Hi all,

I talked to a guy this morning who suggested using a hole saw in a
magnetic drilling machine. I need to cut some round holes between 2" and
3" diameter in 1/4" mild steel plate. The guy said I should be okay
buying a smaller drilling machine with a broach capacity of 32 mm and
using a hole saw to cut larger holes in 1/4" plate, rather than spending
more on a big machine. I assume the saw arbor is held in a Jacob's chuck
adaptor. Does anyone have experience of doing this? Does it work okay?
Thoughts would be appreciated...

Best wishes,

Chris

Hole saws come in all sizes up to around 4 or 5 inches. They are held in a
Jacob's chuck. Run the saw at a slow speed; chosing speed to suit diameter
from a single-point (lathe) speed chart. The saw will choke on it's chips,
therefore it is necessary to frequently lift the saw to evacuate chips. Use
cutting oil, liberally. I recently cut a 4-1/2 diameter hole with a hole
saw in a piece of 3/4 inch mild steel. It took a long time; upwards to 30
minutes as I recall. A lot of the time was "wasted" in chip removal. It
cut a nice hole. The chip removal problem can be alleviated, somewhat, by
drilling 2 or 3 relief holes, say 1/4 inch, around the path of the hole saw
at the edges to allow the chips to fall through.

Bob Swinney

"Christopher Tidy" wrote in message
...
Hi all,

I talked to a guy this morning who suggested using a hole saw in a
magnetic drilling machine. I need to cut some round holes between 2" and
3" diameter in 1/4" mild steel plate. The guy said I should be okay buying
a smaller drilling machine with a broach capacity of 32 mm and using a
hole saw to cut larger holes in 1/4" plate, rather than spending more on a
big machine. I assume the saw arbor is held in a Jacob's chuck adaptor.
Does anyone have experience of doing this? Does it work okay? Thoughts
would be appreciated...

Best wishes,

Chris

"Robert Swinney" wrote in message

....

Good from Robert advice here.

I prefer using lots of water soluable coolant to oil, just because I hate
the oil mess. Oil probably is better for the cutting edges though. I'll add
that a hole saw tends to give a rough edge and be oversized. If you need a
good accurate hole with nice finish, look at rotabroach.

Karl

Karl Townsend wrote:
"Robert Swinney" wrote in message

...

Good from Robert advice here.

I prefer using lots of water soluable coolant to oil, just because I hate
the oil mess. Oil probably is better for the cutting edges though. I'll add
that a hole saw tends to give a rough edge and be oversized. If you need a
good accurate hole with nice finish, look at rotabroach.

Karl

Thanks for the advice. The holes are for dials and switches, so they
don't need to be extremely precise - it sounds like a hole saw would do
the job. But for maximum flexibility I might be better looking for a
magnetic drill with, say, a 50 mm broach capacity. The selection on eBay
is pretty poor, and I'm always reluctant to buy more expensive items on
eBay anyway. Sadly eBay won't provide you with a member's address
anymore, even when you've conducted a transaction with them in the past,
and I think that shelters bad sellers. Keep on looking I guess...

Chris