Myths & Mysteries

[Benchwayze]

You can prove that tearout can appear without chatter. See my chatter free wooden plane causing massive tearout.
The other way is a bit harder to prove. But we do see chatter sometimes. And when I see these typical chatterlines, it's usually without accompanying tearout. Look at that first picture in Sellers blog.
But it could be of course that tearout is worsened when chatter is an issue with a plane.

Obviously you do a lot of planing against the grain Corneel? :lol:

 

[Modernist]

The argument is going round in circles.

Chatter (other than simply deliberate ignorance of basic settings) is caused by vibration of the blade assembly caused by thin blades, bad bedding on the frog, poor cap iron fit etc. It can be easily cured by a thick bevel up blade on a well machined base.They do not, of course require a cap iron, thus illustrating it is irrelevant in this context.

Close cap iron settings work by pushing the shaving down into the work thus preventing lifting and tearing of the grain although they make the plane harder to push.

A better result is obtained by using a thick blade bevel up setup in conjunction with a fine mouth which has the same effect in preventing the grain lifting in front of the edge but with out the disadvantages of being harder to push or clogging a reduced mouth.

Problem solved why delve further?

 

[woodbrains]

Mike,

Thanks for your comments about chatter and tearout. Of course it's nearly impossible to tell what exactly happens at the edge, but lets's try to do some deductions.

First my comment about chatter without tearout. I really have seen that a lot. So when chatter would promote tearout, at least it won't be a standalone cause of tearout. You would need a tricky spot of grain reversal. Well, we know in that case a thicker capiron isn't going to cure the plane. It will tearout nonetheless. It's very easy to get tearout with a solid plane with a 45 degree bevel, while it is difficult to get tearout with a cheap Stanley with the capiron in the proper place, close to the edge. So my conclusion from this, if chatter would be a cause of tearout, it would be minimal.

I was a bit quick to say that I've never seen tearout without chatter marks. You do usually see a rippled surface in the direction of the cut. But I think that is a consequence of the tearout. Because the edge is being pushed down into the wood and springs back up. You could call that chatter, I'd say that's just normal tearout behaviour.

Would a thicker capiron help to make the plane more tearout proof? You would have to do an experiment. The same plane, same iron just sharpened, same depth of cut, same piece of wood with grain reversal. Then just change out the capiron. Will that help? I haven't done that experiment, but I think the other capiron won't really help. The tearout is being caused by the wood, not the capiron.

I have made a video last week to show the effects of the capiron. The plane is a woodie. Very thick iron and very thick capiron. Chatter is no problem with this setup. Still the wood tears out horribly ( no wonder when planing against the grain) and is instantly cured when moving the capiron close to the edge.
http://www.youtube.com/watch?v=P3Nq1sbOhMM&feature=plcp

What you see is a plenty thick shaving, very straight and very strong, but no tear out. I have problems with believing the old theory of the capiron breaking the chip. We know from the work from prof. Kato that a small microbevel, about 80 degrees steep on the front of the capiron really improved its effectiveness of the capiron. With such a bevel the shaving is running into a wall. Kato meassured the force on the capiron and could really see an considerable increase when the capiron did its work. Now, it's not really possible for me to make a hard conclusion about what happens exactly, but my theory kind of nicely explains what could happen.

Any way, just learning to use the capiron is a lot cheaper then buying a Clifton one and more effective against tearout.

Look, I never said it was the only cause of tearout, and of course I know about cap iron position in reducing it. But the statemet Jacob made is that the Clifton Cap iron reduced tearout over his standard one. All things being equal, same plane same cap iron effect, same user on, I assume the same wood. Also, you are not a chatter denyer and you have said you have seen it occur where tearout on adverse grain occurs. Surely a reduction in chatter would improve it too? Kill two birds with one stone. It is not as if I'm forgetting how to set the cap-iron for best performance just because I use one which tames chatter too.

Also, the Kato video just re-inforced the standard description of how the cap iron effect works. The idea of breaking the chip before the split can develop was pretty much proved there, I think. A closer set cap iron breaks the chip sooner after the cut, reducing tearout. A less acute leading edge to the cap iron breaks the chip more radically and prevents the split from telegraphing ahead of the shaving too. I think this is pretty much what we already know. As I said during those posts, I was already setting very close chip-breakers years ago, based on my own logic of, 'break the chip sooner to minimise tearout' and getting better results.

