Here is a marking/cutting gauge (or slitting gauge, if you like). This one is made from Cocobolo. These gauges are ideal for cutting across the grain and do so with ease. Designed particularly for cutting dovetail baselines.
I wanted a cutting gauge for marking dovetail baselines with a crisp, neat line that I could register a chisel in. So, I decided to make one. The one pictured below is made from Amazon Rosewood and brass. The blade is from a utility knife so can be easily replaced if dulled or broken. The brass gives the tool a nice bit of weight so it cuts beautifully and with ease; there is no need to lean on it, just pull it across the wood.
There was a bit more to making this little tool than you might think. I was very aware that everything was going to have to be dead square and there would have to be no slop between the brass beam and the wooden body. Firstly, I cut and milled the brass beam; I actually milled six of them as I felt it would be nice to make a number of these gauges in different woods. Here is a picture of the parts:
The only parts not shown in the pic are the threaded inserts that would hold the beam to the body. The screws and blades aren’t shown either but I didn’t make them. Having milled the beams. I then set about making the knurled thumb screws. The heads were turned & knurled on the lathe, then drilled and tapped. An M6 machine screw was threaded into the brass head and fixed with two-part epoxy. The head of the machine screw was then cut off and the end tidied up. I found this system of making thumb screws much less wasteful of brass than turning the whole thing on the lathe. This would have involved using up to five times as much brass bar; and brass ain’t cheap.
After making the thumb screws I made threaded inserts to match them. These were, for all intents and purposes, knurled nuts and were later epoxied into appropriately sized holes in the wooden body of the gauge.
Next came the blade retention plates which were cut on the bandsaw and filed & drilled. Corresponding holes were drilled in the front end of the beams and these holes were tapped. A very shallow groove was cut in the front end of the beam just wide enough to take the blade.
Then came the body. The first gauge was made from an offcut of Amazon Rosewood which was cut to size and squared on all sides. The groove for the brass beam was then milled out; exactly to fit the beam. Then a rebate for the wear plate was milled out. At this stage I cut a piece of brass for the wear plate and drilled it for two screws. The plate was screwed and epoxied to the body and the edges milled flush. The body was drilled to take the threaded insert.
I finished the wood with two coats of Danish oil, rubbed in. Then came final assembly and testing. Happily the test was successful and I now have a useful and beautiful tool to add to my cabinet. Next on the list is to finish a few more cutting gauges in different woods. I’ll post pics of these later.