Grindstones

[John Saxton]

I don't know whether this topic has been broached before so I thought that I would elicit your responses in the vain hope I and everyone else may learn something.
With the need to keep a grindstone wheel square and with the constant dressing that it does require to keep a clean and straight wheel,what is the limit of wear on a grindstone wheel before replacement should be considered?

With an important tool like this in the shop I am surprised that there is very little in the way of discussion in this regard.

Many a person may have a special tool rest that grinds at the appropriate angle whilst the stone is within the confines of its dimension but what happens when that stone is reduced by wear and maintenance?

I have yet to see any paremeters for the wear of a stone but my guess would say that 10% is too much!!
What are your thoughts???
Cheers http://ubb.ubeaut.com.au/ubb/smile.gif

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Johnno

[Lofty]

You don't need much reduction in grinding wheel diameter to affect tool angles - especially those ground to a small angles like turning chisels. (The angles for scrapers are hardly affected)
I've built one of those stepped swivel block arrangements and compensated for wheel wear by inserting 1mm aluminium shims (7 of them ).

For a 150mm wheel (6ins if you're as old as me), a decrease of 2mm requires one shim to be removed otherwise the included angle (12.5 deg which gives the 25 deg) decreases to 22 degrees which means you will waist time as you grind the angle finer and later lose a lot of steel when you finally compensate.

The seven shims I use will only let me get down to 136mm dia = 10% although I haven't got that far yet.

I've got the steps and shim sizes on an Excel spread sheet if any one wants them. The biggest trouble with blocks is that some of the steps are quite thin.

This post might be of use to the turners BB too.

Lofty

[ubeaut]

Lofty - very few turners who know what they are about use the tool rest as a tool rest. It is more often used as a hand rest to steady your grind a little. Many professional turners don't even have a tool rest.

Most are also very tight and often lazy, meaning that they don't change their 12" wheel until it is somewhere around 5" or less.

Pretty well all re surface their wheels very regularly. This keeps the grit sharp and cuts down dramaticaly on sharpening time.

If you have a 12 " wheel then it would be silly to throw the wheel away when it loses 10%. It could lose 50% and still be the size of a wheel that goes on a 6" grinder which in turn could stand to lose 10%. Yeah, the turners have got it worked out wait till itr's about 5" or less and turf it.

There are lots of great jigs on the market today that will aid in the sharpening of almost all tools. If you match these with a good grinder, the right type and grade of wheel and a GOOD wheel dresser then it should be a breeze for even the the most inexperienced novice. Most jigs allow for ajustment when the wheel wears.

Cheers - Neil

PS this is basically from a turners perspective. One who doesn't believe in using jigs, just skill.

[RETIRED]

Gooday.

I'll second what Neil says.

I have used a wheel that has gone to 4". Had no choice. Demo at a club and that was all they had but it still sharpened the tools.

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Ian () Robertson
"We do good turns every day"

[John Saxton]

That was the response I was kinda hopin' for.......from the guy's who are at it all the time unlike a lot of us part-timers.
Cheers http://ubb.ubeaut.com.au/ubb/smile.gif

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Johnno

[RETIRED]

Lofty emailed this to me and with his permission I have placed it on the board.

C'mon Guys!!!

I'm only a poor part timer. Some of us have to WORK for a living http://ubb.ubeaut.com.au/ubb/smile.gif at things we'd rather not be doing!

My main interest in the shed at the moment is restoring old furniture or making squarish items (mainly because of a distinct lack of room for a decent lathe) and, because I only get to work out there at the weekends (and then only every so often), I enjoy the confidence of using the platform, particularly for plane blades and wide chisels. I don't do a great deal of turning - yet - so I use the blocks for that too. Sorry if it offends you purists *S* but I reckon there are a lot of part timers out there that would agree.

HOWEVER!!!! Just wait for another nine months and I'll be retired. We've bought a property in Tassie with a bloody great barn that's earmarked for my workshop. Then I'll have the time, the money and the room to really get stuck in - but I reckon it might still be a while before I give up the platforms http://ubb.ubeaut.com.au/ubb/smile.gif

I've made this a personal e-mail because I didn't want it to appear as if I were bitching on the board. I thoroughly enjoy WABB - keep up the good work.

Best Regards

Lofty

My answer is as follows

Paul.

Do you mind if I post this on the BB under the original heading.

If you read Neils reply fully he states that there are jigs on the market and a lot of people use them.

We don't mind criticism, it is what makes the world go round and we are quite aware that most posters on the BB are amateurs.

What we try to do is answer the questions from our perspective as those who "have been there, done that" to try to save people from the same stupid mistakes that we have made.

For what it is worth most pros don't sharpen their own jointer, router bits or thicknesser blades prefferring to send them out. We may hone them but not sharpen.

Regards .


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Ian () Robertson
"We do good turns every day"