flattening chisel backs with lapping film

[GazPal]

I don't have any doubts regarding a fine India stone's ability to refresh/create a new chisel edge and do primary flattening in very short time. Especially if considering the minimal amount of work found necessary in Jacob's example chisel.

Matching stone to steel is best done in reverse order and rather than begin with the coarsest stone - I normally begin by using a medium stone - the best course is normally to start the process with a comparatively fine stone and switch to a coarser grit if necessary and work forward from that point. It's a wasted effort working with coarser than necessary grits. India oil stones - unlike water stones and natural stones - don't tend to vary in hardness, so more attention needs to be paid regarding grit size used.

 

[bugbear]

So you are calling me a liar? Fine, that's what I expected from you! I 'd be disappointed otherwise. :lol: :lol:
ot) harder subsequently.

You've edited away the bit where I explain WHY your claim is true!!

If you want to call yourself a liar, be my guest, but I didn't do it.

Once a chisel has a flat back, you only need to use your finest abrasive to remove the burr, which is done at the end of the honing process - No other work is need on that side. You don't sharpen by working the flat face, you sharpen by working the bevel.

Since burr removal is done at the end, it doesn't matter if you're a jigger or hand sharpener, since you could take the blade out of the jig, since you won't need it again.

Everybody's happy.

BugBear

 

[Jacob]

................ You don't sharpen by working the flat face, you sharpen by working the bevel.

I work the bevel until a wire edge appears right across*, then remove it by doing face - bevel - face etc. alternately, usually shorter passes each time, until it's all gone. If you go straight to face the wire edge gets pushed back onto the bevel side so it's handy to work it from both sides.

*right across is particularly important for plane blades as they usually wear most in the middle and the burr comes up there last. If you stop too soon you can have a plane blade only partially sharpened.

 

[Corneel]

This is a very interesting thing about sharpening, we don't read much about. What happens to the wireedge? I have the feeling this bending back and forth is mostly an oilstone thing, because oilstones aren't super fine. Using waterstones you tend to go to finer stones, and I have the feeling that I really remove all the wireedge when I LIGHTLY polish the faceside on an 8000 stone. Then I rub some more with the faceside on the 8000 stone to remove all wear bevels and wearscratches that migh be lingering back in this area. Finally I indeed give the bevelside another lick and at last the faceside.

But I must say, I really don't know if this is correct thinking. It's just how I remove the wireedge. I can't feel that back and forth bending at all with my fingers.

 

[Jacob]

......., because oilstones aren't super fine.

The super fine ones are super fine; black Arkansas etc. That beige one of mine (above) is synthetic but pretty fine for all normal purposes.

Using waterstones you tend to go to finer stones, and I have the feeling that I really remove all the wireedge when I LIGHTLY polish the faceside on an 8000 stone. Then I rub some more with the faceside on the 8000 stone to remove all wear bevels and wearscratches that migh be lingering back in this area. Finally I indeed give the bevelside another lick and at last the faceside.

But I must say, I really don't know if this is correct thinking. It's just how I remove the wireedge. I can't feel that back and forth bending at all with my fingers.

Sounds much the same with oil stones. I've never at all felt that "back and forth bending ... with my fingers" either. :lol:

 

[Corneel]

Ok, maybe you're right. It's really hard to see or feel what happens at that level. It's just when an edge disappoints after sharpening, you start to scratch your head.

 

[Jacob]

Ok, maybe you're right. It's really hard to see or feel what happens at that level. It's just when an edge disappoints after sharpening, you start to scratch your head.

Well actually they often seem to hang around like tiny bits of wire stuck to the stone. Some more than others - it depends on the steel. Some (laminated?) edges seem to develop a big wire edge like thin tinfoil. Stanley 5001s do this.

 

[Racers]

I would have thought the softer steel the more a wire edge would hang on, harder steel it will fracture more easily.
I have had a problem getting rid of the wire edge on a cap iron.

Pete

 

[Modernist]

Hey Ho, another day and the flat backers hone on.

 

[GazPal]

I know newcomers are sometimes misled into believing they have a flawed edge on their chisel/plane blades as they comment on fine edges crumbling or rolling over, but this in fact is often the presence of the wire edge which hasn't yet separated from the main blade/iron. Indeed, this wire edge sometimes disintegrates during the honing process - depending on how one progressed through the grits - while other times it will curl away and separate as a singular micron thin sliver of steel and be left on the stone surface. I've had apprentices complain of their inability to raise such a burr, until shown that a few extra swipes on the finest of their stones will raise and separate this sometimes elusive piece of steel to leave a surgically fine edge behind. A quick strop helps refine/refresh and align the edge ready for use.

 

[Jacob]

Hey Ho, another day and the flat backers hone on.

:lol: Some way to go yet!

I would have thought the softer steel the more a wire edge would hang on, harder steel it will fracture more easily.
I have had a problem getting rid of the wire edge on a cap iron.

