Forum: woodworking.stackexchange.com
Tags: <technique><tools>
Title: Making a small indent/crevice/depression for a ball
Question: I am making my own wooden board game. The game pieces have ball-shaped bases. I want them to move around the board and rest in small indentations. Something like this:    What kind of tools and techniques should I use?

Answers:
sents: text: The usual way to do this I think would be to use the correct bit in a router, but it could also be done using a suitable cutter chucked up in a drill.
text: If using a drill ideally it will be in a drill stand for accuracy and repeatability, or a drill press will be used.
text: Round-nosed router bit: [ Source ] 'Rotary file' or burr for drills: [ Source ]
text: It's a little unconventional but an alternative if using a drill or drill press is to use a ball-headed grinding bit.
text: I use one of these myself on very splinter-prone woods to form a countersink for screw heads: The above image shows the diamond-coated and abrasive stone versions.
text: These will grind wood approximately equally but in general you'll get better durability from the first type.
answer_details: author: woodworking.stackexchange.com/users/243/Graphus
score: 12
sents: text: I'd use a forstner drill bit sized smaller than the game balls in a drill press.
text: This will leave a flat bottom hole with a slight pilot hole in the center
text: but I think that would be OK for your intentions.
text: The drill press should have some sort of mechanism to control the depth.
text: If it doesn't, you could have your table low enough
text: so the stroke of the drill press completes at the appropriate hole depth.
text: I used this method to make a marble "game" for my children.
text: Each child starts with three marbles on a board, throughout the course of the day if they misbehave they lose a marble.
text: At the end of they day the need to have one marble to "pay" for dessert.
text: It's a lot of fun for me, I'm not sure they like it too much...
answer_details: author: woodworking.stackexchange.com/users/1112/popdan
score: 5
sents: text: There are various ball-end cutters available, but balls or ball-shapes also fit into cylindrical or conical holes (and cylindrical holes with flat or conical bottoms) more easily achieved with a "normal" twist drill bit, a center drill, or a countersink.
text: Depends what you want, or how much function is important .vs.
text: the way one or the other looks.
text: You will want a drill press (or a CNC Router) to maintain consistent depth (the router might also maintain spacing for you.)
answer_details: author: woodworking.stackexchange.com/users/3334/Ecnerwal
score: 4
sents: text: Perhaps not as cool as the other ideas you could always have this done in two pieces as well.
text: You could do this with two boards and a basic drill.
text: Top board
text: you could drill straight thru.
text: Use some sacrificial wood beneath to reduce tear out.
text: Then glue that to a normal board below to give the overall project some size.
text: Be sure to clean glue that would come out from the holes.
text: This could add a nice appeal if you use two different coloured woods.
text: Only obvious downside is that you would not have curved recesses with this method.
text: Single tool suggestion
text: A traditional approach for this would be to use something like a spoon bit.
text: Image from LeeValley Tools To prove my point the product description from the page.... One, it will bore a hole with a round bottom .
text: This allows maximum possible blind hole depth in a chair leg to receive a stretcher with no chance of a brad point or spur breaking through.
text: If you do plan on using these the minor con about this.
text: Working with them you need to remove the bit to periodically clear debris.
text: This should only be considered a minor hassle.
text: Also, since they have do not have a central spur or point, they can be hard to get properly positioned.
text: With frequent use its not so hard but making a small pilot hole certainly helps.
answer_details: author: woodworking.stackexchange.com/users/128/Matt
score: 1
sents: text: One other option is a simple bowl gouge .
answer_details: author: woodworking.stackexchange.com/users/4904/Codeman
score: 1

Summary of the answers:
S0: The usual way to do this I think would be to use the correct bit in a router, but it could also be done using a suitable cutter chucked up in a drill.  If using a drill ideally it will be in a drill stand for accuracy and repeatability, or a drill press will be used.  A forstner drill bit sized smaller than the game balls in a drill press would be another option.  There are various ball-end cutters available, but balls or ball-shapes also fit into cylindrical or conical holes (and cylindrical holes with flat or conical bottoms) more easily achieved with a "normal" twist drill bit, a center drill,  or a countersink. A traditional approach for this would be to use something like a spoon bit or a simple bowl gouge.
A router and suitable bit is recommended. Otherwise, a number of bits are suitable, including a forstner bit, , ball-headed grinding bit or cutter, or spoon bit. A drill press is also advisable for accuracy. Another option is a bowl gouge.