Ramped shooting boards - do they really work better?

[MusicMan]

I've been thinking about shooting board design and was considering building a ramped version. They do have the advantage that the wear is spread over a region of blade so one is more likely to be using a sharp edge.

However, the other advantage often claimed is that they simulate the action of a skew blade. I think this argument is incorrect. A skew blade, (or a skew motion of a straight blade in normal planing), attacks the wood fibres with a slicing as well as a pushing direction. It is well known in engineering cutting theory that this gives a faster cut with less effort. When carving your turkey be sure to make a rapid back-and-forth motion as well as pressing down. But this is not what ramped boards do. They are still pushing head-on to any individual fibre and not slicing it. It is as if one skewed a straight edge plane and then pushed in the direction of the axis of the plane rather than along the length of the wood. Planing in a diagonal direction as in flattening as bowed board, is not a skew motion unless the plane is skewed away from the direction of planing.

To properly simulate a skew plane with a straight-edged plane, one would have to build a carriage to hold and tilt the plane at an angle to the horizontal, then push this carriage horizontally on a normal shooting board.

Has anyone using a ramped board done any comparative tests, side-by-side against a normal board?

Maybe this sliding ramped carriage is worth building! Not too hard with a dedicated woodie, just screw it to a wedge.

Keith

 

[marcros]

have you had a look through Derek Cohens site?

http://inthewoodshop.com/ShopMadeTools/ ... Board.html
http://www.inthewoodshop.com/Furniture/ ... pared.html

a few others on shooting boards and planes too

 

[Jacob]

Ramped shooting boards - do they really work better?
Of course not!
It's possible to imagine a situation in which there would be a very slight advantage i.e. for a specific width of board and gradient, with a perfectly straight plane edge. But in the ordinary way of things this is unlikely to be worth setting up.

A shooting board has an obvious logic about it but in fact it's quite easy to manage without one. You mark up the end of the board all round, then plane bevels from each end and side to make something like a hip roof shape, then plane this off.

 

[custard]

Maybe this sliding ramped carriage is worth building!

If you're into making jigs and fixtures rather than furniture (nothing wrong with that, it's your time, you spend it how you like) then it would be a fine way of occupying a weekend.

If you're a practical furniture maker then it's more trouble than its worth. Firstly most plane irons end up with some camber on them. On a flat shooting board you just set the iron so the apex of the camber aligns with the centre of the workpiece. But on a ramped board the camber means the cutting angle would be constantly changing during the cut, so the finished surface would effectively be in wind. Secondly all shooting boards need adjusting from time to time as the fence shifts or the base warps (don't forget MDF and plywood also moves), on a ramped board that becomes a bit more of a faff.

 

[Tom K]

Ramped shooting board works by simulating a skew cut your sawing of a turkey doesn't. Bugbear will be along soon to explain it can't be a skew cut because there is no skew angle to do the equation he doesn't understand wood doesn't do maths.

 

[monkeybiter]

I've never used a shooting board and I'm crap at planning but MusicMan's correct, a ramped plane slide or a ramped workholding bed would not result in a skewed cut, just a conventional straight push cut in a diagonal direction with respect to the work. I do understand maths.

 

[Tom K]

I've never used a shooting board and I'm rubbish at planning but MusicMan's correct, a ramped plane slide or a ramped workholding bed would not result in a skewed cut, just a conventional straight push cut in a diagonal direction with respect to the work. I do understand maths.

(homer) Lack of comprehension and spelling not great.

 

[MusicMan]

Marcros - yes I had read Derek Cohen's and many other shooting board sites, but thank you for reminding me that he did do comparative tests. Derek is wrong about the ramped board imparting a slicing action; it does not. However he makes the point that a ramp allows the blade to enter progressively from the corner of the wood rather than the all-at-once shock on the edge, and this is a good point.

Custard, you are correct for a cambered plane, but the ones I use for shooting are ground square. And thank you for allowing me to spend my time as I like!

+1 for monkeysbiter, -1 for Tom K.

Keith

 

[Tom K]

LOL Yeah I must apologize I've never understood the difference. Present the wood to the blade or the blade to the wood at an angle to the grain seems to produce a shearing cut to me :? Of course you can save yourself the effort there's always sandpaper.

 

[Derek Cohen (Perth Oz)]

Marcros - yes I had read Derek Cohen's and many other shooting board sites, but thank you for reminding me that he did do comparative tests. Derek is wrong about the ramped board imparting a slicing action; it does not. However he makes the point that a ramp allows the blade to enter progressively from the corner of the wood rather than the all-at-once shock on the edge, and this is a good point.

