Wire edge removal

[Mister S]

I've just finished flattening the backs of some new chisels and polished them using diamond paste on an MDF lap - so far so good. I set up my Veritas mk 2 guide to hone the primary bevel using a 1200 grit waterstone. I was just about to start honing when a thought struck me. I can't polish the back of the chisel on the waterstone to remove the wire edge, because it is rougher than the already polished surface.

On the other hand I can't use the lap I polished the blade back with as it could become contaminated with grit from the waterstone. So what's the best way to remove the wire edge? What do other people do?

There's probably a really simple answer that's staring me in the face, but I just can't see it ....

Steve

 

[Cheshirechappie]

Just an opinion - the back of a chisel needs to be flat, but how polished does it need to be? I think the scratch-depth left by a polishing stone in removing a wire edge are not going to be detrimental to good functioning of even a fine paring chisel. A couple of swipes over the polishing stone is not going to remove enough material from the chisel-backs to do any real harm.

 

[Harbo]

Make sure your blades are clean by wiping off carefully and use the MDF/paste.


Rod

 

[woodbrains]

Make sure your blades are clean by wiping off carefully and use the MDF/paste.


Rod

+1

Mike.

 

[Mister S]

Thanks for the quick replies chaps.

I agree there will be no detrimental effect to the back, but I'm looking for a good level of sharpness that comes with a polished back/bevel.

Rod/Mike - I'll give it a go any clean off any polishing medium carefully. I've already found out the hard way what stray grit can do to a polished surface

Steve

 

[Jacob]

Most people don't bother polishing the face (flat side) as there is no point unless (perhaps) you are doing some very fancy long paring such as a pattern-maker might.
Normal is to sharpen the bevel and then take off the wire edge with the face flat on the stone for a few gentle swipes, then strop on your hand or leather. The face ends up a bit polished after enough use.
Waste of time most of this tool polishing!

 

[Cheshirechappie]

Another way of removing a wire edge is to draw the edge of the chisel through the end of a piece of softwood.

A cutting edge can only be as good as the finest finish on both bevel and back. So to get the benefit of polishing the back through to diamond lap, sharpen the bevel on 1200 grit, then increase the bevel angle by about 1 degree and polish on a finer grade, say 6000 grit. Then inrcease bevel angle again and lap on MDF/diamond paste. In use, strop frequently on MDF/diamond to maintain the fine edge. That should give an edge suitable for very fine paring or carving.

For most fine cabinetmaking purposes, polishing bevel and back at 6000 grit would give perfectly adequate service with a reasonably lasting edge. Touch up on 6000 grit when the edge starts to feel slightly dull.

For crash-bang-wallop work such as morticing and heavy chopping, just sharpening at 1200 grit would be plenty good enough - a polished or lapped edge wouldn't last thirty seconds anyway.

 

[bugbear]

Normal is to sharpen the bevel and then take off the wire edge with the face flat on the stone for a few gentle swipe!

Is this after each grit, or only the finest?

BugBear

 

[Mister S]

Another way of removing a wire edge is to draw the edge of the chisel through the end of a piece of softwood.

A cutting edge can only be as good as the finest finish on both bevel and back. So to get the benefit of polishing the back through to diamond lap, sharpen the bevel on 1200 grit, then increase the bevel angle by about 1 degree and polish on a finer grade, say 6000 grit. Then inrcease bevel angle again and lap on MDF/diamond paste. In use, strop frequently on MDF/diamond to maintain the fine edge. That should give an edge suitable for very fine paring or carving.

For most fine cabinetmaking purposes, polishing bevel and back at 6000 grit would give perfectly adequate service with a reasonably lasting edge. Touch up on 6000 grit when the edge starts to feel slightly dull.

For crash-bang-wallop work such as morticing and heavy chopping, just sharpening at 1200 grit would be plenty good enough - a polished or lapped edge wouldn't last thirty seconds anyway.

Thanks Cheshirechappie.
All sound advice, and gratefully received. You're right, it's horses for courses and the greater attention to detail for these chisels is because I want to use them for final, fine paring cuts. I have separate chisels for the roughing out tasks.

