Sharpening under the microscope - lots of gear compared ...

[gidon]

I couldn't resist an Digital Blue QX5 microscope on Ebay for comparing sharpening methods. It works to around 200x magnification. It's a toy really but gives passable results - although you need to employ additional lighting for the 200x magnification. I have tried this before but with a more sophisticated setup which actually gave better results but was a lot more fiddly to use.

Here's a few pics (all 200x mag) I've done with it which may be of interest to some of you. I have a vast plethora of sharpening gear so happy to try anything anyone is interested to see the results of time permitting.

BIC disposable razor (note the three microbevels)

Complete sharpening done on Tormek

Spyderco Ultra Fine (grind Tormek, secondary bevel 1200 grit DMT, microbevel Spyderco UF)

DMT 8000 grit (D8EE) (grind Tormek, secondary bevel 1200 grit DMT, microbevel D8EE)

600 grit DMT stone secondary bevel, polished with Tormek compound on MDF (grind on coarse graded Tormek stone)

Waterstones, 1000 grit raise burr, 4000 1st microbevel and chase bur, 6000 secondary micro bevel

Final microbevel polished on 1 micron diamond paste on maple

Microfinishing film 0.5 micron (tormek coarse, secondary 600 grit DMT, 1st mb 5 micron film, 2nd mb 0.5 micron film)

Some comments / conclusions
All the methods pictured above provide a very sharp edge - all will shave, cleanly pare end grain and cut paper by push alone. How long that edge lasts in another matter all together. For me diamond stones produce the edge quickest with minimum fuss.

The 8000 grit DMT stone is a bit of an anomaly - it's not a polishing stone as it grit would suggest - for removing all traces of the burr and an ultimate edge you still need to go to a leather strop or some honing compound on MDF (or a Spyderco UF just about). But it does cut very quickly and if you sharpen frequently - you could do so on this stone alone.

The Spyderco UF is a polishing stone only - it cuts very slowly compared to the DMT 8000 or my 6000 grit Waterstone. Its grit for comparison is hard to judge - Spyderco won't state what it equates to in Waterstone terms - the only site that puts a value on it is the Axminster site - which states 10000 grit - which I would say seems fair. My stone although flat (the UFs are surface ground so should be flat unlike the other Spydercos) needed a lot of work to remove the surface grinding marks left by Spyderco's flattening process. I hate to say it because it's a lot of money but the 8000 grit DMT and the Spyderco work nicely together in my opinion - if you want to completely avoid messing around with strops and honing compounds.

Waterstones if you don't mind the mess and flattening give a very nice even scratch pattern. And they too cut quickly.

If I had to get rid of evertything except one stone, I'd probably keep the red DMT stone (600 grit). It's fast, and leaves a pretty even scratch pattern. I'd then finish off with Autosol, Tormek honing compound, Veritas green honing compound or Clifton Blue honing compound on some MDF.

Note for more on this stuff have a look here.

Welcome any comments / discussion.

Cheers

Gidon

 

[Paul Chapman]

Hi Gidon,

All I'm getting is red crosses where the pictures should be :? :?

Cheers :wink:

Paul

 

[gidon]

Thanks Paul - whoops - does it work now?
Cheers
Gidon

 

[Paul Chapman]

Ah, that's better

Interesting stuff - thanks :wink:

Paul

 

[Paul Chapman]

Many thanks for all that, Gidon - it's very interesting.

The conclusion I've come to for my own honing is that I need a system that works, is fast and has a low aggravation factor Honing can be a terrible waste of time and is, frankly, rather boring. I've settled on DMT stones with oil and finish on a strop with jewellers rouge - which is currently, for me, the best compromise.

Cheers :wink:

Paul

 

[gidon]

Thanks Paul - absolutely agree - it's finding a system that works best for you - the tricky bit (for me at least) is sticking with it!
Cheers
Gidon

 

[Paul Chapman]

- the tricky bit (for me at least) is sticking with it!

Yes - the other man's hone is always sharper........ :lol:

Of course, it never is - nor is his grass any greener........ :lol:

Cheers :wink:

Paul

 

[Philly]

Very interesting, Gidon - thanks for taking the time to do the photo's!
Cheers
Philly

 

[bob_c]

One thing i notice is how nice and even and chip free the very edge of the bic razor is? Any one know what they use to hone the edge?

 

[woodbloke]

To cut effectively, the Spyderco UF needs to be 'de-glazed' each time it's used...I use a med grade DMT for this. If it's not deglazed each time it just doesn't cut at all. When the stone has been cleaned it cuts quite rapidly for such a fine stone and gives a very good micro-bevel - Rob

 

[RogerS]

Fascinating pictures, Gidon and IIRC you've also got some great videos on sharpening.

You touched on one point....how long does the edge last?

