Thread: Suehiro Gokumyo 20K

Originally Posted by bobski

Only one thing. If you purchased your Gokumyo 20k from Tools of Japan (Stuart Tierney). he says emphatically that using a 1200 Atoma to lap it will void the warranty of the stone, due to particles of diamond breaking free of the plate and lodging in the hone. He recommends the Atoma 400 which I have used for nearly 2 years with great results. E mail him not me.

I did a google search and went to Chef's Knives, and then to Stuart's Japan Tools site. Not a word about there being any problem with lapping using the 1200 plate. I don't doubt Stuart said that in an email, but if there is a potential problem they ought to make it known on their websites. Especially if they're talking about voiding warranties.

The difference between one guy's Atoma 1200 being useful for lapping an SG20k and one guy's being way too slow is simply the amount of wear on the diamond plate. A new or semi-new Atoma 1200 with nice pointy sharp diamonds will tear the heck out of an SG20k, whereas a very worn Atoma 1200 will not do the job even with an hour's work. Mine for instance probably wouldn't do it without at least an hour's work if the hone wasn't already almost perfectly flat. When new it would rip my SG20k down to flat pretty quick.

Originally Posted by eKretz

The difference between one guy's Atoma 1200 being useful for lapping an SG20k and one guy's being way too slow is simply the amount of wear on the diamond plate. A new or semi-new Atoma 1200 with nice pointy sharp diamonds will tear the heck out of an SG20k, whereas a very worn Atoma 1200 will not do the job even with an hour's work. Mine for instance probably wouldn't do it without at least an hour's work if the hone wasn't already almost perfectly flat. When new it would rip my SG20k down to flat pretty quick.

Nope you're wrong. My Atoma 1200 was brand new. That I had to start with 80 grit SiC on glass should make it obvious how warped my stone was.

Originally Posted by eKretz

The difference between one guy's Atoma 1200 being useful for lapping an SG20k and one guy's being way too slow is simply the amount of wear on the diamond plate. A new or semi-new Atoma 1200 with nice pointy sharp diamonds will tear the heck out of an SG20k, whereas a very worn Atoma 1200 will not do the job even with an hour's work. Mine for instance probably wouldn't do it without at least an hour's work if the hone wasn't already almost perfectly flat. When new it would rip my SG20k down to flat pretty quick.

My 20k stripped half of my 1200, that stone is not to mess with. I'd assume for light conditioning of the surface the 1200 Atoma will work but for lapping forget about it if you want to have a useful 1200.

For those $$$$ if it wasn't flat, I would be sending it back.

Originally Posted by mainaman

My 20k stripped half of my 1200, that stone is not to mess with. I'd assume for light conditioning of the surface the 1200 Atoma will work but for lapping forget about it if you want to have a useful 1200.

Is it good for lapping Choseras and the like ? If it isn't good for lapping what the hell good is it ? I wouldn't use it to hone a razor ......... or a knife.

Originally Posted by JimmyHAD

Is it good for lapping Choseras and the like ? If it isn't good for lapping what the hell good is it ? I wouldn't use it to hone a razor ......... or a knife.

I have used my 1200 to lap other stones but its main function in that regard should be surface conditioning and slurry making. The 20k is the hardest synthetic I have seen, the others are soft compared.

Originally Posted by kelbro

For those $$$$ if it wasn't flat, I would be sending it back.

No stone will come flat out of the box, ever.

Originally Posted by mainaman

No stone will come flat out of the box, ever.

+ 1. and I've had Nortons, Shaptons, Naniwa Superstones, and Choseras. Even DMTs aren't always flat.

Originally Posted by kelbro

For those $$$$ if it wasn't flat, I would be sending it back.

And spend another $80 posting it back ? Really ?