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NeilS
24th Jan 2011, 11:53 PM
Took a closer look at my gouge edges with my new digital microscope.

Nothing unexpected, but it does give a different perspective of what a sharp edge looks like close up, before and after use. The edge was paper slicing sharp after honing and before use.

200 x magnification of edge with burr after sharpening on #120 diamond wheel. Image area is approx 1mm wide.

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60 x magnification looking directly at edge (that thin whitish line) after sharpening and honing, but before use. Image area is approx 3mm wide.

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200 x magnification of edge after using gouge until completely blunt. Image area is approx 1mm wide.

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oldiephred
25th Jan 2011, 09:48 AM
Interesting!:2tsup:

orraloon
25th Jan 2011, 11:46 AM
That provides a good mental picture of what we aim for while sharpening.
Thanks for posting it.
Regards
John

Doug Thompson
25th Jan 2011, 02:38 PM
To Cool... everyone needs a toy like that... what digital microscope did you get?

NeilS
25th Jan 2011, 04:41 PM
To Cool... everyone needs a toy like that... what digital microscope did you get?

The family gave me the Digital Blue QX5 USB Microscope for Xmas. Details here (http://www.compuvisor.com/qx5diblmicom.html)

I use it mainly on my Japanese knives to check the finish I'm getting off my various waterstones. The grind pattern you get off the different stones determines the sharpness and durability of the edge. But it is has also been interesting to take a closer look at my turning tool edges.

In retrospect I would go for an entry level microscope digital eyepiece (like this (http://cgi.ebay.com.au/1-3-Mega-Pixel-USB2-Microscope-Digital-Camera-Eyepiece-/400188975156?pt=LH_DefaultDomain_0&hash=item5d2d1f2834) ) and add it to an old secondhand microscope. The image quality would be much crisper than I have been able to get with the QX5, but it will do me, at least for now.

bench1holio
25th Jan 2011, 05:32 PM
neil, do you sharpen and hone after using the 120# diamond wheel?

hughie
25th Jan 2011, 09:31 PM
Darn, sometimes I think these things tell more than I need to know.

NeilS
25th Jan 2011, 10:41 PM
neil, do you sharpen and hone after using the 120# diamond wheel?

Not usually on gouges. I'm yet to be convinced that the extra time taken to hone adds enough cut time to be worth the effort on bowl gouges. It's so quick to put the gouge back into the jig and run it over the diamond wheel, especially with the fine edge that comes off the #120 grit diamond wheel.

Honing the flute on gouges to remove the milling grooves is a separate issue and very much worth the effort, IMO.

NeilS
25th Jan 2011, 10:48 PM
darn, sometimes i think these things tell more than i need to know.

........:aro-u: :U

.

Doug Thompson
26th Jan 2011, 02:01 AM
Neil, thanks... a picture is worth a thousand words.

rsser
26th Jan 2011, 01:56 PM
Great pics Neil. Thanks for posting.

What did you use for honing and is the tool garden variety HSS? What's the bevel angle?

As posted elsewhere, off a dry Alox grinder with a scraper you get a rough edge too though the bur is not so curled back. When lapped and burnished, you get a more even bur, approaching a hook, IME. (Have just been rereading Lee's sharpening 'bible' and he is enthusiastic about burnishing a hook. I've not warmed to it but he says getting the lathe speed right is important).

NeilS
26th Jan 2011, 04:36 PM
What did you use for honing and is the tool garden variety HSS? What's the bevel angle?



Honed on an old #1000 waterstone, but not something I would want to do on one of my good waterstones...:(

Here is a 60x image of a honed area. You can still see a few residual #120 grind marks that haven't been removed.

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All images were of powdered HSS tools (either Crown PM or Thompson). It would be interesting to look at some non-PM tool to see if there's a difference.

Bevel angles all 60deg.

munruben
27th Jan 2011, 09:58 AM
Wow, that is amazing and interesting.:2tsup: