annular cutters: a better way to drill big holes in thick steel

[dfkrug]

I got a nice B&D with a 3/4 chuck for $125.

That's a great find. For most of us who are not fabricating metal for
a business, a mag drill (or an ironworker, or a milling machine) is hard
to justify. Being able to use these annular cutters in a drill press makes
them accessible to the home workshop metalworker.

The first time I saw these in use was at an AG show. The vendor was
demonstrating the SteelMax mag drill product with coolant, and it was
very impressive. My investigations found little testimonial info on the
web about using them in a conventional DP.

Hougen may have invented the standardized annular cutters....their
bits are called "Rotabroaches". Amazon.com even sells an unbranded
Chinese mag drill that accepts Weldon shank cutters. Standard cutters
come in many diameters and alloys, and 1, 2, 3, or 4 inches long.

Now, I am going down to the workshop to drill some more holes.....

 

[TDVT]

What kind of cutting speeds are you using for say a 1" hole?


I've been thinking of a a new drill press & I would want to make sure it has MT compatibility & lower speeds.

 

[dfkrug]

What kind of cutting speeds are you using for say a 1" hole?

I've been thinking of a a new drill press & I would want to make sure it has MT compatibility & lower speeds.

I will drill everything I do at slowest speed (180RPM). That is faster than
I like for the twist drill bits and bi-metal whole saws, but it is very difficult
to find a DP that goes slower. You can find an old relic, or go with a
geared head unit to get slower speeds.

For the annular cutters, the mag drills go much faster than 180, but you
don't have to go so fast. Most DPs don't go under 280-300RPM. That's
another plus for annular cutters. They remove so much less material,
faster speeds work OK.

The HF press is listed at $499, but can be bought for $350 on sale.
It is MT3, and I also keep an MT2-MT3 adapter handy. The chuck is
a 3/4" I think.

 

[jenkinsph]

My lowest speed on my drill press is 180 rpm 1" capacity 1 hp I had an old one years ago with a 1/2 hp motor that turned about 60 rpm. Wish I had the old one and someone else had this new one.

 

[R W]

Take a look at PracTool | Home
The Super Drill is a usefull addition to any workshop.

 

[dfkrug]

My lowest speed on my drill press is 180 rpm 1" capacity 1 hp I had an old one years ago with a 1/2 hp motor that turned about 60 rpm. Wish I had the old one and someone else had this new one

Yes, those old relic DPs are keepers. Even if they have worn bearings,
they are probably replaceable. I would love to have 60RPM.

I do have a replacement motor that runs slower, but I have not gotten to
installing that in my current press.

 

[mjncad]

Thanks for the real world experience report on the annular cutters. I've seen them advertised; but never took the time to investigate them.

I'll bet they are a lot more accurate than hole saws too.

 

[jenkinsph]

Good point about the motor, I will look at mine first chance I get to see what the speed is hopefully it is 3450 and I can change to a 1725. Just wishfull thinking.

 

[MikeD74T]

That's a great find. For most of us who are not fabricating metal for
a business, a mag drill (or an ironworker, or a milling machine) is hard
to justify. Being able to use these annular cutters in a drill press makes
them accessible to the home workshop metalworker......

If you used a mag drill once & could get it relatively cheaply you'd have no trouble justifying it. Attached to a piece of I-beam or a welding table they're as flexible as any other drill press. I've even clamped a 3/4" plate to a beam & bored out mortises on a post & beam project. Nothing like pushing a 1" hole thru a steel truck frame with 2 fingers. A good mag drill can also be used as a power source for a portable boring bar. Try that with a standup drill press when rebushing the boom on your excavator.
Ebay item 180493816304 is only $200 right now, craigslist 1652645127 or 1676040126 are $300, not a lot of money for a power tool. A few others are less than $400, less than a HF drill press. In an ideal world we'd each have both. MikeD74T

 

[kennyd]

Great post D:thumbsup:

Although I am blessed enough to have a small mill, These still would come in handy at times.

The HF/Enco Mill/Drill's come up cheap from time to time, they usually have speeds down to 60 RPM or so and make great heavy duty drill presses and already have the X Y table, with the added benefit of doing light milling. I regularly see them for $500.