They're probably correctly using a cup shaped wheel on a tool and cutter grinder, which has a flat working face OR incorrectly using the side of an ordinary wheel.

I remember in the company workshop where the grinding wheels hadn't been dressed for decades and therefore didn't cut well even the best machinists would lean all their weight against a 1/4 in tool to shape it quickly. This kind of attitude applied to the side would not be good. The heat generated in the wheel can cause the contact area a bit inside the very edge to expand and break the rim as it has virtually no tensile strength.

Sensible use of the side is not a problem but with a big tool like yours it is probably best to do the bulk shaping in short sessions on the perifery until you are down to the final shape.

I have been in tool rooms and machine-shops for 47years. I have always used the sides of grinding wheels to finish off tools and cutters and haven't broken one yet! It is quite ok to dress the side of the wheel. If you were to grind a shaft between centres and grind a flange face square, you would be using the side of the wheel, so I don't understand what the big fear is.

Be brave ! Roy.

The star wheel breaks up the grit and exposes new sharp edges whereas the diamond stick will give a much smoother surface as it cuts through the grit, sometimes this looks a bit glazed to me and the cutting rate is a bit less. I do not advocate a star wheel on the sides of a wheel ,but I am sure with inginuity an engineer will be able to run a diamond down the wheel side to take out any irregularities and make it flat. A collar on the stick and a clamped bar to run down and gently apply the stick is easy!

Dressing wheels seems to frighten people, I have to do this at work as no one else seems to think about it and just carry on pushing tools at the wheel harder and harder. The new surface seems to surprise them, perhaps a lack of knowledge or inexperience there. I have seen a crankshaft grinder wheel go off, it had just started and split in 2 and we only found one half, the other went through the asbestos roof and was never found. Mind you this was a big wheel about 18" dia.. I have never seen a small wheel go yet!

Clive

John,

Why worry about the curve, who says it has to be flat anyway.

The critical bits are getting it the right angles which is where an adjustable tool rest comes into play and getting them sharp which is where the choice of wheel comes into play.

When you start off in this game the learning curve is quite steep, as with any new interest so don't try to read more into this than is necessary.

If you need to account for the curve, puff out your chest and inform the purists that it's hollow ground, a process they have been doing for years on Knives, scissors and slitting saws to get the best shape and cut.

Many even grind a chip breaker groove in the top that forces the chipping to curl up and breakoff and do away with the birds nest stringing.

Remember, right angles and sharp.

Doesn't hurt to have a small motor with a diamond wheel on for lapping. Someone, forget who put one on here only a few weeks ago made out of a central heating pump motor. That would be ideal.

Now some purist is going to tell me that you shouldn't use diamond on HSS as the carbon transfers to the wheel and blocks it. However with these cheap electro deposited ones that doesn't happen. I have been using one for about 7 years now on carbide, HSS, brass where there is a brazed joint, pencils and split finger nails and it's still OK. Put it like this, that £8 ? wheel has probably saved me £500 in tips and other cutters by giving me a second life.

Theory is great but practice rules every time, with lathe tools you need to grind one and try it, that's what gives you experience.

In another thread on chamfering someone posted they hadn't finished a tool and cutter grinder so they couldn't grind a tool to a given shape. What's wrong with freehand grinding ? You don't need a machine for everything.

The only disadvantage to teh "hollow ground" tool faces you get from using the wheel perimeter is that the resulting fine edge will wear quicker than flat-ground faces. The actual angle at the cutting edge is sharper, due to the curve.

I was taught as an apprentice toolmaker never to use the side of the wheel and never have done, much.

Yet I see the classic old model engineering books by the likes of Duplex and LH Sparey recommend using the side of the wheel, and in fact supply plans for sharpening jigs for both tool bits and drills that use the side of the wheel. And these were old timers who knew their stuff. Really knew their stuff. (Although workplace health and safety then was not quite as overbearing as it is now.)

So maybe the answer is as suggested already, compromise. Grind your tools on the perimeter of the wheel, then a light final touch up on the side to take the curve out in the area of the cutting edge. That's what I do — but don't tell anyone. Specially my old foreman.

It ( not by me) has been said…don’t grind on the side but maybe SHARPEN if needed…

….the trick is to know the difference .

..Mark..hear hear