MArMEr
A haphazard, and possibly inacurate, log of the process, lessons learned, and fun had.
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AIR HOCKEY: various Dates (sorry, no detailed records on this one)
Building a (near commercial quality?) Air Hockey Table:
- The back story
I have no real recollection of dates, and no interest to try to figure it out, but the quest to build this has most certainly happened over a vast expanse of time. After seemingly languishing for way too long, I am quickly moving closer to the final goal. I must admit to having a rather vague design to begin with, but the least I could do would be to drill holes of a larger size into, say, plywood, which would also (not an engineer, so maybe not) provide some structural support to the play surface, which requires very small holes. So, with a drill, a 1/4" bit, and a decent setup, I went to town drilling more than four thousnad holes. I think it took on the order of 2 hours. If you want to do the same, please wear ear protection, as two hours of drilling is not what our species was meant to endure. Oh, and dont use a cheap cordless - this many holes requires real power.
- The blower motor
The quest begin in earnest with a random bit of luck. After a long time of thinking about building this thing, and knowing costs would be high with success not guaranteed, I lucked upon a used blower moter. The blower motore is the thing that pushes all that air throught the table to make the puck near frictionless. In professional level machines, these things are somewhat expensive (> $300). Back on the main page (click here) you will see the type of blower motor I bought. Instead of well past $300, its was $20. This kind of price break was just the incentive needed to begin.
- Surface material
The play surface has to be smooth and preferably something which will tolerate all that drilling. I considered whiteboards, countertop laminate, and various other materials. An otherwise unrelated post over at BYOAC mentioned Aluminum Composite Panel (ACP) as a smooth hard durable surface. I drill-tested samples of countertop laminate and ACP. For some inexplicable reason I decided the surface would be ACP. From that decision I found a supplier, and brought home a piece, 8' x 4'. Now this thing needs drilling. Commercial tables have 1/32" holes. Not a common drill bit. Eventually I found a decent supply at a local hardware store. A smallish sample I was given of the ACP was used for testing the drilling and air flow (read, affix to mouth and exhale). My old standard drill left a mess of aluminum and crap - probably acrylic debris - which made a mess of the holes. I dont want to sand what is already a smooth industrial surface. Enter the dremel. Reseach pointed at higher rotational rates as being cleaner holes, and from practice, a clean and STRAIGHT dip of the drill is best. Enter the dremel plunge router accessory. Well, now that the easy part is over, we still have >4K holes to drill. This time however, it's not driving 1/4" holes with little regard for the result, it's 1/32" holes that must all be 1" center on center from each other, perfectly 90° in and out....
The Story In Pictures
Apply pegboard on top as a template. After a few holes drilled in various places, I drove in 1/4" dowelling to ensure the "template" did not move with respect to the the plywood underneath:
Drilling - lots of tear out, but that is irrelevant in this case, as this is just a support piece.
Over 4000 holes drilled, about 2 hours of effort:
Apply random orbital sander to the tear-out, and she's good to go:
Now to drill the playing surface; aluminum composite panel (ACP). I put the ACP between the pegboard and the plywood.
The holes in the play surface are 1/32" (very small). The best way I found to get clean holes in this material was via a high-speed dremmel using a plunge router base to go perfectly straight/vertical in and out:
Since the pegboard holes are 1/4", and we're drilling 1/32" holes, we need a way to find the centre of the pegboard holes. Eyeballing just wont do in this case. One thing I tried was centering 1/4" dowelling in a drill press and punching a 1/32" hole in it. Applying the dowel to the pegboard and drilling would give a fairly perfectly centered hole. However, the drill bits would often pull up the dowelling and then launch it, or break going in.
After a while, I gave up on that and tried taping paper templates on top. I created these in software and printed to ensure perfect 1" on centre holes. This approach worked fairly well, but I still occasionally broke drill bits:
Holding a flashlight under the ACP, I can see that the holes go all the way through:
I have some of the automatic scoring circuit done, as well as part of the base. Two blower motors wait in the wings for testing. Only one will be used in the end, with a furnace filter to ensure "clean" air going in.
