We could do tongue and groove with a router table and with special milling cutters to mill the grooves and the tongues of these wooden joints. Something that seems simple enough. But not everyone has a milling table and those special strawberries. So in this post we are going to see how to make a guide to mill the grooves and the tongues of the tongue and groove joints, using the column milling machine. Also I am only going to use a simple router bit with bearing and a straight router bit.
Guide for milling tongue and groove with the milling machine
In this case I am going to make a tongue and groove milling guide, to mill two different sizes of boards, to make tongue and groove wood. So, to begin with, I have to put the long board 1 that I want to mill with the edge slightly protruding from the edge of the board on which I am going to make the guide. And glued to that board I screw a wooden strip A, of the same thickness or somewhat less thick than the boards that I want to mill.
Now I have to put the other table 2 that I want to mill so that with the edge it aligns the ends of 1 and A according to line LA1. Finally screw the stops B and C so that B, 2, 1 and C are perfectly aligned according to the LN2 line. Now I only have to screw a small stop behind 2 so that it does not move when milling.
In the entry that follows this we will see how to do the guide in the event that all the tables are the same, which will be the most common. This was a test to see how the guide worked.
How to mill the tongue and groove grooves
Now I can install the grooving cutter with bearing and adjust it to mill a slightly off-center groove in the edge of the boards.
So in a first pass I can mill the edge of table 1 and the head of table 2. Then I just have to turn both tables 10 degrees and re-mill the groove on the same edge and the same head. In this way I will obtain perfectly centered grooves.
I have to mill the groove on the edge of the short boards (tables 2), for which I put the two boards in line in the place of table 1, and fasten them with a new stop. And I mill in one pass, I flip them 180 degrees and finish milling in a second pass.
How to mill the tabs to make tongue and groove
To mill the tabs of this joint I am going to use a straight cutter. I install it on the router and want to adjust it so that the end of the cutter is slightly below the bottom of the slot (as seen in the picture).
Now I put the boards the same as I put them to mill the grooves, but keeping in mind that I want to mill the tabs on the opposite edges to which I milled the grooves. And is that to make tongue and groove, we have to mill two grooves and two tabs in each wooden board.
But before milling I have to mark a depth of the reeds slightly less than the depth of the grooves ...
and adjust the lateral guide of the milling machine.
And just as before I am going to mill, turn the boards 180 degrees and mill again. So I'm going to get some reeds centered on the edge of the boards. Although in this case it may be advisable to mill each face of the reeds in two passes. This requires less effort from the milling machine and reduces the possibility of splintering the wood.
But the first thing will be to mill a corner and test how the tongue fits into the slot. And I will have to adjust the depth of milling, very little by little, until the tongue fits perfectly. As I adjusted the drilling depth, the tongue will be a little thicker, so I have to increase the drilling depth very little by little and testing until both parts of the joint fit together. Once they fit, I can mill all the tabs following the same procedure that I followed to mill the grooves.
This way I can mill the grooves and the tabs both on the edges and on the ends of the boards. Although this was only the first test I did to make these tongue and groove joints. In a future post we will see how to do these wood joints using tables that are all the same length. And I will mill all the boards in all their edges and ends, so that I could use them perfectly to make a wooden floor.
I did not imagine that making tongue and groove wood could be so simple.