annular cutters

[shaque]

I see these in the catalogues and was wondering how you use these and would they have a place in the HSM workshop
jim

[DR]

First off, the larger sizes have a 3/4" shank which is too short even for a standard end mill holder so mounting can be a bit of a problem. They must be used in a rigid setup, preferably a milling machine or mag based drill, they break easily if not used correctly. Given the right setup you can't beat them, we use the 2" size for a repeat job making holes in heavy angle iron. They're expensive, the 2" Rotabroach brand is around $160, imports are less (but not as good).

I see kits of small sizes at the welding shop. Presumably these are designed for hand drill usage and probably work very well.

Whether the big or small type, they're only for through holes since they cut out a plug of material.

[Stepside]

I use them all the time. I call them rota-broaches, which probably a brand name.
On a milling machine they work great for larger holes as you don't need pilot or center drills. Another benefit is they use less horsepower than a drill and they make "round" holes. I have used them to make angled birdmouth on tubing. Like a forstner bit in wood, they can drill a hole on the edge of the material.
I had to drill/cut a lot of 1 inch holes in 1/4 plate. I bought a coolant infuser that had an R-8 shank and was made to fit the cutter. A $200.00 well spent. The only thing that would have been faster would have been a 1 inch punch.
The bad news----A bit pricey, unless you have a job for them and the swarf is awful.

[Thrud]

shaque:
Make sure you get the appropriate shank to use them in your mill. R-8 and 40 taper are most common and about the same cost. The Annular cutters screw onto the shank and the shank usually takes a 1/4" pilot shaft/drill. Deep holes require frequent withdrawal of the tool to clear chips. Fein sells carbide tipped units for use in their Magnetic drills and they also have lots of different adapters available including MT#2 & 3.

DO not try to use them by gripping the rear of the tool as DR suggests - real bad idea

[DR]

<font face="Verdana, Arial" size="2">Originally posted by Thrud:
shaque:
Make sure you get the appropriate shank to use them in your mill. R-8 and 40 taper are most common and about the same cost. The Annular cutters screw onto the shank and the shank usually takes a 1/4" pilot shaft/drill. Deep holes require frequent withdrawal of the tool to clear chips. Fein sells carbide tipped units for use in their Magnetic drills and they also have lots of different adapters available including MT#2 & 3.

DO not try to use them by gripping the rear of the tool as DR suggests - real bad idea</font>

Let me clarify what I said about annular cutters, the sizes we use are 1/2" diameter and up and have a "standard" integral shank which is 3/4" diameter. This is very similar to a Weldon end mill shank except a little shorter in length. A standard Weldon end mill holder will not hold these cutters securely unless you grind a new flat on the cutter's shank. Rotabroach, Jancy, etc all sell adaptors to use their annular cutters in mills, etc. These companies all market mag based drills with a spindle that accepts the annular cutter directly.

I have seen sets of smaller annular cutters which probably screw onto a shank as Thud says. These are meant to be used in portable hand drills I assume.

Apparently Thud is not familiar with the larger size cutters having their own integral shanks.

[Thrud]

DR:
I have never seen one with an integral shank - it is news to me! Thanks for the heads-up.

The way you were talking I presumed you were suggesting gripping them in a collet - sorry about the misunderstanding. To use them safely does require a proper shank or adapter of some type.

Please accept my humble appology.

[Peter S]

Can someone please explain 'annular cutters', not something I've seen.
Are these like some tarted-up holesaw? Do they use pilot, or just rigid enough to hold true? How about blocking/clearing chips? I have seen pictures of mag. base drills, but never seen the cutters....(presuming thats the same type of cutter?)
TIA

[G.A. Ewen]

KBC Tools catalogue page 63.

[Peter S]

G.A.Ewen,
Have you got a link to that page? I can't see any cutters.
TIA

[This message has been edited by Peter S (edited 07-27-2003).]

[G.A. Ewen]

Peter S,
That is the page number in the 2003 - 2004 master catalogue ( Canadian Addition ). I have never been able to find anything on their web site except the current sale catalogue.