I think you said yourself, that there are many aspects to planing that all cumulatively add up and we get little improvements at each stage they all add up to a great, overall improvement. A thicker iron adds a little, getting that sharper adds a little more, a better fitting frog, flat sole, less flexing in the cap iron, etc etc. all reinforce the improvement the previous one made. it is a system that can be improved at each stage.

What is bugging me, is that Jacob observed the improvement but will not give a reason why this happened. He just says it just does. Now wasn't it him that started the thread about myths and mysteries?

Mike.

 

[Corneel]

No don't worry, in real life I'll check first for the the most appropriate direction.

But I was on discovery lately and have been experimenting a lot with all kinds of wood. The reemergence of the Kato video really opened my eyes to the possibilities of the capiron.

 

[woodbrains]

The argument is going round in circles.

Chatter (other than simply deliberate ignorance of basic settings) is caused by vibration of the blade assembly caused by thin blades, bad bedding on the frog, poor cap iron fit etc. It can be easily cured by a thick bevel up blade on a well machined base.They do not, of course require a cap iron, thus illustrating it is irrelevant in this context.

Close cap iron settings work by pushing the shaving down into the work thus preventing lifting and tearing of the grain although they make the plane harder to push.

A better result is obtained by using a thick blade bevel up setup in conjunction with a fine mouth which has the same effect in preventing the grain lifting in front of the edge but with out the disadvantages of being harder to push or clogging a reduced mouth.

Problem solved why delve further?

Hi,

I would agree with you to a point. You might have started your list by saying 'is caused by vibration at the blade tip, amplified by the blade assy caused by thin blades made worse by poorly fitting frogs etc ..... This is a system and each relies on the element before it to work properly. If everything exaggerates the effect from the previous one then chaos is the result. Attend to each element and harmony!

The energy at the blade tip needs to be damped by the whole plane being as solid as can be reasonably made, given that some parts must also move for adjustment.

A fine mouth causes pressure to be placed over the shaving just ahead of the cut to prevent grain lifting, I agree, but the cap iron effect is not the same, it limits the 'shock wave', if you like spreading in front of the shaving and going deeper than the thickness of the shaving, which would show as tearout.

Mike.

 

[Jacob]

....
What is bugging me, is that Jacob observed the improvement but will not give a reason why this happened. ...

Mike.

I don't know the reason do I. Not sure that you do either. :roll:

 

[Corneel]

I started a new thread about the capiron pushing or breaking.

So lets talk about chatter and the capiron overhere.

Assume the rest of the plane is in good nick.

We all know it is perfectly possible to get good chatter free operation from a Bailey plane without chatter. It's a matter of good technique. How would for example the woodworkers before WW2 planed their wood when thick blades and capirons weren't available? My Stanley #7 from the twenties is a good solid plane with the original blade and capiron with no hint of chatter tendencies.

For a beginner it's a bit different though. A thicker blade could shorten his learning curve a bit.

Now about tearout and chatter. And thus using a thicker capiron against tearout.

I'd say that is a waste of money, because it only helps a tiny little bit. While setting the capiron at the proper depth is really helpfull in completely removing tearout (except maybe some impossibel Australian hardwoods, that's a skilllevel higher). I have never heard anyone saying his plane is now tearout proof because he's bought a clifton capiron. While using the proper technique is, well maybe not 100%, but at least 99% effective in our local kinds of wood.

 

[Corneel]

It looks like we can draw some conclusions now.

1. Chattering doesn't cause tearout.
2. Tearout comes from the wood not being strong enough to withstand the wedging action of the blade.
3. If chatter plays a role in tearout formation, then the effect is minimal.
4. Buying a stronger capiron is the least effective method in the fight against tearout.

What other myths are there to be debuncked? Tight mouths against tearout in a Bailey plane? Bevel up planes being better then woodies? The magic of infills?

 

[bugbear]

It looks like we can draw some conclusions now.

I'd draw a simpler conclusion.

Planing involves a large number of effects in concert. Changing almost anything changes the planing. Improving almost any single aspect helps. If the planing is already "succeeding" improvements will have no observable effect.

My conclusion? The detailed physics of planing is complex.

BugBear

 

[Corneel]

Yes of course. But your conclusion won't bring you any closer to understanding what is really happening at the cutting edge.

 

[bugbear]

Yes of course. But your conclusion won't bring you any closer to understanding what is really happening at the cutting edge.

I was trying to point that almost any simple statement about planing will only be part of the story.

