This is the next installment of the Join It Series – Episode 4! This time I break down the easy and fast method of achieving the lock joint. This joint is also known as the offset tongue and groove. First you need to start off with changing out the single blade for the two outer blades of the dado stack. You can achieve the same results with a flat bottom single blade, but it will require more passes on the saw.


Next you need to set the height of the blade to 1/4” ( rule of thumb is only a 1/3 of the thickness of your stock )


Now using the stock as a thickness gauge we set the fence so the measurement from the fence will be from the outside portion of the blade.


Then make your cut.


Now for the tongue. It is so much easier to make the tongue to fit the groove rather than make the groove to fit the tongue. This is why I do it in this order. I use a stop block as a gauge to set the stock so that I am only taking off a 1/4” x 1/2” chunk of wood from the end. Thus, leaving the 1/4” x 1/4” tongue to fit the groove perfectly. You need to be patient with this step so you can sneak up on the exact fit.


You should end up with a joint like this one!


Thanks for reading and watching and I hope to see you on the next build!



Follow Rock-N H Woodshop