Quick sharpening questions

[ear3]

I decided to add some higher grits to the dmt sharpening stones I started using last month. Went with a shapton 8000 grit glass stone, and then the 1 micron Dia paste, which i've put on a piece of hard maple. Results are spectacular, as you can see from the picture. As I joked with another FOG member, I'm going to have to change my previous sharpness testing method from slicing the skin in my fingertips --  after just the shapton, I drew blood without even trying.

So two questions.

After the final hone with the diamond paste, should I still lap the back with a few strokes, and if so, what grit? I lapped on the 4000 grit dmt Dia sharp stone, because I was worried about getting the diamond compound mixed in on the ceramic shapton, but maybe that's not an issue? (Back of chisel already lapped flat up to 4000).

Second, the diamond paste instructions say you can store the paste coveted board in a ziplock and reuse. How many uses can you get from the board before having to recharge?

 

[mouppe]

First, after you have polished the back of a new blade you don't need to repeat this step when you sharpen. You are only removing the burr with a couple of strokes on a strop or high-grit stone. My highest stone is a 10,000 Ohishi. I suggest you polish the back to more than 4000 grit, though, as you will get a sharper edge.

Second, surprisingly a long time. I recharge my board every few weeks, if that. Some people don't even use honing compound or diamond paste, they just use a hard board or piece of leather by itself. Some old timers used to just use their forearms!

 

[Kev]

I'm trying to visualise all this are really wanting a video or a pictorial

Sometimes you don't feel like making a mess and firing up the Tormek [embarassed]

 

[ear3]

Thanks.

First, after you have polished the back of a new blade you don't need to repeat this step when you sharpen. You are only removing the burr with a couple of strokes on a strop or high-grit stone. My highest stone is a 10,000 Ohishi. I suggest you polish the back to more than 4000 grit, though, as you will get a sharper edge.

Second, surprisingly a long time. I recharge my board every few weeks, if that. Some people don't even use honing compound or diamond paste, they just use a hard board or piece of leather by itself. Some old timers used to just use their forearms!

 

[grbmds]

Just to clarify, though, when removing the burr on the back, don't use the same grit to which the back was lapped originally or you will degrade the what you have already done. For me, if I'm using an 8000 grit Shapton stone for the final step on the secondary bevel, then that is what I'm going to use on the back to remove the burr since that is also what I finished up with when I originally lapped the back. I don't think I've found the need since I've been hand sharpening to go beyond 8000 grit. Not much to be gained. Even in books written by some well-known hand tool professionals don't indicate a need to go beyond 8000 (or maybe 10000).

 

[ear3]

Got it.  Thanks.

Just to clarify, though, when removing the burr on the back, don't use the same grit to which the back was lapped originally or you will degrade the what you have already done. For me, if I'm using an 8000 grit Shapton stone for the final step on the secondary bevel, then that is what I'm going to use on the back to remove the burr since that is also what I finished up with when I originally lapped the back. I don't think I've found the need since I've been hand sharpening to go beyond 8000 grit. Not much to be gained. Even in books written by some well-known hand tool professionals don't indicate a need to go beyond 8000 (or maybe 10000).

 

[Cheese]

Just curious Edward, are you putting a secondary bevel on the chisel? It's hard to see it in the photo.

 

[grbmds]

Just curious Edward, are you putting a secondary bevel on the chisel? It's hard to see it in the photo.

Can't tell about the secondary bevel either. I've been advised that it isn't necessary to hone the primary bevel all the way to your finest stone; only to about 1200. It's the secondary bevel you would hone with the 4000 and 8000 grit. After that, when you take the burr off the back, just use the last stone. Assuming that the back was also lapped originally to 8000, that would be 8000 also. Don't mean to confuse you but, looking at the picture again, it was unclear whether there was a secondary bevel or not. With hand sharpening, it seems to make sense that a secondary bevel is created and polished. If you use a machine like the Worksharp, then maybe it isn't so important. The secondary bevel is just much easier to maintain when you hand sharpen and hone.

