sharpening plane irons...how do i know what angle?

[Glenn Lewis]

just got a worksharp 3000 for christmas, and am excited to finally get a decent working edge on my chisels and plane irons. However, how do i know what angle my plane irons are supposed to be short of just eyeing it up and estimating with a protractor or square? Are there standard angles depending on the kind of plane? for example is my number 5 supposed to be a different angle than my number 8? Thanks in advance.

Glenn

[Orlando Gonzalez]

Bevel down (BD) planes are usually bedded at 45* and the blades have a 25* bevel angle. You can also grind/hone a back bevel on a BD plane to increase the angle to tame difficult woods. The only time you would grind/sharpen different angle is on bevel up (BU) blades found on block planes and the LN/LV bevel up smoothers, jacks, jointer planes. For chisels you can grind a primary bevel the hone a secondary one if you desire.

I also have the WS3000 but use it mostly to flatten the backs of blades and chisels. I use an 8" slo-peed grinder and the Grizzly 10" wet grinder to set the angle then I sharpen on japanese waterstones and/or snadpaper with honing jigs. Get a bevel gauge from Woodcraft or Lee Valley to confirm the bevel angles of your blades/chisels then set the WS 3K at the correct angle and sharpen away.
HTH

OG

[Mike Henderson]

You only need about 5* of clearance angle on a bevel down blade, so I'd recommend sharpening at an angle greater than 25*. You can go 35* and you'll have 10* of clearance angle and the edge will be stronger.

A bevel down plane will not cut better with a low angle bevel edge - that is, your plane will cut exactly the same with a 35* bevel angle as with a 25* bevel angle and the edge will be stronger.

It doesn't matter what size the bevel down plane is - the same blade angle will work fine on all of them.

A bevel up plane is entirely different but I won't go into that here.

Mike

[Doug Shepard]

My eyes aren't so good that I can figure out the existing blade angle using a protractor. This gadget has the more common blade angles cut in and is pretty easy to see gaps and find what angle you have.
http://www.highlandwoodworking.com/index.asp?PageAction=VIEWPROD&ProdID=6435

[Mike Cutler]

Glenn

There are lots of differing philosophies and techniques on plane blade sharpening. Everyone has something that works best for them concerning angles, micro-beveles, back bevels etc..

If you're just wanting to start out and use the "norm" so to speak, I would go to Lie-Nielsen's homepage,( www.lie-nielsen.com ),and read the description on each plane. The angle the blade is sharpened at is in each plane's write up. From there you'll adapt and modify the angles to suit you best.

That Worksharp is a nice machines. I've only read positive reviews of it here on the board. congrats on the new toyl.

[Glenn Lewis]

thanks for the info guys. the lie-nielsen site was informative for sure. i stuck with the basics for now and got my #4's iron as sharp as it's ever been, at least since i've owned it.

[Larry Williams]

You only need about 5* of clearance angle on a bevel down blade, so I'd recommend sharpening at an angle greater than 25*....

Mike

Hi Mike,

Do you have any reference for this? My experience is quite different and the exact minimum varies according to the cutting angle, wood type, angle forming the edge and a couple other things. 5º of clearance isn't even adequate for most single edge metal working because even most metals deflect ahead of the cutting edge. Even a 40º bedded bevel down plane with a relatively acute cutting edge requires 10º or more of clearance.

Inadequate clearance angles make a plane more difficult to use, harder to push and reduces edge life. Users of bevel up planes with obtuse angled irons should be familiar with all this.

The big drawback of inadequate clearance angles, though, is surface quality. When there isn't enough clearance angle the surface of the wood will be burnished to a shine. A well planed surface should be dull, uniform and smooth. The dull non-reflecting surface is a result of all the pores of the wood being left open and clean. A burnished shiny surface impedes uniform penetration of adhesives, stains and/or finishes. If you want strong glue joints and a uniform finish, one who pays attention will learn to make sure a planed surface has that dull open pore quality. A shining surface after planing is something I definitely want to avoid.

[Mike Henderson]

Hi Mike,

Do you have any reference for this? My experience is quite different and the exact minimum varies according to the cutting angle, wood type, angle forming the edge and a couple other things. 5º of clearance isn't even adequate for most single edge metal working because even most metals deflect ahead of the cutting edge. Even a 40º bedded bevel down plane with a relatively acute cutting edge requires 10º or more of clearance.

Inadequate clearance angles make a plane more difficult to use, harder to push and reduces edge life. Users of bevel up planes with obtuse angled irons should be familiar with all this.

The big drawback of inadequate clearance angles, though, is surface quality. When there isn't enough clearance angle the surface of the wood will be burnished to a shine. A well planed surface should be dull, uniform and smooth. The dull non-reflecting surface is a result of all the pores of the wood being left open and clean. A burnished shiny surface impedes uniform penetration of adhesives, stains and/or finishes. If you want strong glue joints and a uniform finish, one who pays attention will learn to make sure a planed surface has that dull open pore quality. A shining surface after planing is something I definitely want to avoid.
Only personal experience. I think it's the minimum clearance you'd want. If 5* doesn't work for you, you should use more.

Mike