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Wooden Planes #3: The Mouse

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Blog entry by Mark Kornell posted 04-13-2014 06:07 AM 2458 reads 3 times favorited 10 comments Add to Favorites Watch
« Part 2: A Jack Part 3 of Wooden Planes series Part 4: Shoulder Plane »

I wanted plane #3 to be another block plane, but I wanted it to be a different kind of block. By this point, I’d done a lot of reading about planes in general and plane-making, and some of it was starting to sink in. Low angle, bevel-up planes sounded like a good thing because of the versatility, so I hit on the idea of making one from wood.

The Internet is a wonderful resource for finding information on just about any conceivable topic. Usually, there is too much information, requiring you to sift through dozens, hundreds or even thousands of pages and decide what is good and what is not. Wooden low angle bevel-up hand planes, however, is one of those few topics for which very little information is available. There is some, yes, but most of what I found related to the problems to be encountered in trying to build one and get it to function well.

And yes, there are problems. First, the mouth opening. On a bevel-down plane, the cutting edge of the iron touches the wood somewhat ahead of the front of the bed. It depends on the thickness of the iron and the bed angle, but at 45 degrees and using decently thick iron like a Hock or the LV, the iron hits about 1/4” ahead of the bed. Add a small opening ahead of the iron, and you have a total mouth of a bit over 1/4”.

Why is this important? The standard practice is to glue up the pieces so that you start with a smaller than desired mouth opening and then open it up using some kind of tool. A float, a file, or perhaps some kind of sanding board. Obviously, the tool has to be narrow enough to fit into the small mouth opening, but still function well enough to accurately remove wood. For a bevel-down plane, it is easy to make a sanding board that is exactly the thickness necessary width using 1/8” MDF and sandpaper.

For a bevel-up plane, the cutting edge of the iron hits immediately in front of the bed, and in order to get a fine mouth opening of, say, 1/32”, you need to have some way of gluing it up so that there is a finer opening, and then find a very thin tool to fit into that very thin opening and still be able to remove wood.

The second problem is that of a relatively thin bed. Typically, a low-angle plane has a bed of 12 degrees. A wedge of wood 3 1/2” long and tapering at 12 degrees is only 3/4” thick at its thickest. That’s not particularly strong.

And there is a lot of pressure on the bed at the point immediately behind the cutting edge of the iron. Precisely where the bed tapers to a thin point. This makes the bed susceptible to cracking or chipping.

The third problem is created by requiring a fairly large opening in the body to accommodate space for the iron, wedge, pin assembly and clearance for shavings to escape. On a bevel-down plane, this opening is typically 60 to 70 degrees of arc. On a bevel-up, the opening would need to be larger, a minimum of 80 degrees, if only to allow a line of sight to the tip of the iron from directly above the plane. A larger opening means weaker cheeks on the plane.

Thinking through all of this, I came up with a design. First, build the plane seriously overlong in the front, and with zero mouth opening. After glue up, use my jointer to take down the sole until the mouth opening appears, and then cut off the unnecessary length in front. Second, build a small flat into the front of the bed, about 1/16”, so that the bed doesn’t actually taper to a point. Third, forgo the pin assembly arrangement, and glue in a piece – I won’t call it “ears” – for the wedge to act against.

The plane is wenge and purpleheart, with paste wax as a finish. It works quite well, and I’ve successfully used it with blade angles of 25 degrees to 50 degrees, for effective cutting angles of 37 to 62 degrees. Simply swap out the iron (or regrind), and it becomes a plane for a different use.

Despite my concern with structural integrity, it is solid. That is partially due to using two strong, hard woods, and (I’m pretty sure) partially due to the inner piece the wedge jams against.

It isn’t perfect, of course. There are two primary issues which prevents it from being my daily user. First, it is too wide to be comfortable for single-hand use for any length of time. I used the LV wooden plane iron, and the narrowest available is 1 7/8” wide. Add to that the cheeks and clearance spacing around the iron, and the plane is about 2 1/2” total width. For someone with large hands, that might be OK, but something closer to 2 1/4” would be more comfortable for me.

The second flaw is that the bed slipped slightly during the glue-up and I didn’t notice. As a result, the iron sits at a slight angle to the cut. There isn’t enough clearance around the iron to skew it to compensate, so the cut ends up being uneven. I suppose I could grind an iron with a slight skew to match bed and solve the problem.

I tend to pull this plane out when making chamfers. The slight skew doesn’t matter, and the plane works well with a two-handed grip using knuckles as fences.

I might make another of these, but build it for a narrower iron. Ron Hock sells a 1 1/2” by 4 1/2” iron which would be just about perfect.

-- Mark Kornell, Kornell Wood Design



10 comments so far

View CFrye's profile

CFrye

8751 posts in 1305 days


#1 posted 04-13-2014 11:18 AM

This is a beauty, Mark. Too bad about the skew. Thanks for sharing your plane making journey.

-- God bless, Candy

View Don W's profile

Don W

17969 posts in 2033 days


#2 posted 04-13-2014 11:47 AM

Another great build Mark. I’ve thought about building a BU block as well. I wonder if you could taper the sides to the top of the plane is narrower to help with comfort.

I like your wood combo to.

-- Master hand plane hoarder. - http://timetestedtools.net

View JayT's profile

JayT

4785 posts in 1676 days


#3 posted 04-13-2014 01:23 PM

Mark, thanks for sharing your plane building journey. I have marveled at some of the beautiful planes you have posted and now to find out you have only been making them for three years! It’s great to hear of your successes and struggles so that others like me may be able to use your experience to improve our own learning curve.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

View Tim Dahn's profile

Tim Dahn

1511 posts in 3030 days


#4 posted 04-14-2014 01:41 AM

Could you skew the sole to counteract the bed?

Interesting build, something I would like to try.

-- Good judgement comes from experience and experience comes from poor judgement.

View Mark Kornell's profile

Mark Kornell

1061 posts in 1996 days


#5 posted 04-14-2014 05:39 AM

Tim – Took me a bit to figure out what you meant, but I think that would be possible. It would give the plane a bit of a lean :-)

Don – yes, there’s enough meat at the top of the plane so that I could taper it in. I might just try that.

-- Mark Kornell, Kornell Wood Design

View WayneC's profile

WayneC

12642 posts in 3563 days


#6 posted 04-14-2014 05:43 AM

Very interesting design.

-- We must guard our enthusiasm as we would our life - James Krenov

View Andygulfcoast's profile

Andygulfcoast

29 posts in 1303 days


#7 posted 04-14-2014 11:17 AM

I appreciate your candor re: all the mistakes you make and what you learn from them

I’ve never shared a project on LJ because I’ve never produced a perfect piece. But your work is beautiful, and the honesty about mistakes will help prevent me from repeating them.

Thx

View Mark Kornell's profile

Mark Kornell

1061 posts in 1996 days


#8 posted 04-14-2014 02:35 PM

Andy – while perfection is almost always the goal, don’t let that get in the way of making something really good. If nobody notices the flaws until you point them out, you’ve done your job well.

-- Mark Kornell, Kornell Wood Design

View Mauricio's profile

Mauricio

7115 posts in 2617 days


#9 posted 04-14-2014 02:47 PM

Love this little plane.

-- Mauricio - Woodstock, GA - "Confusion is the Womb of Learning, with utter conviction being it's Tomb" Prof. T.O. Nitsch

View Tim Dahn's profile

Tim Dahn

1511 posts in 3030 days


#10 posted 04-14-2014 08:33 PM

Mark, skew was probably not the correct word but yes the plane would lean a little.

-- Good judgement comes from experience and experience comes from poor judgement.

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