Waterstones: Can't poilish the back of a blade

[Fromey]

I have a 3000/8000 combination waterstone. After flattening the back of a plane iron and then sharpening it on oil stones (course, medium, fine) I move on to polishing the edge. This works wonderfully and I get a mirror finish quite easily. However, as I chase the wire off the back of the iron, rather than polishing it up, it actually dulls the metal compared to coming off the fine oil stone. I know metal's coming off because a waterstone slurry develops and it goes black. What I'm wondering is that I may be pushing too hard and so producing too much slurry which is not polishing.

Is there a trick to this (such as using copious amounts of water) or is it normal and/or nothing to worry about?

Thanks.

 

[Mr T]

Hi

Do you get the dulling with the 8000 grit or just the 3000? I find that the 3000 will give a duller surface. For instance going from 600 grit wet and dry when lapping a blade to the 3000 water stone it will go from shiny to dull, don't know why. But the 8000 should give a fairly shiny finish.

I suppose the test is does it get your blade sharp regardless of whether it's shiny or dull!

Chris

 

[jimi43]

It's quite easy to slightly lift when you are concentrating on "polishing" and end up dulling the edge.

Don't worry too much about polishing anything but the extreme edge. It's the cutting bit after all.

Or just try Scary Sharp.... :wink:

Jim

 

[Jacob]

I have a 3000/8000 combination waterstone. After flattening the back of a plane iron and then sharpening it on oil stones (course, medium, fine) I move on to polishing the edge. This works wonderfully and I get a mirror finish quite easily. However, as I chase the wire off the back of the iron, rather than polishing it up, it actually dulls the metal compared to coming off the fine oil stone. I know metal's coming off because a waterstone slurry develops and it goes black. What I'm wondering is that I may be pushing too hard and so producing too much slurry which is not polishing.

Is there a trick to this (such as using copious amounts of water) or is it normal and/or nothing to worry about?

Thanks.

Doesn't matter about actual polishing. Modern sharpening is all a bit exaggerated and semi mystical. Why move from oilstone to waterstone? Where did you encounter this bit of cr@p advice? Ignore it. Just stick to oil - and don't over do it.

 

[BigShot]

"Waterstones: Can't poilish the back of a blade"
Perhaps a bookshop isn't the right tool for the job.

Ba-dum tschhhh.

Sorry - carry on.

 

[bugbear]

I have a 3000/8000 combination waterstone. After flattening the back of a plane iron and then sharpening it on oil stones (course, medium, fine) I move on to polishing the edge. This works wonderfully and I get a mirror finish quite easily. However, as I chase the wire off the back of the iron, rather than polishing it up, it actually dulls the metal compared to coming off the fine oil stone. I know metal's coming off because a waterstone slurry develops and it goes black. What I'm wondering is that I may be pushing too hard and so producing too much slurry which is not polishing.

Is there a trick to this (such as using copious amounts of water) or is it normal and/or nothing to worry about?

Thanks.

Coupla' things; what (particular) oil stones do you have? do you go straight to the 8000 grit, or via the 3000 grit?

I'm thinking of this (of course):

http://sharpeningmadeeasy.com/grits.htm

However, surface shinyness can also be deceptive. Anyone who's done much metal finishing will have encountered the unpleasant phenomona where a surface appears fairly shiny on a coarse grit, but when polished further appears shinier but scratched.

BugBear

 

[Fromey]

Thanks for your comments. I'm using three new Norton oil stones (course, medium, fine; not sure what the grit numbers are for these). I test my edges by pushing/slicing through the edge of a piece of paper. I've noted that although coming off the fine oil stone is indeed sharp, a blade gets much sharper after a polish on the 3000 grit waterstone. Probably not that much improvement after the 8000 grit stone, but since it's on the other side, I give it a go.

I understand that it's only the very cutting edge that needs to be honed the most. Thus, I don't sweat trying to get the entire bevel polished. As for the back, I simply thought I'd polish it up a bit since I was at it, but was struck by the observation that it didn't work. Next time I'm at it, I'll try going directly to the 8000 grit stone.

The reason I'm jumping from oil stone to waterstone is because I can't find an Arkansas stone (that isn't silly money).

 

[bugbear]

Thanks for your comments. I'm using three new Norton oil stones (course, medium, fine; not sure what the grit numbers are for these).

They're listed on the table I linked to.

BugBear

 

[Mr T]

Doesn't matter about actual polishing. Modern sharpening is all a bit exaggerated and semi mystical. Why move from oilstone to waterstone? Where did you encounter this bit of cr@p advice? Ignore it. Just stick to oil - and don't over do it.

One reason might be to stop getting oil on your work.

Chris

 

[Jacob]

Doesn't matter about actual polishing. Modern sharpening is all a bit exaggerated and semi mystical. Why move from oilstone to waterstone? Where did you encounter this bit of cr@p advice? Ignore it. Just stick to oil - and don't over do it.

One reason might be to stop getting oil on your work.

Chris

Er, have you ever thought of wiping it off with an old rag? That's what everybody else does (and have been doing since the year dot). I'm surprised you didn't know.

 

[RogerS]

Doesn't matter about actual polishing. Modern sharpening is all a bit exaggerated and semi mystical. Why move from oilstone to waterstone? Where did you encounter this bit of cr@p advice? Ignore it. Just stick to oil - and don't over do it.

One reason might be to stop getting oil on your work.

Chris

Er, have you ever thought of wiping it off with an old rag? That's what everybody else does (and have been doing since the year dot). I'm surprised you didn't know.

YAPP....Yet Another Pointless Post

 

[Mr T]

Hi Jacob

You're not from Yorkshire by any chance!

Chris

 

[Woody Alan]

Perhaps It's possible you have contaminated the waterstone with oil and other particles, I certainly wouldn't mix the two methods.

Alan