How to Use End Mill Grinding Fixture
Just because an end mill becomes dull doesn't mean you have to scrap it or buy a new one. You can regrind an end mill to be sharp again using a special fixture that allows you to grind the relief angle and the edge. By carefully following a strict procedure you can save yourself hundreds of dollars and save end mills from the scrap bin.
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Instructions
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1
Cut off the dull edges of the end mill with a cut-off saw. You want to start with a new surface to grind the end mill correctly.
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2
Insert the end mill into the grinding fixture. The fixture has the capability to grind the edges of the end mill at two different angles. The first angle is the relief so that the end mill is out of the way during the cut. The second angle will put a knife edge onto the flute being ground for the cutting.
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3
Tighten the bottom Allen wrench head screw to tighten the collet in the fixture to securely hold the end mill. The end mill must be held tightly as to not cause damage to the grinding wheel. If the end mill comes loose during the grinding process it may cause damage to the wheel.
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4
Place the fixture on the magnetic grinding table in the flat position. This will allow you to grind the relief first. Place it so that one side of the fixture is resting against a flat surface. Place a block against the front lip of the table and then place the fixture against the block so that it is near the center of the table. The fixture should be straight to assure that your grinding is straight as well.
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5
Bring the wheel to just above the first flute at the highest visible point. Slowly lower the wheel until you see and hear it grinding. Be careful to not plunge too quickly as you may damage the wheel and the end mill.
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6
Turn the handle on the front of the grinder to move the table in a left to right motion. Continue to lower the grinding wheel while moving the table side to side until you have the correct amount of relief, which is dependent on the end mill size and amount of flutes.
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7
Turn the fixture counter-clockwise and repeat this procedure to the other flutes. The top part of the fixture will move but keep the base in the same position. You want this operation to make the end mill look like it was when you got it from the factory. The fixture will automatically line up the next flute for you.
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8
Push the fixture forward to grind at the angle necessary to sharpen the end mill. Repeat Steps 5 through 7 at the new angle. This will sharpen the end mill and it will run as a new end mill.
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Tips & Warnings
You can cut and grind an end mill about three times before it becomes too short to work.
Do not touch the end mill with your bare hands after grinding. It will be too hot and will melt your skin. Use gloves or an instrument to hold it and run it under cold water before handling.
