Best tool for cutting factory vent holes?

[doodah man]

So, I'm installing a Vintage Air system sometime in the next couple of months, and I'm trying to get all the tools and whatnots lined up. I want to use factory vents.

I've searched on here and found the template for the holes, but I'm not sure what's the best tool to make them. Since it's a round hole on through a curved surface, I'm worried I might get into trouble with a hole saw. Some guys over at GarageJournal recommended an air nibbler but I don't think I'll have room for that. I was also thinking about one of these bits in a drill or dremel:

[HeavyD]

Is the interior fairly complete aka nice? If it is still in the build stage there are many a/c dashes posted for sale..might be easier just to weld in the new one with the holes already done? Just a thought..

[gringoloco]

I used a hole saw- just have to keep it straight. The vents will cover any small imperfections, but don't let it slip too much. Cut the center with a dremel...

[AirSpeed]

I've used hole saws on curved surfaces without issue, the only thing you would need to do is use a longer pilot bit so you can cut the hole squarely with the flat surface of the dash. If the the pilot bit is to short the saw edge will touch the curved section next to the gauge panel before the pilot bit can keep the saw centered.
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[doodah man]

HeavyD: It's still pretty (see pic below).

You guys that used hole saws. Do you know what size to use? Is the diameter equal to the diameter of the smaller part of this part?

And, thanks.

[Eddie H.]

If the cab is stripped with nothing flamable in it, a plasma cutter. If not, a rotozip tool or dremel with a sheet metal cutting bit, a hole saw, or a body saw will work.

[cleszkie]

I cut out holes in my dash for factory A/C vents. The absolutely best way to do this is with a pneumatic reciprocating saw with a fine metal cutting blade. You start by drilling a hole big enough to stick the saw blade through and then go to town. This saw will cut nice smooth curves and leave a nice edge without scaring up the surrounding metal. There is no better way to do it. Period.

[1972trucks]

i drew the template on drilled holes all the around it cleaned it up with a dremel. It took about an hour a hole but i did it that way because the dash was just painted and dint want to get the paint hot. I was worried about doing but take your time and you will be ok and the vents will hide imperfections

[57larry]

hole saw, take your time

[pickupman]

small air saw, recipricating

[chopnchaneled]

Used a hole saw with mine, like above a long pilot drill and go slow.

[john]

I did mine with fresh paint too. cut templare out of shoebox like cardboard and bored with a 1 1/4" hole saw then put rotary file in a die grinder and went to town. Only took 20 min. per hole going slow around the edge to keep things cool.

[Boog]

Way back when there were no dremels, sawzalls, plasmas, etc I put vents in dad's 72 by marking the area to be removed then drilling a number of small holes around the edge of the opening then cuttting through them by using a rat tail file. Yeah it took quite a while. Be proud of the tool options you have today.

[JCD]

One of the biggest problems in using a hole saw on a curved or angled surface is the side pressure you put on the saw..

Here's a tip.. drill your center hole first, and remove the drill bit center from the hole saw.
Replace it with a piece of smooth metal rod the same diameter as the drill bit.

As you apply the side pressure to cut the odd shaped dash panel, this keeps the hole saw centered over the hole and won't drift off center, or side cut the hole like a drill bit would.

[derotoreut]

Originally Posted by HeavyD

Is the interior fairly complete aka nice? If it is still in the build stage there are many a/c dashes posted for sale..might be easier just to weld in the new one with the holes already done? Just a thought..

This is an interesting thought. How hard would this be to do? How would you go about doing it? I am planning the same Vintage Air project, but my dash was butchered up with holes and the radio mount cut out by the PO.

[4xshort]

I'm also considering converting my non a/c cab to a/c. I have been looking on the for sale forum and the uncut a/c dashes come up alot. To me the outer vent holes don't look like a perfect circle is that just because of the curve or are the holes not a perfect circle?

[MARKDTN]

I used a jigsaw and a long blade and just took my time. The outer ones cover well, the center one not so much.

[67lowered]

Originally Posted by doodah man

HeavyD: It's still pretty (see pic below).

You guys that used hole saws. Do you know what size to use? Is the diameter equal to the diameter of the smaller part of this part?

And, thanks.

I think I used 1 1/2", then a little filing to get it to fit. If you can get a variable speed drill, then just go slow, oil helps and shouldn't screw up the paint. As said already the lip of the vent does cover a hole a little.
If you do a search, you can find posts about welding in a dash, looks like a lot of work instead of patching holes, but I haven't done it

[doodah man]

Originally Posted by 67lowered

I think I used 1 1/2", then a little filing to get it to fit. If you can get a variable speed drill, then just go slow, oil helps and shouldn't screw up the paint. As said already the lip of the vent does cover a hole a little.
If you do a search, you can find posts about welding in a dash, looks like a lot of work instead of patching holes, but I haven't done it

Do you mean a 1 1/2" hole saw? I looked at the factory vents I have and the part that goes through the hole is about 3 1/2" diameter.

[67lowered]

I gave you wrong info, the side vents I have are 2 1/2" hole, I got them from vintage air