Skewed-blade Dado Plane

[Raymond Stanley]

Hi all,
I got a Stanley #39! dado plane! woohoo!
I grabbed it right out of the box and immediately tried to make a dado (yeah, I know, probably should have sharpened it...)
What I noticed about the resultant dado is that one side of it is deeper than the other. Looking at the blade, I realized that the cutting edge was diagonal when looking from the top. Then I thought...so this is what a skewed blade is. Or is it?

Should my dado plane be cutting angled dados? Is my blade sharpened wrong, or seated wrong? What could I be doing wrong? Am I supposed to go in both directions, and just have a dado that is higher in the middle than the edges?
Thanks!
-Ray

[Deirdre Saoirse Moen]

It should be making a flat cut. The skew of the blade is only so that it works better cross-grain.

My first guess would be "blade seated wrong."

[Raymond Stanley]

Thanks, Deirdre.
Perhaps I am misunderstanding what "skewed" means, because now I am having trouble picturing how my understanding of a skewed blade could ever make a flat cut. Maybe my blade is not really "skewed"...this is the first "skewed" blade I've seen with my own eyes (I need to make some local WWing friends). :)

[tod evans]

raymond, here`s a few pics of skewed stanleys the last being a 39-1/2..02 tod

43497

43498

43499

[Deirdre Saoirse Moen]

Skewed blades generally mean a front-to-back skew, that's how. The plane sole is still flat. :)

There are planes that are designed to make an angled cut (e.g. a sliding dovetail plane (http://knight-toolworks.com/graphics/dovetail.jpg)). Link is to one I own, but mine is made from shedua.

[Mike Wenzloff]

Hi Raymond,

It is a skewed plane. Looking directly at the sole, the blade is angled from one side to the other. This is the result of the bed being skewed. The bed for the iron is angled--or skewed. This is as it should be.

The issue as regards the dado being lower on one side or the other is most likely techinique. Using a batten clamped to the right edge of the dado as you are facing it and resting the plane against it can aid in cutting straight down.

Another issue which can affect the dado bottom being square to the face is the iron can be misadjusted so one side--typically the leading point--is actually lower. In that case, even a batten won't help.

When cutting dados by hand, it helps to mark the depth of the dado on the near and far edges of the dado so one can peridically check to see if the cut is remaining square to the face.

Take care, Mike