who has veritas bevel up smoother or low angle smoother?

[Cheshirechappie]

I did say earlier that I didn't want to take part in this debate, and most of me still doesn't. However, I have been thinking about the forces acting on a handplane during use. I've ended up with a question to pose, which I ll come to in a bit.

A planing stroke usually consists of a start (accelerating the plane) a middle (plane moving steadily, so the forces acting on it are in equilibrium) and a finish (decelerating the plane, lifting it off the work, and returning to the start point). For now, let's forget the start and finish, and just consider the middle, steady planing at a constant pace, bit.

The forces acting on the plane are fourfold:
1) The user will be applying a force to the handle, to move the plane forward and overcome the cutting resistance of the wood, and possibly also slightly downward to keep the plane sole on the wood.
2) The user will be applying a force to the front of the plane, mostly downwards to keep the plane 'in cut'.
3) There will be some friction between the plane sole and the workpiece, resisting the forward motion of the plane.
4) There will be a force exerted by the wood on the tip of the plane iron.

All these forces will vary, depending on such things as the resistance to cutting of the workpiece, the width and thickness of cut being taken, the sharpness or otherwise of the cutting iron, the position of the user's hand on the rear handle (pushing low down with the heel of the hand or higher up), the coefficient of friction between the plane sole material and the workpiece and the area of contact, the mass of the plane and the load applied by the user to the toe end of the plane.

Also - and here's the question - what exactly is happening where the tip of the plane iron is engaged with the wood? There's a resistance to forward motion - a horizontal force opposing the user's push - but is there also a component of force acting vertically upwards on the plane iron tip trying to force it out of cut? If so, how large is it relative to the horizontal force? Does the angle at which the plane iron is bedded relative to the plane sole affect the way the horizontal and vertical components of force acting on the plane iron tip are absorbed by the plane, and does the user notice the difference between high and low bedding angles?

The problem with questions like this is that there are too many variables. What sort of plane - jack, try, smoother? Planing a face or an edge? What species of timber? Does thickness of iron affect results?

Must admit, despite my engineer's analytical mind, I'm more inclined to go along with centuries of practical experience and set the planes up and use them according to long-held knowledge of what usually works rather than bother about quantifying forces acting.

Still, might give someone something to mull over as they're digesting their Christmas pud.

 

[Corneel]

The Japanese professors actually meassured the forces in their planing setup. So that should answer your question about the vertical and horizontal forces. The complete article: http://planetuning.infillplane.com/html/review_of_cap_iron_study.html



The bedding angle of course makes no differences to the forces involved, but the cutting angle certainly does. But I can't quantify how.

 

[J_SAMa]

Before you know it some genius in Japan is gonna make a model of the forces on a plane with different weights, sharpness and tote angle and whatnot...

 

[Sgian Dubh]

... I'm more inclined to go along with centuries of practical experience and set the planes up and use them according to long-held knowledge of what usually works rather than bother about quantifying forces acting.

Sounds like the plan I've been following on hand planing techniques for all my time in the industry. It saves a lot of angst and tedious nitpicking along with unnecessary navel gazing over what seems to be very little of consequence. I'm a simple "sharp'n'go" man myself - it gets the job done, and done quickly I've found.

Still, might give someone something to mull over as they're digesting their Christmas pud.

Not me, ha, ha. Slainte.

 

[Corneel]

Been thinking hard all evening while muddling around in my pudding. Maybe I'm completely wrong on all points I've said in this thread, so if someone can point out a fundamental mistake in my meanderings, I'll be the first to acknowledge that.

What happens with these forces on the edge of the plane? Let us assume an extreme example. You are hitting a knot and the plane comes to a sudden halt. Because of the momentum the plane wants to move forward and starts to turn around the edge. What happens next? What is the fulcrum point? Is it trying to bend the blade? Probably but when everything is clamped down tightly would that make a difference? Or would it just pull the plane tighter against the wood? Maybe the length of the sole in front of the edge is the most important part in the equation.

The same thing happens to a much lesser extend when the plane just meets resistance but continues to move.

Time to let things rest and go to bed. Tomorrow I hope to be healthy again and do something usefull.

