How flat can you plane your work? With a flat plane?

[ivan]

Quick follow up for David C, now grandchildren away home:

With newly sharpened blade in no.6, planed the ~600mm softwood as hollow as possible (no more cut) with stop shavings, leaving unplaned ends ~10mm each. S'wood tested on surface plate between 10 and 12 thou* hollow. 8th full length shaving was first complete one end to end, at which point hollow was 6 thou. 10 more reduced it to ~2 thou. Another 10 to reach 1.5 thou, and another 10 more no change. Pivot point remained at ends of stuff throughout. Estimated shaving thickness ~1.5 thou.

When using the stop shavings method I have always been careful to stop planing soon after 1st full length shaving, as taught years many ago, but for this plane at least, such caution is not necessary.

* feeler gauge

 

[David C]

Ivan,

Thank you for those interesting results.

Not what I was expecting.

When I take ten through shavings off a straight edge, say 16" long, with a 5 1/2, it becomes convex.

I was demonstrating this all weekend at Westonbirt, for Mike Hancock's Masterclass lectures. It was good to meet some of the forum members.

best wishes,
David Charlesworth

 

[bugbear]

When I take ten through shavings off a straight edge, say 16" long, with a 5 1/2, it becomes convex.

Interesting.

If using a Japanese tuned smoother (2 point contact), which takes off (AFAIK) perfectly parallel shavings, continuous planing should leave the board straight, if (and, of course, only if) it started straight.

BugBear

 

[ivan]

One might be forgiven for wondering if David C's No.5 1/2 is just a trifle hollow? What does your engineering st. edge say, DC? Published photographs have shown DC flattening planes on plate glass, silicone sealed to timber? Possible plate glass edge distortion under grinding pressure? For what it's worth, I do mine on a granite surface plate from Ax. tht's about 700mm on the diagonal.

 

[bugbear]

One might be forgiven for wondering if David C's No.5 1/2 is just a trifle hollow? What does your engineering st. edge say, DC? Published photographs have shown DC flattening planes on plate glass, silicone sealed to timber? Possible plate glass edge distortion under grinding pressure? For what it's worth, I do mine on a granite surface plate from Ax. tht's about 700mm on the diagonal.

IMHO there's more to making flat plane soles (should one believe such a thing important) than a flat rigid lapping surface

BugBear

 

[Paul Chapman]

One might be forgiven for wondering if David C's No.5 1/2 is just a trifle hollow?

I doubt it. In my experience, David is right - if you keep planing a piece of wood from end to end, without taking stop shavings, you will eventually plane it convex.

Cheers :wink:

Paul

 

[David C]

My experience tallys with Paul's.

My 5 1/2 and most of my other planes are all very slightly convex, due to failure to use Bugbear's superior flattening methods!

David

 

[bugbear]

My experience tallys with Paul's.

My 5 1/2 and most of my other planes are all very slightly convex, due to failure to use Bugbear's superior flattening methods!

David

Which (of course) one might well expect to plane concave (the mirror image of a convex plane).

BugBear

 

[newt]

All my planes produce a convex surface, unless I significantly reduce downward pressure at the beginning and end of stroke. However I do not practice that technique only a reduction at the end. Bad practice to only use light pressure at the beginning as there is a high probability of not engaging the cut.

 

[woodbloke]

All my planes produce a convex surface, unless I significantly reduce downward pressure at the beginning and end of stroke. However I do not practice that technique only a reduction at the end. Bad practice to only use light pressure at the beginning as there is a high probability of not engaging the cut.

Pete's description is the standard way to teach planing. Vertical pressure on the front at the start of the cut with an easing off (or removal of the hand completely) at the end of the stroke. Continual downward pressure at the end of the stroke will make the board, or edge go convex...just like the guy planing in the Wickes ad - Rob

 

[bugbear]

Pete's description is the standard way to teach planing. Vertical pressure on the front at the start of the cut with an easing off (or removal of the hand completely) at the end of the stroke.

I'd seen that description, in some cases with a diagram, in several books.

An "a-ha" moment for me was when someone described it as "trying (and failing) to scoop out the middle of the board", which is much easier to visualise, and results in the same pressure changes.

BugBear

 

[Jeff Gorman]

One might be forgiven for wondering if David C's No.5 1/2 is just a trifle hollow?

I doubt it. In my experience, David is right - if you keep planing a piece of wood from end to end, without taking stop shavings, you will eventually plane it convex.