Custard, you are correct for a cambered plane, but the ones I use for shooting are ground square. And thank you for allowing me to spend my time as I like!

+1 for monkeysbiter, -1 for Tom K.

Keith

Hi Keith

I am not sure where you read that I say that a ramped board adds skew - I have not said this, quite the opposite.

The advantage of a ramped board is the reduced impact as the blade enters the wood. This is worth the price of building such a plane. The plane must have a square, not skewed, blade. The ramp will reduce the skew. Use a skewed blade on a flat board.

Regads from Perth

Derek

 

[MusicMan]

Thanks for the correction, Derek. In the article of yours that I read you wrote: "While there is a much debate whether the ramped board can be said to impart a true slicing cut, there was no mistaking that any plane on the ramped board cut with less effort and less apparent impact than a flat board." But I may well have missed other things that you wrote about this. I agree with you except about the ramp reducing the skew. The skew is the angle of the blade relative to the direction of motion of the plane, and thus depends only on the plane and the direction in which it is moved. It isn't affected by the ramp. What is affected is the angle of the blade relative to the entry edge of the work. What I have learned from you is that the effect of the ramp is to change the attack on the entry edge from full-frontal shock to progressive entry, and of course that will be more effective with a straight blade (or one skewed in the opposite direction to the ramp). Your tests show this very well and your conclusion is very useful.

Keith

 

[Derek Cohen (Perth Oz)]

Keith, on reflection, what you state about the skew not affected by the ramp makes sense. It is the same as I wrote about the ramp not creating a skew. Thanks. In which case, any shooting plane may be used on a ramped board.

Regards from Perth

Derek

 

[mouppe]

I didn't find a ramped shooting board to offer any improvement over a regular one, but it did reduce the maximum thickness of wood you can plane so I stuck with a regular one. I use a blade with no camber (re Custard's post).

 

[Derek Cohen (Perth Oz)]

How thick do you want to plane? A shooting board is ideal for thin boards. Thick boards are planed held in a vise.

Regards from Perth

Derek

 

[dzj]

With a ramped SB a greater portion of blade width is used, so it stays sharp a bit longer than on a straight board.

 

[condeesteso]

Not worth it I reckon. The geometry dictates that they won't slice really - as the OP says. You get a few degrees which is nothing worth bothering with. Maybe OK on thin wide boards but as a general all-round board for say cabinet work, no gains I don't think. Regarding using the width of iron/edge, I do have a few offcuts of mdf lying by the bench, a 6mm, 9mm, 12mm. Place any combo of those under the workpiece and this helps use the iron across its width. For true slicing I do think you need a skewed iron.

 

[Beau]

Maybe this sliding ramped carriage is worth building!

If you're into making jigs and fixtures rather than furniture (nothing wrong with that, it's your time, you spend it how you like) then it would be a fine way of occupying a weekend.

If you're a practical furniture maker then it's more trouble than its worth. Firstly most plane irons end up with some camber on them. On a flat shooting board you just set the iron so the apex of the camber aligns with the centre of the workpiece. But on a ramped board the camber means the cutting angle would be constantly changing during the cut, so the finished surface would effectively be in wind. Secondly all shooting boards need adjusting from time to time as the fence shifts or the base warps (don't forget MDF and plywood also moves), on a ramped board that becomes a bit more of a faff.

Spot on Custard =D>

 

[ED65]

They do have the advantage that the wear is spread over a region of blade so one is more likely to be using a sharp edge.

I think this is their chief advantage, although an inconsequential one for anyone who believes in the mantra of little and often when it comes to honing.

However, the other advantage often claimed is that they simulate the action of a skew blade. I think this argument is incorrect.

Any angle other than 90° to the board's axis the blade can be considered skewed. It's possibly not enough to be significant but even 5° is still a skew.

 

[Phil Pascoe]

I wouldn't use an iron with any camber on a shooting board. It would seem to me to negate any benefit of the board in the first place. I assume there must be a point or purpose to ramped boards or no one would make them. They've been around for a long time.

 

[bugbear]

Ramped shooting board works by simulating a skew cut your sawing of a turkey doesn't. Bugbear will be along soon to explain it can't be a skew cut because there is no skew angle to do the equation he doesn't understand wood doesn't do maths.

Neither does a falling cannon ball, but the law of gravity still applies.

“The good thing about science is that it's true whether or not you believe in it.”
-- Neil deGrasse Tyson



BugBear