If you use a lapping plate to flatten your stones what grit(s) of sandpaper do you use?
What grit(s) sandpaper do you use to flatten your stones?
- Thread starter Brassplyer
- Start date
220 and a steel cookie sheet will get you flat, but a $30 400/1000 grit plate from Chef Knives to Go will make your life much easier. You will need to refresh your stones and a Diamond Plate is quicker and easier to use.
Most of the eBay plates are good, just make sure you are getting an 8 inch plate.
You do not need dead flat to flatten a stone.
Most of the eBay plates are good, just make sure you are getting an 8 inch plate.
You do not need dead flat to flatten a stone.
- Thread starter
- #3
I've got a 9 x 12 granite lapping plate.
Do not lap on your surface plate, unless you want to take your plate out of flat. Buy a $1 steel cookie sheet and lap on the sandpaper on the cookie sheet, on the surface plate.
You might check the cost of having your surface plate re-calibrated, before you trash it. If it is not calibrated, it is just a piece of granite.
You might check the cost of having your surface plate re-calibrated, before you trash it. If it is not calibrated, it is just a piece of granite.
What's the purpose of the cookie sheet between the W/D sandpaper and the granite surface plate?
EclipseRedRing
I smell like a Christmas pudding
This reminds me of my woodworking lessons at school. I got a rap across the knuckles with a metal rule if I said 'sandpaper' and not 'glasspaper' 
Steel will not wear like Glass, marble or granite and it contains all the swarf and grit. The surface plate remains flat. I use the cement floor of my shop with a steel cookie sheet.
If you lap on a certified surface plate, it will quickly go out of flat, $175 to re calibrate, about 350 if they come to you. Really cheap surface plates are not that flat.
I bought a 20X18 piece of granite counter top for $5, it is flat enough.
If you lap on a certified surface plate, it will quickly go out of flat, $175 to re calibrate, about 350 if they come to you. Really cheap surface plates are not that flat.
I bought a 20X18 piece of granite counter top for $5, it is flat enough.
Sandpaper on a granite plate is what I use on occasion. Atoma's other times.
Sandpaper on your plate should not alter your plate at all. The stone never meets the granite.
Mine is 9x11 I think and the paper is 8.8x 11.
600 w/d to 2k w/d. 600 is fine for everything.
Sandpaper on your plate should not alter your plate at all. The stone never meets the granite.
Mine is 9x11 I think and the paper is 8.8x 11.
600 w/d to 2k w/d. 600 is fine for everything.
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400 Atoma most times.
60 grit SIC for flattening hard stones on a disposable piece of glass, followed by 240 and 600 paper to smooth.
60 grit SIC for flattening hard stones on a disposable piece of glass, followed by 240 and 600 paper to smooth.
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Synth’s and most naturals get 400 w/d and then naniwa rubber stoned
Really out of whack arks get SIC’d 80-120 through 300ish and then 400-600 w/d maybe
I generally use diamond lapping plates to flatten. Sometimes I finish on w/d paper.
Choice of grit depends on the stone, and how much material needs to be removed.
I have 5-6 plates of 140x and 400x grits, in varying degrees of wear.
If I have a...
New very hard stone, needs a lot taken off - new-ish 140x diamond plate to start.
New Naniwa SS needs very little taken off - 400x diamond plate to start.
And so on.
How I finish the stone depends on what stone it is - finishing Arks get final laps on 600x w/d.
Most Jnats are fine with a very worn 400x diamond plate finish. I evaluate the surface and make change in the game plan when needed. Better to work toward and achieve a goal, as opposed to just following a recipe.
If I was just using w/d paper for the entire job, the same ideas would apply and the grit selection would be similar.
I use quality diamond plates, they're generally flatter and stay flatter longer than cheap variants. When I use w/d paper I put it on the back of a old DMT plate that I check for flatness regularly.
I check every stone's flatness with a Starrett straight edge.
I find it best to lap under running water. Working with granite reference plates in the sink isn't my idea of a good time. A 10x4 plate in the sink is ideal for me.
