Hello,
I want to make a perfect round hole of 16mm in a pinpong ball.. but i think just drilling it wouldn't go real nice. does anyone of you now what's a good way to do it? perhaps using a dremel?
the idea is to desolder the 2 sensors of a parralax ping sensor and put them into 2 pingpong balls making real nice looking eyes.
hmm.. let's call it "Parallax PingPong)))"
ok, maybe the wires
ok, maybe the wires shouldn’t be too long then… i could use shielded wire like headphone wire, with the shield connected to ground. about the desoldering, i can lower my soldering iron temperature, so that shouldn’t be a real problem.
Drilling probably won’t do it
Drilling probably won’t do it, like you mentioned. When drilling a ping pong ball the hole won’t be perfectly round, at least not with my skills. Here’s an example done with 2mm pilot hole and then 9mm drill bit:
When I did my AVR Night Light I used 4,5mm drill bit for 5mm leds. After drilling the hole I filed it bigger until the led fit in (I think Geir suggested that). May be that kind of approach could be used here too.
Ping pong balls also seem to melt quite easily and they catch fire easily too (I liked the video link, Amando). I have noticed that they get really soft when you use hot glue on them.
When I did the “caster” in my LadyBugBot clone I first taped a ping pong ball to a drill like this:
Then I just turned on the drill with enough speed and touched the ping pong ball gently with fine tipped magic marker. This way I got nice round stripes around the ball and could use them to help cutting. The ball looked like this:
Then I just cut along a stripe with Dremel.
maybe sand paper?
Could you sand down a pinpong ball? Lay the sand paper on a flat surface. Keep sanding until the hole is the exact size?
Maybe you could by yourself
Maybe you could by yourself a special drill bit for cutting sheet metal. They are great for making perfectly round holes in thin plates of aluminum, Plexiglas etc.
The Unibit is correct.
The Unibit is the correct way to go on this one. However, you really have 2 problems --actually one problem making the second worse. The real issue is holding the ball steady whilst drilling.
Grab you self a chunk of wood and drill a hole in it slightly smaller than the diameter of the ball. Now you have a cradle in which to set the ball for drilling. The ideal situation would be to do this on a drill press. The ball could be temp. secured to the board with a few drops of hot glue then the board could be clamped to the drill press table. The chunky hole on your first attempt is an issue of A) the drill bit not being exactly the best one to use and B) the ball scooted around when you drilled it.
Keep the ball from moving, use the step-bit (Unibit) and go slow --you will be all set.
** A rainy day here, so I**
A rainy day here, so I just give it a try:
It went pretty well with the dremel tool. First I drilled a small hole as the beginning, then carefully with the dremel at its slowest speed.
That looks pretty good
That looks pretty good. Much better than holes I made to a metallic can for SRF05 today (but I didn’t have any intention to make them perfect ;-).
Nice idea there!
Nice idea there!
Maybe securing the ball to a
Maybe securing the ball to a piece of wood and sanding away at it on a belt or disc sander? I have done something similar for woodworking projects. Also, a band saw works pretty well. 
