I need to cut 3and 1/2"round forms in 1/8 thick materiel for candle dish pans.
Is there an easy way to do this?
The only thing I can come up with is cutting square, then octogonal, grind here, cut some more there etc...

I tries a bi-metal round saw and gave up after 10 minutes on the press drill!
Maybe the saw was a cheap one ???
If so, what should I look for in a saw of that type ??

Thanks in advance !

Naz

hole saw and be done with it in a blink.
use oil, sounds like you definitely have a dull one, I cut 5/8 with a bi metal holesaw even.
oil and a sharp holesaw is your friend

You should be able to cut a hundred or more holes with a good bi-metal hole saw. Use a good cutting fluid, keep the saw wet, it's not that hard, once it starts cutting it forms a chanel that will hold the fluid. The speed is important, the hole saw needs to go slow. There should be no chatter or it is too fast. You may need to rig a jackshaft to slow down your drill press.

I don't think I'd bother to cut them when I can buy them. I forget the name of the place here but they already have precut(stamped) rounds that are cheaper than my time would be to cut them. Check around and see if there is a place like that near you. ;)

Looking for cowboy hat blanks a friend of mine found that the local pipe place had round blanks with a slight dimple (easily reduced with a good whomp) considerable cheaper than having them cut. Various sizes used to weld ends of pipe closed IIRC.

I agree with the hole saw idea. I've cut a lot of holes with mine and they work great! As said, keep oil on it. :D

Well if I couldn't just buy the blanks as suggested I'd use my hole saw. White Bimetal, turn the rotation as low as you can, oil and not a lot of down pressure. I've drilled I don't have any idea how many hundreds or more holes in steel with hole saws. I also use hole saws to cut pipe to length for fabbing frames and such. It's mostly a matter of knowing what to listen for and paying attention to the action.

Frosty the Lucky.

Hole saw, band saw, or torch/plasma cutter. That would be quick work with a plasma. If you have some industrial shops around you, one may have a plasma, oxy torch, or a waterjet.

Do you have access to a lathe? I have friction turned circles out of thin plate like that before. Cut the blanks, then press them against the chuck with the tailstock center to turn the O.D.'s.

Thomas...

No need to "whomp" that dimple. Just use it to center the top tool. The dimple should be streched smooth, and generally, the top is pushed in anyway...

I've actually found that when cutting out drip pans with a hole saw to slightly shim up one side of the plate. Less teeth cutting at a time. Obviously the higher you shim it the more oval your part will be, and of course speed and lube as said. Oh and a bench top sheer works well also .
Btw do a search for fender washers, they are large OD washers with a small ID.

If you only need a couple you can cut them out with a cold chisel. Not the fastest way but it is the blacksmith way to do the job. With a little practice it is easier than you think. If you are making a lot please disregard this idea. A metal cutting band saw with a narrow blade works well too.

If you have a vocational high school near by you can see if they have a CNC and if they will cut them for you. I go back to my old school all the time to get stuff cut for me.

If you are cutting 10 or more it's cheaper to get them laser cut out. Cheaper than the time it takes to do it with the methods in most shops. Plus no cleanup. Only draw back is the 7 - 10 days most shops need to do the job for you.

If I were stranded on a dessert island with nothing but 1/8" thick stock, a file, and a cold chisel, I'd start by cutting hexegons. I'd also wish for a clamp so I could file more than one at a time.