What size cove router bit for recessed knobs?

[Perry Colomb]

I like the look of recessed knobs and I was wondering what sized bit to get. My understanding is I need a 1 1/4" recess but is that a bit with a 1/2" radius that is taking a 1/4" shaft into account or am I looking for a different size altogether? Thanks in advance!

[David King]

Perry,
I'm not sure what you mean by a cove bit, they generally have a bearing hanging off the end which would get in your way. How big are your knobs? You could cut the recesses with a Forstner bit that's a 1/16th" larger than the knob (before you drill the hole for the pot)! If you wanted to radius the top edge of the recess you would need to find some tiny piloted round-over bit or have a custom cutter made up for your drill press. I guess you could take the pilot bearing off a small round-over bit and use it in a pin router to get the correct diameter. It all seems like a lot of fuss.

[Perry Colomb]

I guess the recess is really a matter of esthetics. I like the looks and don't have a guitar with them so I thought I would give it a whirl. If you look at the pics on this site, you can see what I mean. The bits are pretty expensive for just a "look". I know that.

http://www.exit45.com/ttnp/RecessedKnobs

[Louie Atienza]

You probally mean a core box bit. I don't know if they make a piloted one, but you can get a 5/8" with a 1/4" shank and add abearing of proper ID and OD and shaft collar...

[Dave Stewart]

Core box bits are unguided. The cove bits that LeeValley offers come standard with 3/8" bearings, it looks like. So if your predrilled hole for the pot is 5/16", that's a problem & you'll need a replacement 1/4" brg as well. I'd guess that, because your not going full depth, he's using a 1 3/8 cove bit, with the result being about 1 1/4", but draw it out.

[David King]

Ah-ha, I see what you mean now. Yes that's a 1-1/4" cove bit with the bearing removed. You drill the pilot hole to match the bearing journal (stub axle). Now that you mention it I like the dished look too. I wouldn't trust any old drill press to do this cleanly, make sure the quill isn't loose. You'll want a fresh whiteside bit and only use it for this one operation. Here's the 1/4" shaft version: http://www.holbren.com/whiteside-cove-b ... shank.html
For a larger knobs like speed knobs you might need the next size up: http://www.holbren.com/whiteside-cove-b ... shank.html

[Louie Atienza]

Amana makes a few bits that might work... 45950, 1/2" D with 1/4" shank and pilot (used for fluting with guide or straightedge), 45983, 45988, 45990, 45992 bowl and tray bit in 1/2", 3/4" and 1-14" diameters, and 57232, 1-1/8" cove/backsplash bit (normally used for rounding corners of backsplashes). Either case, use a template, DO NOT use these on a drill press!

The pilot is on top, so you only need to make a template with a hole the same size you want your recess.

I get most my Amana router bits from ToolsToday.com, being only 2 hours away I get next day UPS shipping. I mainly use Amana and Onsrud router bits for wood...

[Perry Colomb]

Great info. Thanks to each one of you for responding!

[John Sonksen]

Core box bits are unguided. The cove bits that LeeValley offers come standard with 3/8" bearings, it looks like. So if your predrilled hole for the pot is 5/16", that's a problem & you'll need a replacement 1/4" brg as well. I'd guess that, because your not going full depth, he's using a 1 3/8 cove bit, with the result being about 1 1/4", but draw it out.

I used a 5/8" cove bit and simply took the bearing off running the cylindrical portion of the bit that the bearing was attached to around the inside of my 5/16" hole. It won't burn if you're quick and once you install your pots any discoloration won't matter anyways

[Christopher Boswell]

I like the look of recessed knobs and I was wondering what sized bit to get. My understanding is I need a 1 1/4" recess but is that a bit with a 1/2" radius that is taking a 1/4" shaft into account or am I looking for a different size altogether? Thanks in advance!

Perry, I assume you're talking about a recess much like on a PRS. I do this by taking a 3/4" wood spade drill bit and rounding the profile from a flat to a convex shape on the grinder, and finish with a file. Works perfectly, and costs about $4 rather that the $45+ for a router bit. I went through the same search as you did, and someone posted this solution on here within the last two years.

[mike wingate]

I use a router cove bit. It runs inside a guide bush that bears against a template. The template is round, cut with a forstner bit. You can make the template to suit your bits and guide bush. I stick the template to the guitar body with a couple of small dabs of hot glue.

[Chris Canfield]

Funny, I didn't even think of using a router bit, mainly because I would have had to buy one. I decided to customize some spade bits that I hardly ever use for my last build. A few seconds on the grinder and they were done. They didn't leave the smoothest bottoms, but with a few seconds of sandpaper they were perfect. I made two sizes so I could recess the jack on the side of the guitar too.