sharpening for beginners

[Jacob]

Yes obviously a flat surface helps in general, but talk of "reference surfaces" is pseudo science. Even "fine workpieces thin enough to flex" don't need to be "flat", as they will flex and will be pulled into shape by the construction process whatever it is.

Not sure what you mean by pseudo science. That's normally applied to homeopathy and dowsing.

This is simple mechanics.

It's not straightness in the workpiece that causes the main trouble.

It's thickness.

Consider trying to plane something down to 1/4" on a bench with a 1/8" concavity in length...

If the bench were flat, and the ends were 1/4" thick, and a #6 or #7 were used, the middle of the work would be 1/4", or near enough for a practical man.

But a 1/8" concavity in the bench would result in a workpiece 50% too thick in the middle.

Timber framers probably don't know this!

BugBear

Yebbut you wouldn't use a 6 or 7 on 1/4" stuff anyway. Still less if you had a 1/8" dip in the bench top - you'd probably plane out the dip first - but just to normal tolerances for any table top i.e. to seen to be "flat" by eye.
There is a lot of "pseudo engineering" talked about in woodwork as we all know. "Flatness" features to a large extent, along with bevel mania. A work bench just needs to be "flat" like any other work surface and isn't itself a "reference surface" for flatness.

 

[bugbear]

Still less if you had a 1/8" dip in the bench top - you'd probably plane out the dip first

Yes - the bench top needs to be flat to roughly the tolerance of the pieces you're working, at least if they're thin enough to flex.

A bench top is indeed a "reference surface", but a reference surface only needs to be sufficiently accurate for the task at hand. Excess precision is a waste of time, effort and money. The judgement comes in having the right amount of accuracy, the engineers' concept of "tolerances"

 

[woodbrains]

Hello,

Just a few general obsevations; It cannot be said that sharpening with a piece of P150 wet and dry and one combo waterstone is anything but simple, it is spurious to start talking about sharpening getting 'sciency and over-complicated' when no one has mentioned anything more simple than a grinding grit, sharpening grit and honing grit. This will get you from as dull as a hoe to sharp as a razor in quick time for 32 quid.

Norton, the manufacturer of the India oilstones do not grade their Fine India as a honing stone and recommend a finer stone subsequent to its use for planes and chisels. In fact they list India oilstone in the culinary section of their website, listing waterstones and Arkansas stones in the professional woodworking section.

Despite the liking from some contributors (not mine) of Paul Sellers' sharpening tecniques, there is seldom any mention of the fact that he uses expensive diamond stones to get his tools sharp and to a grit size much finer than India Oilstones. More expensive and 'complicated' than some would like to think. Sellers' 1200 grit diamond hone is about 6.5 micron whereas Norton India Fine is about 42.

Even oak 1 inch thick cannot be planed flat on a concave work surface, if it is long enough. Anything longer than about 2 ft would be long enough, especially, ironically when used with a short plane. Please ensure you bench top is flat by surfacing it with the longest plane you can get your hands on. Thickness of the workpiece has nothing to do with the length of plane chosen to work it, but length of the work is. I have planed sawn veneer of 2mm thick with a 7 or 8 plane, because I wanted it FLAT. Even Jacob knows the importance of stable workholding when planing. Work rocking and rolling on a benchtop full of humps and hollows cannot be stable either and will lead to chatter.

Finally, if everything could be planed flat enough with a No. 4, can anyone explain why planes of 24 inches long exist? (That is rhetorical, please DON'T)

Mike.

 

[Jacob]

............
Finally, if everything could be planed flat enough with a No. 4, can anyone explain why planes of 24 inches long exist? (That is rhetorical, please DON'T)

Mike.

You can plane anything flat with a 4 but long straight edges are more easily done with a long plane. It's always a compromise between hand-and-eye skills on one hand, and the particular qualities of the tool on the other.
What I'm saying about flat work surfaces is that ordinary "flatness" will do and engineering tolerances don't come into it. There's a lot of mystification of woodwork - often coming from the engineering direction and potentially off putting for beginners.

Even oak 1 inch thick cannot be planed flat on a concave work surface, if it is long enough.

Of course it can be done if you do what you are supposed to do i.e. pick the workpiece and look at it at regular intervals - then plane off the high points etc etc. Hand and eye skills.
If it really was a problem you'd do the normal thing of putting a bit of packing under the workpiece, etc etc. Otherwise it'd be absolutely impossible to plane a bendy board with both sides bent, as is normal; one tending to concave and the other the opposite. Though a bent work surface might help here!

 

[bugbear]

Of course it can be done if you do what you are supposed to do i.e. pick the workpiece and look at it at regular intervals - then plane off the high points etc etc.

Well, that's certainly how an engineer files and scrapes a metal surface flat, but woodworkers have a clever tool that saves a lot of peering and squinting.

