Ramped shooting boards - do they really work better?

[ED65]

Jacob's arguments in favour of lighter planes seem to be borne out by the physics, but only if you look at it a certain way. How about factoring in that it's much harder for the wood to stall a heavier plane than a lighter one?

And as I made reference to a couple of pages back, in the days of woodies only the standard plane for shooting was a jack or larger. I don't think this was at all an accident since you can shoot perfectly well with a coffin smoother*. It's of course impossible to prove either way, but I would contend they specifically chose not to.

Much user experience firmly argues that a plane of greater mass can be the better choice, and there are at least three here that are in favour of this in practice and I know of at least two references to this in books (explicitly stated, not something you have to infer).

*And in fact used appropriately that's one easy way to introduce a skew action!

 

[woodbrains]

Hello,

Not going to get into a silly tit for tat, as I said plane weight is personal preference, and I have used light planes and heavy ones and in between ones, it really doesn't matter. BUT, you can't go trying to prove lighter is better, by spouting twaddle.

No, you cannot have a massless plane with monentum, hypothetically or not. Momentum is a function of mass so zero mass, zero momentum, I'm afraid. In fact something with zero mass will have to travel at the speed of light and have no kinetic energy. Dangerous things, hypotheticals.

Also, the mass of a heavier plane will not be affected differently by friction, but speed of travel WILL. Which is why bigger mass is more useful to get more momentum than high speed. I never said you get something for nothing, and the higher mass will require more user effort to get going. The lighter one will require more effort to keep it going as the higher speed needed to give an equivalent momentum is fought against harder by resistance in the cut. The only downside is, as custard says, the return stroke. Shooting boards take the weight of the plane, though, and a bit of wax to reduce friction will be more important than how heavy the plane is here. I never heard anyone who complained that they tired because of the rearward stroke being difficult, though! Just as an experiment, try shooting with a block plane and then a try plane. I know which I find easier.

I have done a lot of shooting experiments at school, using the students, all girls, and just through observation concluded that they succeed with a Record T 5 or LA jack over LA block planes.

Mike.

 

[Jacob]

Hello,

Not going to get into a silly tit for tat, as I said plane weight is personal preference, and I have used light planes and heavy ones and in between ones, it really doesn't matter. BUT, you can't go trying to prove lighter is better, by spouting twaddle.

No, you cannot have a massless plane with monentum, hypothetically or not. Momentum is a function of mass so zero mass, zero momentum, I'm afraid. In fact something with zero mass will have to travel at the speed of light and have no kinetic energy. Dangerous things, hypotheticals.

Also, the mass of a heavier plane will not be affected differently by friction, but speed of travel WILL. Which is why bigger mass is more useful to get more momentum than high speed. I never said you get something for nothing, and the higher mass will require more user effort to get going. The lighter one will require more effort to keep it going as the higher speed needed to give an equivalent momentum is fought against harder by resistance in the cut. The only downside is, as custard says, the return stroke. Shooting boards take the weight of the plane, though, and a bit of wax to reduce friction will be more important than how heavy the plane is here. I never heard anyone who complained that they tired because of the rearward stroke being difficult, though! Just as an experiment, try shooting with a block plane and then a try plane. I know which I find easier.

I have done a lot of shooting experiments at school, using the students, all girls, and just through observation concluded that they succeed with a Record T 5 or LA jack over LA block planes.

Mike.

Confused again Mike! It'd help if you read what was written and tried to understand it, before commenting.

 

[Jacob]

......
Much user experience firmly argues that a plane of greater mass can be the better choice, ...!

It's the length of a plane which helps on a shooting board (or edging a board etc), not the mass - it's just that longer planes are heavier, a.o.t.b.e.

 

[bugbear]

Jacob's arguments in favour of lighter planes seem to be borne out by the physics, but only if you look at it a certain way. How about factoring in that it's much harder for the wood to stall a heavier plane than a lighter one?

Short version - heavy planes smooth out the planing of knots, etc.

