Lapping Soft and Hard Arkansas

[algebro]

Hi all,

I decided to pick up a Soft/Hard Arkansas combo from Dan's and I was curious if they're soft enough to lap with an Atoma 600 or if you need to do the whole loose SiC thing like with Black/Trans arks. I have the loose grit if necessary but am not looking forward to doing that again if I can avoid it

Thanks!

 

[Bowmaker]

I wouldn't use any diamond plate I cared about but yes they are effective.

Being from Dan's there is a good chance it doesn't need lapped just the surface dressed as you might see fit. I wouldn't do it on any surface that isn't flat.

 

[algebro]

Thanks, so it sounds like the soft and hard are still hard enough to quickly destroy the diamond plate?

 

[H Brad Boonshaft]

It is not that the grit in Arks is so hard, but the binder is hard, and the grit is actually low, and densely packed and it is the combination of low, densely packed grit and strong binder that will rip out diamonds. You can get away with a bit of lapping under running water and using lite pressure allowing the diamonds to cut, good for beveling or rounding edges.

But 600 grit will not do much to flatten an Ark.

What you should do is lap each stone on a sheet of 220 on a flat surface. A dollar store STEEL cookie sheet works well. Mark a grid with a sharpie and if you can completely remove the grid in less than 10 laps, you are good.

If you have to fatten, 60 grit loose Silicone Carbide will get you flat. A Carborundum combo stone is a good finisher, a fine India will finish similar to a 600 wet & dry, great for Hard Arks or at least a good starting point for experimentation.

Once flat you can change the stone face easily and quickly with Wet & Dry.

 

[Legion]

Check the flatness with a straight edge. If it is flat enough and just needs dressing, use wet/dry paper.

SIC will convex the stone very slightly, and no need to wear out a diamond plate if you don’t have to.

 

[kcb5150]

I haven't had to mess with sic since I have been lapping arks on a diaflat with plenty of running water. Thing is still cutting like mad and it's had an all star team of nasty laps thrown on it between those and am hones and more.. Whatever that protective layer on the substrate is, it's doing the job so far..

 

[Darth Scandalous]

I haven't had to mess with sic since I have been lapping arks on a diaflat with plenty of running water. Thing is still cutting like mad and it's had an all star team of nasty laps thrown on it between those and am hones and more.. Whatever that protective layer on the substrate is, it's doing the job so far..

Which grit do you use?

 

[kcb5150]

160 mesh

 

[kcb5150]

I used to use an xxc as a lapping plate and would limit myself to washitas at worst with it. It lasted quite some time before it started giving up. Even that paid for itself vs the sandpaper I would have had to buy.

 

[kcb5150]

I was late to the game with diamond plate lapping but the quality of sandpaper lately is just horrible imo.

 

[Legion]

I was late to the game with diamond plate lapping but the quality of sandpaper lately is just horrible imo.

Yeah, and since covid it seems harder to find in various grits, at least where I live.

 

[kcb5150]

The substrates are just terrible. They either shed or they want to curl no matter how much you soak them