How would I go about making a jig to grind carbide V cutter/engraving bits?

[HankMcSpank]

Subject says it all really, I'm talking about these .

http://www.ebay.co.uk/itm/10-Carbide-PCB-Engraving-Bits-CNC-Tool-20-Degree-0-1mm-/130408480405?pt=UK_Home_Garden_PowerTools_SM&hash=item1e5cf37e95

after when a fragment has snapped of the tip...seems a shame to throw them away if they could be re-ground

What type of wheel ....how can I get accuracy etc.

[motoxy]

Jig would not be hard. Use a keyless chuck mounted on a bearing. You could use a belt sander with one of the specialised grinding belts used for wood turning tools so that you would get a flat edge.
Just a thought.
Bruce

[John S]

These are ground on a Deckel or Alexandra single lip grinder, often called a Universal tool and Cutter grinder which they are NOT.

5460

Because the engraving cutters are made of micrograin carbide they have to be ground with a diamond wheel to get the finish needed.
A simple jig could be made from a spin indexer and a small motor with a diamond wheel acting on a pivot so the wheel can pass the cutter as it swings at the correct angle.

Sharpening these is a simple job once setup.
I save mine and when i get about 5 or 6 chipped or blunt ones I do them all in one go, takes a couple of minutes per cutter tops.

Because these are actually made from powder it stands to sense that the actual tip is very fragile and it pays to take a fine diamond file and take a swipe at the end to purposely put a flat on it before it chips it off.

It's very, very easy to chip the tip on one of these, with a grinder it's very easy to grind them up or even grind a complete new one from round stock out of HSS, doesn't last as long as carbide as regards wear but is far more forgiving on fine work in soft materials.