Sharpening -- pushing and pulling?

Re: Sharpening -- pushing and pulling?

Brent Smith

>Can't give you a sensible reason why, but, I push and pull on chisels but only pull on plane blades.

Brent

Re: Sharpening -- pushing and pulling?

Denis Ch�nard, Orl�ans, Ont.

>I once asked Rob Lee whether pulling or pushing made a difference in edge keenness and durability, and the answer was that it made no difference.

Hope I am not misquoting him...

DC

Re: Sharpening -- pushing and pulling?

mikew

>Hi Dave,

I sharpen and hone with the edge tool moving across its width, similar to Harrelson Stanley. So I also hone thatta way. For me, it uses more of the stone's surface evenly.

So in answer, neither...or is that both and?

Take care, Mike

Re: Sharpening -- pushing and pulling?

Pam Niedermayer - Austin, TX

>Tiny oval motions all around the stone, so push, pull, and round and round.

Pam

Re: Sharpening -- pushing and pulling?

mikew

>"Tiny oval motions all around the stone, so push, pull, and round and round."

Now all we need is the mulberry bush .

Yep, in practice, I rarely make truly straight back and forth motions, nor would it be the best if one could. Add in a few full-length strokes, slight diagonal motions across the previous round of paths...

I gave him a bad time once at a Woodcraft demonstration. Kind of played the devil's advocate as people were just standing there not interacting at all. Still feel a teensy-bit bad about that. But he sold a bunch of product over the following weeks.

Take care, Mike

Take care, Mike

Re: Sharpening -- pushing and pulling?

William Duffield, on the Cohansey

>If you use ScarySharp and push and are not cardeul, you can dig into the paper and cut it and peel it off the glass. Of course, this problem has a remote possibility of occurring with stones.

Final honing is just the smallest scratches you can manage to make in the edge. Some people theorize that scratches that are not perpendicular to the edge have a greater tendency to undermine the support the carbide particles that are doing the cutting, thus allowing them to be chipped off the edge sooner or faster. According to this theory, round and round or figure-eight or crosswise sharpening weakens the edge, so that it dulls faster. Makes sense to me, but whether there is any measurable, practical difference in performance is not at all clear.

It depends on the bevel angle ...

Derek Cohen (in Perth Australia)

>Note: "push" is defined as being the direction towards the back of the blade, while "pull" is defined as the direction away from the back of the blade.

I use waterstones, mainly a 1200 and 8000 King. I will hone freehand if I am working a flat bevel, or I will use a honing guide if it is a microbevel. Regardless of which method I use, or whether it is a chisel or a plane blade, the choice of Push vs Pull will depend on the bevel angle to be honed.

The higher the bevel angle, the greater the danger of the edge digging in when pushed. Bevel down planes tend to have smaller bevel angles (generally around 25 - 30 degrees) and the risk of digging in is small. Bevel up planes may have much larger bevel angles (25 - 50 degrees). With the larger bevel angle one is holding the blade progressively more towards the vertical, and this it is much easier to dig the edge in under those conditions. A honing guide helps a little but not enough.

For large bevel angles it is safer to just pull the blade on the waterstone.

For smaller bevel angles I both push and pull.

As a contrast, for narrow blades that are honed freehand, I will hone sideways. This can include the microbevel on otherwise wide blades that are used bevel down.

Regards from Perth

Derek

Always start with a pull stroke, but figure 8's

Andrew F in Australia

>ydbmd...

Trade are trained to start with a pull-stroke - sets up the hands at the correct angle so that the first push stroke doesn't catch and dig into the stone.

You sharpen in figure 8's

I've made a simple sharpening video that may be out soon - quality's not the best, but it's a reasonable how-to summary of trade sharpening techniques.

If you want more on correct trade sharpening technique, do a search of the handtools archives, using the following in the search terms

Elvis

wrist

cheers

I spent a while working on a summary a while ago - these search terms should find them in the archives.

CHeers,

Andrew

Cheers,

Andrew

Re: Always start with a pull stroke, but figure 8'

paul womack

>You sharpen in figure 8's

I've seen this time and time again, sometimes for straight blades, and often for gouges.

It's normally claimed that this distributes wear on the stone, which is obviously balderdash, since every stroke near the middle (in length) of the stone goes through the middle (in width) of the stone.

Thus, the "waist" of the stone is unused; figure 8's seem a good way to accentuate the normal problem of stone hollowing.

BugBear

Re: Always start with a pull stroke, but figure 8'

Miles

>Bugbear, sensible as always... I must admit that after reading many, many threads on sharpening, I am less enlightened than I ought to be - there was one 'Japanese Tool Forum' that was akin to a political catfight, a great deal of heat and very little light! As a scientific type, I'd like to see some more detailed testing and microscopy of edges to address the sort of issue about carbides and non-perpendicular scratches that is mentioned above.

