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I'm trying to create a curved coffee table leg - I'll bandsaw the profile, but then I'd like to give the face (the face created by the wood exposed by the bandsaw cut) a long concave recess. It'll look like a less-extreme piece of celery, if that makes sense.

I was thinking about doing it with an angle grinder. Any issues/tips/other ideas?

Link: this sort of thing

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up vote 2 down vote

I have not used a grinder for shaping wood as deeply as your project may require, but have free-form shaped concave surfaces using a disc grinder air tool. My suggestions include:

  1. If the leg is straight along its length you might also be able to use a router to block out the cross section profile.
  2. Make certain that the leg is securely anchored before applying the grinder. It will be easy for the grinder to dig in a pull the piece off your bench.
  3. Test drive the grinder on sacrificial pieces before attempting it on your actual wood legs. Odds are you will not get it right the first time (or two, or three, or ...) and you will learn important techniques.
  4. Your experimental pieces should be of the same or similar species to your final leg. Soft woods may not respond to the grinder the same as hard woods.
  5. I would suggest selecting straight grain stock for the legs that is free of knots or burls. Straight grain might make long grinding strokes more uniform, although with a tool as aggressive as the grinder that may not be an issue. Knots are much more dense and will be much more work to hand finish.
  6. You will need multiple grinding wheels with different grit sizes and you will probably end up doing a great deal of hand sanding to get an acceptable surface for finishing.
  7. Safety first, use goggles and face mask. You may be tempted to remove the guard to get deeper access in the depression. This is not recommended, however, should you attempt this wear heavy clothing including thick gloves.

Good luck and consider adding an answer to the question with your experience including a picture when you are done.

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  • Good call on the species match. The table material is walnut; I can try to rustle up some maple for the test – DeltaG Sep 9 at 16:21
  • @DeltaG, I think Ashlar's Answer here covers this in sufficient detail so I won't bother trying to salvage mine and will delete it in a while. One additional point I have a little beyond #4 here, because of the difficulty in controlling material removal in this sort of way you may want to actually make more than four legs to prepare for one or more not turning out right, e.g. six legs may be needed to end up with four good ones. I do this all the time for tricky things where there's a good chance of a screwup during shaping, but generally at a much smaller scale than a coffee table leg! – Graphus Sep 10 at 11:33
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If I am understanding what you are looking for, I have been able to do this by passing a piece of wood diagonally across the blade of a table saw.

I also know that is not the normal way that a table saw is used. So, to get to your desired depth, make A LOT of passes. When I do this, I start with the blade so low, that it takes barely any wood off. After that I raise it, just a bit. Also each time, I am checking how the wood is looking, the depth of the cove, and of course readjusting my fence.

Here is a link to a video describing the process: Cove Cutting on Table Saw

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  • I know it's counterintuitive, but cove cutting on a table saw is routinely practiced and is generally considered safe as long as you prepare correctly for the cut. I suppose I might be taking you too literally when you say, "not the way a tablesaw is meant to be used," but I do think it's an important distinction since you often hear people say that if you want to be safe, you shouldn't use a tool like a table saw in ways it is not meant to be used. – Charlie Kilian Sep 10 at 14:47
  • @CharlieKilian - True. What I said was not clear. I was more mentioning it because I had never thought of using a table saw that way until somebody showed me. And showed me how to do it safely. I will edit the answer. Thanks for the clarification. – RabidPrimate Sep 10 at 15:44
  • Good edit, I think. Thanks! – Charlie Kilian Sep 10 at 15:50
  • This is a good technique, but will only work if I'm putting the cove on a straight side. This one is on the curved side left after the bandsaw is used/ – DeltaG Sep 10 at 17:08
up vote 1 down vote

Where's Roy Underhill when you need him?

This sounds like it would call for a gouge chisel like this one and some hand carving.

https://cdn2.grizzly.com/pics/jpeg500/g/g7956-b5d0ad95cd90cfd433b52cc2d6356cb8.jpg
Image courtesy of grizzly.com. No specific recommendation, that's just the first image I found on Google

It might not be quite as quick as the angle grinder, but would probably be much more precise and much less likely to accidentally take off too much. On the other hand, by significantly reducing the likelihood of removing too much material, it might be much quicker in that you most likely won't have to redo any legs.

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  • Roy Underhill - that's a blast from the past! :) – DeltaG Sep 13 at 3:18
  • 1
    "It might not be quite as quick as the angle grinder" I love it LOL – Graphus Sep 13 at 12:51
up vote 0 down vote

Here's what I ended up doing: bandsaw to cut the profile, spindle sander with a large-radius drum to hollow out each end, hand sand to taste. There's not a huge amount of recess in the middle, but the eye doesn't really notice, and the leg itself came out of the bandsaw much thinner than I was envisioning. After all of the necessary requirements were met, the 2 1/4" blank was about 1" thick.

Table leg

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  • That looks a really ambitious piece and well done on the execution. One quick thing, seeing what looks like a continuous row of pocket screws at the back — if the top is solid wood have you screwed it down this way all around? Doesn't matter if the top is a man-made board of some kind but if it's solid wood you'll have constrained seasonal movement. – Graphus Oct 16 at 14:21
  • Thanks - it was a lot of fun. The inside there actually holds a 2-axis gantry which I program to drag a ball through sand, making a tabletop zen garden :) The wood's solid, but the grain's aligned with that row of screws, so it shouldn't be too big an issue (hopefully) – DeltaG Oct 16 at 18:08
  • The grain being aligned with the screws isn't the issue, the main problem would be if there's a matching row on the other side so that between the two of them the wood is no longer free to move. – Graphus Oct 17 at 12:24
  • There's that line of screws at the back, not on the front, though – DeltaG Oct 25 at 18:48

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