Thread: help! How do you flatten this flattening stone

I bought this stone to lapp my naniwas a few weeks back when I bought them and have tried sandpaper/wet and dry without any success down to grit 80. It wears down the sandpaper completely and unevenly.

NANIWA Flattening Stone Grain Size 220
recommended for stones with grain size 1000 - 12000

NANIWA Flattening Stone (Truing Stone)

I cannot even draw a grid on it given its colour, no ideas of what to use to get a visible grid.

I know the stone isn't flat as I lap a naniwa on a plate of glass with grit 600 and the grid I draw quickly disappears evenly after a few rubs. I know it's flat.
I redraw the grid and try it on the flattening stone and the grid wears off unevenly.

I bought this flattening stone to lap my stones over the sink as taking the coffee table to lap my stones is messy.

I'm going to be abroad for 3.5 weeks on work and really want to bring this stone with me so I can continue to hone in the evenings(I'm determined to get this), I lap the stones before I start so need a flattening stone with me...I don't think the coffee table plate of glass will fit in my luggage

any ideas?

Perhaps I should just write off the eur60 and buy another one that is flat from the begining - like one of the DMTs?

You would probably be better off just writing it off or reselling it. That stone looks like corborundum (sp?) and that stuff is HARD. I'm not much of a "lap-happy" person and think folks are really shortening the life of their stones. You can easily lap your stones by the sandpaper on ___________ (countertop, granite piece, tempered glass piece, and so on). You could also order a true lapping plate. I've heard that one of the best is the Shapton, closely followed by the DMT. That's a lot of $$$ when my countertop works just fine...

Shooter is probably right! You could try lapidary grit on a stout piece of plate glass (or a thinner sheet on a bed of sand) - it works quicker than DMTs as the surface area is as big as the plate of glass you use. It will wreck the glass, so don't use your coffee table top!

You would have to get a plate of glass and grit though, which adds to the expense. You can get the grit from hobbyist shops and even Ebay a lot cheaper than from Naniwa.

Regards,
Neil

To flatten the plate I'd suggest finding a nice flat piece of concrete and have at it.

Most people use DMT 320 for lapping their honing stones.

Originally Posted by mainaman

To flatten the plate I'd suggest finding a nice flat piece of concrete and have at it.

Most people use DMT 320 for lapping their honing stones.

Another old way is a paving slab and wet coarse sand. The slabs with the glittery granite flakes in are good, but hard to find nowadays. Plus you'd probably be arrested!

In one of the pics I saw of the Tam O'Shanter honeworks the flattening was done on a big revolving steel plate with wet sand on it - worked well for all those old stones!

Regards,
Neil

You have me thinking, there is a granite works about 55-60 miles away from me who has a huge hard of slabs. I hear that they have a lot of pieces that they just throw away...could be used with our "sport" couldn't it...

Originally Posted by shooter74743

You have me thinking, there is a granite works about 55-60 miles away from me who has a huge hard of slabs. I hear that they have a lot of pieces that they just throw away...could be used with our "sport" couldn't it...

Some of the dead-flat reference plates they use in engineering are made from trued granite. Costly, though.

BTW, I used to lay granite kerb stones and paving for a living once upon a time - it weighs a ton! I'd like to see how much your suspension goes down when you load your vehicle up with those off-cuts!

Regards,
Neil

You need a lapping lapper

But what do you do if the lapping lapper is not lapped flat?

I guess if I do go there and pick up some peices I should carry a straight edge...