Not too shiny sharpening.

[Chris Knight]

Regardless of how a sharp edge is obtained, it will have a couple of characteristics that are easily checked.

1. You cannot see it - I use my Optivisor to check this and whilst of course a microscope would reveal it, I feel that the low power magnification of the Optivisor is enough. Any reflection, no matter how tiny, seen along any part of the edge under a strong light, indicates a blunt spot

2. When you cut a softish piece of wood across the grain, the edge should leave a perfectly smooth surface with no scratch marks evident in the cut surface behind the advancing blade. Invariably, scratch marks will be found to correspond with reflections as in (1)

It pays to keep a lump of wood to hand so that during sharpening, the edge can be checked at various stages. The difference between a sharp edge as noted above and one that is "nearly" sharp is very noticeable in terms of the effort need to push the blade through the wood. Pretty soon, one comes to recognise what remains to be done to make the edge truly sharp and this knowledge helps inform the process of maintaining a sharp edge on the tool between major grindings etc.

 

[Noel]

I find ears are a good indicator of sharpness too.

Rgds

Noel, who isn't waiting for a witty reply....

 

[Shady]

Noel that would be reported to a mod for making me ill - er, if you weren't one...

 

[Noel]

Shady, listen to the cut, with your shell-likes.

Rgds

Noel

 

[Alf]

Oh, that's what you meant. #-o I thought you meant like my parrot; he tests the sharpness of his beak on my ears... :roll:

Cheers, Alf

 

[Shady]

Thanks Alf -I thought it was just me being thick... :roll:

 

[Noel]

So, is listening to a blade cutting through timber cross fibres not a normal thing to do straight after sharpening? Maybe I'm a bit odd.........

Noel

 

[trevtheturner]

Of course it's normal, Noel - just like the 'swish' of a plane, isn't it?

Cheers,

Trev.

 

[Alf]

Shady, it may well still be you being thick, but at least you have company :wink: :lol:

So, is listening to a blade cutting through timber cross fibres not a normal thing to do straight after sharpening?

Well the sound of the blade cutting is one factor in when I think a blade needs resharpening certainly. Straight after I've sharpened it I just assume it's sharp and don't really take much notice of the noise to be honest.

Maybe I'm a bit odd.........

I - will - resist... :wink:

Cheers, Alf

 

[Chris Knight]

Just noticed Alf's avatar change - is this skew I see before me a gloat, or simply a comparison with some exotica that is even as we speak, being reviewed for the delectation of the masses?

OTOH it may be that Rob C's dovetailing technique is being applied! The possibilities are endless - only limited by your imagination. (Terms and Conditions may apply)

 

[Alf]

Just noticed Alf's avatar change - is this skew I see before me a gloat,

Yes. Thank you for noticing.

or simply a comparison with some exotica that is even as we speak, being reviewed for the delectation of the masses?

Well I did think I might give it The Treatment, if anyone's interested?

OTOH it may be that Rob C's dovetailing technique is being applied!

Drawers loom in my future, so could be.

The possibilities are endless - only limited by your imagination. (Terms and Conditions may apply)

Book early to avoid disappointment? :-s

Cheers, Alf

 

[dddd]

Wow, seems like I've started a bit of a debate here, but thanks for all your replies, although I'm still not sure if I'm any closer to an answer. However, help arrived last weekend in the form of DC's sharpening DVD and it did make some very interesting viewing, plus I was a little sickened at the end of it when I saw how little relative effort and time he put in and got some pretty amazing results.
Anyway I digress, in the DVD DC was sharpening with exactly the same cryogenically treated A2 blade as me and using the same King 800 and 1200 grit stones as me and by the time he'd finished on the 1200 grit he had a definite shiny surface on the back of the blade. Haven't had time to try again using his exact technique yet but will be giving it a go this weekend. Will let you know how I get on. Although can't wait to here the results of the various experiments that seem to be going on at the moment.
Thanks again guys.

N.