Most people don't bother polishing the face (flat side) as there is no point unless (perhaps) you are doing some very fancy long paring such as a pattern-maker might.
Normal is to sharpen the bevel and then take off the wire edge with the face flat on the stone for a few gentle swipes, then strop on your hand or leather. The face ends up a bit polished after enough use.
Waste of time most of this tool polishing!

Ah, Jacob.
I am a relative newcomer to the forum, but I have lurked long enough and read sufficient posts to know that some people like to eat their eggs starting at the blunt end, and others at the pointy end. I am happy with either.

So today, the fish are not rising. :wink:

Steve

ps - I will resist stropping on my hand, I get a fair few nicks on my hands already!

 

[woodbloke]

Most people don't bother polishing the face (flat side) as there is no point unless (perhaps) you are doing some very fancy long paring such as a pattern-maker might.
Normal is to sharpen the bevel and then take off the wire edge with the face flat on the stone for a few gentle swipes, then strop on your hand or leather. The face ends up a bit polished after enough use.
Waste of time most of this tool polishing!

Ah, Jacob.
I am a relative newcomer to the forum, but I have lurked long enough and read sufficient posts to know that some people like to eat their eggs starting at the blunt end, and others at the pointy end. I am happy with either.

So today, the fish are not rising. :wink:

Steve

Good...long may it continue. I use the 3M films from Workshop Heaven and all I do is give the bevel a coupla swipes on the strop with a bit of green icky chromium dioxide paste on it and then remove any wire edge on the 1 micron film - Rob

 

[Jacob]

........
So today, the fish are not rising. :wink:

......

Don't kid yourself - you have already taken the tool polishers bait, hook, line and sinker!
There are some on here who do little else. :roll:

 

[David C]

I would suggest that Steve uses a finer stone.

Get a small wire edge with the 1200 stone. Clean. Polish tip with 6000. 8000, or 10,000 grit at perhaps one or two degrees steeper angle.
Polish the back on the same stone.

This result should be very similar to Rob's on 3Mfilm.

My wire edge floats away, either on the stone or on a sponge cloth. No stropping required. The palm of the hand stropping just bent the wire edge back and forth till it dropped off. The end grain tore it off leaving a jagged edge. Stropping followed by leather strop with compound was widely used by cabinetmakers who sharpened on an India combination stone. The fine side was not really very fine at all and did not produce a particularly fine edge.

I think we will find that all craftsmen polish the backs of their bench chisels. The polish being the result of their finest (polishing) stone.

It is a very rare event, when students turn up with well prepared backs on their chisels. Performance is transformed when the backs have been corrected. This operation depends on understanding the dangers of the hollow stone.................

best wishes,
David Charlesworth

 

[matthewwh]

The wire edge created by honing should be so tiny that it barely exists at all, if the blade is hardened correctly it should almost fall off all by itself.

The only reason for pulling it off with something abrasive is that that is normally what you have in front of you when you have just sharpened, the something doesn't need to be abrasive to remove it.

Just lay the chisel over something soft (scrap of pine, leather, rag etc) and draw it towards you - job done.

 

[Mister S]

Rob
Thanks for that, it looks like the principle is the same, regardless of the medium you use.

David
Excellent advice. I had not thought about only removing the wire edge after polishing at the much higher grit stage. Rest assured the backs are flat, even though I used a waterstone. I had some very good advice about how to move the chisel around the waterstone while using it (and flattening the waterstone regularly). I got it from an excellent book (one of a series of three) purchased from an establishment in North Devon Signed by the author too!

Matthew
These are Ashley Isles chisels purchased from you - small world isn't it? Thanks for your reply. If the wire edge is small, your method should work, if the wire edge is a little larger, I will use a very fine abrasive.

I have also realised that cleaning up thoroughly when moving to a finer grit, should include not only the chisel, but also the roller of the honing guide. DAMHIKT

Steve

 

[Benchwayze]

Just an opinion - the back of a chisel needs to be flat, but how polished does it need to be? I think the scratch-depth left by a polishing stone in removing a wire edge are not going to be detrimental to good functioning of even a fine paring chisel. A couple of swipes over the polishing stone is not going to remove enough material from the chisel-backs to do any real harm.

