Kerf Maker Box Joints #2: Making uneven Box Joints

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Blog entry by George_SA posted 03-13-2018 06:39 AM 1434 reads 0 times favorited 0 comments Add to Favorites Watch
« Part 1: Easy Box Joints - How To Part 2 of Kerf Maker Box Joints series no next part

With my 5 Minute Kerf maker, I can make custom sized box joint fingers. This tutorial is mainly for me to remind me in the future how this works :)

Here are a few diagrams and pictures that explain the how to.

EDIT 13 Mar 2018
Diagrams at the end explain how to when there are more than 3 fingers.

Important to take note of the Kerf Maker orientation and also that the fingers that are cut will be the reverse image of the spacers on the sled. Never mix up the sequence of the spacers.

The actual width of the spacers are not very important.
What is important is that:
1) the total width of the spacers are equal to the width of the work piece.
I used scrap wood for the spacers. The middle spacer was cut so that it’s width together with the width of the other two spacers equals the width of the work piece. You can customise the width of the spacers, just keep in mind that the total width of the spacers must be equal to the width of the work piece.

2) It is also important that the sequence of the spacers must not be mixed. Keep the spacers in the same sequence from start to end by numbering them. For this tutorial SL = Spacer Left; SC = Spacer Centre and SR = Spacer Right.
The width of the spacers can be used to create a custom hand cut look.
Please note that the photos are mirror images of the diagrams because I had to take the photos from the front for clarity. The diagrams give you the perspective of standing behind the saw, while the photos were taken from the front of the saw.

The 1st step is alignment

Take note of the position of the Kerf Maker on the diagram

The 2nd step work piece 1
Remove the spacer block next to the saw blade. (Spacer SL in the diagram)
Flip the Kerf Maker (see diagram for Kerf maker position)
Move work piece 1 up next to the spacer blocks and kerf Maker
and make the 1st cut on the inside of the waste finger.

The 3rd step work piece 1
Remove the 2nd spacer (Spacer SC on the diagram),
flip the kerf maker as shown on the diagram, align the work piece and make the 2nd cut.

The 4th step work piece 1
Nibble out the waste


Now on to the 2nd work piece that will mate in the 1st work piece.

Step 1 work piece 2
Place the Kerf Maker and spacers 2 and 3 (SC & SR on the illustration) next to the Stop Block.
Remember to keep the spacers in the same sequence from start to end and
keep the Kerf Maker in the same orientation as it was in step 3 work piece 1 as shown on the diagram above.
Make the 1st cut on work piece 2

Step 2 work piece 2
Remove the 2nd spacer (Spacer SC on the diagram), flip the Kerf Maker and move the work piece over.
Make the 2nd cut on work piece 2.

Step 3 work piece 2
Nibble out the waste.

If you kept everything in alignment and didn’t get confused about the orientation of the Kerf Maker ;) you end up with a Kerf Maker precision tight box joint fit.

At first this may seem complicated, but it is quite simple actually when you get the hang of it.

Simple rule to remember (See diagrams below)
Kerf Maker A on top moves over the full width of a solid finger to cut on the outside line of the solid finger.
Kerf Maker B on top moves over the width of a waste finger minus the thickness of a saw blade to cut on the inside line of the waste finger.

A few diagrams to show how to when cutting more than 3 uneven custom size fingers.
Cuts on Work Piece 1

Cuts on Work Piece 2

Thanks for watching.

-- Sometimes life gets in the way of one's woodworking :)

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