Tiny grinder

[Nitai LeviParticipant @nitailevi73768]

Hi

Does anyone know this tiny Proxxon grinder? **LINK**

After looking for a long time, I just happened to notice this grinder and it's the first one that is small enough to fit my space.

OTOH I've managed without a grinder for years so it's ok, I rather not buy something terrible. It's more expensive than most other basic grinders (about double or more here).

Thanks

[Nitai LeviParticipant @nitailevi73768]

[Bob MurrayParticipant @bobmurray]

Ian Bradley described a small grinder in Vol. 146 that may fit your needs.

Regards,

Bob

[David Clark 13Participant @davidclark13]

The wheels are much to small to sharpen lathe tools properly.

[Jesse Hancock 1Participant @jessehancock1]

From what I've seen, Proxon tools are perhaps meant more for watch making and so might suite 5mm Unimat lathe tools. Their machines are expensive but one supposes they are high quality.

Ultimately you can grind small tools on a small grinder. You can grind any tool on a large grinder.

[Boiler BriParticipant @boilerbri]

Hello nitai, I would suggest that you try to find a machine with 6" (150mm) wheels. These are much commoner and a wide range of wheel grades can be bought from lots of different outlets. You can buy spindles for them that hold buffing wheels as well for polishing parts.

Brian

[Nitai LeviParticipant @nitailevi73768]

Thanks.

The lathe cutting tools I use are 6mm-8mm square.

Re a 6" grinder, I found many 5"-8" grinders and simply don't have the space even for any of the 5" grinders. This is why I don't have a grinder yet.

If it takes longer that's not a problem. I just don't want to get the Proxxon and then find out it's not possible to do what I want at all.

[Michael GilliganParticipant @michaelgilligan61133]

Nitai,

[My personal opinion] …

• 50mm diameter grit wheels are too small
• Yes, you could sharpen [as opposed to shape] 6mm Tools on the Proxxon
• Something with a Cup Wheel would be much more realistic.

Consider buying a good, and decent size, flat plate Diamond Lap instead … Mount this on a flat slab of Granite or Corian [makes it easy to wash] and sharpen your tools by hand.

MichaelG.

.

User Manual, here, includes some interesting views of the construction

Edited By Michael Gilligan on 20/07/2015 08:41:36

[David Clark 13Participant @davidclark13]

What about a small belt and disc sander. Quite small and would be capable of grinding 8 mm tools?

[WorkshopPeteParticipant @workshoppete]

Hi Nitai

Why not mount a 6" grinder on a board that can be clamped to your workbench then when you have finished unclamp and put away. Not as convenient as being permanently mounted but you generally do not use a grinder frequently or for long periods. I have three grinders mounted onto a turntable which is easy to swing around so the grinder required is at the front.

Peter

[Phil PParticipant @philp]

I will second that, both my grinders are mounted on wood boards that have rubber door stops as feet.

The grinders live "under" the bench for 99% of their lives, the other advantage is you can take them outside and make all the mess there instead of all over the bench.

Phil

[GoCreateParticipant @gocreate]

Hi Nitai

I bought one if these grinders a few years back and personally would not recommend it. In my experience it would not be suitable for grinding up lathe tools from 6mm or 8mm HSS tool bits other than sharpening an existing profile. It will cope OK with 3mm or 4mm tool bits and sharpening drills up to about 6mm.

For it's size it is quite powerful, it has a variable speed control which to me seems of no benefit on a grinder. I was disappointed with mine, during a longish grinding session mine stopped working, I resume there is a fault on the speed control board, I have been meaning to see if I can re-wire it to bypass this board but till now it remains under the bench.

ARC sell some 40mm diamond coated discs, maybe these combined with a small motor could make a neat little grinder but for 6 – 8 mm tool bits I would recommend a 6" grinder as others have and find a way store it away when not in use.

Nigel

[Nitai LeviParticipant @nitailevi73768]

Thanks. I probably won't get one then.

I can sharpen cutting tool already so don't need a grinder for that. I only need a grinder to make new cutting tools but can leave without it like I have for years.

I'd have to grind on my porch anyway, I don't have a place for the grinder on my bench at all, not even temporarily. The grinder would have to stay on a specific shelf and I just haven't found a grinder small enough (other than this one) that would fit. The smallest 5" grinder I found wouldn't fit. Any other possible space is either also too small or other tools have priority.

Re the suggestion of diamond discs, although I can't get anything from ARC (they have astronomical international shipping) I already have a bunch of diamond and other grinding wheel for my dental micromotor. I considered this instead, since I only need to grind a new tool maybe a couple of times a year, but didn't get good results with it so far. Maybe I just need to work on that or don't have the correct wheels.

[WorkshopPeteParticipant @workshoppete]

Hi Nitai

Why not mount a 6" grinder on a board that can be clamped to your workbench then when you have finished unclamp and put away. Not as convenient as being permanently mounted but you generally do not use a grinder frequently or for long periods. I have three grinders mounted onto a turntable which is easy to swing around so the grinder required is at the front.

