Insert Endmill
A homemade long-reach endmill using carbide inserts
For a special application, we needed a very long reach endmill that would be doing light milling in cast iron. Cast iron is fairly abrasive on tools, and wore out the endmills frequently, so I made a insert mill so that we can just replace the comparatively cheap inserts, rather than replace the whole endmill. Three pockets were milled into the tool body, a small pin fit into the bore in the middle of the insert, to retain it, and then a clamp was made that holds the insert down tightly. The endmill worked alright at first, but I quickly found that the oversized clamping piece interfered with chip flow when trying to take very heavy cuts in ductile materials with a large axial length of engagement. This didn't matter for our intended application, but was an interesting oversight to note. When used with low axial engagement, so the chip flow doesn't impinge on the clamp, I was able to get very high feed rates and material removal.