skipping grits on waterstones or sandpaper

[zyhano]

Hi folks,

I was wondering what kind of grit sizes you can skip when you go up in grits towards polishing the edge. Both for sandpaper and waterstones. What would be a good or ideal progression when going from coarse to polishing?

I personally have 220/1000/3000/5000/10000 grit naniwa 'super' waterstones.
this seems to work out fine for me.

But lately I've been getting into straight razor shaving and they (at straightrazorplace.com) all keep going on about 4k/8k combo. They are into total sharpness there and very edgy about knifepeople (ask knifenut), they also seem to be very dogmatic about their sharpening routines and I was wondering if I should get some 4/8k stones too, just for the fun of it I also know that I can do my razor at 5k/10k combo.

In another post here, both cotdt and knifenut agreed/posted "You can save (-waterstones/money-)by skipping grits. 10x jumps are fine for starting out, it's just a bit more work. 2-4x jumps are more ideal in the long run."

I understand about grit patterns and can get my knives plenty sharp, but this is just an experience thing and you can say something about this by careful observation over time when using these stones, so I was hoping that some guys with experience on this could say sumpin' meaningful about this.

Like in the statement above I make 2-4 times jumps and it works fine. but the statement above also says by implication: you can go from 100 to 1k to 10k, how about that?

 

[myt132-cu]

I have almost the exact same grits that you do. I have 400 instead of 220, and mine are Choseras except my 10k is a super.

I sometimes skip the 5k before the 10k, and seem to get a little more tooth that way. I have to be on top of things to notice the difference.

With paper I go 400, 800, 1500, 3k.

I've always thought doubling works well, as it's a quick transition between grits. That is, it doesn't take long on each grit.

Tripling works well enough too, going from 1k to 3k, then straight to 10k, but it definitely takes longer with the 10k in that scenario.

 

[Jason B.]

Yes they seem to think razor sharpening is some sort of magic. Sharpening is sharpening, is a abrasive contact that creates a sharp edge, its a scratch pattern on steel that you continue to refine until it is so small that it turns into a mirror. Its just a different technique the science behind the process is all the same.

For a razor you shouldn't need to go any lower than a 1k and while your stone set should be fine the way it is I would probably add a 8k and 12k.


Its just steel don't be scared

 

[zyhano]

I have almost the exact same grits that you do. I have 400 instead of 220, and mine are Choseras except my 10k is a super.

I sometimes skip the 5k before the 10k, and seem to get a little more tooth that way. I have to be on top of things to notice the difference.

With paper I go 400, 800, 1500, 3k.

I've always thought doubling works well, as it's a quick transition between grits. That is, it doesn't take long on each grit.

Tripling works well enough too, going from 1k to 3k, then straight to 10k, but it definitely takes longer with the 10k in that scenario.

Yeah, it takes a good deal of attention to notice the difference I guess. I like the 'doubling' or 'tripling' as a rule, easy to remember.

Yes they seem to think razor sharpening is some sort of magic. Sharpening is sharpening, is a abrasive contact that creates a sharp edge, its a scratch pattern on steel that you continue to refine until it is so small that it turns into a mirror. Its just a different technique the science behind the process is all the same.

For a razor you shouldn't need to go any lower than a 1k and while your stone set should be fine the way it is I would probably add a 8k and 12k.


Its just steel don't be scared

Thanks, as I said, I'll probably get some more stones

But the question is more about how to go about with your grit sizes. I wasn't being specific enough in my post, but the str8 razor thing was actually because 4/8K stones are an increase in grit of 2 (2*4=8) so I was using it as an example.

So a better question would be: when I go from the 1k, should I go to my 3K or to my 5K. and if I go to my 3K, should I still go to 5K or should I go to 10K (etc. for all permutations). What are the advantages and disadvantages for skipping/not skipping grits when going up.

Time is a factor of course, more steps mean more sharpening time. Cost obviously, more stones is more expensive. But on the other hand, less stones means more time on a higher grit to get rid of the previous' stone's scratch pattern.

So what is good? what step is too much? what constitutes too much work? when aren't you doing enough?

I'm interested in sandpaper for convexing. Right now I'm working on a knife which was so damaged I started with 60, then 120, 400, 1000. This works fine. But what is - for the guys with the experience - a good series of grits to work with.