It's called a plane (of suitable length). Due to it's long sole, it ONLY cuts high spots, when used correctly.

BugBear

 

[Jacob]

Of course it can be done if you do what you are supposed to do i.e. pick the workpiece and look at it at regular intervals - then plane off the high points etc etc.

Well, that's certainly how an engineer files and scrapes a metal surface flat, but woodworkers have a clever tool that saves a lot of peering and squinting.

It's called a plane (of suitable length). Due to it's long sole, it ONLY cuts high spots, when used correctly.

BugBear

It seems to be a popular delusion that once you have set it all up properly that the plane will do the work for you just like a machine and "ONLY cuts high spots"
It just isn't that simple. *
You have to keep looking and adjusting your technique accordingly.
I guess this is the reason for so much of the obsessive ramblings about precision, bevels, flatness, jigs etc - all in the hopes of avoiding having to use hand and eye skills.

*PS it isn't that simple with a machine either - if you look at all those threads about snipe and other machine plane problems.

 

[bugbear]

It seems to be a popular delusion that once you have set it all up properly that the plane will do the work for you just like a machine and "ONLY cuts high spots"
It just isn't that simple.

BugBear

 

[Jacob]

......... Work rocking and rolling on a benchtop full of humps and hollows cannot be stable . .......

No really? You mean work that is rocking about isn't stable? Well there's a surprise! Is that what is known as a "naive truism"?
So how do you stop work rocking about if for instance both sides are uneven, bowed, un-planed etc?
And ditto for a flat underside placed on a less than perfect bench top?
Clue - the answer is the same in both cases.
If you feel you need a dead flat "reference surface" it might be better to use a machine bed, or make up something from mdf. Benches get a bit roughed up and are rarely perfect.

 

[woodbrains]

No really? You mean work that is rocking about isn't stable? Well there's a surprise! Is that what is known as a "naive truism"?
So how do you stop work rocking about if for instance both sides are uneven, bowed, un-planed etc?
And ditto for a flat underside placed on a less than perfect bench top?
Clue - the answer is the same in both cases.
If you feel you need a dead flat "reference surface" it might be better to use a machine bed, or make up something from mdf. Benches get a bit roughed up and are rarely perfect.

When was the last time you scrubbed out some rough-sawn timber fo a window frame, Jacob? Your timber comes off the planer doesn't it and that flat, machined reference surface is what goes agaist your bench and it will only remain flat, durnig hand planing, if the bench top is also flat.

Scubbing out from sawn is totally a different starting point, but once it is renderd flat from scrub plane to jack, then it too, will only remain flat during dimensioning and smoothing, if the bench top is flat. This is nothing new, it has been done since Noah built his arc.

My bench top and every good cabinetmaker I know has a benchtop, which is flat. We do not bash them up or gouge them or screw fences and hold downs to them to them, and once in a while we true them up flat again, in case there has been a bit of seasonal movement. We do this because we know how important it is and because we have pride in doing accurate work and because fitting drawers and the like to a piston fit cannot be acomplished if the work is not made supremely accurate. You cannot gauge how flat work is to these tolerances by eye, nor by running your hand over it, or guessing. Reliable datums are imperative. However, just because the work is done to fine tolerances does not mean we know what they are. I do not measure drawers (or my bench top flatness) with calipers. But I do know when taking a thou or 2 off will get the fine fit I want or when a few more will make something unacceptably sloppy. Only you have mentioned measuring to engineering tolerances and then beat us up over it.

Mike.

 

[bugbear]

Only you have mentioned measuring to engineering tolerances and then beat us up over it.

http://www.don-lindsay-archive.org/skep ... html#straw

Jacob has quite a bit of history with several items from that page.

BugBear

 

[Jacob]

No really? You mean work that is rocking about isn't stable? Well there's a surprise! Is that what is known as a "naive truism"?
So how do you stop work rocking about if for instance both sides are uneven, bowed, un-planed etc?
And ditto for a flat underside placed on a less than perfect bench top?
Clue - the answer is the same in both cases.
If you feel you need a dead flat "reference surface" it might be better to use a machine bed, or make up something from mdf. Benches get a bit roughed up and are rarely perfect.

When was the last time you scrubbed out some rough-sawn timber fo a window frame, Jacob?

"Scrubbing out" is a new term for me - is it American?
I recently bought a scrub plane to see what all the fuss is about. It's very handy as an alternative to the axe, for rough trimming. I'm experimenting in using reclaimed timber and the scrub plane is really good for taking off a rough surface. I wouldn't use it on new sawn stuff though, as the scrub finish is worse than a typical sawn finish.
In answer to your question - I often planed up by hand from sawn before I got a planer. I still do for smaller pieces - I like to keep my hand in.

Scubbing out from sawn is totally a different starting point, but once it is renderd flat from scrub plane to jack, then it too, will only remain flat during dimensioning and smoothing, if the bench top is flat.

