Thread: Sharpening End Mills and measuring Relief Angles.

I have been sharpening some end mills, slot drills and small slitting saws lately using a Harig Air Spindle which has always produced excellent results but setting it up to achieve the recommended relief angles has always been a bit awkward so I decided to make a relief measuring attachment based on the one shown in the Clarkson Cutter Grinder operators manual.
The attachment is very simple, the hardest part for me to make was the angular scale which required a bit of thought to make sure that the finished item would look presentable with regard to the degree scale engraving and stamping, it came out pretty good but bid take a lot of concentration and time.

The attachment is used in conjunction with a dial indicator (with a pointed contact tip) and the clearance chart shown in the Clarkson manual.

Relief Measuring Attachment 1.jpg

Relief Measuring Attachment 2.jpg

Relief Measuring Attachment 3.jpg

Relief Measuring Attachment 4.jpg

That looks pretty good. How did you engrave the lines and get such even numbering?

I engraved the degree lines on a rotary table using a 20 degree bit, the numbers were stamped using a cobbled together jig.