BugBear

 

[Kalimna]

Corneel - the only thing that will actually bring closer understanding is direct evidence, not talking on a forum. Direct evidence in this instance would mean microscopic high speed video/photography of the propagation of the cut surface as it is being cut, with and without all the variables so far discussed. Until that is possible, we are merely talking about fairies and pinheads.
Empirically, if you try something and it works, keep doing it. If it doesnt, then stop. This doesnt bring understanding of the process, but it does allow gradual improvement in technique for an individual person. To take an example (and this is just an example, not meant to fire off the discussion along a tangent), I use a honing jig to sharpen edges. I find it works well for me. I know other folk recommend freehand honing, and it works for them. I have tried it, and I didnt like it, so I reverted to the jig.

Adam

 

[Corneel]

Well, the Kato video is a nice start isn't it?
And apart from high speed video, there are more ways to get to understand things. Like observating what happens with the wood surface. Change one thing and observe again.

My conclusions so far ar pretty solidly backed up. There is one item remaining mysterious. What is the role of chatter DURING a tearout event.

 

[Modernist]

The above has already and recently been done. There was a link to a thread on WoodNet with the high speed photography which clearly showed the damming effect of the cap iron pushing the shaving into the wood surface prevent it lifting and causing tearout. When the dam was made steeper the effect was increased but so was the effort to push.

I don't think they interpreted the results in quite the same way as I do but I stick to my opinion that the best solution is a fine mouthed, sharp, high angle, bevel up plane and that this is an almost universal solution up to the point of having to scrape, at which point surface finish deteriorates requiring subsequent sanding.

 

[Corneel]

Do you have a link to that thread?

When bevel up planes work for you, that's fine.
For me I see two disadvantages:
- I don't have bevel up planes.
- A 45 degree bevel down plane leaves a nicer surface then a steep pitched single iron plane.

 

[Jacob]

.....up to the point of having to scrape, at which point surface finish deteriorates requiring subsequent sanding.

Not according to the man (Mr Sellers) A sharp card scraper is for fine finishing. This is the trad view as well: Card scraper (or stanley 80) best as they bend to form a camber. A rigid bladed scraper plane is a different thing altogether
The word "scraper" is misleading, as properly sharpened gives a fine cutting edge. Mr Sellers describes in detail how to sharpen scrapers, with various options; 2 cutting edges on one 90º edge, bevelled edges etc.

 

[Modernist]

Do you have a link to that thread?

When bevel up planes work for you, that's fine.
For me I see two disadvantages:
- I don't have bevel up planes.
- A 45 degree bevel down plane leaves a nicer surface then a steep pitched single iron plane.

http://giantcypress.net/post/2315954813 ... created-by

I simply do not agree with your last point. In my direct experience with Veritas BU Jack and smoothers they leave a better finish on difficult timbers, when honed to say 45 deg, than a LN BD and certainly far superior to any thin blade plane.

 

[Modernist]

.....up to the point of having to scrape, at which point surface finish deteriorates requiring subsequent sanding.

Not according to the man (Mr Sellers) A sharp card scraper is for fine finishing. This is the trad view as well: Card scraper (or stanley 80) best as they bend to form a camber. A rigid bladed scraper plane is a different thing altogether
The word "scraper" is misleading, as properly sharpened gives a fine cutting edge. Mr Sellers describes in detail how to sharpen scrapers, with various options; 2 cutting edges on one 90º edge, bevelled edges etc.

Well, yes, it is for fine finishing but, IMHO does not give the burnished shine obtainable from a well set plane, nor do abrasives.

 

[woodbloke]

Do you have a link to that thread?

When bevel up planes work for you, that's fine.
For me I see two disadvantages:
- I don't have bevel up planes.
- A 45 degree bevel down plane leaves a nicer surface then a steep pitched single iron plane.

http://giantcypress.net/post/2315954813 ... created-by

I simply do not agree with your last point. In my direct experience with Veritas BU Jack and smoothers they leave a better finish on difficult timbers, when honed to say 45 deg, than a LN BD and certainly far superior to any thin blade plane.

+1... I don't use any BD planes for that reason, apart from the odd few that lurk under the bench and are there for decoration only - Rob

 

[Corneel]

Well, I can't really give my own experience because I don't have bevel up planes.
The Japanese have the low cutting angle thing pretty good worked out. They prefer the lowest possible cutting angle, even go a lot lower then 45 degrees. It seems to give the surface a righness, glow and depth that isn't doable with high pitch planes.

I do know that I get a beautifull razor sharp surface with cheap planes now I know how to use the capiron.