Thread: Back & forth, or circular?

OK, I've got my 600 grit wet/dry sandpaper and a sheet of glass. Do I go back and forth or in circular patterns to flatten a Norton 4K/8K? Also should I soak the Norton in water first and should the wet/dry paper be wet or dry? Oh, is there anything else I should know? Thanks.

Personally I do figure 8s. Wet the paper so that it sticks to the glass. There's a general recommendation here to draw a 1 inch by 1 inch grid in pencil on the stone, and lap until it disappears. I also look out for the feel - the hone starts to "suck" when it's flat. Try to round the edges of the stone too.

I personally use two separate sheets of paper - one for each side of the Norton - to avoid grit contamination from the other side. Don't really know if this is a consideration, but I tend to assume worst case scenario and act accordingly. There's probably more clever ways to avoid this with the one sheet of paper, but paper's cheap so...

James.

Like Jimbo says.


Justin

well you've kind of touched on a question i was pondering. Can you lap the 4000 side and the 8000 on the same sheet without cleaning the stone and the paper? seems that the slurry left from the 4000 side would not really hurt the lapping process on the 8000 and might actually give a smoother finish? would going from 8000 to the 4000 be a concern? it seems the slurry from the 8000 wouldn't not anything to the 4000 side. or it it a good idea in general to rinse your sheet (or use a different sheet as you said) before flattening the other side?

one more question. when flattening the 4/8k, is it necessary to use sandpaper grits in progression? like use 220, then 400, then 600, then 1000? or can you do the initial flattening on something coarse like 300, then finish it with something like 1000 grit. (or should you add at least some intermediate grit to bridge the gap) recommendations?

once it's been lapped, you could probably use just 1000 grit periodically to touch it up and skip the lower grits? or not?

The Norton flattening stone (about $30) really helps to get the stone flat quickly. Draw pencil lines first. I followed up with 1200 grit sandpaper on glass (wet) for the 8K side. I used lower grit for the 4K side.

Scrub the stones well with your hands afterward and dislodge any sandpaper in the stone, especially on the 4K side. If you have a dud razor, slide it down both sides of the hone a few times to check.

E

Originally Posted by edk442

well you've kind of touched on a question i was pondering. Can you lap the 4000 side and the 8000 on the same sheet without cleaning the stone and the paper? seems that the slurry left from the 4000 side would not really hurt the lapping process on the 8000 and might actually give a smoother finish? would going from 8000 to the 4000 be a concern? it seems the slurry from the 8000 wouldn't not anything to the 4000 side. or it it a good idea in general to rinse your sheet (or use a different sheet as you said) before flattening the other side?

one more question. when flattening the 4/8k, is it necessary to use sandpaper grits in progression? like use 220, then 400, then 600, then 1000? or can you do the initial flattening on something coarse like 300, then finish it with something like 1000 grit. (or should you add at least some intermediate grit to bridge the gap) recommendation

once it's been lapped, you could probably use just 1000 grit periodically to touch it up and skip the lower grits? or not?

The 1000 grit is fine for both sides of the Norton. You should not have to use a progression unless you really need to remove alot of material quickly. I would recommend that you lap the stone under running water in the sink to remove the swarf that builds up in the sandpaper.

I like figure 8's.

X

Willist,

While it is obvious from my initial attempts a honing a razor that I don't know doodly whoop about that process, I can remember being told and shown the lapping process for diesel injector parts. The key, the instructor said, is to balance the imprecise forces that one's hand applies to the part by using a figure eight pattern. Thus, it would seem to indicate that if such a motion works for something where tolerances make hairs look huge, that a similar pattern would also be recommended for lapping other things we want to make flat.

good luck, Bruce

You shouldn't have to do this with a new Norton but if you want to go ahead and go forth and back the long way and not side to side.