monophoto
Member
It is generally understood that Forstner bits can easily and quickly be sharpened using an ordinary diamond paddle. Execution is another matter - I'm right handed, and I've found that holding the bit with my left hand while manipulating the diamond paddle with my right hand was clumsy at best, and I've often been very glad that I thought to put that rubber matting on the floor of my shop because dropping a bit on the mat causes far less damage that dropping it on a concrete floor!
So I made a jig to hold a Forstner bit while sharpening from a scrap of 2x2" construction pine. My bits all have 3/8" shanks, so I drilled a 3/8" hole through the pine, and then cut a saw kerf from the end of the jig down through and just past the hole. I can then insert the shank of the bit to be sharpened into the hole, and then lock it in my bench vise - the saw kerf provides enough flex to allow the wood to clamp down on the bit and hold it firmly enough to be able to wipe the cutting edge a few times with the diamond paddle, while not allowing the vice jaws to mar the shank of the bit. Essentially, the jig is a collet to hold the bit for sharpening.
I added a couple of small scraps of wood on the sides of the jig that align it to the vise so that it sits in the same position every time I use it. They also support the jig on the vice jaws while I switch between bits. Finally, I mounted the jig in a scroll chuck and rounded over the top end of the jig so that it would be more comfortable in the hand when I'm using it.
So I made a jig to hold a Forstner bit while sharpening from a scrap of 2x2" construction pine. My bits all have 3/8" shanks, so I drilled a 3/8" hole through the pine, and then cut a saw kerf from the end of the jig down through and just past the hole. I can then insert the shank of the bit to be sharpened into the hole, and then lock it in my bench vise - the saw kerf provides enough flex to allow the wood to clamp down on the bit and hold it firmly enough to be able to wipe the cutting edge a few times with the diamond paddle, while not allowing the vice jaws to mar the shank of the bit. Essentially, the jig is a collet to hold the bit for sharpening.
I added a couple of small scraps of wood on the sides of the jig that align it to the vise so that it sits in the same position every time I use it. They also support the jig on the vice jaws while I switch between bits. Finally, I mounted the jig in a scroll chuck and rounded over the top end of the jig so that it would be more comfortable in the hand when I'm using it.
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