Drilling Easy Precise Angles

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About: Jack of all trades, master of none! Check me out on YouTube!

When I first started woodworking XX years ago, I did something so moronically stupid that it kept me grounded with paranoia from ever doing that thing again. No, I didn't burn down the parents house with grinder sparks and sawdust, I didn't impale myself with a scrap from the table saw, nor did I electrocute myself with an ungrounded prehistoric hand drill (well, no, I did do that). Dear reader, I tried to drill a hole, with a Forstner bit...at an angle.

*GASP!*

I know, I know, not life shattering terrifying...unless you were me. I remember looking down at my project, all chewed up from the spinning garbage disposal looking monster that was slowly powering down, and thinking, "Never again will I attempt an angled hole with a Forstner bit." And it stuck with me for a long time afterwards. It wasn't until I saw a demonstration for a Forstner bit actually doing that forbidden thing did I begin to wonder if it were possible or if the host was using a trick bit.

Look at a Forstner bit and you'll see teeth on the outer rim with a pyramid point in the exact center. From the point to those teeth are a pair of chisel like cutters that slowly skim the wood surface and cut a hole. Flip the Forstner bit onto its side and you'll notice that the pyramid shaped point extends past the blades and the teeth, and protrudes farthest from the cutting side of the bit. There's a good reason for that, and it's not for cutting. Nope, it's major, important duty is to act as an index for the rest of the bit. Without it we are fighting to keep it where we want it to go. This is why cutting a larger diameter hole after drilling a smaller hole is nearly impossible to do, unless you're using a drill press (and even then I'm not a fan of doing it).

So if we're going to drill at an angle with a Forstner bit, we need to be smart about it. We need to secure the work piece to the drill press table. We need a nice solid defense against the wicked witch of the Press and her evil sister, Forensa the biddy. Let's also make it precise and easy to measure the angle, just for chips and giggles.

Step 1: Gather Materials / Tools Needed and Used

Material List

  • 7 1/2" x 12" x 1/2" Plywood
  • 11 3/4" x 12" x 1/2" Plywood
  • 1 7/8" x 8" x 1/2" Plywood
  • (2) 1 1/8" x 6" x 1/2" Plywood
  • (2) 1" x 5 7/8" x 1/2" Plywood
  • 1 1/2" x 3 3/4" x 3/4" Hardwood (I used hard maple)
  • (2) 1 5/8" x 14 3/4" x 11/16" Hardwood (VERY strongly suggest hard maple)
  • 1 7/8" x 12" x 3/4" Hardwood
  • 1/2" x 7" Piano Hinge
  • Square head protractor
  • (1) 1 1/2" x 3/8" Lag screw
  • (1) 2 1/2" x 3/8" Lag screw
  • (2) 3/8" Washers
  • 1/2" x 4" Aluminum tubing (step 2 has more information)
  • (2) #12 x 1/2" Combo pan head screws
  • (2) #8 x 1/2" Combo pan head screws
  • (8) #6 x 1/2" Wood screws (should come with piano hinge)

Tools

  • Drill press
  • Socket Wrench w/ 9/16" socket
  • Table saw
  • Compass
  • Hand saw
  • Drill
  • Drill press vice (not absolutely required)
  • Scroll saw (handy but can be done with a coping saw)
  • Brad nailer
  • Chisel (1/2" should be fine)
  • Bandsaw or a handsaw
  • Sander
  • 5/8", 1/2", 1/4" Forstner bits
  • Awl or nail

    Step 2: Building the Extendable Arms

    Okay, maybe "Extendable" is not the most correct word here. Both of these arms won't actually become larger. Rather, they will rotate in a way that will hold the platform in different positions, allowing a precise angle to be used. Admittedly, I made a mistake while I was making the video and didn't take into account that one of the arms would actually need to be run through the table saw to create an angle. As the two arms are used to hold the platform (with the sacrificial drill plate), I didn't realize that one of those arms would actually be closer to the platform and need to have that angle (duh, I know). I've included a fail picture to show that mistake as well as a picture for the fix.

