Burning blades, argh!

[jisk]

Well, I got an abbot and ashby 8" bench grinder for christmas, woohoo! :D But now I've burnt two blades, argh! :((:((

I started with a chisel, for practise. None of my hand tools are particularly expensive, and I figured a chisel would be easier than a plane blade. I burnt it almost immediately but I kind of figured I'd do that - that's learning. I hogged off the 2mm or so of steel that I need to so I could get past the blued section. That was all good, and I got that off without any further burning of the chisel. I just ground back directly against the edge of the chisel, so I was effectively flattening the bevel.

I started regrinding the bevel at 25 degrees, and that went pretty well until I got close to the tip - and it burnt again! And I thought I was being pretty bloody careful with it. :?

Right, I figured I'd try a HSS plane blade. HSS is harder than whatever steel my chisels are made out of, so I figured it should be more durable. I went about trying to regrind the primary bevel from 30 degrees to 25 degrees... and I burnt it quick bloody smart! I did use a light touch, and didn't spend a long time there - probably less than two seconds for the whole width of the plane blade.

I figure that this is happening because the steel is pretty thin at the tip of the bevel, and some of it is the learning process...

How much difference will a white wheel make? I've gone and ordered one in at the special orders desk at Bunnings but I don't know how long it will take to come in. Is it with persevering with the grey alox wheel, or should I just wait for the white one?

Thanks guys,
JK.

[Groggy]

...
How much difference will a white wheel make? I've gone and ordered one in at the special orders desk at Bunnings but I don't know how long it will take to come in. Is it with persevering with the grey alox wheel, or should I just wait for the white one?All the way to this point I was thinking "grey wheel", then you confirmed it. Get a white wheel and retire the grey for the stuff your neighbour wants you to do for free.

[watson]

What Groggy said!!
Grey wheels are for axes and things like that......and then only lightly, or my missuses ride on blades.
Have fun

[munruben]

Have used my grey wheel a couple of times but haven't burnt the steel yet. I got a $40 Bunnings gift card for Christmas so might see if I can get a white wheel with that

[munruben]

Can I get a white wheel for my small grinder, I think its an 8" one. Do the wheels fit all model grinders?

[Groggy]

John, you should be able to get white wheels for just about any grinder. If it is a 'small' one, as you say, then it is likely to be a 6", not 8". Best check it before you splash the cash. If in doubt, take a wheel with you (make sure they check it when you carry it in the store).

For jisk, are you dunking the steel in water regularly? You need to grind for 1-2 seconds then dunk for 3-4 seconds, depending on the material and its thickness, when nearing the edge you should do less grinding and more dunking.

[powderpost]

Short answer... yes. Smallest wheel I have bought was 150mm diam x 12.5mm thick. The hole in the wheel is usually about 30mm diameter and often sold with plastic inserts to suit the grinder shaft diameter. If no inserts are available, I turn a wooden bush with a hole to suit the shaft, (usually 15mm diam.) and outside diameter to suit the hole on the wheel. That's been my experience any way.
Jim

[Ron Dunn]

This is why I don't have a grinder.

Wet-and-dry paper does me just fine. Even if I was to sharpen every cutting edge in my workshop ... 6 chisels, 3 planes and a marking knife ... it would only take me 30-40 minutes.

A little time is a good trade-off against the cost of a grinder and ruined steel, and I've got a feeling my tools will last longer.

[J.E. Mike Tobey]

May I humbly suggest getting an accessory grinding platform. Often when one first starts on a grinder, even with the factory guides(they are lousy), one fights to retain the desired bevel. This leads to too much pressure and often staying on the wheel too long just to finish off that grind. Always have your can of water and dunk even if there is no burning. mt

[jisk]

Groggy, I was dunking the blade in water regularly, although not exactly to the tempo you described - I was doing 1 - 2 seconds on the wheel, then a quick dip in water (less than a second).

I think I'll wait for the white wheel, rather than getting frustrated.

Mike, getting a secondary grinding platform is certainly on the "todo" list. The stock tool rest is terrible. At the moment I'm tossing up between the:

Sabre Sharpening Centre (http://www.cws.au.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107144916&product_id=1107398012) ($49, CWS)
CJ-04 Grinding Jig (http://www.cws.au.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107144916&product_id=1107369825) ($49, CWS or Carbatec), or
Veritas Grinding Jig ($expensive)

I figured I'd leave that for a little while though, to see how I do with the stock tool rest. 95% of the time I will be grinding a 25 degree bevel so I won't be doing a lot of complicated stuff.

[China]

As Groggy said you must dip the blade in water and long enough for it to cool down, as you get close to the edge it will heat up faster, if you don't do this it will not make any difference what type of wheel or what type of rest you have.

[Groggy]

jisk, I had one of the CJ-04 until just after I removed it from its wrapper, then I returned it - what a piece of junk. The rest was soft aluminium and the steel slide "stuck" to it as you moved it, I would not recommend it. The other one looks better, but it is hard to tell from a pic.

(I did not buy the CJ-04 from Carroll's btw)

[Tiger]

As others have said, white wheels are the way to go. Only ever use the grey wheels to clean up welds.

[jmk89]

I have taken to using a spray bottle of water squirted at the edge when I am grinding. It keeps the edge cool and means I don't have to move the the blade back and forth from the water bath to the grinding wheel. The squirt bottle is in my left hand and I hold the blade (etc) in my right.

My next development may well be to take a cheap airbruch unit and set it up to spray cool water at the edge (it will have to be able to move a bit to accomodate different angles of grinding). I haven't yet worked out all the details, but I reckon it should work.

PS - I also use a white wheel. But id you really want to stop burning, a Blue Max wheel is meant to be even better.

[fred.n]

Get a white wheel and retire the grey for the stuff your neighbour wants you to do for free.
Nice!! :2tsup::2tsup:

[China]

I have a Blue Max wheel my personal opinion, not realy that much better than your standard white wheel, in fact I think it tends to glaze quicker than the white wheels

[jmk89]

I think this comes back to an issue we have debated before - there are two aspects of dressing:

to de-glaze - for which either a point diamond dresser or preferably (IMHO) a star wheel dresser is the way to go;
to square and round the wheel - and here I prefer a diamond dresser