Cutting cast aluminum with a hole saw???

[billlsbird]

....can I cut a hole in my cast aluminum Edelbrock valve covers with a hole saw??? Or is cast aluminum like cast iron??? THANKS, Bill

[BigTruckDriver]

I think so , I also thought you could cut cast iron with a hole saw too?

[billlsbird]

.....Ok, Thanks ... I guess I'm mistaken on cutting cast iron, anyway my valve covers are cast aluminum so I'm headed out to try it...... thanks again, Bill

[pat mccarthy]

you need to watch out hole saw cut big you are better off with a step drill or a carbide hole cutter no run out to make the hole bigger.the center drill in the hole saw can add to run out. drill were you want the hole with a 1/4 drill then run a 1/4 drill rod or cut the head off a long bolt and put it were you would run the 1/4 drill bit in the hole saw. this will help some but it will still cut big

[61bone]

Use lots of stick wax lube and clear the chips often. low speed cuts are a lot cleaner than fast ones. Keep spindle length as short as possible. Dont even think about freehanding them. Quick way to have junk valve covers. This isn't going to work if you are trying to make the hole bigger. use a step bit or find someone with a mill.

[billlsbird]

....Thanks Pat, Thanks 61Bone, I'll get a step drill as I found one for a good price {$25 bucks}. The carbide cutter was $75! BUT before I get it I took an old metal valve cover & drilled it out to 1 3/8" & put my new baffle in. I want to make sure it doesn't leak oil before drilling the aluminum ones. That's what the 1 3/8" hole in the valve cover was all about; to install a baffle..... Bill

[pat mccarthy]

....Thanks Pat, Thanks 61Bone, I'll get a step drill as I found one for a good price {$25 bucks}. The carbide cutter was $75! BUT before I get it I took an old metal valve cover & drilled it out to 1 3/8" & put my new baffle in. I want to make sure it doesn't leak oil before drilling the aluminum ones. That's what the 1 3/8" hole in the valve cover was all about; to install a baffle..... Bill

i see alot of valve cover that leak were the hole was to big

[billlsbird]

LOL.... well, the baffle seems to work so I'll order the step drill .....

[C9x]

Step drills work well, especially in sheet metal.

Another way round the problem is to scribe your circular pattern and use a drill press to drill many 1/8" holes just inside the scribe marks.
As close together as you can - there'll be a lot of them.

Depending on the thickness of the metal you can use a small cold chisel to connect the holes.
But . . . don't do this if the metal is thin or you'll spoil the flat surface.

Fairly thin metal, you can tip the drill sideways and let the flutes do the connecting.
Sounds crude - and perhaps it is - but it doesn't hurt the drill unless you push it too hard.
1/8" drills are pretty cheap anyway.

Use a half round file to clean up the hole out to the scribe mark or better yet, use a mandrel with 80-100 grit sandpaper drum.
Goes fast, but is easy to control.

I've done a few large holes in 1/8" steel plate this way.
Some of them were less than half a circle - "C'ing" the frame for instance.