    Before we get started let me also add that in order to fold both of these arms down past the other (so that our angle drill plate lays flat at zero degrees on our protractor), we'll have to notch out areas in both arms. This will require a chisel for one side and a bandsaw or some sort of handsaw for the other side. We'll also be using aluminum tubing as both a spacer and as a method of keeping the arms tight against the back. I have never tried using this without the tubing but think it would be problematic. If you choose to not use aluminum tubing, please leave me a comment below and let me know how it turned out for you.

    Let's take the two 1 5/8" x 14 3/4" x 11/16" pieces of hardwood (I recommend strongly hard maple as you'll be cutting part of it out and will need that extra strength) and draw lines down the dead center of both, on the 1 5/8" face. From here we want to make the one end of both pieces rounded, so we'll get a compass and set our radius at half of the 1 5/8" distance which equals 13/16". We'll put our marking point at the very end of the 14 3/4" side and the metal point on the line we drew in the center, and we'll draw our curves. Again, this needs to happen on both pieces.

    It is crucial that you get it as round as possible as we'll depend on that curve being able to hold pressure from the drill press as it supports the drill plate. You can either rough cut it on the bandsaw and clean it up with a belt sander, or just sand it. Again, it's crucial that it rocks against the plywood when this is complete.

    Finding the center and using the trusty compass.

    While we're at it we'll skip a little farther in the video instructions and go ahead and drill the holes for our aluminum tube to go into. We'll use a 1/2" Forstner bit and place it where we put our compass point, and we'll do both arms the same way.

    Drilling holes in the arms.

    Step 3: Sketching the Base

    The base isn't really a difficult chore. In this step (and the next) we'll be able to knock off these items from the overall materials list:

    • 11 3/4" x 12" x 1/2" Plywood
    • 1 7/8" x 8" x 1/2" Plywood
    • (2) 1 1/8" x 6" x 1/2" Plywood
    • 1 7/8" x 12" x 3/4" Hardwood

    With these materials we'll make a box (albeit it a strange one) without a ceiling. Norrrrmally I would refrain from using 'box' as the appropriate term for such an abnormally shaped structure, but it's an easy idea. The half box is tall enough to house both the reinforcements for the sacrificial drill plate as well as my drill press clamp to hold the entire thing down to the drill press table (which is important, as we talked about in the introduction).

    But waiiiit a minute Rob, there's more to this than just making a box, or a convoluted one at that, I mean, I watched the video!

    Have faith, dear reader! While it is true that there is more to this, we are simply going to place all the pieces on the plywood base and sketch out exactly where everything goes. We'll do this to use reference points later on as we ho-goo (hot glue + wood glue) this all together.

    Included, in this step, are the exact dimensions of the base. Grab the pieces of wood from the list up above and build it exactly as I have specified. Once it is to scale and looks identical, use a pencil and trace each piece to the base.

    Step 4: Building the Base (Base Pt 1)

    Everything has been traced onto the base plywood. Check. Now it's time to use those lines and build our base. The first thing we want to work on is the front piece (1 7/8" x 8" x 1/2" plywood). We'll add the 7" piano hinge to the inside of our plywood board so that the hinge folds towards the back. Before we attach it we'll make sure we find the center of the hinge (3 1/2") and the center of the plywood (4"). We'll draw a line in the middle of both, use a little hot glue to keep it exactly where we want it to go, center our pieces and drill our pilot holes.

    Now let's take off that hot glue. It should come off easily with or without a chisel, but it's one of those times where we really don't want the space between the metal and the wood to exist (and hot glue is really bad about creating voids). Once you've removed the hot glue, screw in our #6 x 1/2" screws (or probably the ones that came with the hinge, so long as they're not longer than 1/2").

    Attaching the hinge.

    Now that our hinge is attached on one side, we'll want to attach the board to the base. Again, make sure the hinge closes towards the back of the jig box and we'll ho-goo (hot glue + wood glue) the plywood to the base. Afterwards, and this is purely for those that are just as impatient as I am, I tacked some brad's in instead of waiting for the glue to dry.

    Attaching to the base.

    Next we'll add the flanks, directly butting these against the hinged front we've already ho-goo'd down. We'll ho-goo these as well and use a few brads to attach them both to the plywood and to the front hinged piece.

    Adding the Flanks.

