Acurate drilling for marble games

[OrioleMark]

Hello everyone, I'm new here.  I mainly do woodworking projects to sell at craft fairs locally and am no expert by far at the craft of woodworking.  I am in northern Illinois.  This year I've decided to make a few games from wood.  The old Aggravation game is where my problem comes in.  I've got to make about 132 divots for marbles to rest in and my problem is how do I keep them straight.  I made a template out of plywood from an old Aggravation game board.  I am doing this all by hand, no CNC machine, just a plunge router.  How do I keep from expanding the holes in my template which will ultimately lead to the holes not lining up properly.  A friend mentioned that maybe there is some sort of collar I can get to put around the router bit but I've never heard of nor seen such an animal.  Any advice?

[clockman]

rockler has a marble drilling router bit

http://www.rockler.com/search/go?w=marbl...d=&sli_sid=

[CARYinWA]

You are looking for .

https://www.amazon.com/PORTER-CABLE-4200...r+bushings

[wjt]

I think your friend was referring to a guide bushing which fits in the base plate of your router.

At least this what I have used.

Bill

[fixtureman]

The bushings are what I use for cam locks and drilling with a router

[srv52761]

I did something similar.  I needed 410 1/4" holes (21x20 minus the offset in alternate rows) such that the holes were linear vertically and every other row was offset by 1/2 space; the same pattern you will have.
The difference was my project was in plexiglass, and the holes were through holes. I used my drill press. If you have a drill press you could chuck the core box bit and set the depth stop.

 I clamped an extended work surface on my drill press table, set up two perpendicular fences, cut spacers from 1/2" MDF, stacked them against the fences and removed a spacer after each hole, then each row.  I had 3/4" spacers for the even numbered rows.  I had heard that MDF was extremely uniform in thickness, but I numbered the spacers anyway so I was able to stack them in the same order each time.

[Steve N]

"my problem comes in.  I've got to make about 132 divots for marbles to rest in and my problem is how do I keep them straight."

Regardless of tool to make your divots, I use DP, but could use a router is to first make an exact copy on a piece of 1/8" hardboard or similar with through punched holes the diameter you want yours to be. Then you clamp, or double stick your wood blank on keeping grain orientation in mind. After that you are officially centered and the holes can proceed. That way if they sell, you have the path to make a bunch more, and with either a drill bit or router bit getting 1/8" more depth, when you are only making a 1/4" to 3/8" depression is not problematic.


"How do I keep from expanding the holes in my template which will ultimately lead to the holes not lining up properly."  





Harbor Freight 16 bux less on sale These will be for a porter cable base. Bosch and possibly others use different hole, and thread patterns on their base. Name the brand and model of router you have and someone can tell you what you need.


That Rockler router bit would be pretty cool I would still use the guide though. I can see this thing slipping across the surface of the wood, because it lacks a sharp point to act as a locator. Round rolls, sharp sticks, yada yada yada....

[JGrout]

I agree with Steve, a template and a bushing make the ability to repeat accurately is the answer  

size the bushing to allow for the bit suggested and determine the template hole diameters 

That is the cheap simple way, the more expensive way is CNC  and it is way more expensive 

Joe

[Alan S]

For a plunge router, the template and collar approach sounds good.  If you were to use a drillpress, a different kind of template might be better. 

For that, a carrier board with blocks to position the workpiece with clamps to lock it on top, would be the template.  It could have holes drilled through in the positions you want dimples, and there would be a dowel directly under the bit that fit into the holes.  Positioning the work to drill would entail sliding the carrier until it dropped onto the pin, then drilling the dimple using the depth stop.  Chamfering the holes or rounding the dowel ends would make it easy to find the holes, and dropping it on would make the position precise.

The nice thing about a template of any sort is that if you screw it up, you just make another.  It's only after you've checked it's good that you risk any real parts.