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I'm drilling holes in 4"x4"s in order to put magnets in them. The magnets are 1/8" deep and I'd like to install them to be flush with the surface of the wood. All I have is a Ryobi cordless drill and my bit set.

How can I drill only to a certain depth into the wood? Using a drill press would be great, but I don't have the money or the space to house one at this time.

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    So you want to drill holes that are 1/8" deep such that the magnets seat flush. That shallow depth implies some precision, which will depend on the condition of the bottom of the hole. Even brad-point bits leave a scruffed (in exact bottom), especially in softwoods like your 4x4s. ----- What is the diameter? How many? How far apart? Not knowing the answers, I'm inclined to think a router will be your best tool one way or another, perhaps by routing a few 1/8" deep grooves, each holding several of the magnets.
    – mike
    Sep 13, 2013 at 22:11
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    Do you have a Forstner bit that you are using for this? If not, I would highly recommend you acquire one; using one will ensure the bottom of the hole is flat, which you can't do with a standard twist drill bit. Sep 14, 2013 at 0:28
  • Why does it matter if its too deep, being careful could you not glue them in? Keeping then flush. You can cut a drill bit so it only comes out the chuck to the desired length
    – Ben
    Sep 15, 2013 at 10:48
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    Rather than getting the depth perfect, I'd drill the holes a little deep, and then fill with a caulk, putty, or glue that you can squeeze out of the hole as you press in the magnet. Press in the magnet until it's perfectly flush and wipe off the excess when done.
    – BMitch
    Sep 15, 2013 at 12:32

2 Answers 2

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Homemade Stops

Wrap a bit of tape around the bit, to mark the desired depth. Then carefully drill your holes, stopping when you've reached the tape.

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I've also seen this done with a bit of wire.

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WARNING: Wrapping the wire in the wrong direction, can lead to property damage, injury, and death.

Store Bought Stops

Or you could purchase a drill stop.

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Which are also available in plastic

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Portable Drilling Guide

There are also portable drilling guides available.

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I tried one of these and it was total crap, so I wouldn't recommend it. Your mileage may vary though, so give it a try if you like.

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    Agree with the "total crap" statement about the drilling guide. So much play in the bearing that it was impossible to precisely hit the desired entry point. Freehand was an improvement.
    – mac
    Sep 13, 2013 at 17:42
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    for more than a few holes, those are prone to fail, and fail in the wrong way (too deep of a hole). what is needed is a short length of wood, say 1x1, that butts up against the jaws of the chuck and leaves the right amount of drill bit exposed.
    – mike
    Sep 13, 2013 at 22:17
  • I've had an old Craftsman 'port-a-line" portable drill guide that has been as accurate as a press and even better for finding the center of a board edge. But that's just been my experience. Obviously your experience will vary based on the quality of the tool. Apr 28, 2021 at 21:59
  • Cable Gland works too: youtu.be/HJifKVabLgI?t=88
    – JinSnow
    May 4, 2022 at 12:18
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Some drills include a depth stop in a secondary handle.

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Some people drill a hole through a cork from a wine bottle (or similar dowel) and trim it so that it leaves the desired length of drill protruding.

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    +1 for the wine bottle cork idea. But ... if you have to finish the bottle of wine before you can take the cork I'd recommend putting off the hole drilling till the next day.
    – Michael Karas
    Sep 13, 2013 at 23:42
  • +1, I completely forgot about drill motor attached stops.
    – Tester101
    Sep 14, 2013 at 12:02

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