Wednesday, 6 May 2015

Wall mounted Plane and Tool Cabinet - Part 6 - Drawer parts (Pin boards)

The front panels of the drawers will have half blind dovetail sockets. The rear will just be through dovetails. The stock was milled to size and cut to fit the drawer aperture. In my country on drawers of this small size 95 deep x 202 wide (3-3/4" x 8") I am able to have just 1/32" clearance on the top of the drawer and slightly less for the sides. We don't get massive swings of humidity so those clearances are fine.

There are a variety of methods of marking from the tail boards onto the pinboards - balancing the tailboards on bench plane while holding the pin board in a vise, trying to mark them whilst balanced on your knee, getting somebody else to do it for you - to name but a few.

My method of marking

The first thing I do is very lightly mark the end grain with the marking gauge (you remembered not to alter the setting didn't you?) Then I clamp the pin board in the bench vise and have the endgrain end just slightly proud of the vice (only a hair). Then I square the board to the bench top with my engineers square.

Taking the tail board I lay it onto the pin board with the top of the tails just on the scribed line ensuring the bottom end of the tails are lined up with the other edge of the pinboard. Then I square the board to the front edge of the apron of the bench.

Holding the tailboard down to the bench with some light pressure from my free hand I use my 0.5mm mechanical pencil to mark around the tails. Remove the tail board and then the tails are marked onto the pin board. Put a few crosses into the waste if you want.

Then using the engineers square line up with the intersection of the lines and the edge of the face. Draw lines down the face. Then use the marking gauge to draw a knife line across the face. It's not necessary to go to the edges with the gauge line as it will only frustrate you trying to fill in the notch in the top edge of board after glue up. DON'T DO IT :)

I know this is not the way that some woodworkers do their 3 minute joints in exhibitions but it is a method that works well for me and I enjoy doing it.

Cutting blind dovetails in the pin board

Return the tail board to the vise with the "open" end facing you - aim to have it protruding above the vise about 3 to 4" (whatever feels comfortable for you). Keep the board plumb if you can. On half blinds you need to start the cut with the saw at around 45 degrees. You also need to angle the cut in the horizontal plane to line up with the pencil line. Practice helps to develop muscle memory.

Cut slightly inside the pencil lines on the waste side. You can try to split the pencil line but as it is only 0.5mm (about 1/64") it can be challenging. Keep watching either end of the kerf as you don't really want to go beyond your gauge lines and go slowly trying to keep the blade plumb.

When you have cut all the kerfs take the board out of the vise and place it onto the bench. I find it easier if it is butted against a bench dog and then clamped down to the bench top with a holdfast.

Next undercut all the gauge lines as described in Part 5 (cutting the tail boards). Now comes the easy bit. Take your favourite  bench chisel and use combinations of chopping cross grain and taking slivers down the end grain. When you are approaching the gauge line on the end grain change to paring cuts.
Then clean up all the internal corners of the socket with skew chisels or a fishtail. You can also take light paring cuts down the face of the sockets to split the pencil lines. Use the marking gauge as a depth gauge (again not changing the setting) to check the depth of the socket from what will become the internal face AND the end grain. See the Veritas gauge is very useful :)

You should end up with sockets cut into the pin board looking like this

Pin board and tail board

Alternative method

Chopping out the sockets is time consuming so there is another way utilizing your favourite small router. I use a Dewalt  DW670 laminate trimmer
A random DW670 image lifted from the internet
with a 1/4" bit to remove the majority of the waste. This router is small and well balanced to can be use on the end grain if you clamp a support across the board. Set the depth of cut to the same as the marking gauge and carefully route away the waste from each socket. Then turn the board thru 90 degrees and route using the inside face of the board as a reference. Finally finish off with chisels to get perfect sockets.

The other end of the pin boards

The other pins are very easy to do as they are just simple through dovetails. Again mark out as above and cut on the waste side of the pencil lines.
This time there is no need to angle the saw as you can cut straight. Don't forget to under cut the base knife line as it produces tighter, cleaner finished results.
You can either cut away the waste as before with the band saw (remember that the pins have an angle to them) removing the bits the bandsaw can;t get with chisels.
Or you can using a coping saw. I don't get on with coping saws and much prefer the chopping and paring method but that's me.

Have the board a little closer in the vice than this. I left a little on for paring.

Undercutting the knife line
on both sides of the board

The bandsaw only gets so much of the waste
due to the angle of the pins,
I then chop and pare with chisels.
Make sure you go in from both sides to the centre of the board
and work on a sacrificial surface.

Test fit and you should get it right first time.
If not you simply do as I did on this board - pare down the pins a little at a time.
Don't worry about the pins or tails protruding
as it will be removed with a plane after glue up.

The joints should be a light push fit.

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