Grinder question?

[woden]

I know this is the hand tools forum but I got the grinder pretty much exclusively for sharpening chisels, etc.

My question is how long can you reasonably run a bench grinder before it gets bad for it? I'm asking because after having to send the previous one back due to damage in transit - and faulty parts having to be replaced on this one - today's the first opportunity I've had to use my Axminster slow running grinder in earnest and it seems to heat up very quickly. It's not cooled by a fan and maybe this is the reason but middle of the range grinders don't have air cooling, or do they?

With the heat build up within a short space of time I'm not sure I'd like to attempt any long, time consuming grinds.

 

[George_N]

I know this is the hand tools forum but I got the grinder pretty much exclusively for sharpening chisels, etc.

My question is how long can you reasonably run a bench grinder before it gets bad for it? I'm asking because after having to send the previous one back due to damage in transit - and faulty parts having to be replaced on this one - today's the first opportunity I've had to use my Axminster slow running grinder in earnest and it seems to heat up very quickly. It's not cooled by a fan and maybe this is the reason but middle of the range grinders don't have air cooling, or do they?

With the heat build up within a short space of time I'm not sure I'd like to attempt any long, time consuming grinds.

How long you can run the grinder for at a time, will depend on the rating of the motor. An industrial strength motor will be rated for continuous use ie. running all day long. Others may be rated to only run for 30% of the time...run 5 min off for 10 min to cool down. There should be a plate on the grinder showing voltage, rpm etc. the rating is usually on that, if it is given at all.
I would only be using a grinder, even a slow speed one, to re-grind the primary bevel if the edge got badly nicked, not for sharpening as such, so how long do you envisage running the grinder for at one go?

 

[woden]

I would only be using a grinder, even a slow speed one, to re-grind the primary bevel if the edge got badly nicked, not for sharpening as such, so how long do you envisage running the grinder for at one go?

That's all I intend using the grinder for but although a small nick shouldn't take that long, regrinding a new bevel angle could be more time consuming. Also, I was thinking of having a go at a beat-up lawn mower blade that might need a major amount of metal removal!

There isn't a plate on the side of this motor but I will take another look to be sure. How is the rating written: just something like 1, 2, 3, etc. or is it a more complex code involving numbers and letters?

 

[DaveL]

Woden,

If its an Axminster machine, it should have a rating in on the WEB site.
Is your grinder the AW8SRG2? Looking in my catalogue, that machine is TRADE rated and the definition of trade is:-

Continuously rated high power and heavy duty construction.

Looking at the machine in the picture, the motor is sealed, so all of the cooling will be by raising the temperature of the casing, it will run hot. I think if used continuously probably too hot to hold your hand on. If you are still worried about this, give the Axminster support team a ring they will be able to tell you how hot it should get.

 

[Grinding One]

I would only be using a grinder, even a slow speed one, to re-grind the primary bevel if the edge got badly nicked, not for sharpening as such, so how long do you envisage running the grinder for at one go?

That's all I intend using the grinder for but although a small nick shouldn't take that long, regrinding a new bevel angle could be more time consuming. Also, I was thinking of having a go at a beat-up lawn mower blade that might need a major amount of metal removal!

Watch out doing that lawn mower blade,if your mowers are like the ones over here the blade is the motors flywheel.We have to take off metal evenly from both sides so we don`t lose the engine , ie balance the blade

 

[woden]

Is your grinder the AW8SRG2? Looking in my catalogue, that machine is TRADE rated and the definition of trade is:-

Continuously rated high power and heavy duty construction.

Looking at the machine in the picture, the motor is sealed, so all of the cooling will be by raising the temperature of the casing, it will run hot. I think if used continuously probably too hot to hold your hand on. If you are still worried about this, give the Axminster support team a ring they will be able to tell you how hot it should get.

Thanks, Dave. The penny never dropped to look up the trade definition: I was looking for a number on the machine. Doh!

But yeah, it does get very warm, quickly. Don't know if I'd have the courage to run anything until it got too hot to touch - are there really motorised machines intended to be used in that way?

 

[Anonymous]

I run mine for ages when I'm having a sharpening session and it does get very hot. I reckon you would 'smell' anything amiss (like my cheapie hobby hand drill I got for £10, it starts to smell and smoke if I give it any welly) so wouldn't worry too much.

 

[big soft moose]

on occasion ive run my cruesen allday (by forgetting to turn it off) with no ill effects - i'd expect axminster to be equally well made so probably much the same

not something i'd want to try with el cheapos though

 

[woden]

on occasion ive run my cruesen allday (by forgetting to turn it off) with no ill effects - i'd expect axminster to be equally well made so probably much the same

I don't think I'd chance letting the Axminster run for 15 minutes never mind an entire day; this 'running hot' business is totally new to me and not half worrying. Is the Creusen fan cooled or a hotty?

As for the build quality of the Axminster I doubt it would be in the same league as the Creusen: it's rough enough in places and the grinding rests are poorly thought out - indeed, the little ridge that provides positive alignment when you want them horizontal is actually a design flaw as this stops them from being parallel to the wheel surface at more accute angles.

There's no vertical adjustment either - the rests just pivot on a single bolt - so as the grind angle becomes finer they end up further from the wheel. You're also left grinding much further down the wheel than the preferable position allowed for with after-market rests - almost on top of it. I imagine the vertical adjustment on the Creusen allows you to replicate the 'height' that can be attained with after-markets.