Archive for May, 2010

Plane Irons

Monday, May 17th, 2010

In the continuing saga to build a spar plane from scratch, I cut out the planes irons from 3/16 x 1 1/2 x 18″ blank of 01 tool steel. Using permanent marker instead of Prussian blue and an scratch awl I marked the outline of the shape of the iron I wanted.  

I cut the rough shape with a hacksaw and then used a bench grinder to refine the shape.  I also knocked off the edges so the iron is easier to handle.   The iron on the right is for the spar plane and the one on the left is for a backing out plane.

The tools steel is in the annealed state until it is hardened.  To harden the steel it has to be raised to a temperature of 1450-1500°F.  At that temperature the steel is converted to austenite.  The steel become non-magnetic and can be tested with a magnet.  The color of the steel is cherry-red.  I built a propane furnace to heat treat the irons.  Unfortunately I was not able to get them hot enough to go non-magnetic.  I am going to add a second torch to the furnace and if that does  work I will borrow an oxy-acetylene torch.  If I could get the irons hot enough I would then quench them in vegetable oil.  Then I would need to temper the irons because they would be too hard and brittle to use.  To temper the irons I will put them in a oven at 350 to 400°F for an hour.

Spar Plane From Scratch

Sunday, May 2nd, 2010

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.