/8 hole for a gauge?
 

Use a smaller hole saw and then reem it out for a perfect fit, you can use a grinder, rotozip, rasp, whatever. Have one of your buddies stand next to you with the shop vac and you'll reduce the mess a ton.