Experimenting with the Grimsdale method

[bugbear]

Steve
Have you tried hollow grinding your irons? Freehand sharpening then takes seconds, regardless of the stones used. And I'm sure the old boys used to grind their blades on big water cooled wheels, so its a time tested method?
Cheers
Philly

Since their grind wheels were big, I suspect their bevels were more flat than hollow.

If I'm using this page correctly:

http://www.atmpage.org/contrib/Prewitt/sagitta/

A 300mm wheel (Radius of curvature) and a 8mm long bevel (diameter of mirror) gives a 0.02mm sagitta.

So the bevel is only hollow by 2 hundreths of a mm.

BugBear

 

[Philly]

Ahh...so you really need flat stones for that. Oops, did I just open another can of worms.....? :lol:
Philly

 

[Paul Chapman]

I'm interested in hearing opinions on the details of either method. These are the two best demonstrations and descriptions I've seen of stropping (most books and articles just say "strop the edge"), and of course, they are completely opposite in approach!

In my experience, if you don't keep the blade dead flat on the strop you will dull the edge - the blade might have a nice shine but it won't be as sharp as it could be.

I use a piece of leather glued to MDF

I use a little Vaseline and jewellers rouge on it. I always use a honing guide and keep the blade in the guide as I draw the bevel across the leather a few times. Then remove the blade and holding it dead flat on the strop, draw it backwards a few times. If you try it that way, I'm sure you will find that your blades are much sharper

In effect, the strop is just another honing medium just like your stones, so it makes sense to treat it as such IMHO.

Cheers :wink:

Paul

 

[Modernist]

I'm sure you are getting excellent results Paul but I think any strop with a soft(ish) surface tends to curve around the edge under pressure. I'm not suggesting it dulls the edge, it probably only removes a slight burr.

I still think that a Tormek, which produces microscopic hollowing of the edge, followed by fine waterstones and some minor stropping produces a fine edge quickly. I'm sure round bevelling works but it is too dependent on the skill of the operator to maintain the angle and I don't think it is as sharp as the above.

 

[Paul Chapman]

I'm sure round bevelling works

I'm sure it doesn't When we were discussing Jacob's round bevel method a long time ago I thought I'd try an experiment. I had bought several second-hand pig sticker chisels and these all had rounded bevels, just as Jacob advocates. I tried chopping a mortice with one and also with a normally honed pig sticker chisel with a flat bevel. I found that the curved bevel pushed the chisel off line and made it harder to drive the chisel into the wood.

Not worth the bother IMHO.......

Cheers :wink:

Paul

 

[sdbranam]

Well, all this has generated some excellent discussion on how to strop. I'll have to give some of these tips a try.

Of course, that also means everyone's backed into their separate corners where they say across the room to each other, "Yer crazy, mate!"

And if Andy thinks the chisel could be sharper, then I'll have to give it another go. Part of the problem is that I don't have a good reference to know how good an edge can be achieved. I was able to pare down to a line just like shooting it on the shooting board, so that seemed pretty good. When is it good enough? When is it not? I've seen plenty of books and videos, but never actually laid hands on one sharpened by someone who was really good at it so I could feel it in action. What I think may feel pretty smooth someone else may think is laughably dull.

Everybody has their preferences based on their experience; I don't yet have that experience to judge by.

I can definitely say this has made another step up in the sharpness I get. Making the commitment to invest in the DMTs and jig was the first step, getting my planes to at least be usable. And with effort, I could return them to that state after they got dull. Sandpaper on glass freehand was the next step. That was faster (mostly because of less fidgeting around with the jig) and I got a better edge. This is faster yet, and an even better edge. I can feel the difference planing quatersawn white oak. Maybe better stropping will be the next step. It's all a learning experience.

Cheers!

 

[sdbranam]

And the results are in: Paul's Vaseline and rouge strop does indeed work as he predicted. I had to dig around the basement for a while, but I knew I had a stick of red rouge somewhere.

I tried it on four chisels that I had considered sharp already. In each case, before stropping they could take a few hairs off my arm and leg. After, they took a clean sweep of all the hairs. I'd post photos, but I wouldn't want to make the ladies on the forum swoon. :wink:

I'll make a better strop, but for the moment I just clamped a piece of leather to the bench. I spread around a couple pea-size gobs of Vaseline, then liberally scribbled on it with the rouge stick.