Peter

[AjohnwParticipant @ajohnw51620]

You could make up something for yourself. A 2,800rpm pump motor with one of the thick recessed wheels mounted on the spindle and put it on your shelf end on

The type of wheel I'm referring to is this one but I would probably try to find a finer grit but this one would be ok especially if you currently sharpen by other means – I polish mine up with a stone.

**LINK**

You could mount the usual wheel edge grinding rest and use it side on and something fancier for the side of the wheel.

When looking at cheaper 6in bench grinders the power they specify seems to be input rather than output. On that basis 250w in seems to be ok. Output will be a lot less. I suggested a pump motor because they are sealed. The plates these grinders have to support the wheel are generally pressed so have wobble built in. Machining up decent ones at home should make a distinct difference as they can be an accurate fit on both the wheel and the motors shaft. There usually isn't much space for that sort of thing in the commercial ones – otherwise I might suggest modifying one of the them and forgetting the wheel on the other end. – unless for some reason the whole thing is turned around because the wheel on it is needed.

You could of course just fit a thick wheel.

John

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[Tim ChambersParticipant @timchambers76147]

I've got one of these , I sharpen my mower blades on it as well as lathe tools and for twenty quid its not a lot of outlay.

Yes the tool rests are a bit flimsy looking but if you bend them,then you're doing something wrong.*

*In my opinion others may disagree!

[Neil WyattModerator @neilwyatt]

Worth looking at this too – compact and self contained.

http://www.chesterhobbystore.com/tool-sharpener-9931-p.asp

Neil

[BazyleParticipant @bazyle]

The Chester one is a wood shisel and plane toucher-upper. 140rpm. No danger of overheating the tool even in the 3 weeks it would take to grind it

A 5 in wheel one from a car boot or other sale would be smaller and suitable. Everyone was happy with 5 in at home until 30 years ago when 6 in got cheap. Now you see people wanting to get 8in ones to beat the Jones next door.

[AjohnwParticipant @ajohnw51620]

If you have ever used a 10in industrial off hand grinder some where that have also bothered to sort out the correct grade of wheel you would think size does matter Bazyle.

The answer I have found to work fairly well is the 6in aluminium oxide wheels the Axminster sell. They wont grind super quickly but the main reason that they handle HSS well and even Tantung G is that they are probably a bit more friable than what would generally be thought ideal for tool bits so they cut slower than an ideal 10in wheel but coolly.

I recently bought a 6in FERM grinder, same as the Record one but a lot cheaper for the wide wheel. The FERM ones are on amazon, some one on ebay was trying to sell them at near Record prices. They have the usual wobbly wheels problem probably due to the flange washers. I'm wondering if there is some way I could increase the size of the hole in the wider one that comes with it. as a replacement to put on something else would cost more than the grinder.

John

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[john carruthersParticipant @johncarruthers46255]

Hi Nitai, have you considered making an arbour to take a 115mm diamond disc and using it on the lathe (with suitable dust proofing) ?

Edited By john carruthers on 20/07/2015 15:00:29

[clivelParticipant @clivel]

You may be able to modify the Unimat 3 grinding attachment to fit your lathe – they do appear on eBay from time to time, but sometimes the prices for Unimat stuff is insane.

Here is a picture from the page at **LINK**

[duncan webster 1Participant @duncanwebster1]

This covers your lathe bed with grinding dust. Horrible. You'd have to cover everything with cloths before you start and then e very careful when you take them off.

I have a cheap <£20 grinder, fitted with decent wheels and rests it does all I ask, and can be taken outside for dressing, or stored under the bench.

[MuzzerParticipant @muzzer]

That picture makes me shudder. It's got to be the very last place you'd fit a grinding wheel, where the carriage spends most of its time and right above the (hopefully) oiled leadscrew. What were they thinking of? At the very least, a comprehensive grit guard would have been a sensible / essential feature. Woo.

Murray

[Nitai LeviParticipant @nitailevi73768]

Yes, I won't grind on my lathe and not even on my bench. I repair musical instruments and the lathe and mill are a relatively small part of that. I won't grind on my bench where a lot of musical insturment parts and tools are. If I do get a grinder it will just have to fit on a specific shelf for most of the time and then get it to the porch to actually grind in the few times a year that I need to do that. Or the alternative is to continue without a grinder like I have for years.

So my impression is that for making new HSS lathe cutting tools, having no grinder or the small Proxxon grinder is not realistically different…?

I was trying to find silicon carbide grinding wheels for my micromotor but couldn't find any other than thin cutting wheels. Diamond worked poorly and the grinding wheels I have are extremely slow and wear out very fast.

[MuzzerParticipant @muzzer]

I'm probably not the best person to advise you on that. I generally have loads of space and use a fairly basic bench grinder! I usually tell people that I'm more of an agricultural engineer than a watchmaker.

Just been watching / listening to you on Youtube. Incredible clarinet playing! Used to play the violin years ago to about G7 but evidently quite a few levels below your standard.

Murray

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