sharpening for beginners

[woodbrains]

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.

Perhaps you should read all the posts before you write your repy. It was Jacob who is saying we are obsessing over engineering flatness and then beating us over the head with it. I only said it is better to true up your newly made benchtop with a longer plane than a number 4. Come on Richard, I know you wouldn't plane a large surface such as this with a smoother. It is quicker and more accurate with a longer plane, and the resulting benchtop will yeald more accurate results in the work done upon it. There really is no argument.

Mike.

 

[Sgian Dubh]

Perhaps you should read all the posts before you write your repy. Mike.

Mike, I always read all the posts, carefully, before I make a contribution. I stand by what I said. Slainte.

 

[woodbrains]

Perhaps you should read all the posts before you write your repy. Mike.

Mike, I always read all the posts, carefully, before I make a contribution. I stand by what I said. Slainte.

Hi,

Not quite sure what you think you are agreeing with, then. No one has talked about engineering tolerances in benchtops, except Jacob, who then shouts us all down, saying we are obsessing about perfectly flat benches. It is a 'tactic' he employs constantly, putting words into peoples mouths and then arguing against them with things they didn't say, until everyone gets fed up defending their original statement, which was almost always true and often about something completely different than Jacob has decided it is. Bugbear has it to a tee here:

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

I really hope you are NOT agreeing a No 4 smoother is the best tool to flatten a large area such as a newly constucted bench top, that would be too much for any sensible person to stomach.

Mike.

 

[Jacob]

........ 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.

You are talking engineering tolerances yourself, in the preceding sentence.

It doesn't do to be dominated by the bench. I suggest you should bang a few nails into the top, impart a few cigarette burns on the edges, leave some hot tea cup or frying pan marks, scratch your name, and generally show it who is boss.
It is not an altar, it's a work surface.

 

[woodbrains]

And now you are taking my words out of context, The statement actually read:

..... 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.

My planes will take off the required thou or two, because they too, have flat reference surfaces (their soles) and I know how to sharpen (Ref to original post). I do not measure this, it has become intuitive because I have a reliably flat bench and planes with reliably flat soles. This is what a reference surface is all about. It enables a craftsman to get on with his work unhindered, because all the variables and inaccuracies have been ironed out, once and for all (reasonably, they do need checking once in a while) before work ever began.

Mike.

 

[Sgian Dubh]

Not quite sure what you think you are agreeing with, then. No one has talked about engineering tolerances in benchtops, except Jacob...

I'm suggesting Jacob has a point about benches. Perfectly flat is ideal of course, but I've never seen a perfectly flat wooden topped bench. I've seen good, very good, and absolutely horrible. My bench is probably in the good to very good category, ie, not far out of flat, but it's not perfect.

I really hope you are NOT agreeing a No 4 smoother is the best tool to flatten a large area such as a newly constucted bench top, that would be too much for any sensible person to stomach. Mike.

I said nothing about which plane might be suitable for a particular task-- in my only other contribution to this thread I did mention putting boards into purgatory by purposely warping them on a bench between dogs, clamps, etc to get at them with an unspecified plane. I said nothing about No 4 planes and flattening large surfaces-- I can't imagine what made you think I might support Jacob's position. (Er, you did read my post carefully before you responded to me, didn't you, ha, ha?)

I'm not the most prolific contributor to woodworking forums. Sometimes I go weeks between my utterances of verbal diarrheoa here, and elsewhere. I generally only say something if I'm in the mood and feel my contribution may be useful. But, and here is the important bit, I always read everything in a thread before I respond. I may misinterpret what's already been said, or a pertinent bit of information may slip below my radar, which I put down to failings of one sort or another on my part, but that's another story. Slainte.

 

[bugbear]

Perfectly flat is ideal of course, but I've never seen a perfectly flat wooden topped bench. I've seen good, very good, and absolutely horrible. My bench is probably in the good to very good category, ie, not far out of flat, but it's not perfect.

Descriptions like "perfect", "dead on", "flat", "reasonably flat", "normal" are useless in a written forum. Indeed, they're useless except between people with a physically shared, common working practices, such as apprentices with a common master.

When people are disagreeing (strenuously...) in a written forum, some degree of measurement in standard units is needed for meaningful communication, even if it's just an honest estimate.

It is noteworthy that the people making the most accurate flat or straight surfaces (e.g. NPL engineers) never use words like "perfect" - they just tell you what the errors are, and they tend to be small.

The only guy I know of who's ever mentioned the kind of tolerances more normally associated with metal work is Ian Kirby, with his (famous?) statement that a bench should be flat to a thou. This is not generally taken very seriously

We already know that Jacob would plane out of 1/8" dip in a bench, so we have a start to the process of people actually stating how flat they actually mean.

BugBear

 

[David C]

To complete the set, I think Jacob needs spilled glue to defile his benchtop.

 

[Jacob]

To complete the set, I think Jacob needs spilled glue to defile his benchtop.

Glue, paint, beer, you name it I've spilled it!
Seriously though, if you can't nail or screw stops to your bench you are missing out on a very useful facility. Where needed for a longer period I have done this on a piece of chipboard instead, with a rail under at the front to locate in the vice.

 

[Jacob]

..........
We already know that Jacob would plane out of 1/8" dip in a bench,

If it was proving to be a problem

so we have a start to the process of people actually stating how flat they actually mean.

BugBear

Easy - flat enough for the inaccuracy not to impede the work being done upon it.
You could say "precision is the last refuge of an engineer trying to win an argument", in the way that "patriotism is the last refuge of a scoundrel". :lol:

 

[Sgian Dubh]

Descriptions like "perfect", "dead on", "flat", "reasonably flat", "normal" are useless in a written forum. Indeed, they're useless except between people with a physically shared, common working practices, such as apprentices with a common master.