I don't know quite how it works but the wire edge on hard steel 5001s seems quite persistent - springy and tough. I'll try and take a photo.

 

[GazPal]

I would have thought the softer steel the more a wire edge would hang on, harder steel it will fracture more easily.
I have had a problem getting rid of the wire edge on a cap iron.

Pete

Stropping normally removes the wire edge, but I tend to find burr more tenacious if jumping grits instead of steadily progressing through them to remove all scratch marks to create an edge.

 

[bugbear]

Hey Ho, another day and the flat backers hone on.

The person demonstrating flat back preparation is Jacob!

BugBear

 

[bugbear]

I would have thought the softer steel the more a wire edge would hang on, harder steel it will fracture more easily.
I have had a problem getting rid of the wire edge on a cap iron.

Pete

Stropping normally removes the wire edge, but I tend to find burr more tenacious if jumping grits instead of steadily progressing through them to remove all scratch marks to create an edge.

Burr persistence seems to happen at the hardness extremes. As Pete said, if you work a cap iron, the wire edge prefers to flop from top to bottom rather than stay put and be abraded away. I also had difficulties when I put a knife edge on an old saw (to cut loft insulation rolls - worked a treat!).

Conversely, in the world of knives made from VERY exotic, hard and abrasion resistant steel, burrs can be monumentally persistent. In the case of a symmetric bevel on a knife, it's quite easy to end up such that the wire edge is actually nice and centrally aligned, so that the cutting is actually being done by the wire edge, not the true edge. With some of the exotic steels, such an edge can last a couple of weeks (in domestic kitchen use) before chipping of flopping over (which is amazing, but irksome).

 

[Kalimna]

Out of interest, what kind of exotic steel are you talking about wit regard to knives? CowryX, or more rareified?

Cheers,
Adam

 

[Modernist]

Hey Ho, another day and the flat backers hone on.

The person demonstrating flat back preparation is Jacob!

BugBear

We tend to be joined at the bar, rather than the hip you know

 

[GazPal]

I would have thought the softer steel the more a wire edge would hang on, harder steel it will fracture more easily.
I have had a problem getting rid of the wire edge on a cap iron.

Pete

Stropping normally removes the wire edge, but I tend to find burr more tenacious if jumping grits instead of steadily progressing through them to remove all scratch marks to create an edge.

Burr persistence seems to happen at the hardness extremes. As Pete said, if you work a cap iron, the wire edge prefers to flop from top to bottom rather than stay put and be abraded away. I also had difficulties when I put a knife edge on an old saw (to cut loft insulation rolls - worked a treat!).

Conversely, in the world of knives made from VERY exotic, hard and abrasion resistant steel, burrs can be monumentally persistent. In the case of a symmetric bevel on a knife, it's quite easy to end up such that the wire edge is actually nice and centrally aligned, so that the cutting is actually being done by the wire edge, not the true edge. With some of the exotic steels, such an edge can last a couple of weeks (in domestic kitchen use) before chipping of flopping over (which is amazing, but irksome).

I'd intentionally added the pointer that stropping typically removes any residual wire edge, because it's often impractical for one to continue with honing. Refining your progress through grits does tend to reduce such problems and regardless of steel grade or the alloy involved.

Old brick trowels also make great loft insulation cutters, but don't need to be razor sharp in order to work well. :wink:

In terms of knife edges, the burr you mention is often the best cutting edge for butchery/carving meat and capable of being re-aligned and maintained using a polished steel/burnisher until performance drops off and the edge is re-honed. The world of knives tends more toward use of far finer whetting angles than the ones used by woodworkers - barring marking knives.

 

[Mister S]

...... A quick strop helps refine/refresh and align the edge ready for use.

Reading the last few posts it seems to me that the outcome of so many threads that veer into sharpening territory seems to be a "quick strop", especially when the usual protagonists get involved

I try, I really do. I promise myself that I won't keep reading sharpening threads, but I can't help it. I see a new post bump the thread up to the top of the list and I'm drawn in.

Maybe I need some sort of help :shock:

Steve

 

[GazPal]

...... A quick strop helps refine/refresh and align the edge ready for use.

Reading the last few posts it seems to me that the outcome of so many threads that veer into sharpening territory seems to be a "quick strop", especially when the usual protagonists get involved

I try, I really do. I promise myself that I won't keep reading sharpening threads, but I can't help it. I see a new post bump the thread up to the top of the list and I'm drawn in.

Maybe I need some sort of help :shock:

Steve

Enough said.

 

[Mister S]

Gary

Sorry if I caused offence, I only quoted you because of the reference to stropping. It was others I was actually thinking of who seem to ride their favourite hobby horse at the drop of a hat and get upset with others.

It's just that there is a lot of good advice and information given out about sharpening, by pretty much all the posters, including your good self (and I have to say the hobby horse riders too), but it seems to get a bit lost in the arguments between some posters.

Steve