Kerfing Plane; an Aid for Rip Sawing.

Finished Kerfing Plane

I hadn't really planned to make a kerfing plane but have made a rip frame saw and used it, I decided that a plane would make sawing to a line easier and so ensure less work in planing to get stock pieces to size and establish good reference faces. Tom Fidgen has given an excellent description of making a plane  on his website https://www.theunpluggedwoodshop.com that I studied before my attempt and found this very useful and full of ideas.

 Basically, if you want to rip a piece of stock to a particular size, the kerfing plane can be used to form a cut around the stock of  10 to say 20 mm depth that the rip saw blade can follow. I decided on a large version made entirely of wood (apart from the blade!) and quite bulky and hopefully bullet-proof to last some time. I had the option of fitting different blades and having a wide fence but also capable of ripping 1/8 th inch veneer. Again I will be mixing measuring units partly because of my scientific background in metric and my use of traditional hand tools that are invariable in fractions of 1/16 th of an inch.

I started with a piece of kiln dried beech (30 x 11 x 7 cm) left from other projects and ripped this to get a piece 30 x 11 x 3 cm which I planed with a joining plane. I then sketched a template on paper that would enable a 12 inch blade, handle and some form of knob at the front to guide the saw. I used a No. 18 drill to open the handle space and smaller drills to cut the sharp corners. The rest was shaped with a coping saw and turning saw and then filed with a wood file.

Cutting the handle  grip using a coping saw, brace/ auger and carving chisel.

Carving the handle grip; for this I used a 7F/14 gouge and sandpaper to finish.

The shaping was finished using carving gouges (mainly 7F/14), wood file and sandpaper to round the edges to make the fit comfortable. 

The next step was to thread the two arms. These were 25 cm long and threaded to 22 cm in length. The holes in the plane were 5/8 inch approximately, 16.5 cm apart and threaded to receive the 3/4 inch threaded arms. Care is needed using the brace to drill holes at right angles to the plane face. Large nuts to fix the fence to the arms were also made from beech.

Plane so far with the two arms installed.

Sawing the threaded nuts to hold the fence.

The fence was made from the other piece of ripped beech (30 mm thick). This was planed to size and  shaped to allow access to the plane handle.

The fence ready for shaping and installing through the arms of the plane. The shape was decided by the shape of the plane and access to the plane handle. The holes were drilled to 11/16 th inch (No. 11 auger).

The centres for the holes were marked to match the plane side and checked by clamping the fence to the plane and marking with the auger tip. The holes were drilled 1/16 th larger than the threads to allow easy adjustment without much play. The fence needed a lower guide bar to be shaped and attached, but more of that later.

The plane with the temporary fence attached. The lower part of the fence (I will call the lower guide) will come later after the blade is installed.

I next attached the blade (Nobex 14 tpi, fast cutting available from "Axminster Tools"; "Workshop Heaven - Fine Tools" also sell a rip 7 tpi kerfing blade) by sawing a narrow groove in the plane base to a depth of about 20 mm allowing 20 mm of the blade to protrude for cutting. This was positioned 1/4 inch from the inside face of the plane to ease the fastening of the blade and also to be able to rip narrow  veneers without a fence guide fitted. This proved straight forward by using a block to get the blade perpendicular to the base of the plane and using a dovetail saw with a narrow kerf to get a tight fit for the blade.

Sawing the channel for the saw blade using a guide block and saw.

The next step of making the holes for the screws and caps to hold the blade was tricky. I had purchased the brass fittings from "Thomas Finn & Co. Ltd." which were designed for 1 inch width saw handles. The process of fitting is discussed by Paul Sellers : "Replacing Screws and Caps", (February 18, 2020). I followed a similar method of using a 15 mm Forstner bit (the closest to a 13 mm that would have been ideal) to drill an insert of 5 mm on both sides of the handle and then brad bits to locate the barrel and screw. It is important that the hole in the saw blade locates on the barrel and so again it is important to take this in to account when positioning the saw blade in the base. Drilling holes in the blade was hard!! although cutting the blade to length was relatively easy. I fitted one screw and cap first and then marked the position of the other hole, drilled the wood and with the blade in place punched a centre indent for drilling the steel.

I used the plane, without a lower guide on the fence, to prepare wood for making a guide for the plane :

The plane in use cutting the lower guide for the fence from some stock beech.

After rip sawing the wood for the guide and planing, my plan was to have a removable guide on the fence to allow more versatile use of the plane. To do this I made a couple of beech screws to pass freely through the fence and screw into the plane guide to hold it in position. This fitted well after planing the base of the guide and fence flat.

View of the handle side with the blade in place.

View of the other side with the fence adjustment nuts and also the wooden screws holding the lower guide in place.

The front of the plane showing the position of the fence and guide.

The plane upside down showing the blade and extent of the fence set for a 1/8 th inch veneer.

Finally the beech was treated with linseed oil and waxed.

There is a lot of scope for altering the design, especially the handle and also the option of installing different blades. The important thing is to get a comfortable fit and a good fence so that the blade can be kept at right angles when sawing. The dimensions that I've given are not particularly important to the design.  The blade I have is good for thin veneers and cuts quickly but I may try a coarser blade for heavier work. I've learned a lot about fitting blades on saws! I would have liked to have gotten the blade deeper into the body (I'm not sure why) but was limited by the position I'd chosen for the two wooden adjustment screws. I would have been better to have placed them 1 cm higher to give me more space for the blade. I like the idea of being able to remove the guide and fence easily but only time will tell if I use this feature. Removing the guide will permit a wider cut and also act as a fixed fence saw.

I have used the plane to make a small box from beech and lime veneers that were cut to 1/8 th inch thickness using the kerfing plane and tenon saw. The fine blade in the kerfing plane fitted the task perfectly and enabled me to cut thick veneers that needed very little further preparation apart from a few passes with a block plane and sanding. Strips of lime ( 1/8 x 1/8 th inch) were cut with the kerfing plane and  inserted into each corner. The bottom was rebated into place and covered with a thin beech veneer. The wood was treated with Shellac.

 

Finished box made of two pieces of 1/8 th veneer of lime and beech glued so that the grains were crossed.

Showing the details of the construction with the lime inside and beech outside.

As an addition to this post, I have recently made another Kerfing plane from beech but using a different blade obtained from: Kerfing Saw Blade (workshopheaven.com). This has much coarser teeth at 7 tpi but is shorter in length. I would have preferred a longer blade just for ease of sawing.

Finished plane ready for use.

 I basically followed the same method described above but made smaller square section screws and attached the guide bar permanently  by glueing and using two oak dowels for extra strength. The handle is larger and higher but I'm not sure this is a good thing. I think having the handle lower and less downward pressure does help in using the plane and keeping it level.

The base of the plane showing the blade in position and also the guide bar. This can be set close to the blade and make veneer cutting much easier.