What kind of bit do I need?

Use a forstner bit with a brad point. If you have a drill press use that to drill it. Good luck.

-- I wish wood grew on trees so that this was a cheaper hobby.

A Forstner bit will work fine especially in a drill press.

-- Bondo Gaposis

As the others have said, a forstner bit would work fine. If the magnets you’re using are nickel coated (shiny silver) be sure to scuff up the back and sides before epoxying them in the holes. This helps the adhesive have some tooth to grab on to. I had good luck with any hardware store 5 min epoxy.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

I have loctite quick set multi purpose epoxy and the magnets just say they’re neodymium disc magnets that measure ”.47 in. D. x .11in. (12mm x 3mm)”. I don’t own a drill press so I will be just hand drilling them. Any tips or anything I need to know before using a forstner bit as I have never used one before? Also do I just use sandpaper on magnets to scuff them? I have between 60g and 600g but Im assuming the more coarse the better. Thanks guys.

-- "For long you live and high you fly, but only if you ride the tide."

60 to 100 grit should do fine. If you don’t have a drill press I would recommend a brad point drill bit. Less chance of it walking on start up. If you do decide to use a forstner freehand with a drill be sure to put good pressure down when starting to prevent it from wondering. Practice on some scrap. This will also let you get your depth dialed in. I put a cheap stop collar on to control my depth.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

Thanks Gary. I am going to use a brad point bit with a stop collar. Do you have a preference between setscrew and split ring stop collars? The only stop collar I have used is the set screw type on my pocket hole jig bit.

-- "For long you live and high you fly, but only if you ride the tide."

That was a quick pic I found online. I have the set screw type also. You need to make sure the screw hits on the top of the flutes of the bit or it will twist.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

I do this all the time in my Secret Stash Jewelry boxes. I do however have the advantage of a drill press. I use brad point bits and use the depth stop on my press. Sometimes I rough them up but have not heard of any of them, roughed or not coming out of the epoxy.

-- Made in America, with American made tools....Shopsmith

For 3/8ths, I would just use a brad point bit,

-- The mark of a good carpenter is not how few mistakes he makes, but rather how well he fixes them.

I like the split ring depth stops better than the set screw type.

Is there any reason why you prefer the split ring stops?

-- "For long you live and high you fly, but only if you ride the tide."

Yes, as Gary L mentioned above, with the set screw you have to be sure it lands on a flute, not into a groove. The split type don’t have that problem, and I imagine they are easier on the bit (not damaging the sharp edged flutes).

Additionally, I don’t like forstners in small diameters, as they don’t clear the chips well and clog up. However, your holes will be so shallow that shouldn’t be a concern. If you do use a brad point twist drill, get a good one with sharp spurs. Cheapies often cut a rough hole, which you don’t want.

Valid point I would say. I’ll check out both at tbe store in the morning and will probably go with the cheaper of the two.

-- "For long you live and high you fly, but only if you ride the tide."

Well I got a set of brad point bits and set screw stop collars. But only to discover my drill won’t accept a bit with a 1/2” shank, the biggest it takes is 3/8” . Is there some type of extension I can buy for my drill to take a bigger bit or should I just look for smaller magnets?

-- "For long you live and high you fly, but only if you ride the tide."

If your magnets are 3/8” then a 3/8” bit should work and it should have a 3/8” shank that should fit your 3/8” chuck.
That a lot of “should of”s but I think you get the point. Are you sure the bits are 1/2” shank? I’ve never seen that on brad point bits.
For a box, 3/8”x1/4” mags may be a bit big. It will take a good tug to pop it open. 1/4” would work fine.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.