Hand Plane sharpening question

[woodbloke]

Hi, Woodbloke

I thoght they used shark skin for smoothing.

Pete

pre 1700?..after that date and into the 18cent, yes, but I'm really not sure about before 1700 - Rob

 

[Jacob]

Sand has been around for many millions of years. Tool and other stone polishing has been going on since the mesolithic (about 10000years BC). It seems unlikely that sand as an abrasive would have been completely overlooked until discovered by woodworkers in the 17 C.

 

[Sawyer]

Makers prior to 1700 didn't use abrasives simply 'cos there weren't any...

Not quite; there is reference to the Chinese making abrasive parchment in the 13thC. Earlier still, I've heard that Theophilus mentions use of abrasive grass stems: possibly horsetail, as used by the brilliant Grinling Gibbons from c. 1670. Evidence for medieval use of abrasive techniques is inconclusive, but the possibility cannot be discounted.

Similarly, there are some jointing procedures that can't be finished straight from and edge tool...

Quite - there are all sorts of techniques available to us now that simply weren't practical, or even possible before. Nothing wrong with progress!

so please don't knock abrasives.

Don't get me wrong, I'm no Luddite. I actually enjoy machining and have plenty of power tools too. The belt sander is frequently in action as I have a living to make and have to be pragmatic. Where abrasives are appropriate, I use them, but they are not an automatic choice for me, especially on repro. or restoration work.

 

[woodbloke]

Makers prior to 1700 didn't use abrasives simply 'cos there weren't any...

Not quite; there is reference to the Chinese making abrasive parchment in the 13thC. Earlier still, I've heard that Theophilus mentions use of abrasive grass stems: possibly horsetail, as used by the brilliant Grinling Gibbons from c. 1670. Evidence for medieval use of abrasive techniques is inconclusive, but the possibility cannot be discounted.

Similarly, there are some jointing procedures that can't be finished straight from and edge tool...

Quite - there are all sorts of techniques available to us now that simply weren't practical, or even possible before. Nothing wrong with progress!

so please don't knock abrasives.

Don't get me wrong, I'm no Luddite. I actually enjoy machining and have plenty of power tools too. The belt sander is frequently in action as I have a living to make and have to be pragmatic. Where abrasives are appropriate, I use them, but they are not an automatic choice for me, especially on repro. or restoration work.

Fair enough...from the wording of your previous post it sounded like you avoided abrasives like the plague. Probably just me - Rob

 

[Benchwayze]

That curve is called 'camber' and can be very desirable. A deep camber will allow material to be planed away rapidly in a controlled manner (search for 'scrub plane'). A mild camber will allow wider, thinner shavings to be taken more easily and without tearing as the sharp corners cannot dig in and cause planing racks. A very shallow/small camber will allow very fine shavings to be taken without leaving tracks from the corners making the plane excellent for final planing and smoothing of a board.

A square edge is fine for most work too, and is essential for making the edges of boards square and true for edge to edge gluing.

Maybe the only thing I could say here is make sure the blade is sharp (always!) and try to take a lighter cut. You should not have to fight with the plane to take a shaving. I'm not saying it's not actual manual labour, but there should be no grunts, groans or curses when planing. Just a rapidly enlarging pile of curly bits of ex-board.

For now, aim for a thin shaving which will make planing easier and try to work out which way each board should be planed. Don't worry too much about anything else for now, just making shavings is enough.

Stu.

Stu,

Not so I fear. A cambered blade will square an edge just as easily, but it has to be moved across the face of the board as you plane.

A well known cabinetmaker, who I am sure you will know, says in one of his books that he would love to hear from anyone who can explain how you can obtain a flat face-edge with a square blade.

I don't know exactly what he meant by that to be honest, but I know you can get a true edge with a cambered blade.

regards
John :wink:

 

[dunbarhamlin]

There are four (or more?) ways to true an edge.
With a straight cutting edge:
1) Just hold the plane true to the edge and go at it - probably good enough for most applications, or at least to get close to true.
2) The same, but using a guide - either a shooting board or a plane attachment such as the Veritas "Jointer" Fence
3) Step plane - the straight equivalent of the cambered approach. High on the nearside? Then plane just the near 2/3rds. the peaks come off when jointing (not the same as truing.) Works just fine.
4) Weighting. High on the nearside? Then move thumb pressure in front of the mouth to the nearside. Great for fine tuning only.
5) (oops, I've already exceeded my quota) Lateral adjustment of the plane iron. Not great, and requires that the edge is already out of wind.
and
6) With a cambered iron.

Must admit I do use a cambered iron in my try plane, but if it isn't to hand, the straight edged iron in my jointer gets the job done just fine.

For board faces, if you want a truly flat surface, use a straight edged iron. This does necessitate methodically planing the entire surface, and setting the iron sufficiently square, such that the next pass just removes the step left from the previous adjacent pass. Considering finishing shaving thickness (sub 1/1000") "sufficiently" square is quite easy to achieve with a toffee hammer or similar.
I use this approach to get a strong vacuum fit between parts to be face joined.
I suspect our good friend was either being facetious or referring to localised smoothing operations, which do require a cambered iron if the sub 1/1000" step is too much.

Having said that, I'm sure Jacob is quite right, that a truly straight age is something of a rarity.

 

[Benchwayze]

I have used a cambered blade, ever since I discovered that it was the way to avoid tramlines. That was after I tried taking the corners off, which left scuff marks.

The David Savage DVD isn't the only source, but it does explain quite clearly how to true surfaces with a cambered blade; and to my mind, whilst it's probably old news, it's the last word on the subject.

Of course, another angle is given us by the 'Mouseman'. Isn't it great to feel the small undulations left by the adze? 8)


Regards
John