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Sliding dovetails with the Veritas Small Plow Plane



It is not by chance that I spent some time today turning the Veritas Small Plow into a plane to shape the male section of a sliding dovetail. Last weekend I was demonstrating hand tool joints while building a bedside table (night stand) at the Perth Tool Event (formerly the LN Tool Event). The stand alongside was that of Terry Gordon (HNT Gordon Tools), plane maker extraordinaire. Terry is an old friend and it was great discussing handplane design together.


Terry had adapted his side rebate plane to shape the female sliding dovetail.



To use this he would first plough a dado with his dado plane, and then shape a sidewall.

I figured I could do the same with a simple addition to the fence of a Stanley #79 side rabbet plane, and set out to do this …



Don’t try this in pine. It is frustrating if the blade is not ultra sharp. But the concept works –Terry’s works very well – however I did not persevere as another idea came to me as I was playing with this plane. (Incidentally, if you are looking for a plane design to create the female joint, here is one).


For some while I’ve been thinking about the Veritas Small Plow and how it could be used to create a sliding dovetail. The Small Plow is incredibly versatile (grooves, rebates, T&G) and many own it because it is such a good little plane. I do not need another plane for the male end of a sliding dovetail, having built one that works very well (pictorial here) … however this was a problem I wished to solve. I am sure that there are others who could profit.


My dovetail plane ..



It was while fiddling with the modification to the Stanley #79 that the light bulb went on. With a little trial and error, the plane came together, and it works reliably.


The parts needed include a new subfence for the Plow, a blade from the Stanley #46 (I used a 5/16”, but thereabouts will do) or you could make one (dimensions to follow), and a new depth stop.


The Stanley #46 is a combination plane that uses skew blades and is designed to plane dados and rebates across the grain …



The blades fit into a skewed bed and create a horizontal surface. Note that the #46 cannot be used to plough a sliding dovetail no matter how you try. This will become clear as I explain how to modify the Small Plow.


The #46 blades are skewed at 70 degrees and “relieved” at the back for clearance. The plane beds the blades at 45 degrees, but the bed is skewed, not square as with most planes.


A couple of fortunate coincidences came together:


  1. my dovetail planes create a sliding dovetail that is in the ratio of 1:6, which I chose as a compromise for strength and depth.

  2. It is possible to add an angled subfence fence to the Small Plow to form the 1:6 angle.

  3. If one were simply leaning a plane over it would not be possible to create the square shoulder. However the skew angle of the #46 blade, along with the fence, enables the shoulder to be planed square.


Note that the #46 plane does not have a way of adjusting the depth of the blade, and this will need to be set with a hammer.


Build the subfence


Mark a 1:6 angle on a scrap of hardwood, and plane to dimension ..



Checking with a dovetail gauge ..



Rationale


Below you can see how the subfence caused the plane to angle away from the shoulder.


Here I am planing with the grain to test the concept. The plane does not have a nicker to plane across the grain.



The angle of the #46 blade combines with the fence to create the male 1:6 angle.



I think that the reason that the shoulder is planed square is because the blade is taking a progressively wider cut. It starts with just the sharp (pointy) end of the skew, and then the fence maintains the depth of the cut.



Square shoulder ..


Perfect 1:6 dovetail angle ..



Using and developing the plane design


Time to plane across the grain for real.


There are two strategies to incorporate. The first is to use a cutting gauge to define the shoulder as there is not nicker to (pre-) sever the fibers as the plane cuts across the grain.



The second strategy is to deepen the line at the far corner to prevent spelching …


After a couple of practice runs I noted that the edge of shoulder was bruised …



I recalled when building my male dovetail plane that it did this as well as a result of the depth stop being square to the plane body and at an angle to the shoulder. This created extra pressure and wear at the edge. What was needed was a depth stop with a parallel lower side (similar to the modification to the Stanley #79).


I did not want to modify the Veritas depth stop, and so built one out of a bolt for a sliding track. This simply involved grinding the steel plate at the desired angle …



Note that the underside of the depth stop must be right angles to the subfence …



One last design feature: note above that there is a cut out of the subfence for the blade. This allows a wide blade to be closed up.


Now we try again – and it works perfectly …



The result is a square shoulder ..



And a 1:6 dovetail angle …



For parallel sliding dovetails, leave the depth stop on.


For tapered sliding dovetails, mark the taper (typically 1/8” is sufficient over the length), plane as per a parallel sliding dovetail, then remove the depth stop and plane to the lines.


Regards from Perth


Derek


April, 2014