Sharpening 120 - Stroke

[silentC]

Spent another hour or so on the sharpening project this weekend. I finally got the back of the blade flat and polished down to 4000 grit waterstone. I'm still waiting for my green honing compound to come in the mail. Someone has bought up all of Timbecon's stock (was it you?), so it's on back order.

Now, turning attention to the bevel. I've set the blade in the guide to 25 degrees, then run through the grits (800 - 1200 - 4000).

My question is, how would you characterise the stroke you use? Do you use a lot of pressure, or a light touch? Could too much pressure cause the blade to deform?

What about speed. Do you zip back and forth across the stone at two strokes a second, or is a slower, more deliberate stroke more effective?

If you're using a guide, do you hold the blade and the guide, or just the guide?

Does it really matter?

[derekcohen]

Hi Silent

My question is, how would you characterise the stroke you use? Do you use a lot of pressure, or a light touch? Could too much pressure cause the blade to deform?

I use a light-to-firm touch. Where you put pressure on the blade is critical. It is possible for the blade to rock slightly side-to-side. There are times when this is actually desirable, such as with smoother blades. The aim is to achieve a very (!) slight crown effect by relieving the outer edges of the blade. This will reduce, hopefully eliminate the tendency the plane may have to cut “tracks” in the timber.

Similarly, too much pressure with a thin blade can cause it to deflect and sharpen in the center of the blade and not evenly across the bevel.

What about speed. Do you zip back and forth across the stone at two strokes a second, or is a slower, more deliberate stroke more effective?

For the most part I work slowly and carefully. Mostly I sharpen freehand and, when I get into a rhythm I find myself moving faster. Then I must slow down as it is possible to round over the bevel. I try to work in a figure 8, with occasional figure 0 as well, then diagonals /// and \\\. Using a guide one is mostly limited to straight up and down, and this causes greatest wear in one spot (that central strip). Consequently, you must check the stones for flatness frequently. The other stroke I find relevant is to push down when drawing the blade backward. There is less danger here of the blade digging in. But this is probably more of an issue for freehand sharpening than with a jig (or “than with a jog” as Crabtree might say!).

If you're using a guide, do you hold the blade and the guide, or just the guide?

I hold the guide in my right hand and press down on the blade with the fingertips of my left hand.

Regards from Perth

Derek

[LineLefty]

I hold the guide with my thems and push down on the middle of the blade with my two index fingers. I also zip over the paper really fast.

I'm not saying this is correct technique! It's just what I do.

[silentC]

Thanks Derek.

Using the guide, I found I could cover a fair area of the stone, even allowing the blade to come partially off the edge of the stone doing the // and \\ strokes, as long as there were the same number to each side of the stone/blade. I would do 100 or so and then reverse the stone, do another hundred, and then flatten the stone. It was surprisingly even because the pencil marks would be gone with one or two passes and no obvious hollows.

I tend to be a bit impatient and so I found my self pressing fairly hard and going up the stone and back in a second or less. It's hard to measure but it seemed as though this was removing material quicker. It may have just been wishful thinking on my part.

[silentC]

I'm not saying this is correct technique!

This is the reason I started the thread. I don't know whether or not there is a correct technique. I imagine that everyone will have their own ideas on it. I'm interested to see what others have had success with and what observations they might have.

[Wongo]

I'm still waiting for my green honing compound to come in the mail. Someone has bought up all of Timbecon's stock (was it you?), so it's on back order.

Silent, I bought some of that stuff last year. It was about 1kg and it will take 100 years to finish it. I can send you half of it if you like (for free of course). :)

[silentC]

That's a nice offer, thanks Wongo. I'm up in Sydney in a week or two, I might take you up on it ;)

[Wongo]

That's a nice offer, thanks Wongo. I'm up in Sydney in a week or two, I might take you up on it ;)
Sure, just let me know.

[LineLefty]

I find that if I just roll the guide back and forth with no downward pressure then it takes forever.

The biggest concern for me is polishing the back. You are supposed to hone on the bevel on one grit, flip it over and do the back, then go to the next grit and so forth.

I find that when I flip the blade over while its still in the guide, then theres not enough blade sticking out to ensure that it stays flat as I polish it on the edge of my Scarysharp plate.

But if i take it out of the guide it's introducing repeatability error and takes too long. :confused:

[silentC]

Hmmm, OK, that's different to what I was doing. I flattened the back first, all the way up to 4000 which is the finest stone I have. Then I put it in the guide and did the bevel.

I used the 4000 again to remove the burr. Phil from Mik prefers to use his leather strop and the honing compound to do that. I tried a bit of EEE. It did shine the blade up nicely but didn't remove the burr :(

[LineLefty]

Sorry, I dont think I've explained correctly.

The back of the blade is already flat i.e lapped. Take that as a given.
It's when I'm removing the burr that I feel i might be rounding the edge becuase theres only an inch or two of the blade sticking out the end of the guide.

[silentC]

Yes, I got you. What I'm saying is that I left the burr on until I'd gone up to 4000 on the bevel, then I took the blade out of the guide, polished off the burr and was done.

[AlexS]

Darren, looks like Wongo has helped you out anyway, but apparently artist's chrome green oil paint is a suitable substitute. Haven't tried it m'self, but a bloke at work swears by it (his swmbo is an artist).

[Dan]

I've seen photos of Japanese guys using a stick over the top of the blade when fattening the back. They also usually have their stones on the floor and therefore can put a lot of pressure on the blade by using their upper body weight and a two handed grip (also saw this in David Finks book). Add in the fact that japanese blades have a hollow back (less surface area=more pressure) and the result would be a lot of pressure being exerted between blade and stone. Of course all that pressure would be useless without good control.

I think if you can use a lot of pressure and speed and still have good control over the blade then you're going to get the job done quicker and be back doing the fun stuff faster.

[silentC]

I think if you can use a lot of pressure and speed and still have good control over the blade then you're going to get the job done quicker and be back doing the fun stuff faster.

That's the way I think of it but the old hare & tortise proverb keeps coming to mind. Seems that some niggling feeling is always out trying to spoil my fun. :rolleyes:

Alex, thanks for the tip. We don't have woodworking shops here but we do have artists' supplies aplenty...

Cheers