 

[ear3]

No secondary bevel on the chisels.  I was under the impression that it didn't have any functionality in chisels other than cutting down on sharpening time.

 

[grbmds]

[member=37411]Edward A Reno III[/member] As far as I know you are correct, but based on my experience with hand sharpening over the past year or so, I'd say it makes sense when you hand sharpen. With a secondary bevel, it's quick and easy to return that tiny profile to sharpness with strokes on the 4000 and 8000 stones. It's not nearly as quick and easy if you need to maintain the entire edge. Without the secondary bevel you now need to work on the entire bevel. That's a much bigger surface than 1/32 or 1/16 of an inch micro bevel. As far as functionality probably no difference. (This is based on information I have collected and my brief hand sharpening experience. Maybe others will contradict me.)

 

[HarveyWildes]

[member=37411]Edward A Reno III[/member] As far as I know you are correct, but based on my experience with hand sharpening over the past year or so, I'd say it makes sense when you hand sharpen. With a secondary bevel, it's quick and easy to return that tiny profile to sharpness with strokes on the 4000 and 8000 stones. It's not nearly as quick and easy if you need to maintain the entire edge. Without the secondary bevel you now need to work on the entire bevel. That's a much bigger surface than 1/32 or 1/16 of an inch micro bevel. As far as functionality probably no difference. (This is based on information I have collected and my brief hand sharpening experience. Maybe others will contradict me.)

That's my understanding too.

Front and back should be polished to the same grit.  Think of sharpening like sanding - you make little ridges in the metal, and the ridges get smaller and smaller as you work to finer grits.  Those ridges show up in the edge, and the bigger the ridges, the more jagged your freshly sharpened edge.  The jaggies will fracture in use, and the bigger they are, the duller the edge after they fracture.

If you've polished the back and bevel to two different grits, the edge is going to be as jagged as the coarser of the two.

Nice mirror finish, by the way.

 

[nclemmons]

Edward, I've used the paste on a piece of hard maple and left it for months and reused it.  The ziplock helps.  A little water or oil depending on what you are sharpening with might be necessary, but a little paste goes a long way.

I'd echo what others are saying on a secondary bevel.  Will definitely give you more enjoyment out of the plane or chisels as you can keep them sharp with much less effort. 

Great shine on the one edge so far!

The true test is the shavings!

Thanks for sharing -

 

[ear3]

Yeah, I went back over the weekend and polished up the backs of all the chisels to 8000 grit.  I figured there was nothing to be gained by using the 1 micron paste on the backs.

[member=37411]Edward A Reno III[/member] As far as I know you are correct, but based on my experience with hand sharpening over the past year or so, I'd say it makes sense when you hand sharpen. With a secondary bevel, it's quick and easy to return that tiny profile to sharpness with strokes on the 4000 and 8000 stones. It's not nearly as quick and easy if you need to maintain the entire edge. Without the secondary bevel you now need to work on the entire bevel. That's a much bigger surface than 1/32 or 1/16 of an inch micro bevel. As far as functionality probably no difference. (This is based on information I have collected and my brief hand sharpening experience. Maybe others will contradict me.)

That's my understanding too.

Front and back should be polished to the same grit.  Think of sharpening like sanding - you make little ridges in the metal, and the ridges get smaller and smaller as you work to finer grits.  Those ridges show up in the edge, and the bigger the ridges, the more jagged your freshly sharpened edge.  The jaggies will fracture in use, and the bigger they are, the duller the edge after they fracture.

If you've polished the back and bevel to two different grits, the edge is going to be as jagged as the coarser of the two.

Nice mirror finish, by the way.

 

[Holmz]

Yeah, I went back over the weekend and polished up the backs of all the chisels to 8000 grit.  I figured there was nothing to be gained by using the 1 micron paste on the backs.
...

There is certainly points for style when it is a mirror finish.