Sharpening a Forstner bit?

[willisl]

I have a large (3.5") Forstner bit that has lost its edge. Is there a DIY way to sharpen it, or is this something that must be done by a professional? It looks like I might be able to hone the teeth and the knife edges, but I'd like to hear what you folks have to say about it before I do.

Thanks.

Lynn Willis

[Pat]

I use a file on mine all the time.

[Lew Hodgett]

Even an el-cheapo 3.5" Forstner bit is in the $40-$50 range.

Quality bits are more.

Willing to make that bet, you screw it up, you replace it, or would you rather have a pro do it?

Lew

[jo4hn]

Here's an instruction page that I printed out years ago:

Hdwe has one at or better yet mahalo, jo4hn

[news]

I've not (yet) needed to sharpen a Forstner bit, but Rockler has a kit of sharpening tools and instructions for $18:

[Tom Veatch]

open a white paper on the subject by Highland Woodworking.

If it doesn't, go to

to the bottom of the listing on the left under "More Info" and click on the link "Woodworking Tips Map". In the right column near the bottom of the page under "Woodworking Library", click on the link "Sharpening Forstner Bits"

Tom Veatch Wichita, KS USA

[Jeff Gorman]

wrote

I recall that some sixty-five years ago, ie before diamond tools and suchlike, my revered woodwork teacher told me (with some satisfaction) how he had managed to sharpen the peripheral edge with a triangular engineer's scraper.

I've never tried it, but I imagine it would get into the corners more easily than the rotary and other tools.

Jeff

[Upscale]

Guessing yours doesn't have a carbide inserts.

[David Nebenzahl]

On 8/5/2009 8:48 PM jo4hn spake thus:

That seems to be the Google search page you used to find it. The Highland page is actually at

[jo4hn]

oopsie. Thanks.

[Tanus]

I've never sharpened a Forstner.

However, I've sharpened a lot of other tools in the shop. Most of them successfully. One of the things that has helped me with my approach towards sharpening is Leonard Lee's book "The Complete Guide to Sharpening". It's a bit of a heavy read, but virtually anything that can be sharpened is covered in that book. I recommend it to anyone who ever thinks they'll have to sharpen any woodworking tools especially, but most tools in general.

[Martin H. Eastburn]

That is a fast and heavy way - I like a cone stone myself. Use a curve to sharpen a curve.

What I see with the Dremel method - while fast and 'easy' - it can cut notches and make a wavy line if one isn't perfect in the use.

A stone can be used wrong, but does less in a second to clean up later.

Mart>

[Phisherman]

Sure it is possible and sharpening is a good skill for woodworkers. Natural lighting, magnification, and patience helps.