How flat is flat enough?????

[bugbear]

but just how far from flat is the planed timber?

The corrolation between tool precision and work precision is neither simple nor linear.

BugBear

 

[bugbear]

6 thou hollow would inevitably mean that timber would plane high in the centre I grant you

On a flat wooden surface, with a 3 thou blade projection, it won't plane at all!!

BugBear

 

[Karl]

[
Wood that doesn't move? - hah!

BugBear

BB - I think you've misunderstood me - I was talking about older metal planes, not wooden ones. I don't even know how wooden planes got brought into this - Digit mentioned it earlier.

Cheers

Karl

 

[Paul Chapman]

Karl,

Getting back to your original question, when I flattened the sole of my Record #4, like you I didn't want to spend ages doing it. I did it in stages, whenever I had the odd half-hour to spare. Also doing it like that, the plane gradually got better and better until I reached a point when I was happy with it. It's not completely flat all over, but flat where it matters and it now performs very well.

It's probably doubtful that many of us have the ability or the necessary equipment to measure the nth degree of flatness. I would say, just keep going until the plane performs how you want it to. You'll know when it's flat enough.

Cheers :wink:

Paul

 

[woodbloke]

In the good old days of the 1970's when Record made half-decent planes I was shown a brand new No5 and the lad using it couldn't get any sort of shaving, no matter what he did to the cutter. He asked me what could possibly be the matter (didn't use that precise language :roll: :wink:...'twas a little more industrial ) When I put my 2' straight edged across the bottom the sole was concave. Now it's a long time ago and the grey matter occasionally fails but I seem to recollect that under the surface of the straight edge was a gap of approx 2mm.

...just to repeat....approx 2mm :shock: - Rob

 

[Digit]

The corrolation between tool precision and work precision is neither simple nor linear.

Maybe so, but if the piece of timber is flat why worry about the plane's sole?
The reason I mentioned wooden planes Karl is that they have been used for very many years by some real craftsmen, and I ain't never seen a flat one yet!

 

[Karl]

Rob - kind of puts my "problem" into perspective :lol:

Anyway, had a little play with my edge jointing jig this morning, following David C's advice. After my first set of through shavings, done with a fine shaving, there was a minimal bump in the piece (probably more my planing skill than anything!). After some stop shavings (till it stopped cutting) and then 2 through shavings - hey presto. Slightly hollow edge (between the thickness of 1 and 2 blue rizzla papers). On an 18" piece.

Cheers

Karl

 

[Digit]

Slightly hollow edge (between the thickness of 1 and 2 blue rizzla papers). On an 18" piece.

Exactly my point Karl, if it does the job it's good enough!

 

[woodbloke]

Rob - kind of puts my "problem" into perspective :lol:

Anyway, had a little play with my edge jointing jig this morning, following David C's advice. After my first set of through shavings, done with a fine shaving, there was a minimal bump in the piece (probably more my planing skill than anything!). After some stop shavings (till it stopped cutting) and then 2 through shavings - hey presto. Slightly hollow edge (between the thickness of 1 and 2 blue rizzla papers). On an 18" piece.

Cheers

Karl

As Digit says, that's good enough - Rob

 

[Karl]

Digit - point taken

Cheers

Karl

 

[David C]

Karl,

Excellent.

I don't think bumps in the length are neccesarily due to "lack of planing skill".

The other experiment I like to get my students to do, is to plane a straight or minutely hollow edge, on timber of the size you used.

Now take ten or fifteen through shavings from the edge, and see if the small bump returns and gets bigger as you proceed?

David

 

[bugbear]

[
Wood that doesn't move? - hah!

BugBear

BB - I think you've misunderstood me - I was talking about older metal planes, not wooden ones. I don't even know how wooden planes got brought into this - Digit mentioned it earlier.

Cheers

Karl

Sorry - I got mixed up.

BugBear

 

[bugbear]

It's probably doubtful that many of us have the ability or the necessary equipment to measure the nth degree of flatness.

