Grinders

[Redtails3]

Is it better to use a slow grinding  wheel speed or a fast one to grind has wood turning tools?

[seventhdevil]

slow...


with modern HSS tools the speed is less of an issue but slow is still best.

[The Bowler Hatted Turner]

Redtails I use the grinders from B&Q, they revolve at 1420 rpm. It is not the speed of the grinder but the person using it that makes a difference. All this rubbish about using slow run grinders and wide wheels is made up by the people that make or sell the grinders.
          Just put some time in on the grinder, the same as you would to become proficient on the lathe, a light touch and if you feel the tool is getting too warm dunk it in a jar of water. It shouldn't get so hot that it is quenched.

[Paul Hannaby]

John, your grinder is a slow grinder! The fast ones run at around 2800 - 3000 rpm.

Another factor in the equation here is the wheel diameter. If you buy a standard 8" grinder, the wheel's peripheral speed will be 33% faster than a 6" wheel so even if you found a fast 6" grinder was fine, the extra speed on an 8" wheel might be too much.

I have a slow 8" grinder. It grinds more than fast enough for my purposes and still has the ability to overheat the tool if abused!

[Redtails3]

Thank you for the comments very good.
I think that if you get some high speed steels hot the shock waves could crack the steel
Some of these steels are of dubious quality .
so I do not hold entirely with the comment that slow grinders are a manufacturers ploy to get hold of your hard earned cash.
Do they make a slow speed bench grinder with a six inch wheels?
Like the man says a eight inch wheel travels 33% faster. Thanks

[julcle]

Use light touches on the wheel and cool the steel before you start to grind and you should be fine. I use the pro edge for turning and a Tormek for plane irons and hand chisels so no problems
Julian

[Eric Harvey]

I have three grinders,a cheap Aldi 6" one,been in use for getting on for 20 yrs now,as said a light touch works best,it also makes the wheels last a lot longer as well as the tools,the second grinder is a homemade slow grinder with 8" wheels again from Aldi,spins at around third to half the speed of a standard one,it has been in use for around 15 yrs,the newest one is the cheap wet grinder that Axminster used to sell,modified with wood to get a better position for the toolrest,I like this one for touching up the tools on the fly,had to dress the stone before use as it had a poor surface when bought new,thinking of getting a tormek 8" stone for it to see if it gets a finer finish on the tool edges,but saying that being dressed with a fine stone seems to give a fine edge,so swings and roundabouts I think,cheers,

Eric.