 

[Shady]

Don't worry dddd/N - this subject is a bit like the question of pins vs tails first for dovetails: once someone's found a method that works for them, they tend to become a bit evangelical... :wink:

Just keep trying until you find the one that works for you. The DC stuff is good for starters, because his perfectionist approach will help toward repeatability, which is the hardest thing to feel confident about initially. One day you suddenly realise you've gone from "Oh crumbs, I hope this works" to " I know this'll put my standard useable edge on" - great feeling.

 

[Alf]

I was a little sickened at the end of it when I saw how little relative effort and time he put in and got some pretty amazing results.

Ah, don't worry about that. He's been doing it for a long time, so he should make it look pretty easy. Keep plugging away and one day, as Shady says, you'll tip the balance from "half an hour spent on this blade is time well spent in the long run I suppose..." to "well it's nice to have a small break from planing tha- right, all done. Back to work". :wink:

Cheers, Alf

 

[Midnight]

using the same King 800 and 1200 grit stones as me

you absolutely sure that 2nd stone wasn't an 8000 grit??

FWIW, I've been playing with a new stone lately, 12,000 grit; the business end is... shiny...

Cuts pretty well too.. 1 thou full width shaving, zero tear out... and that's against the grain... with the grain feels so effortless it's bordering obscene...

I gave the back of my scrub plane blade a wee polish on the 12,000 too; it went from lethal to **** Fire..!!

safety glasses were worn while conducting this experiment... 8) :wink:

 

[Philly]

Interesting Mike!
Which brand 12000?
Philly

 

[Midnight]

Philly... same as my others... King...

 

[David C]

Just a few observations for this fascinating thread.
I find it interesting to note how my approach changes subtly over the years.

Diamond stones give a shiny but scratched surface. Therefore shinyness is not necessarily a good indicator of quality of edge.

Scary sharp, or the use of wet & dry, produces shine but usually seems to round off the edges of the flat back of the tool.

Diamond lapping paste produces an incredible perfect mirror surface if you go to 1/2 micron. The absence of scratches gives a wierd view as if looking at the surface of liquid mercury. Can't see any point in going the extra distance to get this result for normal cabinetmaking.

A2 does not seem to get particularly shiny on my waterstones, but when I look at the surfaces with a 50X stick microscope the edge is very good and the surface does not show deep scratches.

The ruler trick band which is narrow, does get quite shiny if I let the paste on the stone dry out and use more pressure as it dries (on A2). I have recently taken to the APTC 10,000 grit stone because it is better value and comes on a nice wooden base!

The ruler trick, (NEVER for chisels please), will save you a huge amount of time and effort over a lifetime. Sharpening needs to be quick and repeatable or we will put it off and struggle on with blunt tools. My method has been developed entirely for speed and certainty.

I still only use 3 stones, King 800, King 1200, and 8 or 10 thousand grit. There may be some argument for including a 4000 grit for chisel backs but I don't find it necessary. The back finish is refined with every sharpening and will improve with time.

The Norton stones are excellent though I don't like the feel of the 4000 grit and have asked them to look at the bonding matrix. I am not so keen on the price in UK.

I have not used Shaptons much because I am perfectly satisfied with the results from my King stones, their price and ease of flattening.

The main issue with sharpening is to keep the back of the tool flat or minutely concave, in the length. I see immense damage done to tools by the failure to appreciate that waterstones must be religiously flattened every few minutes. You find the same damage on old tools which were sharpened for years on hollow oil stones. I have specifically developed two techniques for keeping the edge of the tool, off the edge of the stone for 50% of the the time, to avoid the menace of hollow stones. (Movements 1 & 2 in the DVD).

best wishes,
David Charlesworth

 

[Noel]

David, welcome to the site. What do you use for flatening your stones?

Noel

 

[David C]

Noel,

Thank you.

Wet & dry on float glass.

240 grit, though 180 & 150 will do. Sometimes I use 320 for the super fine stones but blunt 240 does just as well.

I have also used coarse diamond stones.

best wishes,
David