The Ultimate Grinding-Sharpening Set Up?

[Derek Cohen (Perth Oz)]

Hi Charles

I agree with you. It is simply not possible for any medium for long to be used without a way to remove swarf. It has to build up in the valleys. It is not only Spyderco that state they can be used dry, but diamond stones - and indeed you suggested sandpaper for a dry system as well. But we know that swarf has to be brushed from sandpaper, and then there is this dust.

When I think of the way I use the Spyderco stones I recognise that I am actually not using them "dry" in the sense that they are used without any lubrication. My workshop has running water, which was plumbed in specifically for sharpening with waterstones. I hone on the draining board. After each grit a blade water runs over it to remove the swarf on the blade. I could just use a paper towel but water is easier. I do not dry the blade, and consequently the water on the blade lubricates the next stone.

I do envisage these stones will need some maintenance, such as scrubbing, but that this will be far less than the upkeep of waterstones. There is also far less paranoia about flatness, although I do suspect that they will wear and that this needs to be part of the maintenance cycle.

What I can reaffirm is that the Spyderco stones have not loaded up, do not have the mess associated with waterstones - even ceramic waterstones, and produce a good finish. In other words, they are a cleaner medium, for which my hands are grateful.

Regards from Perth

Derek

 

[Corneel]

Spyderco's don't need to be so expensive. Here in The Netherlands for example, the ultrafine 20x5 cm is 63 euro.
http://www.knivesandtools.nl/nl/pt/-spyderco-302-keramische-wetstenen-ultrafijn.htm#
But this size is more suitable for hand sharpening without a jig, especially when you want to sharpen wide blades too.

At the moment I am enjoying myself with natural oilstones, a Washita and an Arkansas. In that regard I don't see myself switching anytime soon. But those CBN wheels are intruiging. I hear you when you write about the dust, Derek! I have one of these Norton 3X wheels and while they grind lovely, the dust is indeed problametic. Not so much when grinding (or at least I don't recognise it) but when dressing the wheel the dust cloud is pretty bad.

The link to the website of Peter Child in the UK is interesting but I don't get very far. All the links are broken and I get lots of error messages.

 

[Trafalgar]

Derek, you certainly won't get an argument from me that the Spyderco stones are an improvement over waterstones. They are and they can also be used as a base for using finer grit loose powders for instance.

 

[bugbear]

Derek, you certainly won't get an argument from me that the Spyderco stones are an improvement over waterstones. They are and they can also be used as a base for using finer grit loose powders for instance.

You mean the loose powders are a finer grit (small particles) than the underlying Spydeco?

BugBear

 

[Corneel]

A question about the CBN wheels. Say, I scored a nice ancient chisel or plane blade, but the pitting near the edge is pretty bad and the angle of the bevel is close to 45 degrees. The usual state of afairs in these things. Would you be comfortable to grind back half a cm and establish the bevel again on these wheels? And what kind of grit would you want to use for jobs like that?

 

[Derek Cohen (Perth Oz)]

Derek, you certainly won't get an argument from me that the Spyderco stones are an improvement over waterstones.

Charles, I would not go that far

In fact, I would not try and convince anyone that one media type is better than another - they all have pro and cons, all may be "best" for a specific task or at a specific price. Spyderco are only less messy than ceramic waterstones, but they do not cut as fast. It is only with a minimal amount of steel from the hollow grind that they are able to perform this well.

Regards from Perth

Derek

 

[Derek Cohen (Perth Oz)]

A question about the CBN wheels. Say, I scored a nice ancient chisel or plane blade, but the pitting near the edge is pretty bad and the angle of the bevel is close to 45 degrees. The usual state of afairs in these things. Would you be comfortable to grind back half a cm and establish the bevel again on these wheels? And what kind of grit would you want to use for jobs like that?

Hi Kees

5mm is a lot to grind. The 80 grit CBN wheel could do it better than most/all wheels, but it would still take a long time. I would prefer to take off 4mm with a thin cutoff wheel on a Dremel, and then grind the remaining 1mm.

Regards from Perth

Derek

 

[Corneel]

Yes 5mm is maybe a bit too much for this example. But 2 mm happens more often, and then it is regrinding the bevel that takes so much time, not grinding back at 90 degrees to remove that 2 mm. Especially when you also need to regrind the angle when it is way too steep.

 

[Trafalgar]

Derek, you certainly won't get an argument from me that the Spyderco stones are an improvement over waterstones.

Charles, I would not go that far

In fact, I would not try and convince anyone that one media type is better than another - they all have pro and cons, all may be "best" for a specific task or at a specific price. Spyderco are only less messy than ceramic waterstones, but they do not cut as fast. It is only with a minimal amount of steel from the hollow grind that they are able to perform this well.

Regards from Perth

Derek

Yes. The whole 'fast cutting' bit really doesn't apply to hollow ground cutters does it. In fact, I would think it's almost a drawback - removes more metal than necessary at each honing. When removing steel right at the tip there's no need for speed. Even a so-called "slow" stone is done in seconds.

 

[Phil Pascoe]

Why should you remove more metal than is necessary? It's entirely up to you how much you remove.

 

[Corneel]

The speed comes in when you are a few honings further along, you have a secundairy with some size and then you want to raise a wireedge again on the primairy angle. Then a fast stone is very helpfull.

 

[bugbear]

The speed comes in when you are a few honings further along, you have a secundairy with some size and then you want to raise a wireedge again on the primairy angle. Then a fast stone is very helpfull.

