# Grinder Station, Part Ii



## francist (Sep 6, 2020)

The second half of this grinder setup, and second half of the actual grinder for that matter, is the result of what happens when one acquires more machines. More cutters to sharpen, more wheels to accommodate, you name it — more of everything.

My milling cutter needs are not huge but I do like to be able to sharpen things as opposed to just tossing them when they get dull. Plus, the ability to grind a small chamfer on a bit for instance can really extend the usefulness of a cutter. There are several popular designs out there for sharpening and from what I hear they work well, but I always have to be just a little different...

For some reason I envisioned a rolling or pivoting motion as being desirable as opposed to a back-and-forth sliding motion. I also had a really cool Linhoff tripod head that I hadn’t used for years that was just begging to be repurposed into something useful. There was a lot of head-scratching in this project, not because it’s terribly advanced but more because everything is interrelated. Almost all the parts and relationships were developed first in AutoCAD, proven for functionality, and then taken to the shop for production. 

Starting at the table, an adjustable fence along one edge provides left-to-right as well as front-to-back registration of the end mill holder. A small thumbscrew provides some clamping pressure with a steel shim to prevent dimpling the holder. The Linhoff head can tilt up or down through 120 degrees and slew a full 360 degrees uninhibited.














The rolling motion in and out of the wheel zone is provided by an independently hinged leaf that supports the tripod head and also allows the tripod head to be raised or lowered vertically relative to the wheel centreline. A lock ring holds vertical elevation and controlled advancement of the hinged leaf into the wheel is obtained by a threaded wheel and keyed washer. Each hash mark on the wheel advances the assembly roughly 0.001” towards the grinding wheel with an opposing coil spring providing a small resistance. A thumbscrew and outrigger outboard of the hinged leaf provide an adjustable stop for controlled grinding up to the centre web of an end mill, say. And much like the “standard rest” in Part I, the entire head assembly can be adjusted fore and aft using threaded fasteners through slots in the base plate.






I had a real struggle trying to get my head around how to use the two different rests on opposite ends of the grinder without taking up large amounts of real estate. I like things portable, or at least moveable anyway, as my shop area has to be adaptable to a number of different interests. Finally it occurred to me that instead of bringing the rests to the grinder I could bring the grinder to the rests, and that made all the difference. 

To use the milling cutter rest, the grinder is positioned endways facing the operator which gives good access to the end of the cup wheel. To switch back to grinding a lathe tool, I just pull out one locating pin and undo a few jig-fixture knobs to rotate the grinder ninety degrees bringing the straight wheel up to the standard rest. The operator position is unchanged, but now the grinder is crossways. It took more time for me to write that process down than it does to actually do it.










More in Part III


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## RobinHood (Sep 7, 2020)

Very well thought out system, Frank.


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