I'm keen on a job well done: using tools safely and effectively so they perform in a beautiful way and for a long time.
And so I offer to you what I know about drilling holes in metal with a drill press.
(When you're planning a project, resist the urge to say, "... and then just drill a hole in it"! Good practices will guard the life of your tools. Also, you'll learn a LOT about the qualities and "feel" of your materials.")
And, as ever, I put this together at Techshop Detroit www.techshop.ws. It's a great place, I tell ya what. Come in and make... ANYTHING!
Step 1: Tools and Materials
Talking about the tools and materials you need for this process is a little like asking, "what's the shape of water?" Just depends on the circumstances!
More to the point, you'll need metal material to drill through; the right bit for the kind of hole you want to drill; a method for centering your drill bit in your intended hole; AND ADEQUATE TOOLS FOR HOLDING MATERIAL SAFELY IN PLACE.
This is a kit of tools and materials you might assemble for metal-hole-drillin'. The things circled in green are what we MUST have to drill a hole in steel, strictly speaking.
- Ruler/straight edge. Steel is durable; durable = accurate
L to R:
- Scrap angle iron
- Fine point permanent marker
- Center punch
- Drill bit - common twist drill bit; find this kind at the hardware store - HSS (High Speed Steel) is common and effective
- Tape Measure
- Wrench and Rite Hite clamps for holding work.
Step 2: Preparation Fast-Forward
Step 3: Anatomy of a Drill Bit
From top to bottom we have:
- The shank: Solid portion of the bit meant for gripping in drilling tools. Heat-treating a drill bit is controlled so the shank stays softer while the cutting end becomes hard; this helps with the grip. You'll find the diameter of the bit stamped on the shank
- The flutes: spiraling channels which carry away drilled material or "chips."
- The cutting edges and the chisel tip: the edges are sharp and angled to scrape and lift material. The chisel tip (or web) is a flat space between the edges to support the cutting edges and the bit point in general.
Step 4: Load the Drill Bit in the Drill Press
A drill press has a chuck on it that holds cutting tools. Usually this is a Jacobs Chuck, with jaws that open/close when you twist the outside of the chuck.
"Chuck" your drill bit in. Make sure it's centered between the chuck jaws. I like to chuck my bits in just about the flutes, as shown below. This makes the most of the shank and supports the bit as much as possible.*
Use the chuck key to tighten the bit in (again, be sure it's centered in the jaws.) Tighten in one place around the chuck, then tighten from a second direction. That way you know the jaws are evenly engaged.
*I've heard arguments to chuck the bit higher on the shank; the shallowest I'd go is just above the size stamp.
Step 5: Center Your Bit
This is a very important step. When you're working with metal, you can't just hold with one hand and drill with the other. Abandon any ideas of "just really quickly" or "one little counter sink" or anything that suggests that being safe might be a waste of time.
PLEASE don't ask for corroborating stories.
Now locate the drill in the center of the hole. Lower the quill on the drill press and "touch down" into the center punch mark. You should feel the bit nestle in, with lighter material actually shifting over and centering itself. You're looking for the chisel tip to sit within your center punch mark. When it looks good from one angle, swing around and look from another angle just to be sure.
Step 6: Clamp Your Work
This step can be done in many ways, but it's essential. Drilling metal is slow and requires of force from the drill press. If the bit grabs your material instead of cutting it, the material can spin or launch. And between you, the material, and the drill press - you're going to sustain the most injuries.
By contrast, a well-clamped drill operation is nearly fool-proof.
I used Rite Hite clamps These clamps are bolted to threaded rods which are in turn anchored to slots in the drill press table. C-clamps are fine too, just make sure they're seated sturdily and tightened down.
Step 7: Drill!
A pre-step to drilling is to make sure the motor speed on your drill bit is correct. A VERY loose rule of thumb for this is 500rpm or slower is good for mild/"hardware store" steel. In tandem with this rule is "the smaller the bit, the faster you can go."
Check for the RPM setting that matches your material and bit choices, then set your press.
When you're drilling, use both hands on the quill feed (that's the wheel that lowers the bit.) If you're worried that your material might move if you don't have a hand free, better re-clamp!
Ease the bit into your work, and after you've cut for a few moments, lighten up on the bit to cut chips free. Keep this "pressssss-lighten, presssss-lighten" rhythm until you're through the material.
How will it feel? With decent steel and the right RPM setting, you'll hear a "shuh-shuh" sound, maybe a low scraping sound, but the cutting action will be smooth and leisurely. Any rattling or smoking means you're not working optimally; squeeling or grinding means you'd better stop and recheck your configuration.
and... YOU'RE DONE!
Step 8: Clean Up
Vacuum/sweep your chips. Please. Respect yourself, respect your tools, respect those who share the space.