Paul

I wonder whether David's bench top is slightly hollow?

Though I haven't yet tried to repeat David's experience (that for me defies all logic) the workpiece will deflect while under pressure and return to a slightly convex form when pressure is released.

Even a few thou's hollow can make a difference, which is why to reach some mild tearout at the mid-point of a length, I've had to put a few turns of a rolled-up shaving under the wood.

Jeff
www.amgron.clara.net

 

[David C]

Jeff,

I am well aware of the effects of timber deflection on a bench surface which is not flat.

This is why I suggested planing the edge of a 15 to 20 " board, about 4 1/2 inches wide. This is held in the vice. Mine is about 16" long.

The edge should not be subject to deflection.

best wishes,
David Charlesworth

 

[Tim Nott]

You must be the David Charlesworth that wrote the plane-tuning piece for FWW Sept-Oct 2004. I've just been applying it to an Anant jointer, with excellent results. The big problem was that they (Dick.biz) supplied a nice thick blade, but unless you set the chipbreaker about 5mm back from the edge, the shavings couldn't escape. So, doing the 15 degree mouth filing thing did the business. I haven't tried flattening the sole, but it seems pretty good in terms of performance.
So, many thanks for the article.

Well,


We had two current Stanley No. 5 planes in the workshop this summer and they were both about 6 thou" hollow in length. With a two or three thou" shaving set, neither was capable of planing a straight edge.

best wishes,
David Charlesworth

 

[afreegreek]

why on earth would you need something absolutely flat in the first place is beyond me. but, you don't need a perfectly flat surface on your plane to make one on a piece of wood.. Japanese planes are an excellent example of this as they are purposely relieved in places along the sole (depending on use). smooth and polish planes are set up to touch only in front of the mouth and at the front of the sole. the space between is relived and so is the entire sole behind the blade. on jointers it's the front of the sole, in front of the blade, and the back of the sole. set this way they will straighten an edge as good as a steel plane with a sole machined to within a billionth of an inch of flat.

 

[mr grimsdale]

You can make a flat surface on a piece of wood with an adze (curved in all directions) if you really have to.
The point is - the plane doesn't do it, you do it, i.e. use the plane (or adze, or your teeth, or anything) to remove the high points.

 

[bugbear]

You can make a flat surface on a piece of wood with an adze (curved in all directions) if you really have to.
The point is - the plane doesn't do it, you do it, i.e. use the plane (or adze, or your teeth, or anything) to remove the high points.

So why do we use planes, not adzes? Surely all that design has some benefit.

I think the oft-repeated picture of a long ship and a small ship on ocean waves may be informative here.

A plane inherently hits the peaks, and (if long enough) cannot cut the troughs, regardless of operator intent or skill.

BugBear

 

[newt]

A plane inherently hits the peaks, and (if long enough) cannot cut the troughs, regardless of operator intent or skill.

BugBear

A technically sound statement.

 

[o_LuCaS_o]

Hi!

I read this subject with great interest. I'm struggling with a planning problem and I think this thread shall solve it.

My problem is, of course, that I'm unable to achieve a flat surface. I get the surface reasonably flat (no cup or bow) with a fore plane (no. 5 or 6 with significant camber) by shoving across and diagonally to the grain. Check for twist and eliminate. But then, when I turn to the jointing/smoothing part (no. 5 with local slight convex no bigger than 2 thou) I get a convex surface. And again...I try to do the stopped shavings hollow out...and again convex surface. What I've read is, that the through shaving are naughty and change the board to a convex shape. The scooping technique of planning is another hint. Board deflecting on bench unevenness following.

Are there any other things in my technique or karma, that could be pulling me away from the Land of flat Stock? I think the conclusions of the thread should be sticked somewhere for newbies, as flattening by hand is the first and very important task one shall learn, if using only hand tools.

Thanks!

 

[Benchwayze]

..flatten wood only until toe, cutting edge, and heel are just touching. In short, producing a shallow curve through these three points

A plane sole should touch in three points, not two as described. Toe, immediately in front of the cutter and at the heel, but that aside if I worried about the absolute flatness (or not) of a bit of wood I'd never get anything made. As long as the timber can be prepared to my requirements so that I can make stuff, I'm happy Whether it's flat to within a gnats dooberie is purely academic - Rob

Yep.. Fit for purpose again.
regards
John