+1
Also a polished back can 'turn' ( a bright line appears along the edges) including the back of the cutting edge. This ain't quite the same effect as the ruler trick on a plane iron, where again, polishing can 'turn' the edges. I like enough reflectivity in the surface to enable me to read newsprint in it. (Yes I can read mirror-writing!) :mrgreen: It also enables me to judge angles when mitre-cutting inlay for instance.

I strop the edge on the heel of my palm.

HTH

 

[Jacob]

....
I think we will find that all craftsmen polish the backs of their bench chisels. The polish being the result of their finest (polishing) stone......

Dunno. How often does one buy an ex craftsman's chisel and find it has a polished face? Never basically, except for the accidental polish due to regular use and honing. It's another of those funny little modern woodworking myths IMHO. Favoured by the ET.
After all what would be the point?

 

[Benchwayze]

Albeit that I worked for only a couple of years in the trade, I never came across mirror-backs at my workplace. There just wasn't time to spend on it. My woodwork 'mentor' never did it either. What was drummed in was the need for the backs to be flat, and as long as that is the case, then a satin smooth finish suits me, and reflects enough for my purposes. I believe my chisels are sharp.

I flatten the backs of my plane-irons for about 3/4" back from the cutting edge. That's enough to allow me to go from 'something' to 'nothing' (Theoretically speaking). and gives me a sharp edge. Any further flattening is wasted effort, I could be expending in the actual process of planing.

I haven't tried DC's ruler trick, and have never been inclined to, so I can't debate its efficiency. If I visualise it properly, then the rear of the iron is tilted up slightly. This must produce a knife edge at the business end, rather than a chisel-edge, which is the way I was taught. The way I sharpen suits me, but this doesn't mean I am 'knocking' something I haven't tried.

So that's me then! :wink:

 

[David C]

John,

Ruler trick is used for plane and other blades blades, but never for chisels

best wishes,
David

 

[Benchwayze]

Hi David...

Thanks for that. Yes, I was aware you do this only on plane irons.

When I mentioned a 'chisel edge' hone on a plane, I was referring to the 'section' that the back makes at the intersection of the honed bevel. This is going to be difficult to explain... :mrgreen:

When I treat the back of the iron, I flatten with the iron overhanging the edge of the stone, just far enough back (about 3/4") to give a flat surface to hone to, for a good edge, and a good seating for the chip-breaker. This also gives me leeway to alter the distance from the edge to the chip-breaker, as circumstances dictate. Thus, the backs of my irons, intersect their bevels to give a 'chisel-edge' section, as viewed side-on. I.e., a triangle.

I was trying to compare it to the section you would see on a knife-edge; ground on both sides, which I imagine is what you would have, after using the ruler-trick. It's entirely possible that I don't understand how the ruler trick works in practice and as stated, I have never used it so far.

However David, I promise you, when I have finished my current project, I will give it a go on a No. 4. I will then be in a position to report back.

In for a penny... as they say!

Many Thanks.

 

[Jacob]

......... It's entirely possible that I don't understand how the ruler trick works in practice and as stated, I have never used it so far.

The ruler trick is just a particular way of doing a little bevel on the flat face of a plane blade in addition to the normal bevel on the back.
It's easy to do without a ruler and TBH I've never seen the point of the ruler for this job.
It's an old way of dealing with a poor quality face e.g. rust pitted, as it takes the edge into good metal below, but will alter cutting angles and if too far back will stop the cap iron seating properly. In other words it's a bodge for a rusty old blade.
Talking of double bevels - carvers use these a lot on chisels and gouges. They also polish behind the edges but usually just a few mm as necessary, as unlike most woodworkers the actual chisel cuts may be visible and may need to be perfect.
In most other woodwork most chisel cuts are hidden away and polishing isn't necessary and nobody bothers (except the tool polishing brethren - you name it; they'll polish it!)