The Twisted Truth

Need a hole?  Many of our plans require drilled holes, so here are some Tips about drilling in metal, like steel, as well as in wood, and other materials.

Two-Handed Power Drill
Use a two-handed grip for a steadier, smoother drill.

There is a ton of information on the web about drilling, so I won’t go into a lot of detail, but I will point out a few tricks for the DIY builder — because we don’t always have the perfect tool for the job.

Background

  • A drill is tremendously efficient at removing material.  Some manufacturing folks claim it’s the most efficient — meaning you remove more per watt of power.
  • Drilling metal is arguably the most common form of machining.  Almost every home has a drill, and most DIY’ers have a few.  If you think of drilling as machining, it changes the way you approach it.
  • The process of Drilling involves one moving (spinning) part that cuts another stationary part (the workpiece).  If the cutting part (the drill bit) is drastically harder and stronger than the workpiece (like wood, for instance), then drilling is simple and usually without problems.  If, on the other hand, the materials are similar (steel drilling steel), there are some things to pay attention to.  Oh, and if the drill is softer than the workpiece, you’ll likely fail.  Make sure you know what your drill bit is rated for so you won’t damage your tools – or the project.

Drilling Metal

Let’s look at drilling metal.  The tips are the same for all metals, but you can get away with more if the workpiece is softer (like aluminum).

First:
Tools for Marking for Drilling
Make sure the hole you drill is the hole you want.

Make sure the location of the hole-to-be is well marked.  If the project is less constrained, like using a hand drill, then the drill will “wander” if the location is not well defined.  We recommend a carbide tipped scribe to mark the location, then a center punch to create a small divot for the drill to locate on.

A guided hole like in this tip about Matching Bolt Holes takes the measuring and center punch out of the equation.  It’s an easy way for drilling matching holes in metal.

Second:

Use a drill designed for metal.  The cutting angles and features are important.  If you’re not really familiar with drill bit angles for materials, you may want to start here for a basic explanation, and a list of point angles for metal and others depending on basic work materials.

Make the drill work for you.

Third:

Combination Center DrillStart with a small drill (or a center drill) to initiate the hole.  A small drill will wander less, stay in your punch divot easier, and take less force to get started.

Side Note:  A larger drill will follow a previous, smaller drilled hole.  Once you start a hole, it’s really hard to move it a little, so be sure you get it right the first time.

Fourth:

Increase drill sizes going larger and larger until you reach the desired size.  The amount to increase depends on power available, and the steadiness of the drill.  With a hand drill, for instance, smaller steps up in drill size help a lot.  Bigger steps with a big drill press.

Side Note:  Maybe more of a common sense note.  Don’t try to drill big holes with a small drill.  You’ll end up hurting your tools or yourself.

Fifth:

The most common causes of drill failure are:  Over Speeding & Under Feeding.  In wood it isn’t a big deal, but in steel it’s important.  The bigger the drill diameter, the slower it must turn, and more force is required to “feed” it.  So, Bigger = Slower + Push Harder.  That also means more power required.

Another common drill failure comes with cutting on just one side of the bit, or trying to drill an interrupted hole.  This drilling technique (see the article) is a great way to align holes, but will likely take a toll on the cutting edges of the drill bit.

Sixth:

Use lubrication.  That may seem counterintuitive, but they make cutting fluids for a reason.  Cutting fluids do a few things:

  • Help cool the cutting edges.
  • Lubricate the non-cutting areas (sides) of the drill that are spinning in the hole.
  • Helps chips move away from the cutting edges, and helps make a clean cut .
  • Cutting fluid helps the bit stay sharp.

You don’t need something specific for drilling.  Tap fluids like Tap Magic, for instance, are great for drilling metal.  I personally prefer something with a little more body and apply it with a small brush, but any like these with a squirt top work fine too.

Drilling and Cutting Fluids

Side Note: You don’t have to use special cutting fluid.  It’s preferred, of course, but in a pinch, use motor oil or some other lubricant.  It stinks when it burns and often smokes as you drill, but it works.  It’s much better than drilling dry.

Seventh:

When drilling in metal, go in increments.  If the material is thick, drill some, then pull the drill out, clean off the chips, add some cutting fluid, then resume drilling.