    Step 5: Finishing the Base (Base Pt 2)

    We're going to do something that seems arbitrary and unimportant, but has an importance that can only be appreciated when you're ready to drill a precise diagonal hole. This relief window will allow us to clamp the extending arms into place without bumping into our sacrificial drill plate. I have included a picture to this step for the exact dimensions you'll want to carve out.

    After this has been carved out, we'll ho-goo it to finish off our structured 'half box'. But first we'll need to transfer the holes from way back in 'Step 2' from the holes in the arms to the relief window board. We want to line the rounded ends from each board to the back of each side of the relief window board. I've included a picture showing the marking of each side of the relief window. Use the same 3/8" Forstner bit, make sure everything is lined up and either tap the bit with a hammer or you can do what I did and chuck the bit up in a drill press and 'press' the indentation.

    When it's time to drill both sides, only drill about an 1/8" in. This is enough to keep the 1/2" tube inside. Next we'll drill the rest of the way out with a 1/4" Forstner bit, which will be perfect for our 3/8" lag screws. Once this is complete, be sure the 1/2" part of the hole is facing the back and ho-goo it down to the base board, using a few nails to tack from underneath and to the flanking pieces (that make up the rest of the box).

    Making the 'relief window board'.

    Step 6: Finishing the Arms

    I've added a bunch of pictures to make it easier for you to plot the entire step. I encourage you to watch the video of this step (down below) before you get started so that you can the general idea. Basically, you're going to build two arms that extend upward that will cradle a platform. Both arms will have aluminum spacers that will keep the arms attached to the back plate.

    Before we do anything, sit the jig thus far in front of you. The hinge plate should be right in front of you. The relief window should be in the back. Grab both arms that you created in the last step. The left arm will butt up against the relief window first. The right arm will sit behind that. This is the order of your box. Take the left arm and keep the left rounded side in your left hand. Lay it flat in front of you and measure up on both sides 1". Draw a line across it. With your table saw (you may, of course, use any other method to cut this, but a table saw is what I used) you are going to cut off a 40 degree angle, leaving the 1" on the bottom. After that has been accomplished, set it against the back of the relief window.

    Angling the arm (nothing fishy here).

    We're going to cut two pieces of 1/2" aluminum tubing now. The first one is going to be 13/16". The second will be 1 7/16". With the left arm in position, place the 13/16" tubing through the hole of the arm and push it into the recess we created. If you're using hard maple (or some other hard wood), screwing a 1 1/2" x 3/8" lag bolt (with washer) and unscrewing it (I've done this a few times) won't hurt anything...which is great! Because that's what we're going to do next.

    After it's bolted in, take an awl or a nail and flip the back of the jig down. You'll mark the location of the second tube on the back of the left arm. Grab the 1/2" Forstner bit again and drill out the new hole, finishing the cut-through on the bandsaw. Insert the 1 7/16" tubing through both the right and left arm and check to see if you can open and close it without any problems.

    Now that that's complete, reinstall the left arm by screwing the 1 1/2" x 3/8" lag bolt back inside. Before installing the right arm, install just the tubing for now and let it sit on top of the left arm lag head. Here we'll mark out where the 1 1/2" bolt head keeps the right arm from laying flat on the back. We'll use a chisel to clean up a nice recess large enough that you can lay the right arm flat with the left arm. Now bolt it altogether and make sure both arms lay flat.

    Phew! These instructions almost entirely follow the video. If there's anything that seems unclear, watch the link below before commenting (which I will be happy to answer).

    Putting those wacky arms together!

    Step 7: Sacrificial Drill Press Plate

    Let's think about this one, before we get started. If you only plan on using this a few times, or plan on replacing the entire plate (that connects to the base) when you've drilled the plate to pieces, this step can be skipped. In this step I used a scroll saw. I really do try to limit my equipment as I know most people don't waste all their money on woodworking hardware, but in this case it seemed to be the best choice. Besides all that, a coping saw will work and you can pick one up for less than $10 (USD, secret's blown, I am an American).

    The goal I had when making this project, and more specifically this plate, was that I could take a piece of wood with a 5" x 8" x 1/2" dimension and put it in without much worry of how I treated it. I mean, let's face it, we have far more to worry about than whether or not the plate below will be damaged.

