Drilling 1/4" and thicker metal with a hand drill

NCMau · Jan 13, 2018

BukitCase said:
Not Bob, but maybe I can help - on an actual mag drill (mine, anyway) the center pilot pin serves two purposes - one is to be able to center punch where you want your hole and line the drill up so that pin "clicks into" the punch mark - the other is to automatically eject the "slug" when you raise the mag drill's quill back to the top (this defeats the normally spring-loaded pilot, whose THIRD function is to block coolant flow (sorta) til you actually start drilling...

If I'm understanding your setup correctly, you have the stock MT adapter and chuck in a drill press, then a headless 1/2"-20 bolt in that chuck, then a 1/2-20-to-3/4" weldon adapter (like this)
Steel Dragon Tools 1/2" Female Thread to Weldon Shank Adapter - - Amazon.com

then your annular cutter?

IF so, all those extra items (possibly including your drill press bearings, depending) are introducing too NON-rigid a mount NOT to get wander from the annular cutter - It may not have happened YET, but there's a good chance you may find out why annular cutters don't like a lack of rigidity in a drill - they tend to break under those conditions.

Of course, the best (not cheapest) way is to use them in the tool they were designed for; but unless/until you want to/can DO that, I have one suggestion that may help, if you aren't already DOING it -

MINIMIZE the "floppiness" in your setup as much as possible by making sure all your connections between chuck and adapter are as tight and true as you can, and always raise your DP's table up as far as possible (like having the cutter's teeth within maybe 1/4" of the piece to be drilled, with the quill at the TOP of its travel.)

Also, depending on how old your DP is it might be time to replace the quill bearings - I know my DP is past due for that (bought new in 1983)

Another option is to get some of the shallower "sheet metal" type annular cutters, they don't do more than about 1/2" deep but can even be used in a HAND drill - I have this kit

Blair 119 Rotobroach Cutter Kit Hole Saw Kit - Hole Saw Sets - Amazon.com

They offer several "kits"
Amazon.com: blair rotobroach: Tools & Home Improvement

As do Hougen and others.

I used them when beefing up the deck on my ZTR; plasma cut a bottom plate from 1/4" steel, drilled out the wimpy 1/4" mounting holes to 5/16", clamped the new plate in place, used a 5/16" transfer punch to get a centered punch mark in each hole, then drilled for bigger bolts with the new plate still clamped. No pain, big gain :thumbsup:

Keep in mind though, this type are mostly 1/4 to 1/2" depth of cut - that's a LOT of why they can be used in hand drills; too short for much "side loading"... Steve

(Now I KNOW my typing's gettin' slow - Pat "snuck in there" while I wuz writin' a BOOK :laughing: )

Thanks for directing my annular brain waives. Now I know the purpose of the pilot pin. Since I am not going to use the cutter with a mag drill, I guess I will be using them like I have been, that is drilling a 3/16 hole pilot hole. I have a full set of 1” annulars from 7/16 to 1-1/16”, so for now I will stick with these, but in my situation the Blair Rotobroach would definitely be a good option. I will keep that in mind.

There is a little wandering using a DP with the Steel Dragon adapter, but it is not too excessive. I guess it would be be better if I get an adapter with the morse taper for the DP, but it is a little inconvenient to change the chuck back and forth. With the hand drill, however, I remove the chuck and screw it in and it does a pretty good job. I have to keep in mind the two important things: lubrication and pressure.

My vintage Powermatic DP probably has the QUILL BEARING SYNDROME. I bought it from a school auction over 20 years ago, so it has some milage. I will check it out.

I read some of your very interesting BOOKS. Keep it up do not fall into a writers block. Pulitzer may be just around the corner.

BukitCase · Jan 13, 2018

Just to "stir the pot" a bit more (gettin' pretty good at it

) Here's ANOTHER option - put the morse/weldon adapter into your DP, the shorter coupling might help wobble a bit (pun un-intended, but OK) - then, when you wanna use a twist drill, get one of these
G&J Hall Tools 18Y17 Powerbor Weldon Chuck Adaptor, 1/2"-2 UN Thread Fitting, 3/4" Arbor, For All Electromagnetic Drilling Systems: Drill Press Accessories: Amazon.com: Industrial & Scientific
And one of these
Metabo 63535 1/16-Inch-1/2-Inch Keyed Drill Chuck - Power Lathe Chucks - Amazon.com -

I have those, 'cause using twist drills in a mag drill is at LEAST as much a PITA as the other way 'round - my mag drill came with the regular chuck adapter, but you gotta take about half the mag drill apart to swap it. Ain't gonna happen for the occasional NON-annular hole - with those two above, I can change to a twist drill in the same amount of time it takes to swap annular cutters.

