Guys this is originally a plumber's tool used to cut holes in water tanks, copper and lead, a sharp good quality tool (mine is very old) will also cut holes in old fashioned water tanks made of galvanised steel sheet, take time, and use a woodworkers brace and a ply backer no problems http://www.aluminiumwarehouse.co.uk..._for_Hand_Brace/drill_Stand/product_info.html My prefered method of powering the tank cutter.
Thank's I think I'll use a hole saw and file to fit. I'll use a 3 1/4 " and a 2". Blue one I have a 1" fiberglass lip aprox 1/8" thick to mount dash in the car.
You can also leave the wood slug in the holesaw to stabilize the pilot. I use particle board because it's easier to dig out when you're done. Blue
Lots of useful info here guys thanks. Just not sure about the circle cutter idea. Hole saws for me all the way. I use lenox. They have never let me down.
I've just done mine. Used a 2" hole saw,finished with a flap wheel for the 2 1/16 gauges. For the 3 3/8 i used the closest holesaw i had,trimmed with snips till it was close. Then i grabbed a worn 5" grinding wheel and using a dressing wheel for a bench grinder to take it down to just under 3 3/8. Gives a nice flat edge to clean out the hole (carefully!) Think this is all getting over thought !
I use this circle cutter/ tank cutter/ fly cutter whatever you want to call it... just like pictured above... beats the hell out of hole saws etc... and adjustable so you dont have to go buy 2 or 3 different hole saws for 1 job...
All you guys are certainly doing it the hard way The easiest way is with a Q-Max cutter. leaves a perfect hole with no burrs or deformation.
Q-max cutter is a new term to me. I've always known those as knockout punches and although they work well you need more than a couple holes to justify the cost.
Not sure how much they cost in the US but in england a 2 1/16" Q-Max is $18, drill a pilot assemble the cutter rotate with a key and you have a perfect hole, what could be easier ?
Yup that is what I do unless I have access to a vertical mill and a boring head. Sometimes you have to take a rat tail file and clean them up a little bit.
I have 2 5/8" (2 5/8" hole) and 5" (4 5/8" hole) Autometer gauges. I layed it out using cardboard cutouts of the faces taped to the panel until I had everything where I wanted it then centerpunched the centerpoints through the cardboard through the compass point hole and marked the O.D. with a Sharpie. I had a 2 1/2" hole saw that I cut out all the locations including the large ones. I filed the small ones to fit and used a saber saw to cut out the large ones then finished with a file. Perfect fit for all the gauges and it took less than an hour.
I've known those devices as a Greenlee hole punch since the 1950s. I used them on aluminum panels back then but I think a hole saw would be better for a steel instrument panel.
I just made two aluminum panels with the same holes. Used a very slow speed on my drill press and the hole saws cut like butter. There are no 2 1/16" saws so you must use 2" and enlarge, I used a die grinder
Same method I use, picked it up from doing tile. Also does a good job keeping oil on the blade when cutting thicker materials.
This is the "Greenlee" punch I use, it has a 3.125" punch set installed here. The hydraulic pump, makes punching holes pretty easy.
I marked mine out with a fine marker, then used one of these: Then sanded the last fraction of an inch with one of these in an air drill: I guess it would work in aluminium or steel, the same as it does in 'glass.
How about using something like Blair hole cutters? They are a broach and they cut a really accurate, round hole. Available up to 3"dia.