Rabbet plane mouth

[Steve Voigt]

What is the ideal mouth opening for a wooden rabbet plane?
I'm building one that is pitched at 55*. I started with the mouth undersized and gradually opened it, however I was unable to to get the plane to feed until I had opened the mouth to around .025, which is much wider than I had hoped for. The plane seems to be working fine, though I haven't tried it on anything really hard.
At one point, I had the mouth open around .010-.015. I determined that the shaving was entering the bottom of the mouth ok, but then it was "accordeoning", developing super-dense crinkles that caused it to become bunched up and clog the throat. I'm not sure what caused this, or how to prevent it. I associate accordeoning with chip breakers, so I'm not sure how it happens with a single iron.
Anyway, thoughts, ideas, appreciated.

Steve

[Kees Heiden]

Personally I associate accordeoning with high angle planes, like in this video from Ron Brese. But I don't always get accordeon shavings in a high angle situation, so I am not sure yet. A chipbreakers tends to create straight shavings when it is set close enough to the edge to actually do something.


http://www.youtube.com/watch?v=UeVTI6qXLLE

BTW, very nice plane from Ron Brese.

Another BTW, wooden rebate planes are often used as roughing tools, so a wide mouth to pass a thick shaving isn't a bad idea.

[Jessica Pierce-LaRose]

How far was the shaving making it before "accordianing" ? Was it happening immediately off the blade, or were things getting caught up in the escapement more, or jammed on the wedge? What did your escapement look like?

I don't have as much wooden plane experience as some folks, but from what I've played with with wooden rabbet planes, the culprit for shavings bunching up in the works is less the mouth opening, and more things like how well the tip of the wedge meets the blade, and whether it's got an angle on it, and how well shaped the escapement is. A real blocky escapement, with a straight rabbet, or even a skew, really can lead to shavings just spinning around and getting all trapped in there. A nice conical escapement and a bit of an angle on the end of the wedge can help throw the shavings more out the side.

[Jim Koepke]

My Stanley #93 often makes accordion shavings. It is caused by the shaving having no escape and just bunching up.

You may have to make as thin a cut as possible while watching from the side of the plane as you make the shaving to see where it is catching.

Like Joshua said, it could be catching on the wedge or something else.

Good luck and let us know what you find.

jtk

[Steve Voigt]

Thanks guys.
Kees--good point about the high angle. I have little experience with planes above 50*. This one is noticeably hard to push when taking a full shaving--I may have been better off with something closer to 50*
Josh--it definitely wasn't the wedge or escapement--the shavings were jamming long before they got near the wedge tip. I'm starting to think that maybe the wear angle was just too similar to the bed angle, and that I should have opened up the angle without enlarging the mouth so much. Oh well, next time.
Follow-up question about the escapement, though. The chips are clearing nicely now, but they're not spiraling out the correct side quite the way I'd like. Anybody have any thoughts on that? Pic of the escapement is below. Kind of blurry, sorry.
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[Judson Green]

On my shop made shoulder (http://www.sawmillcreek.org/showthread.php?208755-Shop-made-shoulder-plane) plane (also use for rabbeting) I had the same problem. Ended up just opening the mouth. Still leaves a fine surface.

[Derek Cohen]

Hi Steve

Try shaping the foot of the wedge with an angle. The aim is to turn the shavings - like a chip breaker - in the direction of the escapement/opening. The escapement does not look large enough. Here is the same area of another high bed type, a HNT Gordon shoulderplane ..

http://www.hntgordon.com.au/1shcloseupthroat.jpg

It is not the bed angle. It is how the bed angle is managed.

Regards from Perth

Derek

[Warren Mickley]

Steve, I am thinking you could open the mouth and the angle of the wear. The wedge tip has a pretty complicated shape to it, curves in three dimensions, to encourage the shavings to exit the side. This curve gradually changes the direction of the saving and makes a smooth curve with the bevelled portion of the stock. Here is Roubo, Plate 13
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[Steve Voigt]

Hi Steve

Try shaping the foot of the wedge with an angle. The aim is to turn the shavings - like a chip breaker - in the direction of the escapement/opening. The escapement does not look large enough.


Hi Derek,
Thanks, I think the escapement is large enough, but perhaps reshaping the wedge is the answer. Warren posted something similar.
Best,
Steve

[Steve Voigt]

Steve, I am thinking you could open the mouth and the angle of the wear. The wedge tip has a pretty complicated shape to it, curves in three dimensions, to encourage the shavings to exit the side. This curve gradually changes the direction of the saving and makes a smooth curve with the bevelled portion of the stock. Here is Roubo, Plate 13


Hi Warren,
Thanks for posting the Roubo pic. It looks a lot like the wedge on an old fillester I have. I've been resisting shaping the wedge that way, because from trawling through Google images, it appears that Old Street and MS Bickford both have a simple, flat taper on their rabbet wedges. I figure if they can get the shaving to spiral, there must be a way. But maybe I'll give that a try; I can always make another wedge.
Best,
Steve