I did it free-hand, careful not to exceed the final cutting edge angle on the bevel side as I drew it back 5-10 times, and dead flat on the face side. I tried a few variations of pressure. Moderate pressure seemed to do the trick. Light pressure seemed ineffective, and I didn't want to try too much pressure.

So perhaps a haphazard attempt, but positive results. Another step to add to the recipe, and just as easy as the other steps.

One question, the rouge was part of a Craftsman buffing compound pack that included a white rouge stick. The package says the white is for hard ferrous metals, and the red for silver, gold, and other precious metals. Any opinions on one vs. the other in this application?

 

[bugbear]

Sandpaper on glass freehand was the next step. That was faster (mostly because of less fidgeting around with the jig) and I got a better edge.

Do you mean getting the blade into the jig is time consuming, or using the jig?

If the former, I would suggest that (especially for plane blades) the time taken is a small (and practically negligable) proportion of the overall time of removing the blade, removing the cap-iron, (jig) working through the grits, blade cleaning, replacing and adjusting cap-iron, replacing iron, adjusting iron.

If the latter, I find that the ability the jig gives me to reliably target a tiny secondary bevel of 1-2mm conducive to rapid honing.

(if both, see previous answers )

When the secondary bevel gets big enough that honing on fine stones takes any time at all, waste metal on the primary bevel can be simply hacked off in bulk using a grinder or super-coarse stone (I use 60 grit AlZi sander belts - they cut tool steel like butter).

I find Eclipse jig + depth gauge = speed + sharpness.

BugBear

 

[woodbloke]

In my experience, if you don't keep the blade dead flat on the strop you will dull the edge - the blade might have a nice shine but it won't be as sharp as it could be.

I use a piece of leather glued to MDF

I use a little Vaseline and jewellers rouge on it. I always use a honing guide and keep the blade in the guide as I draw the bevel across the leather a few times. Then remove the blade and holding it dead flat on the strop, draw it backwards a few times. If you try it that way, I'm sure you will find that your blades are much sharper

In effect, the strop is just another honing medium just like your stones, so it makes sense to treat it as such IMHO.

Cheers :wink:

Paul

Paul is spot on here and this is the way I used to strop as well. However since I've transferred my allegiance to chisels from t'Orient which ideally (although a secondary micro bevel can be honed if needed) require a true, dead flat single bevel I don't need to use the strop at all. The dead flat single bevel is easy to achieve on a good honing guide and I use a selection of 3M papers to hone both the bevel and back - Rob

 

[Boz62]

Another thing to remember is that some of us don't spend as much time in the workshop as we'd like, sometimes with long gaps between sessions. A jig makes the process easily repeatable, whereas relying on "muscle memory" and experience would fail due to lack of repetition .

Boz

 

[Paul Chapman]

One question, the rouge was part of a Craftsman buffing compound pack that included a white rouge stick. The package says the white is for hard ferrous metals, and the red for silver, gold, and other precious metals. Any opinions on one vs. the other in this application?

Pleased to see that it worked

Jewellers rouge is the finest of the various honing compounds, so should give the sharpest results.

You will find that the base compound in the various honing sticks varies. Some of them are affected by temperature and in cold winters in unheated workshops they are hard to apply. I find that the base compound used in jewellers rouge stays soft in all temperatures, so is easier to use all year round.

You will find that you don't need to re-apply the Vaseline very often - just occasionally to keep the leather soft.

Cheers :wink:

Paul

 

[woodbloke]

Another thing to remember is that some of us don't spend as much time in the workshop as we'd like, sometimes with long gaps between sessions. A jig makes the process easily repeatable, whereas relying on "muscle memory" and experience would fail due to lack of repetition .

Boz

This is one of the advantages of using a jig, the fact that you can pick up exactly the same angle each time. It may not be exactly 30deg (say) but may be a tad over or under, so if you can guarantee that your honing angle is the same each time through using a guide, you'll end up with a sharp edge.
Although I can hone freehand, making an accurate, dead flat, repeatable single bevel each time would be almost impossible (for me at least) without recourse to an accurate guide - Rob

 

[bugbear]

Another thing to remember is that some of us don't spend as much time in the workshop as we'd like, sometimes with long gaps between sessions. A jig makes the process easily repeatable, whereas relying on "muscle memory" and experience would fail due to lack of repetition .

Boz

I've pretty much forced my (free) saw sharpening services onto work colleagues, just to keep my hand in.

BugBear

 

[sdbranam]

I've posted a follow up blog page based on the discussion of stropping:

http://www.closegrain.com/2010/05/grimsdale-method-part-3.html