Spar Plane From Scratch

Inspired by Bob Smalser’s  article  Making a Spar Plane Inexpensively and “Wooden Planes and How to Make Them” by David G. Perch and Robert S. Lee, I decide to build a spar plane from scratch.  I selected a piece of maple fire wood and cut it down with the band saw to get a rectangular piece about 3 inches on a side and 12 inches long.  I then squared two adjacent sides so that I can cut it down on the table saw to 2 1/2 square and 12 inches long.  Each side is 90 degrees to the adjacent side.

There are three ways to make wooden hand planes, the traditional method with chisels and floats, the two piece method where the two halves of the plane are glued together or the laminated method which three pieces of the plane are glued together.   I chose to do it with the laminated method.  One side is cut off at 1/4 of an inch.  The the center is cut at the width of the blade plus 1/16 and then the second side is cut at 1/4 of an inch.

I used the plans from Popular Mechanics’ article How To Build 3 Basic Hand Planes as a staring point and made some modifications for the spar plane.  I drilled alignments holes in each corner for 3/16 inch dowels.  This make test fitting and gluing easier and the ends are cut off when the shaping the plane.  The mouth is 1/4 wide and made from two cuts so that the mouth won’t be too big when the sole of the plane is shaped.  A 3/8 inch hole is drilled for the cross pin.

The cross pin is made from a 3/4 x 1 x 3  inch piece of Khaya.  I actually made three;  the first one was OK, the second was poor and the third was the best.   Once the cross pin is fashioned the plane can be glued up.    A lot of clamps are needed to ensure even pressure on all surfaces.

A 2 inch ABS pipe has an outside diameter of 2.35 inches which is just right for spars or oars, 2 1/4 inches in diameter or less.   I marked the target shape of the sole on the front of the plane and nibbled away the material with a straight cutting bit on the router.  I could have also used the table saw to nibble away or set up to cut a cove.  The router is slower but allowed me to check after each pass so that I did not any mistakes.

I started with 60 grit sand paper glued to the 2 inch ABS pipe and when I was close to having the correct shape of the sole, I changed to 120 and finished up with 220.  In retrospect, I could have cut closer to the line with the router and that would have save time sanding.  To prepare the sand paper for gluing I would cut a sheet in thirds lengthwise.  I used spray on glue and when I was done with the sand paper I would peel it off.

I used a french curve to draw the profile of the plane.  I like an rounded heel so I use a piece of 4 in ABS pipe as a guide.  Once I have the basic shape of the heel, I continue to adjust the shape until it feels good in my hand.  The left side of the heel is rounded an little more than the right which  allows me to hold and use the plane one handed.

On the next entry Iwill show how I made the blade.

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