One key factor that I have never, IIRC, seen discussed in any detail is one of the main parameters of the process - the PRESSURE applied (vertically) and I think we'd all agree it should make some difference to the relationship of steel and abrasive. High pressure leads to faster grinding, obviously, and so you'd expect different wear patterns at different pressures. I tend to lighten the pressure as I finish on one stone, before going to the finer one - the idea is to reduce the depth of scratches being made in the later stages of the first grinding. (I tend to use a 15um red DMT and then a ceramic, but the same applies to oilstones).

I don't have an 'answer' about this but it just seemed interesting that it is not often mentioned. I guess people push hard for speed, lightly for refinement but don't think of it as analytically as bevel angles & grit sizes.

Miles

PS I am using Tage Frid's belt sander method for getting primary bevels, as I don't have a large grinder - works really rather well, and I even run this with the blade in a honing guide, the roller running on the belt (!) which means a more consistent angle. Great way to hog off loads of metal and even with an 80grit belt, the scratches are taken out by the DMT reasonably fast. I find that it does not lead to serious problems when flattening the back, either (rescuing rusty tools, not a regular sharpening!) which was one worry - one just has to be careful to maintain level pressure.

Re: Science and Experiments...

paul womack

>Both Steve Elliot and Brent Beach have done "some" testing of blade sharpness.

http://cablespeed.com/~sgelliott/blade_testing/index.html

http://www3.telus.net/BrentBeach/Sharpen/index.html

However, I have knowledge of a third, which is both amusing and informative.

A magazine article in the UK attempted a similar trial to Steve and Brent (probably under tighter time constraints).

THe author was attempting to compare the results of different sharpening process, and used a standardised string cutting test for sharpness.

All went well, until the end of the test. Due to some variability in the results, he re-did one of the early tests.

The blade did MUCH better than before.

His suspicions aroused, he re-tried one the other techniques. Yep, also much better than before.

He concluded that over the course of the trials his own personal touch and judgement had improved, despite the fact that he was using jigs to standardise results (which he pointed out invalidated the rest of the article!!!)

Make of this what you will...

BugBear

Re: Science and Experiments...

Joel

>SO what was the conclusion of the auther? my guess it would be that it ain't magic, or a magic bullet - it's learning technique and practicing.

I pull, at an angle, for better control

bill tindall

>Not being able to chew gum, rub my tummy and hop on left foot at the same time, I also can not freehand reliably while pushing, pulling and figure 8ing while standing on one or two feet, with jaw clenched. I pull with iron angled to the direction of stroke, maybe about 30 degrees. The iron is more stable teetering on its bevel in this angled configuration, hence, better control. I find that I have a bias in abrasion, sometimes wearing more on the leading edge, sometimes more on the trailing. This bias shows up quickly with the iron angled and it can then be compensated for by adjusting pressure in later strokes. If I was stroking orthogonal to width of iron, any bias would result in changes in bevel angle, which is not desirable.

I never thought I would ever be able to retire my sharpening jig, but with this technique it now gathers dust.

Re: Science and Experiments...

William Duffield, on the Cohansey

>It is curious that he jumped to the new conclusions without further tests to control the variables and test his new theory. Perhaps the differences were not due to improvements in techniques, but instead due to conditioning of the sharpening media, or to other uncontrolled and unidentified variables?

The basic problem with all these discussions is that our responses, no matter how we state them, are basically "this works for me". But, in only a few words, we cannot effectively communicate all the pertinent variables, so that someone else can consistently reproduce our tests or our results.

It is very easy for the casual observer to request exhaustive, controlled, well designed scientific tests. Often these requests don't even clearly define the expected results. OTOH, actually doing a set of useful tests, especially those covering all the different choices of tooling used by the readership, is virtually impossible, because it would be prohibitively expensive of time and money. Worse, the better job someone does of attempting to perform fair and unbalanced tests, the more likely they are to be attacked from every possible point of view.

YDB, admirably, only asks "What do you do?" but doesn't mention the kind of "fine stone" that we are using. We read into the question, "Why do you do it?" because we want to be of help. But, we can easily get into trouble when we try to defend our methods against those who we believe are getting better results using other methods, or who we believe might be fudging their data because their claimed results differ from our experience, even if our experience has not been attained via scientifically designed and controlled tests.

Re: Sharpening -- pushing and pulling?

ThomD

>In the dark ages a few decades back they used to argue about whether it was possible to work back and forth in both directions. I do my sharpening more or less in a elongated oval As I finish up I try to keep the scratch marks square to the edge. The exception with sandpaper is one has to sharpenen along the edge mostly, I will try and drag it backwards to finish up on the paper. Works great, so one wonders a little about the sanctity of direction.

