The Finest Razor-Sharp High-Speed Steel
Final results depend on the quality of the cutters used. We demand a lot from our Sheffield tool makers, and they give good service using only the finest high speed steel.
Dovetail jig makers seem to favour tungsten carbide tipped (TCT) blades generally, even for dovetails. The stoutish shaft, which has the carbide blades welded to it, makes for a rather dumpy look to the finished dovetail. WoodRat champions high speed steel (HSS) bits as the whole of the blade makes for strength and for cutting. HSS can take a higher rake angle and a finer, more slicing edge.
Also the same diameter of dovetail will give a greater depth of cut in HSS.
The dovetail angle is the same throughout the families. The bit is all structure, and the steel is easily sharpened and flexible. It does have a very small cutting depth at the very top of the neck, so you have to give the cut time and take it steady. Keep the bit sharp, and run it at top speed.
Note that the fingers of some dovetail jigs mean that the end diameter of the bit is ½” whatever its angle. The machine rules.
Matching Hand-Cut Joint
A fine dovetail needs a cutter with a narrow neck, and the correct angle for the wood. Following good practice, that is 1in7 for hardwoods and 1in6 for softwood. Going to 1in8 or 9 even gives you a good looking dovetail, provided that the pin is slim.
Uniquely and because it is not a jig, the WoodRat can make a pin to fit any angle and any size of dovetail. So we can buck the trend and use high speed steel.
Our straight bits match the dovetails and also have a good end cut for mortising.
You can hone your HSS bits on a diamond whetstone to a surgical finish. The smaller stones can be stuck down on the end of the WoodRat Channel. Give the edge a few strokes before use.
HSS is the correct material for cutting joints, but it must be said that TCT is the choice for cutting down the grain, which is why it is used for router tables.
Moulding cutters, matched pairs, spiral up-cut and carbide all work well with the WoodRat, but we leave their supply to others.