JANUARY

All of January was spent programming in CAM, as I learned how to grind bevels on blades using a diamond cup wheel inside of the CNC milling machine.  While I had thought this would become a turnkey solution, what I discovered instead was the limitations of my 3-axis milling machine.  While the diamond grinding method did produce repeatable results on the plunge, and main bevels, I soon discovered that it left a relatively thick tip untouched.  Much like when grinding with a block jig, the tip of the blade remained the crux.  Suddenly, I understood why makers who use this method design knives that turns down, like Wharncliffe and sheepsfoot style blades.   The grind from the cup wheel left some unusual grinding lines, that shows a radial style swoop.  I had seen these style markings before on other maker's blades, but failed to recognize what had caused it.

I ground the blades from tip to plunge, under flooding coolant, and I did have some burning problems.

First my attempt to solve the tip problem, was to program the distal taper in CAM, creating multiple construction planes, on various angles / elevations, and using projections to drive tool paths, that would give me a distal taper.  Unfortunately, this method simulations caused collisions onto my fixture. 

My plan was to correctly grind the bevel on the first side of the blade, and then use that 1st side of the blade as a mold to create a steel epoxy support for the second side.

Lots of experimentation followed thereafter, clocking the blade, putting feeler gauges underneath the tip, having the cup wheel change in elevations while grinding... after spending the entire month of January grinding and scrapping parts, the end result was to return to the 72" KMG (Knife Making Grinder).  I had hit the limitations of the 3-axis machine.  I needed a 4th axis, (the fixture needed to move), and I now understood why some makers purchase 5 axis machines to grind blade bevels.

I still have some more idea's, but they require a rotary.

As for the burning of the blade steel, I plan to purchase an indexing dividing head, and machine some large diameter holes (evenly spaced) into the cup wheel.

In the end, I used a flat platen on the 2" x 72" grinder, setting the angle on my adjustable grinding jig to the matching angle I had used on my fixture in the milling machine.