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I have this wooden beam 12cm x 12cm. I need to remove a 10cm x 10cm x 6cm cube from it. What's the easiest way to approach this? I don't mind buying machinery for it if that makes the task any easier.

Update: I want to end up with the beam and I don't care about the cube. A comment suggested that it might not be obvious. enter image description here

  • My vote would be to do this with hand tools, and most of the work can be done with a single chisel (my recommendation would be a 50mm chisel for this which is about the widest that can easily be purchased currently). However, I would strongly recommend a rethink about what you're planning here as you're removing far too much of the top of this post for many applications. With the post in the photo at least the wood left is all 'short grain', which is very weak indeed — it's quite possible you'd be able to snap off these cheeks just using finger pressure. – Graphus Jun 4 '16 at 18:15
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    Do you want to end up with a nice cube and don't care about the beam? Or do you want to end up with a beam with a 10x10 rebate and don't care about the cube? – Adam Jun 4 '16 at 22:34
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I ended up doing the job with a jigsaw and a drill. Jigsaw saws are available in several sizes. One of them went exactly 10cm deep. Of course it would bang into the wood if I would saw the 3 plains. To minimize the banging I drilled 3 holes along the end of those plains. I hope these pictures help to make sense out of this.

first drilled the holes

Keep the jigsaw firm and progress it slowly forward. The drilled holes might be off a bit and the saw will bang in the wood as it progresses. Need to keep the jigsaw pressed against the wood to absorb the mild blows.

then applied the jigsaw

Here's the end result after shaving a bit with a wood file.

Oh and the 2cm that's left is strong enough. That won't break easily. Not with your bare hands or fingers at least as someone suggested.

end result

This method will probably not work in hardwood.

  • Re. snapping off the cheeks using hand strength, you didn't try hard enough :-) But more seriously, bear in mind that far more force than the hands and arms can exert can be produced by seasonal wood movement, wind loading etc. so being conservative with how much wood you remove is generally advisable. As a rule you never want to remove more wood than you leave where strength is important. – Graphus Jun 15 '16 at 8:07
  • Your solution is excellent! I'm surprised that nobody suggested that - good on you for coming up with that! Do bear in mind that if this notch will be at the bottom of a post for a railing, it will now be fixed firmly to the step/deck and have a long lever for applying additional leverage. Of course, since you haven't (and aren't required to) tell us what you're using it for, we're just speculating and tossing about general precautions. – FreeMan Jun 15 '16 at 16:59
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Here are two approaches:

  1. Saw and chisels. This is the easiest and least expensive approach. A sharp hand saw will make short work of cutting into the wood on all three faces cutting a triangular section on each face. Clearly you cannot saw any deeper without overcutting the outer lines. Next, draw a line across the top diagonally from top left corner to the top right corner, securely clamp the block to solid work surface and remove the outer section of the clock which has had its inner face fully sawcut using a chisel starting at on the top line and working down. This block will come free quickly since you are using the chisel to split the wood along its grain much as an ax splits firewood. Now you can use a 1" +/- chisel and mallet working along the sawn inner faces to cut out the remainder of the wood. Take the wood out in small depth increments, cutting across the grain several mm using the sawn face of the remaining wood as a guide and then with the grain to pry the cut section out. Work methodically and you will soon have the full volume removed.
  2. Router with a long bit. This option will require securing the wood post to a solid bench such that the top is flush with the top of the bench. You will then mount two wood rails to the bench surface to serve as guides so that the router base plate prevented from penetrating into the wood beyond the width and depth of the void are desired. Begin by removing a shallow section (5mm) with the router and use increasingly deeper bit settings until you have desired depth.

The saw and chisel is the quicker/easier method especially in softwoods like in your picture. The router can be dangerous for a beginner so make sure you understand how to use it properly before making this type of attempt. As with all woodwork projects, your first attempt may not be as successful as you hoped for. Practice improves everything.

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    Thanks for the tips. I never knew router bits could go that deep. Good to know. The douglas wood is pretty soft so it might work. However I came up with another solution that I will post soon as an answer. A jigsaw went exactly as deep as needed. To prepare I drilled holes along the 3 axes to minimize the jigsaw bashing in the wood. Your last sentence encouraged me to try this out 3 times before applying it to the intended beam. – Christiaan Westerbeek Jun 5 '16 at 19:51
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I would use an oscillating multi-tool.

Use a technique similar to this- https://www.youtube.com/watch?v=qwpt1ghzdNg Basically removing a small layer (1/2 inch) at a time till your at the required depth.

  • You may want to elaborate on that a bit. A Sawzall™ and a jig-saw both oscillate, is that what you're after? – FreeMan Jun 6 '16 at 19:23
  • This answer is too brief and not clear regaring how the tool can excavate the entire volume needed. – Ashlar Jun 6 '16 at 20:03
  • As Ashlar suggested, this may be clear to those who have used an oscillating multi-tool but could be clarified for those who are not very familiar with these tools. – rob Jun 7 '16 at 2:32
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Along the lines of the comment left by Graphus, I would tend to try to accomplish this a different way, with an eye toward the strength of the piece. Instead of cutting out a cube, start with a 10 cm x 10 cm post of the appropriate height. Then glue two 2 cm boards to adjacent faces of the post. This will let you pick boards where the direction of the grain is much stronger than what will be left if you make the cuts as shown in your picture.

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