Also, since you're using a DP it would be even easier than it is for me - on a mag drill, the chuck and adapter means you need a thick steel "spacer" to get the mag drill high enough for a twist drill to raise up enough to work. With the DP, you'd just lower the table a bit... Steve

That reminds me, I still have to fab that "spacer" some day :=)

NCMau · Jan 14, 2018

That would be a DP good option. I will keep that in mind.

Raspy · Jan 28, 2018

You guys really want to complicate things. I just drilled 9/16" holes through 3/8" thick angle iron on my workbench feet, so I could bolt it to the floor. This, by hand, with my Ryobi battery drill. What's the problem?

Use three progressively larger drills that are sharp. Use a few drops of oil on each hole. Run the drill on low speed which gives max torque and feed easy enough to not overload it. Get a solid grip on the tool so when it catches you still have control of it. This means both hands and a tight grip while prepared for the torque reaction.
As it breaks through, you'll have to reverse it and go forward a couple of times, carefully.

BukitCase · Jan 29, 2018

John, nobody said it was a "problem" - some of us are likely just a bit "further over the hill" than others - I'm 72 and can afford a few "perks", one of which is NOT having to take a break after a few holes (of the larger variety, especially) -

I'm guessing you did NOT drill those 9/16" holes thru 3/8" steel in about 7-8 SECONDS each - that's how long it'd take with a mag drill; or a 1-1/2" hole thru 1/2" steel in under 14 seconds, with NO PILOT DRILL NECESSARY.

At my age, any time I can reduce either time OR effort on a project it means I can get more done.

I also have a plasma cutter, but you're welcome to cut steel with a sharp razor blade, up to you... Steve

Raspy · Jan 29, 2018

Steve,

Good tip! I'll try the sharp razor blade. :laughing:

I would never want to do any kind of production work without a good drill press.

CADplans · Jan 29, 2018

I owned a business where we drilled 1" holes in 1/2" thick steel,,,
and we made LOTS of these parts. Actually, we stacked 6 parts, and drilled them all at one time.

We could literally drill over 1,000 holes, before the drill bit needed sharpening.
The drill bit was nothing special, just a HS bit (high speed)
no carbide, nothing,,,

The trick was the controlled feed of the drill press.

If you tried to drill the same holes, using the same drill press,, but, hand control the drilling rate,,,
you could not drill seven holes before the drill bit would be dull.

BukitCase · Jan 29, 2018

Seriously, I wouldn't actually recommend the razor blade (altho they DO work well for scoring an accurate cut line

)

Agreed on drill press, I have separate metal working and wood working ones, the mag drill is a more recent addition.

Gang cutting (and REALLY good clamping) is another thing I've done, any time more than one identical part is needed - when I built my modular container roof I needed 6 identical length pieces of 2" square tube, with 5/8" holes near each end holes also needed to be exactly the same distance apart so 3 separate 8' wide modules could be bolted together after welding, to make a 12' x 24' "half-roof" (final is 24' square) - so by gang cutting all the tubing (pieces were actually shy of 12', so 24' steel left me a few inches after cutting 2 pieces per length) - the gang cut made identical length, then by setting a depth stop on my "MDVT" (Mag Drill Vise Table) I could drill 21/32" holes EXACTLY 6" from each end of each tube (different but similar operation) -

Feed rate - is a concept you learn fairly early on, usually by getting it WRONG

- I still occasionally struggle with it, but agree it's a HUGE factor in tool longevity - this is also VERY true when using annular cutters - Hougen recommends audibly loading down the drill during cutting, or NOTHING - in between, and you'll either be paying for replacements or sharpening.

All my annular cutters are HSS because carbide's too expensive and there were several sizes I needed in order to get the most out of the drill - presently I have 22 of them from 27/64 up to 1-1/2", (4 of those are TAP drills for 1/2",5/8", 3/4" and 7/8" NC) all 2" DOC.

At a rough average of $20 more for carbide, I'd have had another $450 in cutters with no more size options :=( - so far, none of them are dull enough to notice any change in drilling times so I must be doing something right... Steve