Replies

1. 
   john_c2 | May 25, 2020 12:37pm | #1

   Because of the square ends and rounded middle section, it looks like plunge cuts with a dado blade. It doesn't seem safe.

   If it were me, I would choose a router bit of a profile you like, and make a template. You can do that, it it will be fairly quick, safe, and cleaner than a dado would be.

2. 
   gulfstar | May 25, 2020 04:03pm | #2

   If you like making jigs for special purpose cuts like I do, it would be possible to imagine a jig that has two rockers mounted on a 1/2 baltic plywood onto which a plunge router is mounted this would fit in a box that would be clamped to the butcher block top and limit the movement of the router. You will have to do the maths to find the correct radius of the rockers. Another idea would be to have the plywood adapter base mounted between two pillow bearings with a pin on either side that would create the proper radius of cut.

3. 
   gulfstar | May 25, 2020 07:52pm | #3

   If you can manage to have the ends of the recess rounded you could use a large cove bit and with proper guiding use successive cuts.

   
4. 
   Eideann | May 25, 2020 11:04pm | #4

   A sharp chisel ;)

5. 
   rob_ss | May 26, 2020 06:02am | #5

   I'd do something else and keep your digits, but I can think of two ways to do it that are not as dangerous as plunging onto a dado stack (suicide IMHO) USE AT YOUR OWN RISK:

   1. Use a CNC. This is a good project for CNC - it will cut it well.

   2. Use the tablesaw - this is essentially a 90 degree cove. with very careful setup, you could cut this on a standard tablesaw blade - you pass the coved area over the blade from side to side, raising the blade very slightly for each pass until the required amount of wood has been removed. With care, this can be not very dangerous. The blade is never exposed and kickback is unlikely. You DO need to have good constraints and a sharp blade though.

   I am pretty sure 2 is how it was done as it is much less sensitive to positioning errors. Remember that European regulations prohibit no-through cuts on the table-saw in commercial facilities - this is due to the much higher risk of injury. Higher risk... Your OWN risk....

   Whilst it would be possible to do with a pivoted router (as per @gulfstar) it would require a straight bit. I can't think of a sensible way to move the router side to side so you'd need a constrained sliding base.
   It would be more dangerous, much harder to do and less consistent than the saw blade option.

   Quick way to check though - does the hollow in the board you have match one of your saw blades - if it does, there is the answer.

6. 
   Jkatzowitz | May 26, 2020 07:59am | #6

   I would simply build up the base piece and then cut the radius out on the bandsaw. Then you can glue the two end pieces in place and you're done. It would be a very safe and low stress process.

7. 
   gulfstar | May 26, 2020 08:56am | #7

   It was likely done on a cnc with a hollowing bit, notice the rounded corner and intersection at the ends, they are not a sharp corner. One also notices that there are tool marks running from one side to the other, those are waves left by the arc of the cutter moving vertically to achieve the hollow and not rotating .

   
8. 
   eieio1 | May 26, 2020 09:20am | #8

   If you have access to a radial arm saw you could turn head/blade 90 degrees to the direction of travel. This is similar to #2 in post 5 except you are moving the blade instead of the work piece - this seems a little safer to me since you can see the blade. The only problem might be the width limitation on the radial arm saw.

9. 
   _mj_ | May 26, 2020 09:51am | #9

   Since you say you are building these, why not make the cove cuts before final glueup? Glue up the cutting board, then cut strips off the ends to add back as end caps and spacers. Take the main block and use the tablesaw cove method Rob_SS describes to cut the depression. (The only change I would make is to set up the cove as not-quite 90 degrees so you are feeding into the blade from the front of the teeth and not flat to the side of the blade.)

   Once you have your cove clean it up, cut the board into sections, and add back the strips you removed earlier.