It will remain flat quite independently of the bench or other holding device, if you plane it flat and it was dry enough to start with.

.... ...... Reliable datums are imperative.

yes - straight edge, winding sticks, eyeballs.
What reference surface would you use to verify your work bench top flatness?
How would you plane up a piece of wood which is bent on both sides (as most of them are)?

"Reference surface" is an engineering term I thought. It seems to imply flatter than merely "flat" as per an average table or work bench. Are you saying that you can't plane anything flat without "a reference surface"? I think you could. I think even Bugbear could! :lol: (perhaps)

 

[bugbear]

Are you saying that you can't plane anything flat without "a reference surface"? I think you could.

Yes - and so are you. Your comment on planing out the 1/8" dip in the bench I postulated speaks loudly about the self evident truth.

"Reference surface" is an engineering term I thought. It seems to imply flatter than merely "flat" as per an average table or work bench

It implies no such thing. Straw man again. You are welcome to argue against what I say, but I wish you'd stop arguing against what you say I say.

Did you not read the information about "tolerances" or are you ignoring them for rhetorical effect?

BugBear

 

[David C]

The following bits of advice seem crystal clear to me.

Alan Peter's "treat your bench as a precious piece of equipment and care for it as you would the bed of your planer. It should be perfectly flat, and dressed periodically to ensure this;"

And Jim Kingshott, one of the last apprentice trained cabinetmakers.

"It is probably unnecessary to stress how important a truly flat bench top is;"

David Charlesworth

 

[woodbloke]

The following bits of advice seem crystal clear to me.

Alan Peter's "treat your bench as a precious piece of equipment and care for it as you would the bed of your planer. It should be perfectly flat, and dressed periodically to ensure this;"

And Jim Kingshott, one of the last apprentice trained cabinetmakers.

"It is probably unnecessary to stress how important a truly flat bench top is;"

David Charlesworth

No need to really say any more, bench tops should be flat...period - Rob

 

[Jacob]

Nobody has answered my question about planing a piece which is uneven on both sides - where a super flat bench is no great help at all.
So how do you do it, super-flat-bench-people?

NB I'm not saying that benches shouldn't be flat, it's just that it's become one of those little mantras of the engineering/woodwork tendency. We are instructed by woodbrains: "Please ensure you bench top is flat by surfacing it with the longest plane you can get your hands on." Well I'm going to do mine with a short one, if I do it at all!

PS and how do you flatten a work bench top, without a reference surface?

 

[bugbear]

PS and how do you flatten a work bench top, without a reference surface?

I'm sure you intended that as an unanswerable rhetorical master stroke.

Or something.

And yet...

I explained as clearly as I could for you that it's a FLEXIBLE workpiece that needs supporting.

N.B. A workbench isn't flexible, at least not a good one.

BugBear

 

[David C]

Reference surfaces are ubiquitous. They are the face sides and edges that a crafstman creates on almost every component.

A plane, a straight edge and winding sticks are the only tools needed to create a face side or a flat bench top.

When a thin board is wavy on both sides, I reduce the high points on each side alternately. It can be useful to shim voids under the high points, with paper, card or even piles of shavings. Repeat as often as necessary, till one side sits flat on the bench. Only now can the other side be finally perfected.

Someone said large planes were not suitable for small work. I disagree. I use a 5 1/2 for planing 1/16" stringing lines.

David Charlesworth

 

[Jacob]

Reference surfaces are ubiquitous. They are the face sides and edges that a crafstman creates on almost every component.

A plane, a straight edge and winding sticks are the only tools needed to create a face side or a flat bench top.

....

Agree.
What was being said was that the bench top itself was somehow a "reference" surface.

 

[woodbloke]

A plane, a straight edge and winding sticks are the only tools needed to create a face side or a flat bench top.
David Charlesworth

I've just re-done mine and used a woodie to take off the high spots, going across the grain and then a LV jointer to true it and checked with the longest LV straight edge (one of the really thick ones)...didn't take very long and has made a big difference to the bench - Rob

 

[Sgian Dubh]

I'm with Jacob here to a greater or lesser extent. I do think there's a bit too much cobblers talked about perfectly flat workbenches, or at least flat up to the anal extent that engineers might like to go to for certain space exploration applications or miniature medical uses, etc.

Reasonably flat I've always found to be fine, and as Jacob says, there's always thing like winding sticks and eyesight, as well as a bit of shimming out here and there. Hell, there's many a time I've purposely bowed and/or cupped a piece of wood on the bench between dogs, clamps, vices, etc in order to get at it with a plane to get the piece 'flat' once it's been released from the purgatory of the dogs, vices, clamps, or whatever. So perfectly flat bench tops as a reference surface may be nice, but wood isn't stuff that generally likes to stay flat anyway, and its trueness changes from day to day, and even sometimes hour to hour, so you just have to go with the flow a bit and adjust your work as needed. Slainte.