Long version:

If the wood were uniform, as long as the force from the muscles is
greater than the resistance of the wood to the blade, cutting will
proceed smoothly, and there would be no benefit in adding mass to the plane.

However, consider the case where the wood is NOT uniform
(and who wants to work boring wood?).

Excess energy, from the soft parts of the wood, where the force supplied is greater than that
needed for that part of the stroke, is stored as kinetic energy
(the velocity and mass or the plane); this energy can be drawn
on in the hard parts of the wood, where the resistance
of the blade in the wood temporarily exceeds the force of the muscles.

The mass of the plane acts like a flywheel, smoothing the coupling
of the supplied work to the required work.

It's like KERS for planes.

BugBear

 

[ED65]

It's the length of a plane which helps on a shooting board (or edging a board etc), not the mass - it's just that longer planes are heavier, a.o.t.b.e.

You're simply arguing from your a priori position Jacob. Your belief is that lighter is better so anything that seems to support this.... I, and others, believe otherwise and we can just as easily pick and choose things that support our position. Case in point: the deliberately higher mass of some modern production planes. It is clearly stated that the metal chosen was, in part, to provide additional mass. They could just as easily have chosen a lighter alloy, just as strong, if lighter were better by their lights.

I've only been woodworking for a couple of years, but I've done my fair share of end grain shooting and I have a low-angle block plane that I used to use for this. Once I got good enough at sharpening that a 4 would do the job on most woods I switched wholesale, because there's simply no comparison in the effort needed. So that's further empirical evidence of exactly what Mike was saying.

 

[Jacob]

You can only recover kinetic energy if you've put it there to begin with. But you've also got to stop the plane and reverse it - you don't get the energy back from these (except as body heat?)

 

[Jacob]

...
I've only been woodworking for a couple of years, ...

I've been at it for 50 years or so. I've tried the modern heavy planes and they are more work than the old ones. Obvious and very simple.
If weight was an advantage people would have added weights to old woodies but as far as I know this has never been done - because it would be pointless.
Tools where momentum is used (hammers, axes) have optimum weights, not necessarily maximum, depending on purpose.

 

[ED65]

Not taking a dig, but greater experience doesn't automatically make you right. And naturally there are others with decades under their belts that are among those who disagree with you. So I don't think it's nearly so obvious and simple as you believe.

If weight was an advantage people would have added weights to old woodies but as far as I know this has never been done - because it would be pointless.

I think you're right that that was not done in the past, but there are a number of modern plane makers who add weights to their wooden planes. In fact one was posted here in another thread only last week I think it was, and here's one from last year.

Ignoring what a few individuals believe, let's take your logic and run with it: if <lighter is better> were almost universally thought preferable then modern planes would almost certainly have been made to be lighter. It's easily done with many modern alloys to pick from. But yet, as far as I'm aware, mass is increased, not decreased, given the choice.

 

[Jacob]

... let's take your logic and run with it: if <lighter is better> were almost universally thought preferable then modern planes would almost certainly have been made to be lighter. .......

Heavy planes just a recent modern fashion.
Having said that I wonder what was wrong with the pre war Stanley aluminium plane? Maybe just not durable enough.

 

[MusicMan]

I agree with BB, but would add that I think the advantage of a heavier plane for me is the sideways inertia. It is more resistant to sideways deflection by knots etc (because it needs more force to accelerate a larger mass).

Keith

 

[woodbrains]

I agree with BB, but would add that I think the advantage of a heavier plane for me is the sideways inertia. It is more resistant to sideways deflection by knots etc (because it needs more force to accelerate a larger mass).

Keith

Hello,

I think you mean momentum, not inertia, but your point is correct and what I have been saying.

Mike.

 

[Jacob]

I agree with BB, but would add that I think the advantage of a heavier plane for me is the sideways inertia. It is more resistant to sideways deflection by knots etc (because it needs more force to accelerate a larger mass).

Keith

Hello,

I think you mean momentum, not inertia, but your point is correct and what I have been saying.

Mike.