 

[Vann]

The frog seat of a bedrock is machined at 20 degrees to the sole (your green line). The iron sits at 45°, and it's bevel is ground at 25°. So the clearance angle at the cut is 20° (not your green line), whereas on a low-angle plane it's 12°. Of course if you honed a microbevel at 33°....

Probably makes no difference - just saying :roll:

Cheers, vanN.

Now back to my Christmas pudding, hagelslag, zoutdrop & speculaas.

 

[Richard T]

I'm so sorry dann.

Bevel up planes are great. Try one, you'll like it.

It's paring with a plane rather than scraping.

 

[Jacob]

The frog seat of a bedrock is machined at 20 degrees to the sole (your green line). The iron sits at 45°, and it's bevel is ground at 25°. So the clearance angle at the cut is 20° (not your green line), whereas on a low-angle plane it's 12°. Of course if you honed a microbevel at 33°....

Probably makes no difference - just saying :roll:

Cheers, vanN.

Now back to my Christmas pudding, hagelslag, zoutdrop & speculaas.

If bevel is 30º to 35º then clearance angle is 15º to 10º . Just saying!
25º is too fine - makes a thick blade into a thin one, just where it matter most.

 

[Corneel]

Because it was a mental exersize, you could imagine that the Bedrock angle is 12 degrees....

The face of a plane blade doesn't need to be flat. It can be concave too. Then you could say that a Bailey plane has a 0 degree bedding angle, when you imagine that the frog and blade are one. In order to be able to cut this imaginairy blade has a very concave face.

Jacob, yes 25 degrees sharpening angle is a bit low. But I use it in several planes and found no adverse effects. The planes don't chatter or skitter. Maybe I'll raise the angle a bit in subsequent sharpenings. 30 degrees has the advantage that the bevel is shorter which also helps in reducing grinding time.

 

[bugbear]

I think one of the difficulties of this is that applying 'O' level grade mechanics to planes is too simple. The mental habit of assuming that rigid things are perfectly rigid, flat things are perfectly flat, and inelastic things are perfectly inelastic is great for making the maths simple (or at least simpler) but inadequate in the real world.

Engineering design is all about making items that function well despite real world manufacturing limitations.

One of the notable benefits of a BU plane is that is has a lower manufacturing cost than a Bailey (or Bailey-a-like), and can thus be made either cheaper, or better for the same cost.

BugBear

 

[dann]

The BU do have a different feel to them, they are not as heavy as standard bench planes mainly due to the lack of the frog. I do like to swap and changer between my BU and BD planes I use the BD for more timber prep and my BU for fine finishing particularly if the high angle is required for interlocked grain. I do have a back bevel set up in my Clifton no 5 Jack for working tricky timbers but I find students and beginners find it difficult to maintain a small back bevel.
I had all the planes out on the bench yesterday for a short course I am running to show the guys, I find the students buy which ever feels most comfortable in their hand and once that are either Clifton or Veritas fans that's the way they tend to stay.
Both are great planes, Dann if you need any help with your choice of Veritas smoother please do PM or call cheers Peter

Cheers Peter, ill be in contact in the new year about one once i get back to work after the holidays.

 

[Peter Sefton]

The BU do have a different feel to them, they are not as heavy as standard bench planes mainly due to the lack of the frog. I do like to swap and changer between my BU and BD planes I use the BD for more timber prep and my BU for fine finishing particularly if the high angle is required for interlocked grain. I do have a back bevel set up in my Clifton no 5 Jack for working tricky timbers but I find students and beginners find it difficult to maintain a small back bevel.
I had all the planes out on the bench yesterday for a short course I am running to show the guys, I find the students buy which ever feels most comfortable in their hand and once that are either Clifton or Veritas fans that's the way they tend to stay.
Both are great planes, Dann if you need any help with your choice of Veritas smoother please do PM or call cheers Peter

Cheers Peter, ill be in contact in the new year about one once i get back to work after the holidays.

That's great, we reopen on the 2nd but in the meantime you are more than welcome to PM or Email us [email protected] it would be good to know what you already have and what you are trying to achieve or do with your new years treat.
Cheers Peter