Eighth:

Be careful punching through.  One of the most common times for a drill bit to break is when it punches through the back of the workpiece.  If force down (feed pressure) stays the same, the drill bit takes larger and larger bites of the material as it finishes the hole.  If the bite is too big, it will jam.  That can be dangerous for you if the bit breaks, or if it flips the workpiece — or worse, flips the drill out of your hand.  To avoid these unpleasantries, lighten up on the feed pressure as the drill comes through.  If you’re using a hand drill, you can usually feel the moment it starts to give way.

Ninth:

Drilling Chamfer ToolAfter drilling, clean up the holes.  A round file, chamfer tool, or whirly-gig are all great to remove sharp edges.  This helps bolts enter easy, keeps fingers from getting cut, and generally makes it professional looking.  A small burr left on the hole can also compromise a bolted joint by not allowing the bolted pieces to mate fully. Just take the time and do it.

Drilling Wrap Up

Wow, this post is a lot longer than I intended.  Hopefully you get some good info from it.  We’ll look at techniques for drilling big holes in metal with small hand drills in another post.

Drills Note:  If you need some specific drills or sizes, like to build one of our DIY Projects, you can get nice single bits at Drills and Cutters.  Browse around a little and you can find reduced shank drills with 3 flats on the spindle — which are excellent for drilling medium sized holes with a hand drill — like those needed for our Gantry Cranes. You can choose Made in USA or Imported.  I have found they are better quality than Home Depot or Lowes or Ace, and the price is usually better.

Storage Note:  For easy access to drills near a drill press, here’s a Solutions! post worth reading.

Drill Bit Chuck Flats

For more info in fabricating, read the 7 Ways To Cut Steel article.

Good Luck With Your Projects !!

Comments

Subscribe
Notify of
0 Comments
Inline Feedbacks
View All Comments

We Found These For You . . .

Article
Learn To Calculate the Axle Position
Trailer axle position?  This is a good question.  Unfortunately, there is some popular, but misleading information around.  So, how do you know proper trailer axle position?  Here is the whole answer,

Read The Article

Article
Which Welder To Buy?
“I’m looking to build one of your trailers, but I need to know which welder to buy?”  or  “What type of welder do I need – 110 or 220 volt?”  and  “What about other projects from your site that may…

Read The Article

Product
Hoist Winch Pole Plans

Meet the "Winching Pole".  It’s a simple, mechanical, Out-of-the-Way Hoist Winch to make lifting with a gantry crane easy.  No chains in the way.  No climbing up for a come-a-long.  Plans also include a simple load leveler.

Article
Suspension Mounting Too Close
Shopping online is both a boon and a bust.  It’s great access to a wide variety of components, but it’s a bummer when misleading info causes extra work and frustration.  That brings us to this Customer Story of misguided

Read The Article

Article
Aluminum Trailer Frame Underside
Aluminum is such a great material.  It’s light, strong, and looks sweet to boot.  So, why is there a debate about Aluminum Trailer Frames comparing to others like steel?  Or comparing for beams like with gantry cranes?

Read The Article

Article
What Are Your Essential Tools
We’ve been asked many times about “What are the most essential tools for your shop?” Well, that’s a hard question, because frustration and wailing are the result when the right tools are not available.

Read The Article

Article
Trailer Axle Choices
In the discussion of trailer axle leaf springs versus a torsion axle, let’s put some engineering behind the debate.  I don’t want to change opinions, but I would like to offer a practical perspective.

Read The Article

Article
Stainless Steel Bolts
In the previous articles in our Bolts 101 series, we spoke briefly about Stainless Steel Bolts, but we did not discuss specifics.  With typical alloy steel bolts, there are grades (like Grade 5, Grade 8, etc.), but with Stainless Steel

Read The Article

Product
Canned Food Storage Center

A unique food storage center to hold canned food in a FIFO (First In / First Out) rotation.  The unit sits against a wall so it can store cans anywhere with minimal encroachment into the room.

Article
New Plans for a Perfect Size Homemade Crane
A New Size?  OK, MechanicalElements.com has Gantry Crane plans – for years.  Interestingly, one of our very first plans.  Now, we just released the Perfect Size Crane for your Garage. 

Read The Article