|Project by George_SA||posted 08-17-2015 06:58 PM||6034 views||23 times favorited||7 comments|
I saw the idea for a single blade box joint jig on the Woodfather.com website. He has a SketchUp plan Which can be downloaded as well as an instruction video.
I deviated a bit from his plan as I reused my Digital box joint jig sled for this build. The principle behind the jig is quite simple and can be implemented on various platforms. Although I used a digital caliper on the old jig it is still an analogue jig which has it’s own problems with repeatability. With this jig repeatability is quite easy due to the digital nature of the spacer blocks. I used masonite which is just 0.1mm thicker than 3mm kerf width of my blade. Any material can be used for spacer blocks as long as their thickness is consistent.
The first block on the right hand side is stop block for the pin which can be varied in thickness to get the starting point just right. It can be made thinner on a disk sander or playing cards can be added as shims to make it thicker. Fortunately mine was just right and needed no further adjustment.
The secret of this jig is that the pin you use must match the blade’s kerf width quite accurately. I used an old 3mm twist drill bit which works perfectly for my blade.
I also incorporated a clamp on the slide to hold the wood in which the joints are cut. Another modification that I made is a screw clamp on the left end to keep the spacer blocks nice and tight.
The other advantage of this type of jig is that it is quite easy to make variable pin widths. There is a video on his YouTube channel that explains the procedure.
My first test joint came out quite well (see last picture).
-- There are some things that money can't buy - Manners, morals and integrity