I'm a double bevel user (mainly), and I never raise a wire edge when working the primary; I simply work the primary until the secondary is down to an acceptable size (around 1/64").

But, yeah, coarse grit FTW when working the primary - it's just waste removal.

BugBear

 

[Trafalgar]

Manage the size of the primary with the grinder -- it's the right tool for the job. Properly used, a grinder never raises a burr (therefore reducing cutter length) unless one is taking out a nick. Otherwise, it's just used to keep the primary from growing.

This is why large diameter wheels and thin plane irons do not mix. It's ticklish to grind without producing a burr.

If you own a grinder the last thing you need are 'fast' honing stones.

 

[bugbear]

This is why large diameter wheels and thin plane irons do not mix. It's ticklish to grind without producing a burr.

Could you explain - I don't see problem there at all, as long as the primary grind angle and secondary honing angle are different.

Just don't let the secondary reduce to zero - simple.

BugBear

 

[Trafalgar]

This is why large diameter wheels and thin plane irons do not mix. It's ticklish to grind without producing a burr.

Could you explain - I don't see problem there at all, as long as the primary grind angle and secondary honing angle are different.

Just don't let the secondary reduce to zero - simple.

BugBear

Grind a hollow on a big wheel and see for yourself. It's much easier to tweak the size of the secondary with a smaller wheel.

 

[Derek Cohen (Perth Oz)]

Manage the size of the primary with the grinder -- it's the right tool for the job. Properly used, a grinder never raises a burr (therefore reducing cutter length) unless one is taking out a nick. Otherwise, it's just used to keep the primary from growing.

This is why large diameter wheels and thin plane irons do not mix. It's ticklish to grind without producing a burr.

If you own a grinder the last thing you need are 'fast' honing stones.

Charles, I mostly agree with you - but that is the grinding side. Not the honing side.

Here is a Mathieson tapered blade I am restoring for use in a woodie.

This illustrates the reason I consider how a grind from a CBN wheel can have a profound effect on the speed of sharpening and, more importantly, future resharpenings.

The blade is ground to the edge. The wire edge created is minute - it can only be recognised by feel.

It can be seen that the hollow from an 8" grinder is shallow indeed. That from a 10" wheel is even shallower.

There is another factor to consider in my grinding set up: the reason I use the Tormek system to guide the blade is that it can be accurately set and re-set. It is not important that the angle one uses is exactly anything. It is important for me that I can repeat the setting. This removes waste from the hollow (but to the edge) and does not appreciably shorten the blade.

The speed comes in when you are a few honings further along, you have a secundairy with some size and then you want to raise a wireedge again on the primairy angle. Then a fast stone is very helpfull.

Exactly!.

Bugbear wrote: I'm a double bevel user (mainly), and I never raise a wire edge when working the primary; I simply work the primary until the secondary is down to an acceptable size (around 1/64").

BB, my argument against a secondary bevel (unless there is no option, such as with a BU plane blade), is that it seems a shortcut at the time, but then you pay for it later on.

It appears to me that there are just two ways to maintain an edge:

1. Hone on media that ensures that the bevel meets the back of the blade. this could be divided into two camps: (a) lift the blade and hone at a higher angle (this is the situation where you use a secondary bevel, or the rounded bevel approach of Paul Sellers), or (b) maintain the current bevel angle (easier to do by honing on the face of a hollow grind).

The temptation is to do (a) since it requires less work. This may be misleading since later one has to restore a lower bevel angle.

2. Strop the blade. Again there are two methods here: (a) use a leather strop, either plain or with an abrasive. What this appears to do is create a fine, round secondary bevel. In essence, this is the same as 1a. (b) use abrasive (such as green compound) on a piece of wood or MDF - which we may call a "strop", but is it really? It seems to me that this is really a version of 1b.

Again, the temptation is to do 1a in the belief that it will be quicker. Indeed it may be, but eventually one will need to flatten the bevel.

What do I do? Well I swing back-and-forth between a hard horse butt leather strop and compound on hardwood. At the moment I am doing the latter.

Regards from Perth

Derek

 

[bugbear]

Grind a hollow on a big wheel and see for yourself.

My largest wheel is 6", so experiment is not an option.

So I asked a question on a forum

BugBear

 

[G S Haydon]

I'm not sure there is much of a difference between hollow & secondary. On the hollow you have to touch it on a grinder when there is too much to hone, ditto the secondary. I would think a secondary would last for longer as you aren't having to hone around the perimeter of the hollow, just the tip.

 

[Trafalgar]

Dropping back to hone the primary to control the size of the secondary removes an unnecessary bit of metal at the heel of the hollow. Unnecessary in the sense that it's not really a bench stone's job if a grinder is available RIGHT THERE in the shop. One can hone on the grinding angle, and I've certainly done that to preserve low angle on a paring chisel or two, but if you're going to grind then might as well hone with a small lift and keep all the action at the cutting edge as far as the stone-work is concerned.

And let the grinder do the heavy lifting at all other times.

Once it is understood that the grinder should not be removing steel at the tip (i.e. producing a burr on the flat side and likely overheating the steel as well) one becomes more apt to use it frequently, and deftly.

This is one of those circumstances where the cheap tool is the best one for the job -- a 6" grinder (and gettin' smaller all the time) is perfect IMO. Large stones should always be water-cooled (and historically were) because it's harder to keep them from grinding to the edge on certain tools.

When honing just the tip, a fast stone becomes more a hindrance than a help. Something slower is called for but don't be put off - we're talking in terms of a minute or so at most to hone the tip even with a well settled-in natural Arkansas for example. If it is taking longer it's time to grind.