Grinding Hexagon Thingumybobs

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Ken I

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Oct 31, 2010
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Cape Town, South Africa
Grinding Hexagonal Thingumybobs On A Benchgrinder.

This is a silly little fixture I've had for years and use it for grinding hexagons on my bench grinder.

Basically just a shouldered hexagon with a 10mm bore and grubscrew.


By making up adaptor arbors I can mount various items on the end and grind the hexagons on a bench grinder.

For short shoulders the curvature of the wheel is insignificant.

You obviously set the arbor so that the tangent point is in the middle of the bit being ground.

I find I can work really accurately and its a lot less hassle than a dividing head on a mill for small parts.
It also means you can mount the finished part without having it still attached to the stock in most cases. (Like the gland nut in the photo.)

I also use this to grind custom Allen keys from 1/8" & 3/32" HSS drill blanks (Readily available from Slotcar spares places - its what they use for axles).
You can make them oversize or deliberately tapered to extract "burst" grubscrews.

As an aside I always dress my wheel using a cluster diamond (a segment from an old diamond saw works as well).

If you have never worked on a dressed wheel you will be amazed at the improvement.
If your work goes ding-a-ding-a-ding when grinding, then your wheel is out of true - it should go shhhhhhhhhhhh when grinding or sharpening drills etc.

It will never round itself.

Here in South Africa you can't get small Hex screws - so I take cheese heads, silver solder the slot - face off and then grind the Hex and they look really neat.


Not obvious from the photo, but the bench grinder is wall mounted - many bench grinders can be dismantled and reassembled so that you can bolt it directly to the wall - in this case it is on the vertical riser on the end of my workbench.
Hi Ken, I think the picture fell off or something!! :)
What a great site - you can go back and edit your posts - just discovered this feature.

Many thanks to Gail NM for showing me how its done.
Great Idea!


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