Shapton Users: How Often Do You REALLY Need To Lap Your Hones?

[Scissors]

As the subject sez, I'm asking Shapton glass stone users how often they think the Shapton stones really-o truly-o need to be lapped, assuming they're used exclusively for honing straights.

I can understand that woodworking chisels and like tools that have lots of cutting area and will take a lot of wear may require the Shaptons to be lapped frequently. But a straight? Maybe I'm ignorant and/or in deep denial, but I don't see that you'd need to lap those plates after each use as this FAQ on the Shaptons recommends. Besides, it's a vendor's blog.

OTOH, if I need to be hit with a rubber chicken and told to shaddup and get their lapping plate from y'all, I'll do it....

 

[Neil Miller]

I lightly lap mine at the beginning of each session. Every so often I give them a thorough lapping. It seems to me that the polymer matrix swells and shrinks and is influenced by things like temperature and humidity, so there is more than just the wear issue to contend with.

Darkening the surface a little (by letting metal particles build up during honing or by some other means) can be quite instructive - passing a lapping plate lightly over the hone a few times will reveal light marks at the high points - mine do this, anyway! It takes a surprising amount of lapping to remove all the darkened areas, which is why I do it lightly and often.

Regards,
Neil

 

[Scissors]

Wow I had no idea they were so sensitive. It's actually a bit disturbing to know that temperature and RH will affect them so much. That makes lapping before each use pretty much mandatory, I reckon.

Thanks for the info.

I lightly lap mine at the beginning of each session. Every so often I give them a thorough lapping. It seems to me that the polymer matrix swells and shrinks and is influenced by things like temperature and humidity, so there is more than just the wear issue to contend with.

Darkening the surface a little (by letting metal particles build up during honing or by some other means) can be quite instructive - passing a lapping plate lightly over the hone a few times will reveal light marks at the high points - mine do this, anyway! It takes a surprising amount of lapping to remove all the darkened areas, which is why I do it lightly and often.

Regards,
Neil

 

[richmondesi]

I don't lap mine quite that often. I do a light refreshing every time they start to "glaze", but I don't do a full lapping very often.

Also, when lapping, start at your highest grit stone, and work down to your coarsest grit (Do NOT lap anything below 500 grit on your GDLP if you use one).

 

[ouch]

Shaptons don't need much lapping even when used exclusively for knives. With razors, they'll suffer very little wear, but since razors require a flatter hone, it's probably a wash in the long run.

 

[mparker762]

I lap mine lightly probably about every hundred laps or so, or when they start glazing a bit. Since you only need 5-10 laps on these stones as you work up the progression it's really not that big of a deal.

 

[Ray-man]

The two stones that get the most useage seem to be the 4 and 8k. I find that the swarf buildup begins to change the feedback enough after 4 to 5 razors. Then, lapping is usually minimal, and not what you might think it will be.
The 500, 1k, 2k and 16k require lapping more by feel than anything else.

It's really not a big deal if you just maintain them on a consistant basis. If you leave them go to long, the lapping does take considerably longer, especially on the 16k.

Ray

 

[Leon]

What Neil said.
I lap lightly and often my 16k.

It takes a surprising amount of lapping to remove all the darkened areas, which is why I do it lightly and often.

 

[mparker762]

It takes a surprising amount of lapping to remove all the darkened areas, which is why I do it lightly and often.

You can avoid most of this by wiping it down thoroughly with a wet cloth after each use, and scrubbing with an old soft toothbrush before lapping.

 

[Scissors]

Hrrm...looks very much like a YMMV situation, although there's consensus that when all is said and done, they must be lapped at some point (hardly surprising, duh)

Related question: do you REALLY need the fancy almost $300 diamond/glass plate that Sharpton makes to lap them, or can you use something else? And if you can use something else, what do you prefer?

 

[ouch]

Hrrm...looks very much like a YMMV situation, although there's consensus that when all is said and done, they must be lapped at some point (hardly surprising, duh)

Related question: do you REALLY need the fancy almost $300 diamond/glass plate that Sharpton makes to lap them, or can you use something else? And if you can use something else, what do you prefer?

I find the fairly inexpensive DMT D8C diamond plate does a good job of lapping just about anything, Shaptons included.

 

[Neil Miller]

You can avoid most of this by wiping it down thoroughly with a wet cloth after each use, and scrubbing with an old soft toothbrush before lapping.

Yes, I know that - the point I was making is that it shows high/low points, similar to drawing a pencil grid - I used the example just for illustrative purposes.

I don't let the dark matter/glazing build up - lapping removes it quite adequately, as does a light wipe with a green scrubby.

Like I said, I do it lightly and often - I usually hone between 3 and 5 razors at once, so 'lightly" for me equates to a dozen laps or so.

Regards,
Neil

 

[mparker762]

Related question: do you REALLY need the fancy almost $300 diamond/glass plate that Sharpton makes to lap them, or can you use something else? And if you can use something else, what do you prefer?

No, you don't need it. I don't have it, and I have the shapton lineup from the 1k up to the 30k. I use a slab of faux marble from home depot (~ US$1) and a sheet of 600 grit wet/dry sandpaper. Years ago one of the members that works in a testing lab put one of these on his runout gauge and found that it was as flat as an industrial lapping plate.

 

[Leon]

I find the fairly inexpensive DMT D8C diamond plate does a good job of lapping just about anything, Shaptons included.

That's what I use too, dispite Shapton saying me that if I lap with anything other than the Shapton lapping plate, I'll void the warranty...