What Do You Know About Annular Cutters?

[Bob La Londe]

* What Do You Know About Annular Cutters?

* Do you have some?

* How do you like them?

* Compared to what?

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[David Billington]

On 27/10/2021 18:58, Bob La Londe wrote:
> * What Do You Know About Annular Cutters?
>
> * Do you have some?
>
> * How do you like them?
>
> * Compared to what?
>

I've got 15 of them in sizes from 10mm to 49mm and use them regularly in
the lathe and mill for cutting holes. They produce accurate size holes,
much better than the Starrett hole saws I have, and sometimes the cut
slug is useful. In the BP mill I just hold them in a 3/4" collet, in the
lathe I use a modified MT to MT adapter to take them although I
subsequently found you could buy holders for them to suit various MT
sizes. I think you can tell I like them.

[Bob La Londe]

I do more machining (mostly CNC) than fabrication, but recently in a
fabrication project I had to punch 4 1" holes in 1/4 wall tube, and a 1"
hole in a piece of 3/8 flat bar. I smoked a decent Lennox bi-metal hole
saw, and drilled the 5th hole with Silver and Deming bit on the mill.
It got me to thinking about annular cutters, and yes that the slug might
be usable had not escaped me. If nothing else so I could give away bags
of slugs. LOL.

FYI: The S&D bit (with a web diameter pilot) cut its hole as fast or
faster than the hole saw, and it doesn't even look like it needs to be
sharpened. Ok, it is a 5HP mill and I put it in back gear.

Thanks for the feedback. I'm seriously considering adding a set or two
now.

[David Billington]

I forgot to mention that they come in 2 types. Most if not all the ones
I have will only cut through a single thickness of material, I presume
this is due to the slug having a thin flange the size of the hole which
would spin an any material underneath preventing further cutting. The
other type is obviously ground differently so they can cut through
multiple material layers, I presume producing a cylindrical slug without
the flange.

[Jim Wilkins]

"David Billington" wrote in message news:slc4p6$kou$1...@dont-email.me...

----------------------

I have a small Clausing mill in a crowded basement shop, so I usually cut
and drill structural steel such as the gantry track outdoors. I learned to
locate, drill and tap holes in steel fairly accurately with hand drills when
building large custom machinery. My 16' gantry track assembly has about two
dozen 3/8" (0.370" shank) bolts in 3/8" drilled holes. Most can be started
by hand.

Do you think annular cutters would work hand-held, or in a Portalign drill
guide which isn't all that much steadier?

I save thicker hole saw cutouts to make bushings, spacers, drilling guides
etc on the lathe.

[David Billington]

I think if I was to try it hand held I would put the annular cutter in a
pre-drilled hole in some plate clamped in place as a support guide, the
Portalign may be OK as is and should hold it square to the plate. Once
the cut is started it seems to be self supported/guided by the hole and
the centre stub soon to become the slug. I did ask a company selling
them if they were OK to use in a mill but got a non committal answer as
I expect it was out of their comfort zone in this age of liability. I've
used them for cutting material square on, at angle, cutting tubing,
notching ends of round bar, even cutting semi-circles out of the edge of
plate. I've had no issues so far but if doing an unbalanced cut I'll
take it easy at first until the cut is established just to be on the
safe side.

[Jim Wilkins]

"David Billington" wrote in message news:slcl97$7vi$1...@dont-email.me...

I think if I was to try it hand held I would put the annular cutter in a
pre-drilled hole in some plate clamped in place as a support guide, the
Portalign may be OK as is and should hold it square to the plate. Once
the cut is started it seems to be self supported/guided by the hole and
the centre stub soon to become the slug. I did ask a company selling
them if they were OK to use in a mill but got a non committal answer as
I expect it was out of their comfort zone in this age of liability. I've
used them for cutting material square on, at angle, cutting tubing,
notching ends of round bar, even cutting semi-circles out of the edge of
plate. I've had no issues so far but if doing an unbalanced cut I'll
take it easy at first until the cut is established just to be on the
safe side.

---------------------

Thanks, I'll look for one to test. The support guide with the pre-cut hole
could be done on the mill. Mild steel drill guides usually last long enough
for the few holes in my one-off home projects and when worn can be recycled
to a larger pilot drill size. Much of my work is too large for the mill and
has to be match-drilled to a guide or another part. I wouldn't design for
production that way but it's fine for making one unit.

This is a good tool for punching the center of a large hole into a piece
clamped underneath:
https://www.fowlerprecision.com/Products/Punches/Fowler-1-4-11-16-Universal-Transfer-Punch-52-482-002-0.html
The spring-loaded outer sleeve slides forward against the work to hold the
punch square.

I've used hole saws to fish-mouth tubing for practice welding clusters, and
the surface finish was good enough for welding but not much else.