Machinist

[Lawrence London <lfljvenaura@gmail.com>]

Some friendly tips for anybody with little knowledge of grinding, im a Toolmaker, I ran grinders everyday for 15 years and ground thin sections as a speciality.

I would never put a cut on greater than 0.025mm or 0.001", you only load up the wheel and generate heat, that heat bends the job toward the wheel making an even greater cut resulting in component that is significantly distorted.

Put it face down on the table after grinding and drop a brass drift on it and let it bounce, you will hear exactly what i mean.

Big cuts only crush the grit off the wheel unless you have a very very fine cross feed then you can put a 1.5mm or 60 thou cut on with coolant and a very fine cross feed and remove large amounts of material in one cut or potentially leave the machine to run 20 minutes by itself.

A regularly dressed wheel with a very light depth of cut but a more aggressive cross feed with coolant will give a good removal of material without distorting your job. Coolant or a dribble of coolant even from a hand sprayer is important to lube the wheel, keep the heat away and wash away the cut material.

On hard material you may need to dress a smaller wheel every 20 minutes, if its grunting it needs dressing period.

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there's allot of info online, machinist handbooks and such have allot of info,
Speed is good to get right, feed. Just keep it quick, for wheel grit use soft wheel on hard materials hard wheel on soft materials, coarse grit good for roughing, fine grit for finishing

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I like a white aluminum oxide wheels for everyday use, ideally with a dual rating like 36-42 or similar, it cuts fast enough and 4-6 spark out cuts at a quarter thou or 2 microns will yield a good finish.

When dressing for hard materials when not finish cutting, run the diamond across the wheel (after the centre line of the wheel) aggressively with a 3-4 thou cut and dont come back across it.

The wheel will be much sharper to cut material especially harder material better, within 16 thou or 0.4mm the wheel will smoothen out to allow fine finishing but it will cut longer than a fine dress.

Never had much luck with orange wheels, usally very fine and glaze very quickly. Light Blue wheels are usally for hard materials apparently, ive seen no better performance than white Alum oxide.

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i can vouch for the blue wheels, we did allot of dry grinding recently with blue wheels, staff complained about the dust, we used coolant, which helped, then just went back to white wheels as they lasted longer.--

Lawrence F. London, Jr.
lfljvenaura@gmail.com

https://sites.google.com/site/avantgeared