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I am laying out a frame where I will have to cut approximately 200 aligned 35mm circles in a matte board or foam core board. I will be putting plastic coins into the holes and backing with another board (exposed foam board or something with a little give to mould to the piece) to secure the coins from sliding or rotating.

I purchased a Fiskars Circle Cutter but have discovered through testing that while the device can make the circles, it lacks the depth to cut through the whole board. I checked to see if they sell a replacement blade with more exposed length but they do not appear to.

This then resulted in me fiddling about with an Exacto knife trying to make a clean completion cut.

If I had to do a few holes I would accept this method, but I am somewhat nervous at the thought of repeating the process 200 times without scoring or marring the matte.

Is anyone aware of a simpler technique?
I believe a punch is probably the correct tool, however I am reluctant to invest too much for a one-off project. I also considered using a bore saw and my hand drill but am concerned that it would just make a horrid mess of things.

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    This is the sort of repetitive task that might be suitable for a laser cutter. Is there anyone in your area that offers that service? It requires no special tooling - you can make any sized hole. Note that the software would allow you to choose a honeycomb layout rather than the more wasteful rectangular grid. – chasly - supports Monica Jul 5 at 17:52
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Several years ago I had my own "mount these coins" project. My solution was to use a forstner drill bit mounted in a drill press. In my case I was mounting dimes in matte board and they squeezed into the holes very nicely. It sounds like you are mounting US fifty cent pieces which are slightly larger than the 30mm that you mentioned, but should be able to nicely squeeze-mounted in 30 mm holes.

If you Google "50 mm forstner bit" you will find several choices ranging in price from $9 to $25. If you are going to drill only 200 holes in matte board, a less expensive bit will certainly be adequate.

You will need to carefully mark the locations of the centers of the holes and I would push an awl through the matte board to help make certain that the tip of bit goes to the exact center of the hole. As with any first time project, it would be wise to make several practice holes so that you certain that you can get each hole started exactly where you want it to be.

You will want to set the speed on the drill press to approximately the middle speed on the drill press.

Of course if you do not have access to drill press (any woodworking pals?) all bets are off. I would not try this method with a hand held power drill because the quality and consistency of the holes is quite likely to suffer.

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A hole saw should work fine if you can find a fine tooth model. They are not as easy to find as the common coarse teeth models meant for wood. One with a thin kerf would be best.

I have also used the sharpened steel tubing trick mentioned by @fred_dot_u. An alternative to punching is pressing the sharpened tube against the board and spinning it. The spinning action makes it work like a circular knife, cutting the fibers cleanly. If you can't find a 35 mm steel tube, you can get almost as good a result by wrapping thin aluminum from a soda can around a 35 mm thick piece of plastic or wood.

To align the holes perfectly, it will help to make a template. Cut three holes in a smaller piece of board, align two of them to existing holes on your workpiece and then put your cutting / drilling tool in the third hole to keep it in correct position.

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  • The alignment tip is very apt, keeping things aligned on a project like this is of course one of the biggest challenges. I'm glad to hear you've had some success with the fine toothed hole saw, it's a rather simple solution. The idea of a diy circular saw is rather interesting as well. – Stephen Jul 5 at 13:59
  • I like the idea of a sharp fine tooth count hole saw, it's even better than my suggestion. Additionally, one could drill the pilot hole and tap the hole saw into thin material, remove it, then rotate it a bit and tap it again. – fred_dot_u Jul 5 at 14:15
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You may be able to create your own punch by finding a piece of steel tubing of the correct inside diameter for your holes. Using a file or grinding wheel, work away at the outside edge of the tubing to create a sharp edge. Further refine the edge with sandpaper of gradually increasing grits.

You can stop periodically and test your work by placing a piece of the board atop the pipe, sandwich it between the pipe and a piece of solid lumber. Hardwood end grain is best, also more difficult to source, but for a 35 mm hole, not as bad as a 200 mm hole.

Rap the wood with a mallet until the hole is created. This process will eventually dull the edge, but you can touch it up with a file (or grinding wheel) as needed to keep a clean cut.

You can also place the lumber under the foam board and wallop the pipe.

Laser cutting is an option if there is a suitably equipped maker space, but that will leave burned edges unless the power is quite high. My 60w laser will create discolored edges and also under-cut (melt) the foam in foam core.

Hobby cutters may work but require more than one pass. CNC routers will definitely work (maker space possibly) and if one equips a CNC router with a drag knife, you're good to go.

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  • The pipe solution and creating my own punch is interesting. The other methods you suggest would require more investment than just paying someone to do it for me :) – Stephen Jul 4 at 16:32
  • There might be factory made punches available, not sure if they go up to 35 mm but I do remember them for at least 25mm. – Willeke Jul 5 at 11:40
  • There are punches of that size, but as the OP noted, they are rather expensive and he'd like to avoid the cost. – fred_dot_u Jul 5 at 14:13
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Have you tried using the circle cutter from the front and back? On mine the centre pin is long enough to mark the back of the foam board I've used, but you may need to push a stiff pin through in your case.

You do need to be very careful to hold it exactly vertical if you're doing this, or the holes won't align, but that's always true in thick material.

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  • For this particular model there is no center pin so alignment is difficult but not impossible. – Stephen Jul 4 at 16:31
  • Mine is a cheaper design, and of course damages the removed part, but it's quite useful – Chris H Jul 4 at 17:42
  • I may see if I can drill a hole in the center and cement a pin in if I can get teh cutting technique clean enough, thanks! – Stephen Jul 4 at 21:43
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You're gonna need a bigger boat! .. I mean knife ..

The simplest would be to have a blade manufactured (or 3d printed if that gets sharp enough edges?) that meets your criteria, e.g length. if you order a bigger batch, they might get cheaper.

Also you could try finding a blade from another manufacturer and then build an adapter to fit it to yours. If you post some photos, people could come up with solutions.

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  • Hi Marlice, thanks for the idea. I mentioned the specific item in my question but even their website is rather lacking for specifications.3d printing a holder for a stock exacto blade might be an option though. Thanks for the idea. – Stephen Jul 5 at 5:07
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A "circle clicker die" in a "clicker press" will do the job cleanly and efficiently at just a few seconds per hole. Circle clicker dies are available online in many sizes, and a clicker press can be found in any shop that makes leather goods. The shop might even have the exact size clicker die that you need. If you lay out the matte board with appropriate pencil marks where the holes need to be, it should all go smoothly.

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  • The problem with clickers is that they are unable to cut into a fairly deep matte. Given the size of the project it is pretty likely the mat will be a few feet by a few feet. – Stephen Jul 5 at 23:57
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    @Stephen The typical clicker press that I'm familiar with (industrial, not hobby) has a bed measuring 20 x 40 inches, which would handle a matte board measuring about 40 inches high by any width, provided you flip the matte board. I see there are many much smaller clicker presses out there now, which, as you say, would not handle a deep matte board. – MTA Jul 6 at 0:32

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