How would you machine this?

[Matt Ellis]

I've had a request for an end grain cutting board similar to this:

Ulu.jpg

How would you go about machining the depression/portion of the sphere? FWIW, I don't have a lathe and the board would measure about 12x16, while the major diameter of the sphere is about 5".

[Ken Fitzgerald]

By far, the quickest and easiest method would be to turn it, obviously.

Possibly use a hand tool.....I can't remember the name but neander chair makers use them to scoop out chair seats...

[Rod Sheridan]

Compass, gouge, scraper, sandpaper.

You can complete the above before you figure out how to do it with a machine............Regards, Rod.

P.S I would have suggested a small hand adze however I doubt if you have one.

[David C. Roseman]

Matt, neat project! While we're waiting for someone to come up with a practical way to power machine this without a lathe, may I point out that this is a perfect excuse to buy a new tool! Actually, you may want to contact a local turning club in your area. I'm sure there are probably half a dozen folks with large lathes that would be happy to have you bring the board over to their shop after you've glued it up and thickness sanded it. Would only take a few minutes to mount it up with double-faced tape and turn the recess.

David

[Ryan Mooney]

By far, the quickest and easiest method would be to turn it, obviously.

Possibly use a hand tool.....I can't remember the name but neander chair makers use them to scoop out chair seats...

I believe you are thinking of a Scorp - if you search for "chairmakers scorp" you'll find a number of exampled. It would be .. challenging (but not impossible) to get an even curve like that with one though. I'd bet a square doughnut that the original was done on a lathe as well.

I could swear I've seen a router jig for doing curves like that as well, but darned if I can find it or remember how it would have worked...

[johnny means]

Does it need to match the knife? I would spin it on my table saw. Kind of like a table saw cove. Of course, I would make sure my jig was really stout first.

[bill tindall]

I had a similar problem with an easy to carve cherry block and I just dug it out with a gouge. I wound up leaving the tool marks as I thought they added to the attractiveness. To proceed, mark the circle with a compass, using a Forstner bit drill a hole in the center to provide a depth target and carve away. The new gouge will cost you $35. You will be amazed that it will be done in less time than you have spent studying the replies and pondering alternatives(provided the gouge is sharp).

[Bruce Wrenn]

Use a router either on a pendilum, or curved track. Check out Scooping out a chair seat, using the router. Cutting board would have to rotate 360 degrees to acommandate the Elu knife.

[Jim Matthews]

I suppose you could use the Arbortech Turboplane on a power carver, but I would do this with a gouge followed by scraping.

My preference would be a curved (both laterally and along the length) Japanese compass plane.
With a fingernail profile blade like a scrub plane, you can very precisely control shavings.

A series of drilled holes could provide depth information to follow as you go.

It's my suspicion that a board like this should be carved first, and allowed to season for some time.
When you're satisfied it has "settled" joint and plane the top and bottom surfaces parallel.

[jack forsberg]

if indeed its end grain than hand tools other than on a lathe will be blister forming.

the lathe no question no contest.

[Tai Fu]

You can use a circle jig and a router...

Cut the circle and increase depth as you make your way to the center.

Or Drill press and forstner bit to hog out the middle then finish by hand...

[Bruce Page]

CNC router. Easy Peasy.

[Rich Engelhardt]

HF 4.5" angle grinder + Lancelot
HF 4.5" angle grinder + Galahad
HF 4.5" angle grinder + Arbortech Turbo Plane

or for that matter...

HF 4.5" angle grinder w/abrasive wheel.

[Jeff Duncan]

The picture is of a long grain board which would be much easier to work with hand tools than an end grain board. I wouldn't want to try to scoop that in end grain by hand

If it were for me it wouldn't be a paying job, so it would be something I'd be making for myself. As such I'd probably go with hand tools and avoid the end grain configuration.

good luck,
JeffD

[Brett Robson]

gimbal jig.jpg

You can build a gimbal jig for your router. The one in the picture would work providing you rotate you workpiece as you cut down into it, gradually forming the depression.