How do you tell if a hone needs lapping?

Hello everyone,

Last week my brand new Belgian Yellow Fine/Selected Grade Coticule arrived in my mail. She's a sexy hone I have to admit. My question is simple - How can you tell if a hone (brand new in this case) needs lapping? Judging by eyes only the surface is very smooth and straight imo at least. Are there ANY tests/techniques that can tell you if a hone's surface is perfectly flat? Something that doesn't involve high-tech tools preferably as I have no access to any of those tools. Thank you! Sorry for the newb question :aargh:

almost all new hones need lapping
and the one way to know for sure is lapping it

you will need a flat surface and wetordry paper
or a diamond plate

If you have a good straight edge rule you can hold it on the surface of the stone to check flatness. Test it across the width and also the length. Use bright back light and look for light leaking between the rule and the stone.

Quote:

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Originally Posted by janivar123

almost all new hones need lapping
and the one way to know for sure is lapping it

you will need a flat surface and wetordry paper
or a diamond plate

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Agreed. You simply use a pencil to draw a grid on the surface, lap it a little, and see how the grid has been removed. If the hone is flat, the grid will be uniformly removed. If it's not flat, then the high spots will indicated by the areas where the grid has been removed.

Aside from flattening the hone, you should also chamfer the two long edges so that the sharp corners do not damage the razor's edge by a slight mis-stroke.

The grid method mentioned above is the time tested "honer approved" method.

Hi,

Flatten it anyway; you will happy in the knowledge that the hone is now definitely flat :)

Have fun !

regards

Russ

Besides just flattening it in most cases it will also impart a nice but subtle polish on the hone.

If it's new..it needs lapping
If it's dirty...it needs lapping
If the edge is fine on some spots but feels like it's caught on a hill, it may need lapping.
If the hone doesn't cut like it did two sessions ago...it needs lapping...
And then I lap lightly every time I hone anyway.

These are my general rules for lapping.

Quote:

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Originally Posted by Disburden

If it's dirty...it needs lapping.

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If it's a barber hone and it's dirty, it needs cleaning, not lapping. You'd be amazed what oven cleaner can do for a dirty barber hone. The additional advantage is that you don't wear out your DMT plate simply clearing greasy gunk off your hone.

Quote:

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Originally Posted by Utopian

If it's a barber hone and it's dirty, it needs cleaning, not lapping. You'd be amazed what oven cleaner can do for a dirty barber hone. The additional advantage is that you don't wear out your DMT plate simply clearing greasy gunk off your hone.

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Hmmm.... I have a few I'm going to try this on.

Utopian & Disburden have it covered. There used to be a help file called Lapping 101 showing the pencil grid technique. It is probably in the Wiki now.
All you need is a pencil, wet/dry sandpaper and a flat surface. A countertop will work just fine. I use 320 to flatten & 1000 grit to finish. The 1000 grit leaves a nice texture on the hone.

The only thing I would add is to be reasonable in lapping otherwise you'll wind up getting carried away and lapp your hone away. Do it when necessary not as a past-time.:)

here's the wiki link

Hone Lapping 101 - Straight Razor Place Wiki