When people are disagreeing (strenuously...) in a written forum, some degree of measurement in standard units is needed for meaningful communication, even if it's just an honest estimate. BugBear

Okay then BB, just to give you some quantitave date, I nipped out and did a quick bit of measuring. I can't pick up any significant bowing in the 2300 mm length of my bench, but I can measure a cup of about 3 mm across the 480 mm width (excluding the tool well at the back). The cup is convex on the upper side. I didn't check for winding as I didn't have two decent straight sticks handy to check with.

My testing device was an offcut of sliding table saw ripped MDF about 1220 mm long. I can't say how close to straight the MDF piece was because I didn't have a second piece to test it against, but I've always found carefully ripped pairs of edges of MDF, chipboard, etc off the sliding table saw butt together without any significant gap- not scientific or quantified I know, but it will have to do.

Anyway, my bench is good enough for me, and the slight hump across the width may even be a bit of an advantage if I'm looking to bend the edges of a wider board down a bit as I work it-- the putting boards into 'purgatory' I mentioned in previous posts. Slainte.

 

[bugbear]

..........
We already know that Jacob would plane out of 1/8" dip in a bench,

If it was proving to be a problem

so we have a start to the process of people actually stating how flat they actually mean.

BugBear

Easy - flat enough for the inaccuracy not to impede the work being done upon it.
You could say "precision is the last refuge of an engineer trying to win an argument", in the way that "patriotism is the last refuge of a scoundrel". :lol:

More straw men; it becomes tedious.

I didn't suggest precision as a requirment. I suggested people quantify just how flat (or not) they actually mean.

BugBear

 

[bugbear]

Descriptions like "perfect", "dead on", "flat", "reasonably flat", "normal" are useless in a written forum. Indeed, they're useless except between people with a physically shared, common working practices, such as apprentices with a common master.

When people are disagreeing (strenuously...) in a written forum, some degree of measurement in standard units is needed for meaningful communication, even if it's just an honest estimate. BugBear

Okay then BB, just to give you some quantitave date, I nipped out and did a quick bit of measuring. I can't pick up any significant bowing in the 2300 mm length of my bench, but I can measure a cup of about 3 mm across the 480 mm width (excluding the tool well at the back). The cup is convex on the upper side. I didn't check for winding as I didn't have two decent straight sticks handy to check with.

My testing device was an offcut of sliding table saw ripped MDF about 1220 mm long. I can't say how close to straight the MDF piece was because I didn't have a second piece to test it against, but I've always found carefully ripped pairs of edges of MDF, chipboard, etc off the sliding table saw butt together without any significant gap- not scientific or quantified I know, but it will have to do. Slainte.

Anyway, my bench is good enough for me, and the slight hump across the width may even be a bit of an advantage if I'm looking to bend the edges of a wider board down a bit as I work it-- the putting boards into 'purgatory' I mentioned in previous posts. Slainte.

Thanks for taking the trouble.

That sounds likely - the real fight occurs when a bench is concave in length, since a long enough plane will bridge over such a hollow.

Widthways, the plane will confirm to almost any shape.

BugBear

 

[David C]

My testing device is a 4 foot precision Rabone straightedge.

The bench is 6 foot long and 16 inches wide, it was planed up about 3 years ago.

In the length errors seemed to be less than 0.004inch. (90 GSM Paper).

In width I found some 0.006 thou errors at the right hand end. (Hollow).

David Charlesworth.

 

[woodbrains]

My testing device is a 4 foot precision Rabone straightedge.

The bench is 6 foot long and 16 inches wide, it was planed up about 3 years ago.

In the length errors seemed to be less than 0.004inch. (90 GSM Paper).

In width I found some 0.006 thou errors at the right hand end. (Hollow).

David Charlesworth.

Hello,

Nice work surface.

And I think I am right in saying, this was not achieved with anything but a well set and fettled plane with a long sole and a pair of winding sticks and straight edge. No science or pedantry, nor huge amounts of effort. And it stays within tolerance for at least 3 years, no effort at all, really. But the dividends it pays in the work that is done from that bench will be huge; time will be saved and accuracy assured, without having to tap wedges in, or shim with veneer and other dicey 'fixes'. Important too, especially for beginners, is that there is nothing to blame but yourself, if inaccuracies creep in, because our tools and bench are the best they can be. If the plane is bad, the bench is crooked and you may or may not have bad technique, where do we begin to remedy the situation if the work turns out poorer than expected?

Mike.

 

[GazPal]

Checking for a straight/even plain doesn't need to involve the use of costly equipment, as one of the most accurate straight edges you're likely to encounter among most tool kits is the simple spirit level. The longer the level, the more accurate it will to be (In terms of gauging flatness, as well as level over given distances), as the better ones tend to have an accuracy tolerance of +/- 0.5mm per metre.

There's a genuine risk here of becoming all too demanding - in the eyes of beginners - for the sake of expecting to achieve engineering tolerances when working organic materials via hand tooling. Yes, by all means, it can be done and is very desirable, but is such accuracy truly necessary once we move from cabinetmaking and on to more basic crafting exercises? I honestly think most - shed based - woodworking DIYer's lack workshop facilities with climate controlled atmosphere capable of limiting relative humidity to levels where benches, timber and ongoing projects remain sufficiently stable to maintain a consistently stable accuracy within +/- 0.004" deviation from straight.

............

Back to sharpening....... Perhaps the best approach to learning is to develop technique surrounding the use of primary and secondary bevels of 25 deg and 30 deg, then experiment with variations once you've mastered the basics. An ordinary combination oil stone with course/medium and fine facets - plus bottle of 3in1 oil - is also a reasonable starting point. It's an approach that's worked for many thousands of apprentice and craftsmen.