Hollow grind or linish??

[TomH]

At the woodworking show yesterday, the man from timbecon was demonstrating all sorts of sharpening gear. People were aking him about preferred methods for sharpening, and he was advocating a tormek type machine followed by waterstones.

He also had a benchgrinder and was selling aluminium oxide wheels. I volunteered that I use the linisher more than the oxide wheel and he made a remark to the effect of my chisels would be bloody useless due to the heat. I do this carefully with light pressure and cool often.

Now, heat generation is proportional to speed of the sharpening apparatus and pressure. My grinder/linisher runs off the same shaft (normal bench grinder/linisher). My grinding wheel diameter is 6", but the wheel driving the linisher is smaller - say closer to 4". Therefore, the linear velocity of the linisher is much less than the grinder - so for the same amount of pressure, it should be better. What do you all think? Do you prefer a linisher to hollow grinding?

One more question while I am at it. Hollow grinding obviously produces a hollow (3" raduis in my case) on the chisel. In small chisels, this is easily removed when using the stones. However, when sharpening mortise chisels which are much thicker (1/2"+) this hollow becomes more pronounced. Is it neccessary to remove the entire hollow when using the waterstone?

Cheers,

Tom

[Cliff Rogers]

G'day Tom.

Go here (http://www.woodworkforums.com/showthread.php?t=16776)& read all the links about sharpening & then come back & ask any further questions, it will save a lot of typing. :wink:

PS. The man from timbecon was grandstanding.

[Barry_White]

Tom,

The biggest problem you had was that you were talking to a salesman who was trying to sell you a Tormek and he was going to rubbish anything you were doing to prove his point.

As far as the hollow grind is concerned is that when you sharpen the chisel on the stone the idea is not to remove the hollow grind on the first sharpening. The longer you have the hollow grind the more sharpening you will get out of the chisel before you have to grind it again.

As a pattern maker who used to sharpen chisels and gouges all day everyday the less grinding you did the better. That meant you could touch them up on the stone for a week before having to grind them again.

Keep doing what you are doing. Just remember there are more ways of killing a cat than just beating it to death. Any way you do it will accomplish the same result.

[derekcohen]

Tom

The man wants to sell Tormeks. Nothing wrong with a Tormek, just with his manner.

Using a lowish grit on a belt sander you are less likely to burn an edge than on a bench grinder. I use both, with 120 grit on the belt sander and 60 grit on the grinder when (re)grinding an edge.

The flat face is for all blades used bevel up (that will receive a microbevel) and mortice and Japanese chisels. A hollow grind on these chisels is not recommended as it weakens the backing. Add a microbevel to mortice faces and leave the Japanese ones flat. Microbevels are added with a honing guide.

On bevel down plane blades and all other chisels (except lathe chisels) I hollow grind for ease of freehand honing.

The above represents one of 60 ways to leave your edges sharp (apologies to Paul Simon).

Regards from Perth

Derek

[Grahame Collins]

Tom
Having used both tools I can tell that the linisher wins hands down . Having sharpened hundreds of knives ,many on the linisher they are finish razor sharp,meaning they take off hair.

Not only can a linisher hollow grind but it is also capable of a convex and straight grind.

I use a Multi Tool linisher and my only criticism of of is that there is a bit of fluffing around to set up the guide and keep it square. It gets off square all too easily.Hence I do do my chisels by hand on the stone.Yep! they take hair off too.

As a Man Arts teacher I have sharpened my fair share of chisels.Most of them were done on the stone.,the nicked ones were sharpened first on the grinding wheels.We had a Tormek but it takes too long to sharpen 96 chisels when they need doing.

Grahame

[rsser]

Thanks for the post Grahame.

Tell us more ... what works best with what?

[routermaniac]

Tom,

The biggest problem you had was that you were talking to a salesman who was trying to sell you a Tormek and he was going to rubbish anything you were doing to prove his point.




I can remember walking around the WWW show in Melbourne (last year) with my father in law. Out of interest we decided to look at a Tormek display (dont remember who had it set up). We both hollow grind our chisels and microbevel with waterstones.

The guy behind the counter had sharpened this chisel and was handing it around for people to see how sharp it was, "razor sharp". He passed it on too me, I had one look at it and shaved a couple of hairs from the back of my forearm.

I smiled and handed it straight back to him. That was not a sharp chisel, in fact if he thought THAT was sharp he probably never used a sharp chisel in his life.

The problem with some of these shows is that some demonstrators have no or little clue about what they are demonstrating and this can be misleading to the poor bugger on the other side who is hanging on their every word...

regards

Marios

[derekcohen]

I can remember walking around the WWW show in Melbourne (last year) with my father in law. Out of interest we decided to look at a Tormek display ......

Marios

An old post of mine ...

http://www.woodcentral.com/cgi-bin/handtools.pl?noframes;read=53157

Regards from Perth

Derek