Is there any evidence that edge produced by method A will last any longer than B?

And if A lasts longer (say 3x) but takes 10x as long to get the edge in the first place.....then isn't B the one to go for?

 

[ivan]

Pictures to make you think, Gidon.

Since getting to grips with my Tiger 2500 I've been trying the DC method (more or less, DC used 2 grades of waterstone) - grind at a bit under 25 deg, shape edge at 32 deg with 600 or 1200 grit eze-lap diamond till burr appears, and hone 35 deg on 8000 waterstone, and finish with ruler trick. I was surprised by DC's assertion only a handful of stokes needed on the 8000 grit but it's true! On a newly ground blade, perhaps as few as 4 strokes brings up a narrow polished band. Retaining a waterstone (the hardest, needeing no soaking) and keeping it flat doesn't seem too much trouble as it gets very light use!

I wonder how this compares with your examples?

 

[Chris Knight]

Gidon,

Thanks for a set of interesting pictures. Any idea why the Spyderco produces such a (apparently) black edge compared with the others?

 

[gidon]

Thanks chaps.
Bob - I took the BIC as a reference shot - if you look at the Brent Beach site I linked to he discussed this - he suggests BIC must use a sub-micron abrasive of some sort. The scratch pattern is beyond the capabilities of the QX5 at least.
Rob - yes mine is deglazed - I use an extra coarse DMT stone because that has already been abused flattening waterstones - don't think it's recommended to use your best diamond stone - the ceramic is pretty hard itself!
Roger - it's a good question and hard to answer. Most of the stuff I've read and it's common sense too - suggests that any scratches left on the cutting edge form serrations. These serrations will already leave fine scratches and these serrations breaking off will fairly likely take you back to the stones sooner. If you had a perfect edge with zero radius (doesn't exist) then I guess the only factors at play are the steel and the sharpening angle (all other things being equal)? But have a look through Brent's site - and also Steve Elliot's. Also if you have the Woodworker going back - Keith (Woodsmith) had a very nice article on all this stuff. If a technique really takes ten times as long I wouldn't bother with it! It's got to be quick!
Ivan - yes I used to use that method and it's hard to beat - but since then I've moved away from waterstones. I have tried using a fine waterstone for the last stage but even though it's harder it still requires flattening and I still find that very messy! In answer to your question that blade shown above off waterstones is sharpened just like that - but finished on a 6000 grit. You can see it's one of the cleanest results.
Chris - I would like to say that the blacker the edge the less significant scratches there are to reflect light - that is the case with the BIC blade. And also when I've done similiar shots with diamond paste. BUT, the difficulty is lighting the source and depending on where and at what angle the light falls can significantly affect the images one gets! And the other huge difficulty is depth of field - it's minute. I've tried best I can to make the edge itself sharp - so depending on the angle of the bevel and the postion of the blade - the rest of the blade can easily be out of focus. I need a scanning electron microsope with its huge depth of field .
One other point I'd make from all this is how important removing all traces of the burr is for a truly sharp edge. If you've come off a very coarse grit like a grinder, the burr can be significant and you have to be careful not to rip it off! The finer grit you go to on the bevel reduces the size of the burr. And some abrasives achieve this better - I found that sandpaper / microfinishing film and waterstones, by the time you've worked on the bevel to a high grit the burr has almost disappeared, hence stropping isn't as important or even necessary. Whereas with diamond stones, you can be chasing the burr far longer and really you have to go to something else to remove it completely (MDF or Maple with honing compound / diamond paste or microfinishing film).
Cheers
Gidon

 

[gidon]

Added another pic to first post - results off 0.5 micron microfinishing film (as shown in my vid here).
This method is hard to beat - you get an incredible edge very quickly that needs no (further) stropping. But you need microfinishing film which isn't that easy / cheap to come by. (I get mine here.)
Cheers
Gidon

 

[ivan]

Regarding the honing, it's interesting to see the remaining scratches in the honed area, which presumably gleams to the naked eye. How to tell you've honed enough to avoid premature breakown of the edge??

 

[bugbear]

I've tried best I can to make the edge itself sharp - so depending on the angle of the bevel and the postion of the blade - the rest of the blade can easily be out of focus. I need a scanning electron microsope with its huge depth of field .

Have you tried using a photographic colour filter to minimise chromatic aberration? Since the images are more or less monochrome anyway, you wouldn't lose information, and you might improve definition.

Can't help of DOF though.

BugBear

 

[gidon]

Ivan - I use this pocket microscope to have a close look at the edge :

Bugbear - might be something to try - thanks. I'm sure I could improve on those pics - but they are good enough to see roughly what's going on. I can probably see more clearly and certainly quickly looking through the above pocket microscope really - this digital microscope is nice for sharing pics though .
Cheers
Gidon