Advice on a bench grinder

Hello
I have just recently purchased a wood lathe and am wanting to get a bench grinder to keep my tool sharp.
I have heard mixed opinions on whether a slow speed bench grinder is needed or just a standard bench grinder with an aluminium oxide grinding wheel being fine.
There doesn't seem to be many options on slow speed grinders in Australia. The best priced one I have seen was a sherwood 8in but I have read it may be a bit underpowered?
I am not really wanting/able to spend a lot, so budget friendly options would be appreciated.

Thanks in advance

David

As a relatively new woodturner myself (a few years in now) I picked up a cheap Ozito two wheel aluminium for $40 or so from Bunnings fully expecting to upgrade it in short order once I figured out what I was doing.
I haven't yet (says a lot! ;) )

I use older carbon steel Marples that do need extra care when sharpening to keep their temper (HSS are less heat fragile I believe) but I typically use only a roughing gouge and a few scrapers that are sharpened in about 3 seconds flat. And I use mostly very hard timbers like Gidgee and African Blackwood which wear tool steel really fast! I wouldn't have the patience for a slow speed grinder I suspect.

You certainly can't use a cheap grinder like mine on plane irons or hand/bench chisels (for those I use an oil stone) but for quick sharpening lathe tools I have no qualms using the Ozito. Just keep the steel cool!

The Sherwood looks very nice though but I'm not sure I'd want its purchase holding me up from using the lathe though.

Vaughan

I also use a cheep $50 grinder I picked up in Super Cheap Auto. I put a white wheel on one end. It has done about 10 years now for my turning and the odd other grinding job. I do have a water wheel Seppach that was intended for the turning tools but the bench grinder requires a lot less set up time than all those jigs. I would like a slow speed grinder one day but they are very expensive.
A run of the mill grinder with a white wheel will get you by for turning tool sharpening if the budget is tight.
Regards
John

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Originally Posted by isdavidisgood

The best priced one I have seen was a sherwood 8in but I have read it may be a bit underpowered?

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The claim made on the Timbecon Website is

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The 375W 4-pole motor has twice the torque of 2,800RPM 2-pole motors so while the motor output is lower, it will still perform well when grinding tool steel.

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The claim that the Timbecom has twice the torque is misleading because it assumes a comparison with a similarly powered (375W= 1/2HP) 2800 rpm motor.
Most half decent 2800rpm 8" motors can generate 550W - 750W (3/4 - 1HP) while 375W is more commonly used on a 6" grinder
A 1HP 2880 rpm motor has the same torque as a 1440 rpm motor.
Torque is also just one aspect of grinding, and wheel speed is another.
If the speed is too slow then it will take longer to removed the metal and the tendency for an operator will then be to push harder which will them wear the wheel faster.

Power/torque is only really needed when shaping a new tool and a significant amount metal has to be removed, if just a quick touch up of a tool is needed then a 375W grinder is plenty.
Back to your original question, my suggestion for HSS woodturning tools would be to look for an 8". 3/4-1HP, 2800 rpm grinder.

I have using a standard speed grinder with aluminium oxide wheels for 40+ years, if you really want a slow speed have a look here https://vicmarc.com/index.php?option...=20&Itemid=529

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Originally Posted by orraloon

A run of the mill grinder with a white wheel will get you by for turning tool sharpening if the budget is tight.
Regards
John

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+1 on that advice from John.

And when you can afford better, suggest you put that into CBN wheels on full speed grinder.

The main disadvantage of cheaper grinders are their propensity to not run wheels true (shaft and flange issues). But you might find a good one.

The only advantage of slow speed grinder that I can think of is if you are grinding standard carbon tools. However, most turning tools are now made of HSS and their temper is not affected by the amount of heat that you can generate on a grinder. So why take longer to get the job done than is necessary! Also keep in mind that CBN generates less heat than Alox and therefore is kinder on standard carbon steel.





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Thanks heaps to everyone for the advice :)
Think I will get myself a cheaper HS grinder with an alox wheel for starters.
I really appreciate the advice.
I've only turned twice but im already hooked. can't wait to have a go with actual sharp tools haha.

Any recommendations on good brands? while im on a budget id still prefer to get something as quality as I can

I too have not been into wood turning that long. I started out with the basic cheap setup and it was ok. Not so long ago a bit the bullet and purchased a Vicmarc grinder with CBN wheels and the Tormec bench attachment. This is probably the best investment I made. Fast accurate and repeatable sharpening every time on all my turning chisels. Spend the money and you won't regret it.

Peter

I'd start by looking on Gumtree. Use any cash I saved to put towards a 180 grit CBN wheel.

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Originally Posted by woodtryer

............. Spend the money and you won't regret it.

Peter

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Unless he needs money for more important things! As a newbie too, I think going with a basic grinder and decent wheel is all you need for the foreseeable future :U

Yep that is a good option if you are not 100% convinced that you will stick with a “hobby “ but in my experience if you buy the best or one of the best options you only buy once. You can always sell it for a good price if it’s good quality.

I have used nothing but my $30 Ozito bench grinder with the stock 60 grit grey wheel to sharpen my woodturning tools. My setup seems to be against everything I've read in woodturning tool sharpening articles, yet has performed perfectly well.

I have no slow speed grinder, friable aluminium oxide wheel, aftermarket toolrest or sharpening jig. I only sharpen freehand.

I get a good sharp edge which lasts as it should with my carbon steel, M2 and M42 tools.

I'm certainly no pro so it just goes to show that a very basic setup will do you just fine with a little practice.

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Bit more expensive, but hasnt been mentioned yet is the tormek systems. Preferably the t8. Or you may be lucky and pick up a t7 second hand like i did.

Tormek are made with far superior build quality to all the other copys out there now. And the range of accessories is endless, which means you can sharpen anything you will ever come across. Use it with the 2000 grit Japanese wheel for normal sharpening after you have got you preferred grind on your tools using the standard wheel.

Water cooled slow speed grinding is a better way of sharpening, as even the HSS can still be affected by heat. Also being able to run the 2000grit wheel means you only have to do that rather than grinding + honing.

Hope this helps.

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Originally Posted by Aussie Bloke

Water cooled slow speed grinding is a better way of sharpening, as even the HSS can still be affected by heat. .

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You have to be a blue and white apron wearer to upset HSS using a small grinder. As NeilS says, HSS is deliberately designed to retain its hardness even at red heat. The supposed main way it's upset is if it's ground for too long so that it reaches a high temperature and is then quickly shoved into water to cool where by it can shock the metal and produce micro cracks. I have deliberately tried to do this with some old spare HSS chisels ground on a old grey HD grinding wheel and (unlike carbon steel) could not tell any difference in turning performance before and after doing this. If there was no difference on the grey wheel then it would be even less likely on a white wheel or a CBN wheel.

I reckon a white wheel is a good starter wheel for beginning turners.