Tuning Forstner Bits

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Forum topic by Berg posted 09-21-2009 02:07 PM 1655 views 0 times favorited 2 replies Add to Favorites Watch
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116 posts in 3186 days

09-21-2009 02:07 PM

Topic tags/keywords: forstner bits fix tune question sharpening

I have a set of Carb-Tech (China) Forstner bits I bought many years ago. They have worked OK (punched holes in wood) for what I have needed except that the grind is such that they clog almost immediately, especially the smaller ones. I’ll stop and clean out the 1/4” bit two or three times getting through 3/4” soft wood or plywood. I remember reading an article, again years ago, that discussed fixing that problem. Is anyone familiar with the fix?
Thanks all.

-- Pete - "To every thing there is a season Turn! Turn! turn!" [Ecclesiastes and Pete Seeger]

2 replies so far

View stefang's profile


15881 posts in 3330 days

#1 posted 09-23-2009 05:52 PM

To sharpen I use my Dremel with a abrasive cutting disk, making sure to not change the size. As for drilling in soft of difficult materials, it is a good idea to extract your bit often to excavate the waste while you are drilling. Also take your time and don’t apply too much pressure and you will get a cleaner cut. You probably already know that, but I don’t know anything useful beyond that.

-- Mike, an American living in Norway.

View Berg's profile


116 posts in 3186 days

#2 posted 10-19-2009 01:20 PM

I found the notes about this. The recommendation was to file or grind back the the drill material to taper to enlarge the exit area on each side of the bit. When looking at the side of the bit I’m referring to what would be the point on top opposite the the cutting edge. Tried it on a 1/4” it without much luck. Maybe it was some degree better but I wasn’t wowed. It still clogs pretty quick. oh well.

-- Pete - "To every thing there is a season Turn! Turn! turn!" [Ecclesiastes and Pete Seeger]

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