    Mark a line on both of the 12" sides that is 1 1/4" from the edge. On the perpendicular sides we'll mark a line that's 2" from the edge. That will give us the 5" x 8" x 1/2" inside area that we're looking for. Drill a hole within the inside square that's large enough for your blade and cut on the line (remember, a little extra space will be fine as we don't want the sacrificial plate to be too snug).

    We'll now take the two pieces of 1" x 5 7/8" x 1/2" plywood and we'll add them to the back of the plate frame by ho-goo'ing them on. This will keep the sacrificial plate from falling through. And nobody wants a sacrificial plate to fall through (trust me). I've included precise dimensions, but full disclosure, I didn't measure when I put them on, I just made sure there was an overlap of the inside rectangle with both pieces.

    You'll also notice in the video that I chose to nail it instead of ho-goo'ing it, but I regret that decision. Ho-goo'ing it is the better option.

    Making the sacrificial face.

    Step 8: Saddling Up the Hinge to the Plate and Making an Optional Channel

    Before this step gets started, let me add a thought here. In the video I have provided, you'll see here that I used this clamp to hold the jig down. You could use your own clamps on the sides, but if you choose to add the simple jig hole, this is the time to do it. Unfortunately, due to time restraints, I didn't show how I created the slot. I will briefly describe that process here.

    Place the jig in front of you with the hinge side facing you and the arms in the back. Flip the jig over like you're turning a page. The included image in this step will show you exact dimensions as to where the groove should be. You'll use a 5/8" Forstner bit and drill several holes along the provided line and come back with a file to remove the points left over.

    Now it's time to attach the hinge to the sacrificial frame. We'll use a little hot glue on the hinge again, place the frame a quarter inch from the right side (see included picture) and press down. After it's cooled off (it doesn't dry...why are we still saying this?!), we'll open the top up and add pilot holes before removing the frame from the hot glue (as we did before). We'll then put our newly drilled plate up to the hinge and screw it on.

    Saddle up!

    Step 9: Adding the Protractor Square...For Perfect Angles!

    Hey...we're almost there! This step is unnecessary, unless, of course, you're looking to drill perfect angles! In this step a protractor must die, but be reborn in a beautiful way. We will disassemble this tool by removing the thumb screw and possibly drilling out the inner works. I bought two of things from a local box store and the first one fell apart after I removed the thumb screw while the second needed a drill and an optimized bit. Either way, remove the two parts.

    If your protractor square is anything like mine, the arm will be too long. The length can be cut from the tip of the pointer to 3 and 3/4" total length. I added a second hole about an 1 1/2" up from the hole that came with it.

    Disassembling the protractor square...

    I listed a handsaw for this next step because you really need to have a flat surface for the top of the saw to run against, which was the sacrificial frame. This kept my saw straight, which is what you really want for the square (more like a rectangle, amiright?) to sit parallel to the frame. Whatever the case may be, we don't need to sink that blade very far in...just enough for the metal to sit, about an 1/8" in. We'll add the 1 1/2" x 3 3/4" x 3/4" rectangle piece in and drill two random holes on the protractor square. We'll glue the rectangle piece in place and allow it to dry before continuing. Now is the perfect time to move on to the arm section (meaning don't glue and run yet!)

    Notching the protractor square.

    You'll more than likely need to add a piece of wood to the bottom of your sacrificial frame that we added in the last step as the arm so that you can screw the arm on. A strip of wood that's a little over 2" x 3/8" x 1/2" wide will suffice.

    Adding width to our sacrificial frame.

    Let both of these dry and come back in a few hours to add the arm and put the protractor square in its rightful place.

    Calibrating this is a snap...it really is! We're going to put the sacrificial frame in its upright position and allow the 90 degree line be exactly parallel with the bottom side of the sacrificial frame. This will guarantee that it's perfect...just make sure that the line on your protractor is exactly parallel. Next we'll put a couple combo pan head screws in (pilot holes drilled beforehand) to lock it in place and we'll focus on the arm.

    Aligning the square head.

    The arm has the same necessity for straightness for things to work perfectly. We'll put it back up at the 90 degree angle and lay the tip on the protractor face until its perfectly at 90 degrees. We'll mark the holes, drill and add a couple washers below each hole. Because we made the protractor head flush with the board, we'll want to raise the arm slightly. Four washers will do just that.

