Flattening waterstones
#15
  Re: RE: Flattening waterstones by wmickley (I have used Japanese...)
I think the main thing is as stated to learn to use the whole stone so it does not get too much out of flat.  But occasionally you will want to flatten a stone, like the oilstones you find at a garage sale that are severely dished.  Gluing some sandpaper down to glass or any flat surface is a start, but would wear out before much flattening was done.  However, sprinkling some loose grit on the sandpaper makes it cut better than new, so I just start with dull sandpaper of any grit.  The purpose of the sandpaper is primarily to keep you from wearing out your reference surface, and secondarily to provide a bit more friction so the grit does not slip off too easily.  Loose silicon carbide grit sold for rock tumblers is available in a whole range of grits at significantly less cost than sandpaper.

So why loose grit?  It's cheaper and cuts faster.

As to whether the surface you get is flat, no it's not flat to 1/4 wavelength of light as you would want for optical purposes.  But if the flat reference surface is large enough that your work does not hang over the edge at either side, and you make sure to not rock the work as it moves, it will be flat enough.  If you invert so as to rub the larger flat over the work so it overhangs on each side, it is much harder to keep from grinding the work convex, but it can be done well that way with care.
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#16
  Re: RE: Flattening waterstones by Alan S (I think the main thi...)
(09-14-2018, 05:35 PM)Alan S Wrote: I think the main thing is as stated to learn to use the whole stone so it does not get too much out of flat.  But occasionally you will want to flatten a stone, like the oilstones you find at a garage sale that are severely dished.  Gluing some sandpaper down to glass or any flat surface is a start, but would wear out before much flattening was done.  However, sprinkling some loose grit on the sandpaper makes it cut better than new, so I just start with dull sandpaper of any grit.  The purpose of the sandpaper is primarily to keep you from wearing out your reference surface, and secondarily to provide a bit more friction so the grit does not slip off too easily.  Loose silicon carbide grit sold for rock tumblers is available in a whole range of grits at significantly less cost than sandpaper.

So why loose grit?  It's cheaper and cuts faster.

As to whether the surface you get is flat, no it's not flat to 1/4 wavelength of light as you would want for optical purposes.  But if the flat reference surface is large enough that your work does not hang over the edge at either side, and you make sure to not rock the work as it moves, it will be flat enough.  If you invert so as to rub the larger flat over the work so it overhangs on each side, it is much harder to keep from grinding the work convex, but it can be done well that way with care.
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I just hold those old hollowed oilstones on the platen of my 6X48 belt sander and step on the foot switch...and the hollow disappears.... Big Grin
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#17
  Re: Flattening waterstones by Elijah A. (Hey, I am trying to ...)
That will work.

You can also use a flattening stone like the one Norton sells, but make sure you check it for flat itself.  ;-)

It can be corrected using coarse sandpaper.
Everything is a prototype so its a one of a kind.
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#18
  Re: Flattening waterstones by Elijah A. (Hey, I am trying to ...)
(09-13-2018, 11:08 PM)Elijah A. Wrote: Hey, I am trying to come up with a flattening solution for my new 1000/6000 water stones. I have never used water stones before and I am excited to give them a try. I love the dia-flat plate but at $200 I'm gonna have to wait on that. So I have a piece of granite and some 120 grit wet/dry sand paper. Is this the best option for a low budget solution? I also came across this lapping plate on Amazon and I'm curious if any of you have used it?

https://www.amazon.com/gp/aw/d/B07BW52DZ...op?ie=UTF8

Wondering if this would be better than buying so much sand paper... Look forward to hearing your thoughts!

Eli

Eli,  I've not tried the plate your looking at. Low number of reviews. But should you give it a go let us know how it works out. For the bucks I think it would be worth a try.

I used the sand paper for sharpening and later for flattening my water stones and ended up with oil stones. For me on a low budget $34 bought a lot of sand paper.



Now that I'm down to just
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