No he means inertia, though in fact they mean almost the same (but not quite).
Yes inertia will resist deflection but so would increased pressure from the operator. Heavy/light planes work differently, but overall -lighter means less work.

 

[woodbrains]

Hello,

On reflection, I might have misunderstood, he does mean inertia, but laterally, not in the direction of the cut.

Jacob, inertia and momentum are not the same thing and not interchangeable words. Go look up their definitions before you comment further. You CAN NOT do the same planing task with less momentum than is required to do it. So the light plane and the heavy one will have the same momentum. But the planing operation is resisting the increase in speed required for the lighter plane to have the same momentum as the heavier. The faster you try to move, the more it resists to the point where it is not possible to go fast enough. Mass is not affected by the planing operation, so it is easier to increase mass than speed for the same momentum. If you don't grasp this simple explanation, then I don't know how else to help; makaton sign language?

Mike.

 

[MusicMan]

I most certainly meant inertia. And while I'm at it, planes do not cut by momentum, they cut by force on the blade.

Keith

 

[Jacob]

..... You CAN NOT do the same planing task with less momentum than is required to do it. So the light plane and the heavy one will have the same momentum. But the planing operation is resisting the increase in speed required for the lighter plane to have the same momentum as the heavier. The faster you try to move, the more it resists to the point where it is not possible to go fast enough. Mass is not affected by the planing operation, so it is easier to increase mass than speed for the same momentum. If you don't grasp this simple explanation, then I don't know how else to help; makaton sign language?

Mike.

Momentum is mass x velocity. A light plane can cut exactly the same as a heavy plane (AOTBE) except;
1 the cutting force of the heavy plane will have a greater component of momentum (as the operator accelerates it up to speed)
2 ditto ...the light plane will have less momentum but more force from the operator.

Think of a guillotine - the cutting force is the momentum of the blade m x v as it is accelerated by the force of gravity. If the blade weighed nothing it would not descend. If it weighed a gnats it would descend slowly and come to rest without cutting. If it was heavy it'd cut with force.
BUT if the blade was accelerated by the operator like a swinging axe, even if it weighed zero it would cut with the force of the operator's swing but with zero momentum.
Have a look at some of the school physics sites I'm sure you will get it eventually (perhaps :lol: )

 

[matt_southward]

Also, the mass of a heavier plane will not be affected differently by friction,

Not true. Friction (as well as work done) is directly proportional to an objects mass: http://www.engineeringtoolbox.com/friction-coefficients-d_778.html - so there are energetic losses in using a heavier plane, it's particularly wasteful (energetically) to bring such and object upto the required speed therefore momentum and then to reverse that mass for the return stroke. The user may be happy with the extra energy required (for the benefits people have discussed), but that extra mass (work) is significant if there is a lot of planing to do, which supports Jacob's argument. It can be argued that the lighter plane offers more versatility in that the user may change the speed relatively easily (less inertia/friction to overcome) for a given task and will most certainly use less energy overall. It's therefore more energetically efficient to use a lighter plane - but that doesn't mean it's better! Better is a subjective argument and for the reasons people have argued, they may well prefer a heavier plane. I have no preference at the moment as I'm too inexperienced a woodworker, I just wanted to clarify the physics.

 

[Jacob]

The heaviest planing I've ever done (i.e. maximum rate of removal of material) is with a scrub plane. Oddly enough it's the lightest plane I've got (Ulmia). It removes material so fast I had to enlarge the mouth for the fat shavings. Is still hard work but with a steel scrubber it'd be much much harder which is no doubt why they never caught on and old ones are scarce. Momentum holds you back (most of the time)

 

[n0legs]

. Oddly enough it's the lightest plane I've got (Ulmia).

What would this beast weigh, pray tell?

 

[MusicMan]

Well now, a light scrub with a large blade protrusion would just bounce off end grain in a shooting board, wouldn't it? Shooting boards are about accuracy and quality of finish, not rate of removal of material, and this is where momentum and inertia may be useful.

Keith