Choice of grit depends on the stone, and how much material needs to be removed.
I have 5-6 plates of 140x and 400x grits, in varying degrees of wear.
If I have a...
New very hard stone, needs a lot taken off - new-ish 140x diamond plate to start.
New Naniwa SS needs very little taken off - 400x diamond plate to start.
And so on.
How I finish the stone depends on what stone it is - finishing Arks get final laps on 600x w/d.
Most Jnats are fine with a very worn 400x diamond plate finish. I evaluate the surface and make change in the game plan when needed. Better to work toward and achieve a goal, as opposed to just following a recipe.
If I was just using w/d paper for the entire job, the same ideas would apply and the grit selection would be similar.
I use quality diamond plates, they're generally flatter and stay flatter longer than cheap variants. When I use w/d paper I put it on the back of a old DMT plate that I check for flatness regularly.
I check every stone's flatness with a Starrett straight edge.
I find it best to lap under running water. Working with granite reference plates in the sink isn't my idea of a good time. A 10x4 plate in the sink is ideal for me.
Slash McCoy
I freehand dog rockets
Hear, hear! I have a 9x12x3 granite plate certified to .0001" and it only cost me $45.
However, to totally eliminate overrun at the ends, I now use a 18" x 6" acrylic plate, and 4-1/2" wide roll sandpaper.
Slash McCoy
I freehand dog rockets
The grit needed depends a lot on how out of true the stone is and how hard it is. An ebay rescue might call for 60 or 100 grit to get the heavy lifting done. Usually 200 or 300 grit is a good start, and then maybe 600 grit. There is no hard and fast rule. You might want to surface a hard and fine stone with 1k or 2k paper. Up to you. A finisher almost always benefits from a few passes with a hard stainless kitchen knife to smooth out the surface, especially an arkie.
Grit size is a judgement call. You don't want to start too fine and slow. You will be forever getting it done. You don't want to start too coarse, or I should say too coarse for too long. You are just wasting stone.
Drawing a grid with pencil on the stone and lapping until it is gone is the time honored method, but repeat it. Slurry builds up under the stone and erases the grid before full flatness is achieved. So rinse the lapping medium and the stone, draw a fresh grid, and lightly lap that second one off and you should be good. It should only take a few laps to gitter done.
In years past it was common to see razors honed on heavily dished stones, and then actually used to shave faces. Today you can still do that. Depends on how close you want to be to perfection. I prefer flat stones, if I use stones, and the flatter the better, up to the limit of my ability. I don't like trying to lap a stone on another stone. Overrun is the reason. It is a detail that most honers don't think about and you can still use the stone, but I want it better than that, so I try not to overrun the ends or edges. Obviously, this is impossible if the lapping plate or "flattening stone" is not significantly bigger than the stone being lapped. Your stones, your razors. How good is good enough for you? Perfection is of course optional. Sort of.
Grit size is a judgement call. You don't want to start too fine and slow. You will be forever getting it done. You don't want to start too coarse, or I should say too coarse for too long. You are just wasting stone.
Drawing a grid with pencil on the stone and lapping until it is gone is the time honored method, but repeat it. Slurry builds up under the stone and erases the grid before full flatness is achieved. So rinse the lapping medium and the stone, draw a fresh grid, and lightly lap that second one off and you should be good. It should only take a few laps to gitter done.
In years past it was common to see razors honed on heavily dished stones, and then actually used to shave faces. Today you can still do that. Depends on how close you want to be to perfection. I prefer flat stones, if I use stones, and the flatter the better, up to the limit of my ability. I don't like trying to lap a stone on another stone. Overrun is the reason. It is a detail that most honers don't think about and you can still use the stone, but I want it better than that, so I try not to overrun the ends or edges. Obviously, this is impossible if the lapping plate or "flattening stone" is not significantly bigger than the stone being lapped. Your stones, your razors. How good is good enough for you? Perfection is of course optional. Sort of.
