Thread: Checking stone for flatness?

If you lapped off a pencil grid using a DMT diamond plate, Atoma diamond plate or even just a piece of glass and some loose grit or wet/dry paper, you've already gone waaaay further than most did back when straight razors were the norm.

There is zero need to go any further, and besides, a straight edge is NOT the correct tool for the job.

Once pencil grid lapped... the act of cleaning the hones is generally sufficient to keep the hone in good condition. GSsixgun shows what he does in a series of videos he has on youtube.com, as does Lynn Abrams. Both of these gents hone for money and you can take their advice to the bank.


Regards

Christian

Lapping off the pencil marks will get you flatter than looking for light under a straight edge

We are honing with them and not building pianos. The pencil grid gets you pretty flat and honestly that should be ok. Presuming of course you lapped the pencil grid of on a flat surface like a DMT or granite slab. There are some really soft lapping stones out there that themselves need to be flattened every now and again.

Originally Posted by RezDog

We are honing with them and not building pianos. The pencil grid gets you pretty flat and honestly that should be ok. Presuming of course you lapped the pencil grid of on a flat surface like a DMT or granite slab. There are some really soft lapping stones out there that themselves need to be flattened every now and again.

Yeah I recently ordered one of those norton flattener stones. Hoping it'll cut faster than my dmt, even if I have to lap it semi-frequently

Sandpaper on a kitchen worktop will achieve the same at a much lower price. And yes: it does not have to be 110% flat.

Originally Posted by Kees

And yes: it does not have to be 110% flat.

A hundred and ten percent flat?

The flatness of your stone does not have to be within NASA tolerances. The pencil grid method has served us well. I think if you were to use a straight edge test, you would end up chasing your tail, and eating up too much of your stone.

Originally Posted by Utopian

A hundred and ten percent flat?

Flatter than flat or supadupa flat if you like.

Originally Posted by KenWeir

Yeah I recently ordered one of those norton flattener stones. Hoping it'll cut faster than my dmt, even if I have to lap it semi-frequently

I dunno, Ken. I rather like a worn DMT325 better. I found the Norton flattener needs flattening ITSELF after a bit.
TBH, as long as a stone is close, absolute flatness is overrated, JMO.
On my synthetic waterstones, I mostly have taken to hitting the DMT for maintenance purposes only. To get them cleaned-off and auto-slurrying properly again. I can look at the stone and tell when I am there. No need for the aggressive grid.
On ,say, my Escher hone. Since It is lightly slurried every time I use it and it is used so lightly, it only saw flattening as I first received it.
Never since.... Just me!

Originally Posted by KenWeir

Yeah I recently ordered one of those norton flattener stones. Hoping it'll cut faster than my dmt, even if I have to lap it semi-frequently

I've had 2 Nortons so far.

The first one I completely wrecked trying to flatten some old Arkies. Basically turned it into a bowl in spite of my best effort to use the entire surface. This was before I discovered the DMT or made the connection that a flattening stone could be soft enough to get out of flat. That said...I'd rather wreck a $30 Norton stone on an Arkansas hone than a $60 DMT.

The Norton hone does do better lapping Arkies than a worn DMT. Slurry is your friend in that endeavor. I find the key is 100 laps on the Arkie, 10-20 on the DMT to keep the Norton flat enough to get the job done. Saves wear on the DMT, use that for heavy razor grinding and stones that don't suck out loud to flatten.

It also gets better after breaking in. Right out of the box it leaves some pretty deep scratches in everything. My Current Norton flattener cuts pretty good without making deep scratches. It's also about as flat as my DMT can make it.

For most endeavors I side with folks that like a well worn DMT. For things that are liable to tear through/finish off a DMT, or cost $50 or more in sand paper to flatten, there's the Norton flattening stone. Fortunately those hard naturals don't need regular flattening and burnishing.