If I am using a jig I go pretty much straight back and forth, though moving it across the stone to minimise wear.

I think that the answer is...

Dan Donaldson

>Whatever works for you. You are the ultimate guide to what is acceptable to you, the performance level you want, and how you are going to get there. I am no expert, but it looks to me from all that I have read, the it is possible to get something sharp with a multitude of methods. Just my opinion, but I say just find something that works for you and stick with it long enough to learn how to do it well. Some people can hold a perfect bevel by hand on a cinder block, while others need a bit more help. Does it really matter that much as long as it is sharp enough to do what you want?

I both push and pull depending on what I am sharpening and how. By hand, I usually pull because I can hold the bevel better. For someone shaped different from me, or with a different skill level, it might be the opposite. With a jig, I push and pull. I usually make the last stroke a pull stroke to pull the wire edge. (It may not really, but it seems to me like it does) I do straight strokes because I can't keep it straight when doing circles or figure 8's, but that is just me.

Re: Sharpening -- pushing and pulling?

Stephen Kirk in Quakertown PA

>I both push and pull, with the blade at an angle. I seem to hold it relatively well that way. After watching Harrelson, I started doing the short little strokes, moving around the stone or sandpaper (I do both), and that seems to work a little better for me. If I try to push and pull with long strokes, it's easy easy to change pressure and sharpen one side more, or round the bevel.

I've been sharpening about a year, and I seem to get a sharp edge tha cuts wood, so beyond that I don't think about it much. Whatever way you can hold the bevel and keep the edge flat and straight is good. Try some different ways and see what works. Oh, and if something doesn't seem to be working right, try changing your working height, stance, weight shift, etc. Sometimes that makes a really big difference in control. Heck, I got comfortable sharpening sitting on a couch with the glass and sandpaper on a coffee table in front of me, watching TV - why should I be bored out in the shop??

Re: Sharpening -- pushing and pulling?

Frank D. in Montreal

>I asked the same question a few years ago, and most people seemed to push and pull. Steve Knight said he does both and it makes no difference to only pulling. It certainly can't make much difference before the final stone anyways, so pushing and pulling will make things go faster. I do both most of the time, but for the final few passes on my 8000 I pull, just because I'm superstitious.

Well, I use a

Scott Burr in Ben Lomond CA

>Guide. When sharpening plane blades I push and pull. I tend to just pull chisels so they don't dig into the sharpening medium.

Stone wear

Andrew F in Australia

>Hi Paul,

As strange as it sounds, I haven't had too many problems with stones dishing this way.

When a stone starts dishing, I just rub it flat on a convenient section of concrete - a gutter or a concrete block work well

If you are concerned about stone wear, use half-length figure eights and use the top half and bottom half of the stone, as well as the centre-section. This should even out wear.

Cheers,

Andrew

Re: kiss

Moses Yoder in White Pigeon, MI

>Keep it simple, stupid. But I guess if electron microscope photographs is what floats your boat, go for it. But I think people can spend a lot of time studying sharpening, or they can just go out in the shop and sharpen. It takes a while for the knowledge and the experience to know what knowledge you need. All of this needs to soak and boil for a period of time, and sharpening gets better. I think a person can grasp the basics of sharpening in a short period of time, but will still need time and practice to get comfortable with the process.

Re: Sharpening -- pushing and pulling?

Jim in Burlington On

>I've tried both and making small ovals. I prefer to pull now simply because I can feel a burr. Can't really trust what I see unless I get out the magnifing glass.

Get empirical, get a microscope

Dave Thompson

>I don't recall who it was anymore, but there was a guy on Badger Pond/Neanderthal Haven who was really getting into honing his sharpening technique. Rather than just settling for a qualitative sharpening/planing experience, he picked up a microscope. It was a kid's microscope that plugged into the computer and allowed one to examine images on one's monitor. He posted a few pictures of the edges from sharpening experiments he did, and it proved itself as something useful beyond just being a kid's toy. I bought one of these at the time, intending to do some tinkering myself, but actually haven't gotten around to it yet. I think they were around $50 a few years (?3?) back.

Just an FYI, if you really want to get into it.

enjoy,

Dave

Re: Science and Experiments...

paul womack

>It is curious that he jumped to the new conclusions without further tests to control the variables and test his new theory.

Heh. Reading between the lines of what he wrote, I suspect the following.

As a professional journalist, paid by the line, he'd already put in a few days doing the testing and research.

On the last day he found a result that threw all his previous work into question.

Now, a manic obsessive blogger or web site maintainer might "go around again", but I would claim our food-on-the-table journalist was being pretty decent in even mentioning that his whole (multip-page, illustrated) article was essewntially horse-feathers.

BugBear (speculating wildy)