As I said, I'm fine with my sharpening stuff. I have the dmt diafolds C/F/XF/XXF, a sharpmaker with diamond, coarse, fine and ultrafine rods. Waterstones 220/1000/3000/5000/10000, a wusthof steel rod, 4 strops, plain, green chromium oxide, and jeweller's rouge plus a spyderco doublestuff (doubleduff? not sure). Oh and a file and sandpaper. They all work for me.

So practically I'm all set and doing fine. But I'm also interested from a theoretical point of view.
Furthermore, you see a lot of questions about stones coming up and grit sizes, this might help out for others or as a reference thread of sorts.


How are you doing with razor sharpening anyway? Does it help any in your quest for the perfect edge?

 

[Jason B.]

In my experience more grits makes for a better finish in a shorter amount of time. When you skip to high it just ends up taking that much more time to remove the previous scratches.

I actually haven't purchased a razor yet, I'm still trying to find someone to teach me how to sharpen them ya know because I wouldn't know the first thing about how to do that

 

[zyhano]

In my experience more grits makes for a better finish in a shorter amount of time. When you skip to high it just ends up taking that much more time to remove the previous scratches.

I actually haven't purchased a razor yet, I'm still trying to find someone to teach me how to sharpen them ya know because I wouldn't know the first thing about how to do that

lol, better wait a couple of years then... get some more experience
Got my first one a week ago.. best 3 shaves I've ever had, didn't know it was possible. But I know my angles

 

[cotdt]

How much you can jump grits depends on how fast your stones are, and on how patient you are. After going through many stones, selling my old ones for the "latest and greatest" I find I prefer the fastest cutting ones. I go DMT for my coarser grits and Choseras for the finer grits.

My Chosera 10k cuts so fast for a high-grit stone, I can go to that straight off a 1k stone. I use a 3k in between but I don't have to. All it serves to do is insure complete removal of previous scratches more quickly. It makes no difference in the results how I get to my final stone (the straight razor forum guys may say otherwise, but they only use 10 strokes per stone).

On the razor forums they talk about 4k/8k Norton combination for pyramid sharpening, as opposed to progressive sharpening. Instead of going up the grit range and removing previous scratches, in pyramid sharpening you go from the 4k to the 8k, and then BACK to the 4k for fewer strokes, and up to the 8k again with fewer strokes. The idea is not to remove all the previous scratches, but to use just the right number of strokes to reduce the microscopic peaks-and-valleys that the scratches form to about half-size. It works but I prefer the straight forward progressive sharpening. If you're doing progressive there's no need for a 4k/8k at all.

 

[tiguy7]

The idea of using progressively finer stones is to produce progressively finer scratches. Ideally you would change the direction of grinding/polishing after each stone change to see if you are erasing the coarser scratches with the new finer stone. If you jump too far (in grit size), it will take longer to erase your last set of scratches. Magnification helps to determine your progress. I like to grind at a slightly more acute angle and polish at a slightly more obtuse angle to avoid having to put a highly polished finish on the whole bevel.

 

[zyhano]

How much you can jump grits depends on how fast your stones are, and on how patient you are.

It makes no difference in the results how I get to my final stone (the straight razor forum guys may say otherwise, but they only use 10 strokes per stone).

On the razor forums they talk about 4k/8k Norton combination for pyramid sharpening, as opposed to progressive sharpening. Instead of going up the grit range and removing previous scratches, in pyramid sharpening you go from the 4k to the 8k, and then BACK to the 4k for fewer strokes, and up to the 8k again with fewer strokes. The idea is not to remove all the previous scratches, but to use just the right number of strokes to reduce the microscopic peaks-and-valleys that the scratches form to about half-size. It works but I prefer the straight forward progressive sharpening. If you're doing progressive there's no need for a 4k/8k at all.

Good info cotdt, thanks :thumbup:

The idea of using progressively finer stones is to produce progressively finer scratches. Ideally you would change the direction of grinding/polishing after each stone change to see if you are erasing the coarser scratches with the new finer stone. If you jump too far (in grit size), it will take longer to erase your last set of scratches. Magnification helps to determine your progress. I like to grind at a slightly more acute angle and polish at a slightly more obtuse angle to avoid having to put a highly polished finish on the whole bevel.

thanks tiguy, yup, jumping too far ahead is like stropping away a chip from a blade. It will take you an enormously long time