In the modern era, ludicrously accurate 9"x12" granite surface plates are so cheap that some people use them to support the SiC for scary sharp!

BugBear

 

[Paul Kierstead]

Karl,
The other experiment I like to get my students to do, is to plane a straight or minutely hollow edge, on timber of the size you used.

Now take ten or fifteen through shavings from the edge, and see if the small bump returns and gets bigger as you proceed?

I'd just like to stress to really, really follow David's advice on this. I was learning to joint and surface by hand for a while. I was ok at it, but slow and often had boards that would really challenge me (others would go beautifully). My first breakthrough, before I discovered David's books and DVD's, was Jeff Gormans site and his advice to put some camber on my jointer. HUGE improvement in speed and consistency. The second was David's method of stop shavings and aiming for a very small hollow (or at least erring on the side of a very small hollow). For things which start out convex, especially, this is a world of help.

Not everyone agrees with his methods, but I strongly believe they are the very close to the perfect starting point. Once you have mastered his ways, then you can start to morph them to your own ways.

 

[Karl]

David - yes indeed the board returned to a small bump. V surprising, given that the plane is convex.

Paul - I have a few of Davids books/dvd's, and find them most useful in expanding my skills. I do have a problem (practically, not technically) with the "wandering blade" for straightening an edge, so use my own shooting jig as seen below

https://www.ukworkshop.co.uk/forums/viewtopic.php?t=19760&highlight=

Shown with the Clifton, obviously.

Cheers

Karl

 

[Paul Chapman]

I do have a problem (practically, not technically) with the "wandering blade" for straightening an edge

Hi Karl,

One technique which you might like to try (if you've not done so already) when jointing boards (provided that they are not too thick), is to put them together and plane the two joining edges at once. The advantage of this method is that you don't have to worry about the edges being at 90 degrees to the sides, because when you put them together any error on one piece will be cancelled out by the other. In fact, the angle can vary along the length of the boards and they would still go together perfectly. You still need to ensure that you plane straight in the length, so will need to do your stop shavings - but it removes the problem of the squareness of the edges.

I was taught to do it this way as a young lad at school and find the method foolproof. However, for some reason others seem to be very much opposed to the method, but I've never really understood why :? It could have something to do with cambered blades, which many seem to use these days for everything. When planing two edges together, it's best to use a straight blade.

Anyway, I'll leave the thought with you for what it's worth.

Cheers :wink:

Paul

 

[bugbear]

I do have a problem (practically, not technically) with the "wandering blade" for straightening an edge

I was taught to do it this way [match planing]as a young lad at school and find the method foolproof. However, for some reason others seem to be very much opposed to the method, but I've never really understood why :? It could have something to do with cambered blades, which many seem to use these days for everything. When planing two edges together, it's best to use a straight blade.

The major (perhaps only) "catch" is that if you remove the boards to check them, it's very difficult to get them back in the vice, paired the way they were before.

BugBear

 

[David C]

Paul,

It is a very good method for thin stuff, when combined with shooting. I can think of no other way of doing this.

Old time pro's have their chosen or instilled methods and do not tend to be very flexible in their approach. This may be one of the causes of controversy over methods?...................

David

 

[Paul Chapman]

The major (perhaps only) "catch" is that if you remove the boards to check them, it's very difficult to get them back in the vice, paired the way they were before.

Everyone seems to say that is a problem but it isn't really. Before you start, draw a pencil line across the face of both boards, then square this across the edges. Line up these two pencil lines when you cramp the boards together. You can then separate the boards as often as you like and you can always put them together again exactly as they were - OK, you will plane away the lines on the edges, but not on the sides, and it's simple enough to put the lines back again on the edges

Cheers :wink:

Paul

 

[Paul Chapman]

Old time pro's have their chosen or instilled methods and do not tend to be very flexible in their approach. This may be one of the causes of controversy over methods?...................

I think you are right, David. What I do these days is to use the match planing method with a straight blade for thin boards and the cambered blade method for thicker boards which have to be planed separately.

Cheers :wink:

Paul