    When things look just right, we'll pull out the #12 x 1/2" combo pan head screws and throw a couple into the arm. Be very sure you've made those holes big enough or you'll risk destroy the wood you added and the frame.

    But why combo pan head screws...or what are combo pan head screws? That's a flat surface above the threads of the screw...NOT domed. Domed will not allow you to sneak up and tighten the screws, they'll instead guide you to the center of the holes. The flat surface above the threads on a combo pan head screw makes it great to tighten exactly where you want the screw to go.

    Squaring up the arm.

    Step 10: VICTORY LAP!

    You're finished! Perfect! Wow!

    This baby is ready to drill some angled holes!

    Instructions are as follows to use this:

    1. Find the angle by lifting the sacrificial frame up.
    2. place the right arm against the bottom of the frame. Carefully lift the left arm up and place that against the bottom of the other side of the sacrificial frame.
    3. Use a small c-clamp and slide it where the two arms intersect and tighten.
    4. Alternately, you could drill a hole at this point and put a dowel in for a static point (like if you like to do a lot of 45 degree angles), but you wouldn't want to do that with every angle!
    5. Make sure the c-clamp is squeezed down tightly.

    It is crucial that you make sure that whatever you are drilling in to is held down to the sacrificial frame as well as the entire jig is clamped to the drill press table.

    If you liked this, please give it a heart. If you liked the video, why not give it a thumbs up? If you're new to my channel or my page here, subscribe to both!

    Thank you so much for coming along this journey. I really enjoy coming up with new ideas as well as making videos an writing instructables, so leave me a comment and tell me how I'm doing. If you have any problems or something just isn't clear enough...PLEASE, contact me down below. I'm usually very quick to respond and I need to fix errors or clean things up as soon as I can so I don't lead some poor soul off a cliff in despair!

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      6 Discussions

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      jeanniel1

      13 days ago

      Oh, man, I wish I'd seen this years ago when I had to drill some angled holes for a one-off chair from a slab of wood. Great simple idea for the jig.

      1 reply
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      Make_Thingsjeanniel1

      Reply 12 days ago

      Thank you so much! This was a fun project to make...let me know if you ever make it!

      0
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      Jimichan

      23 days ago

      I had to do this by hand, while sitting on top of a hip rafter, 64 times while building my log house. It's an octagon log house with 6 X 10 rafters. I held the jack rafters in place with a jig I made and drilled 2 through holes for 1" threaded rod, then used a 1 1/2" forstner bit to put in the countersinks on each side. I don't remember the exact compound cut I had to make on those jack rafters because of the 6/12 pitch, but I did that with a chain saw and used a 1/2" Hole Hawg to drill the holes.

      20190624_192626.jpg
      1 reply
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      Make_ThingsJimichan

      Reply 23 days ago

      I’ve been there! Hand made jigs are like an extension to what a tool can do.

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      John Ciccarelli

      23 days ago

      It seems to me that this could be accomplished more simply, at least for some setups, by first cutting a triangular sacrificial block at the same angle as the workpiece, then somehow clamping (or hot-melt gluing?) it to the workpiece so its top face is coplanar with the Forstner bit. Drill through until the bit's center point penetrates the workpiece's top plane, then optionally remove the block (so you can see the workpiece) and drill deeper if needed. The drilled block can be reused for additional holes at the same angle by starting the Forstner within the drilled cylinder. I've drawn a triangular block, however a slightly more complex shape could enable clamping perpendicular to the workpiece.

      Drilling angled hole with Forstner bit.jpg
      1 reply
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      Make_ThingsJohn Ciccarelli

      Reply 23 days ago

      Hello!

      Yes, you could cut several odd shapes triangles, but, assuming you’re talking about using a hand drill (at least from the setup you’ve provided) you would lose the straight depth cut that a drill press provides.

      If you were going to do it on a drill press, you’d also have to have the exact shaped triangles on the opposite side, all of which would have to be in the same plane with each other.

      For a quick, dirty jig, I could see your method working, but you’d sacrifice accuracy and repeatability.