bench grinder recommendations

the photos

If I were getting one then I would say the bar attachment is important, since it ought to take the jigs designed for the Jet and Tormek sharpeners. These greatly extend the range of things you can sharpen.

Yup, good people to deal with generally, and reports from those who have discussed tools with them, suggest they know their stock well.

Thanks. Sadly the reviews on the site complain about the bar: poor welding and not being straight.

Are these attachments available separately and can be fitted to any grinder?

One last question: I see many places sell a metal stand for grinders, in the region of thirty-forty pounds. Why is the stand almost as much as the grinder? Is it just that it is heavy so expensive to transport?

Is the stand worth having or do you bolt yours to your bench?

Thanks.

It seems a bit of bending about can fix it. Some reviews of the much higher end Jet machine have made similar comments as well it seems.

The jigs are, the tool rest needs specific holes in the grinder to locate in though.

(most of the wet grinders seem to share a common rest design though)

Partly bulk I guess. I doubt they sell them in anything like the numbers that the grinder sell in - so the prices won't be as competitive.

They are fine on a bench[1] - although a dedicated stand might be nice to free some bench space!

It seems that the axminster is a no volts switch whereas the machine mart is just a rocker switch, so the axminster one has this extra feature. Curiously axminster describe their model as being diy/hobby level, whereas machinemart claim theirs is suitable for professional use. Someone can't be telling the truth.

The downloadable manuals were an interesting read: the axminster says you should spin the wheels to warm them before grinding. I never knew that. The MM manual says 10 mins on, ten mins off, which makes me doubt the professional duty claim, though to be fair, would anyone want to grind all day? Wouldn't 10 mins be enough for anyone?

Thanks

I expect mm is over egging it a bit....

Indeed - I would expect a pro unit to run all day.

Unless your job is grinding things on a production line!

I thought that too. Axminster don't say anything about a 50% duty cycle but I think they are closer the mark with their "hobbyist" tag.

One last batch of questions if I may:

Re. the spinning to warm up the disc first: do they really get that warm from just spinning in the air? Why do they need to be warm to work? Does this mean I should do the same with my angle grinders too?

Do you think the NV switch is essential? I realise it is to stop the grinder spinning up after a power cut but why should a fixed machine be more dangerous than a 4" angle grinder, which AFAIK never have them?

Finally, thanks for the advice about a stand. Did you buy a separate stand for yours or is it bolted to a bench?

Thanks again.

I have never come across the advice to warm them up first, and hence have never bothered either. The machine seems to grind just fine from cold. I don't think the wheels themselves get particularly hot in use - but that may just be I don't grind much for long enough.

I would not be too worried on this type of machine - even if it does spin up by itself, its not going to do much damage.

I have limited space in my workshop and hence have it loose on the bench

- it vies for space with a small bench sander I have. This is how I know it wanders around the worktop a bit in use! I have thought about getting a stand for it, but then again, am not sure where that would go either! I suspect a more pragmatic soluion would be to screw it to an offcut of

The downloadable manual suggests they warm up from just spinning in air. I've heard of air resistance but I can't imagine that it is sufficient to heat a disc!

Are NV switches just relays or are they more sophisticated than that? If you had a push switch energise the relay coil and then fed the coil and the device from the NO, wouldn't that act like an NV switch? Is that how they do it?

I don't mind paying forty pound for a tool that whirs and sparks and makes a noise but I'm reluctant to spend the same again on a lump of metal that has no lights and makes no sounds ;)

I'm in two minds as well. I definitely need a dry wheel to sharpen my sds chisels which are completely blunt. The advice here seems to be that a wetstone might not really be necessary and an oil stone or something similar might be all I need for the wood chisels. It's just they wouldn't be as much fun to use ;)

I can't tell from the axminster web site whether their two grinders are the same and whether you could retrofit the jig to the cheap one. I would have thought so. I will ask them but it may be that even if all the grinders have the mounting holes, the jig may not be available separately. Why is there a jig only on the wetstone? Isn't it just as important to get the angle right on a fine dry stone? Why don't they have jigs?

I'm waiting until the recommended books arrive, as hopefully these might make it clearer whether I need a wet grinder or not and whether it needs a jig. For what it is, the jig seems to add a lot to the cost for what is essentially just a bit of metal. Do people DIY their own jigs to save a few pennies?

Thanks again.

That's what I was thinking of doing. If you used it all the time a stand might be useful but for occasional use, ply would (ha ha) be fine.You could even store the ply wood mount on a shelf bracket as its own shelf. I'm not sure about the bouncing though because they have a dry wheel on the other side and that still spins fast.

A basic NVR is what you describe.

A crude NVR (American style) is a feeble relay that's only enough to hold a latch on a switch, not hold the contacts itself. These are quite common on cheap machine tools - look for two buttons that are made as part of the relay. They can't have separate start buttons as it needs the button press to engage the latch. They can however use multiple stop buttons, such as knee paddles or foot pedals. Modern Chinese ones of these aren't too bad (and very common), but some older ones (again, largely American style) can become unreliable with wear. They drop out on their own, or especially if there's machine vibration.

A better NVR has an overload current trip too. Sometimes magnetic, usually thermal. This is the usual sort for a separate motor starter in a box, or for motors >1HP.

Mostly yes... you push a contact closed manually and a solenoid then hold it shut. When the power fails, the contact is released.

Much as I enjoy things the spin and make noise, I have to admit that inert lumps of stuff also have their place in a workshop! ;-)

Depends a bit on what you are sharpening as well.

The answer is its probably not as important on a dry stone, since the things that you are likely to be sharpening (SDS chisels etc) are far less critical than a plane iron. (grinding HSS tool steel for use in a lathe may be different!)

I am sure some must.

Most of the big wet grinders (Jet, Tormek, Grizzly etc) don't have a fast wheel at all. The crossover machines like axminster's does - but the geared wet end is sort of grafted onto a more traditional fast grinder.