Skew blade angle?

Re: Skew blade angle?

Warren in Lancaster, PA

>It would be possible to calculate the angle on the iron from the bedding angle and the angle of the mouth opening using trigonometry in 3D. There might be corrections for the taper of the iron or if the sides of the iron are not parallel or if the mortise was not parallel, etc.

I think that a more traditional approach would be to gradually change the angle until it cuts the way you want, using feedback from how the tool cuts rather than a theoretical angle. I enjoyed Todd's post "how does it cut?". If you want you could measure the present angle, aim to change it by a degree or two and then try it out. Once you have it working, you might need to alter the angle occasionally.

Re: Skew blade angle?

Frank D. in Montreal

>Hi Dave,

What I do is let the blade extend beyond the mouth a little, so that the whole length of the edge is sticking out just a little, and set the wedge. Then I grab a scratch awl or a metal scribe and I trace the profile of the sole (right at the mouth) on to the blade. Once you have the profile of the sole marked out on the blade you take the blade out and grind it at 90� right to the line. Then sharpen as you normally do, conserving the blade geometry. No calculation necessary.

Hope that's clear.

Frank

How does it cut?

Dave (Arlington, VA)

>Hi Warren -

Who wouldn't appreciate Todd's down to earth approach to these things? How does it cut? Yep. Still a good question. Originally I thought it was gouging the wood I would plane because the sole was out of square - and it was. But I am getting the sole in shape, and I still get the gouging, only not as bad. That is why I've begun thinking about the blade geometry. Besides when you sight along the sole you can still see that one side of the blade projects higher than the other.

You are also right about the sides. They are not parallel.

I certainly don't have a problem with trial and error. I just thought I would check just in case there was some simple fix of which I was unaware.

Thanks for your post.

Regards -

Dave

I think I got it

Dave (Arlington, VA)

>Hi Frank -

Thanks for the post. I think I got it. I will give it a try. Per Warren's post sounds like there will be some trial and error involved.

Thanks, again.

Regards -

Dave

Me to, but

Jim Reed@Tallahassee

>I paint the flat side of the blade with a sharpie and use a carbide scribe to scratch the profile of the sole. It leaves a nice visible scratch in the sharpie ink.

Re: Skew blade angle? *LINK*

Derek Cohen (in Perth Australia)

>Dave

Have a look at the article I wrote on "Tuning a Stanley #140 Skew Block Plane" (link below). In addition to my own method, Brian Buckner provides a simple and very effective method of getting the bevel angle right.

Regards from Perth

Derek


Tuning a Stanley #140 Skew Block Plane

Re: Skew blade angle?

paul womack

>...and am beginning to think that the angle on the blade might have be ground (or sharpened) a little off...because one side of blade projects further from the sole than the other.

Be VERY sure you've got the body adjusted and tuned, including any sole flattening, (and checking for perpendiculairity to the sides, as discussed) BEFORE you start making the blae conform to the body.

Derek (and Brian's) advice is excellent. But if the error is small, simply lean on the high side every time you hone.

BugBear

Step by step instructions!

Adam Cherubini

>1) mount blade in plane

2) adjust blade to take smallest possible shaving even if a full shaving is the result

3) plane soft arkansas whetstone until cutting stops.

4) repeat steps 2-4 until full width cut is achieved

5) remove blade and sharpen as usual

(no I'm not kidding)

Adam

Re: Skew blade angle?

Dave (Arlington, VA)

>Hi Derek -

Thanks for the link and for taking the time to put together that tutorial. I have looked through the articles, but hadn't noticed it before. I appreciate it.

Regards -

Dave

Re: Skew blade angle?

Dave (Arlington, VA)

>Hi Bugbear -

Thanks. I think the error in the blade is more than slight. I also appreciate the advice about caution. I am proceeding pretty slowly on this because there's alot going on for me right now (i.e. not much shop time), and because I'm more likely to get it right if I go slowly.

One observation that may be of interest about the perpendicularity (a word?) of the sides relative to the sole. I've been using a 12" Starrett combo with the protractor head, and it seems that the sides are "out of square" by only the slightest amount - both sides are between 90-91 degrees - closer to 91. It was less than I expected. It is so small it made me wonder if it was done on purpose.

Anyway, thanks for the post.

Regards -

Dave

Re: Step by step instructions!

Dave (Arlington, VA)

>Wow Adam -

Those are my kind of instructions. So simple even I can follow it! 1,2,3,4,5... I love it. Thanks. I appreciate it! I'll give it a shot.

Regards -

Dave

P.S. In concept I think your and Derek (and Brian Bruckner's) seem like pretty similar approaches.

STUPID!

Adam Cherubini

>I guess I got all confused when he started talking about epoxying frogs and I foolishly, STUPIDLY stopped reading.

Yeah exactly what he said

Adam