'Shapeing' Plane Blade

[SVB]

OK - I am not trying to start a straight vs curved debate - I was confused enough on that after watching Rob Cosman and DC back-to-back demos at Westonbirt with confident mutually exclusive advice from each.

With that out of the way, after watching DC's DVD on plane blade sharpening it made more sense to me and therefore I am sold on the approach so have decided to go down that route.

I have a brand new HOCK blade for my 5 1.2 that I would like to camber.

I have the Jet waterstone m/c, a flat plate with full range of grits, diamond med and 1000g stone and 6000 g waterstone available (and 8" dry grinder but that seems exteme!! :shock: ).

So, how to go about initial shape - I think the jet is not suitable as I do not have the fancy camber jig and given the above list of kit, I am reluctant to spend too much more on this area. I was thinking of a course (ish) grit paper (240g??) for the initial shape and then up through the grits from there finishing on the 6000g stone.

What DC does not discuss on the DVD (from only once through so appologies if I missed it) is the sort of nominal radius curve. Are we talking a thou or two at the edge or significantly more?

I would really like some advice on the best way to proceed.

Thanks
Simon

 

[TrimTheKing]

Have you watched DC's DVD? He shows in that exactly how much he is talking about.

I follow DC's technique as I find it really works for me, and after a bit of a learning curve is quite quick. The 'curve' is literally no more than 2 or 3 more strokes on the outer edges of the edge than in the middle, on the coarse stone.

HTH.

 

[dunbarhamlin]

The curve required is miniscule, being just enough that when the plane is adjusted for the rankest cut you might use, the corners of the blade are just shy of projecting enough to cut. So for a smoother, the corners might only be a couple of thousandths of an inch ( 0.05mmmmms) higher than the center of the blade.

IIRC DC aims to have the middle inch or so of the blade cutting for a normal cut.
Have another look at his DVD - he demonstrates shaping the blade by just selectively weighting the blade for a few strokes (outside edges, then half way to the center each side, I think)

For a try plane, the same approach works, but you just need to be a bit more aggressive. I wouldn't want to shape a scrub blade that way though -I sharpen those like a gouge.

(Note that for most apps I don't use a cambered blade, and it is a while since I've watched David's DVDs, though I too saw the demonstrations at Westonbirt.)

Cheers
Steve

 

[David C]

Simon,

Do try watching the DVD again. There is a lot of information contained in it and it would be difficult to take it all in at one viewing.

I do the shaping of the curve on an 800 grit waterstone so you would use the 1000 grit.

Light showing at the edges of a 2 3/8" blade, approximately 0.25mm or 10 thousandth's of an inch. This is a good shape for squaring edges. For planing wider surfaces it can be much less.

best wishes,
David Charlesworth

PS Cardboard was not a good idea, we now use plastic strips cut from office files.

 

[matthewwh]

Couldn't agree more about watching David's videos more than once, academically they are very compact presentations of a massive amount of learning, thought and practical experience, I continue to learn something every time I watch them.

I've been playing around with cambers quite a bit recently, one thing I've tried is nipping the corners off at a much steeper angle - a very small version of what you sometimes see on Japanese smoother blades. It doesn't take much, just a couple of strokes, but it's enough to remove visible track marks in the planed timber, the remainder of the cutting edge can then be honed square.

Another thing that took me a while to grasp :roll: is that the blade is always ground dead square, the cambering is purely a honing issue (unless you get into scrubs etc).

Years ago, when I was first getting back into woodworking, I bought an old infill plane that had been both cambered and back bevelled. It obviously hadn't seen a stone in decades and in my inexperience I thought, well someone's made a proper pigs ear of that blade now haven't they! So I worked until my fingertips were white on what I later came to realise was much too fine a stone for reworking bevels.

Yet here we are, years later and I'm experimenting with doing the very same thing, albeit on a much smaller scale and enjoying phenomenal results.

 

[graween]

Hi,

Interesting one Matthew. So you're kind of putting some releaf on the corners ?

That's what I'm trying to do. But on my bevel up smoother you must go for more than a few strikes !

I never experienced a camber for edges.

 

[matthewwh]

Hi Graween,

Have you thought about turning the blade over and relieving the corners on the back of the blade? That way the angles would be working for you rather than against you.

 

[woodbloke]

I've been playing around with cambers quite a bit recently, one thing I've tried is nipping the corners off at a much steeper angle - a very small version of what you sometimes see on Japanese smoother blades. It doesn't take much, just a couple of strokes, but it's enough to remove visible track marks in the planed timber, the remainder of the cutting edge can then be honed square.

Matthew - I've been doing this automatically for the last 35 years even if I've been using a cambered blade. If the corners are nipped off you can quite easily forget using a cambered blade and concentrate instead on a dead square one...which of course the KIII will always give you. As discussed earlier, a controlled cambered blade can be achieved with the KIII but it's a more convoluted process - Rob

 

[Evergreen]

I'm another one who's been chamfering the corners of his plane irons for donkey's years.

Andy Rae, in his book "Choosing and Using Hand Tools" (good book BTW), recommends this practice. He suggests making four or five passes on each corner over your hardest stone, tilting the blade at 45 degrees and pulling it towards you.He stresses that you shouldn't put any pressure on the iron or you'll cut a groove in your stone: just let the weight of the iron do the work.

If you use waterstones (like me) which are soft, it's best to do this on the side of the stone.

 

[woodbloke]

I'm another one who's been chamfering the corners of his plane irons for donkey's years.

Andy Rae, in his book "Choosing and Using Hand Tools" (good book BTW), recommends this practice. He suggests making four or five passes on each corner over your hardest stone, tilting the blade at 45 degrees and pulling it towards you.He stresses that you shouldn't put any pressure on the iron or you'll cut a groove in your stone: just let the weight of the iron do the work.

If you use waterstones (like me) which are soft, it's best to do this on the side of the stone.

I do it using the a fine grade solid (no holy bits :wink: ) Trend diamond stone and then hone in the normal way - Rob

 

[Alf]

Knocking the corners off pre-dates even you chaps, you know. :wink: Off the top of my head I believe Hayward was an advocate for smoothing and try planes (although he suggested a camber as an alternative in both cases too), while Jones in The Practical Woodworker (c.1920) just advised them for smoothers.

Speaking as one of those quaint freehand-honers, personally I find honing a camber the easiest across the board, although I did dally with the corner thing some years ago. IIRC there was some discussion at one time on The Porch about the theoretical scraping action the corner method might produce, which kinda put me off it. (This was before I realised that 95% of all sharpening-related discussion on the interweb is, in fact, best ignored - but I have a wide (and shallow) experience of many, many different methods to prove I've served my time believing it all :lol: )

Cheers, Alf

 

[David C]

Yes, in the final analysis, whatever works for the individual has got to be right!

David

 

[SVB]

OK - I should have sat down and watched the DVD a couple of times - all is revealed!

The only problem I have now is whethe to camber or just to releave the edge.

I would like to use my 5 1/2 both on the shooting board and for timber prep. Arrrrggghhhhh!

What do others think?

Simon

 

[woodbloke]

I would like to use my 5 1/2 both on the shooting board and for timber prep. Arrrrggghhhhh!

What do others think?

Simon

If you want to use it on the shooter then the blade ideally has to be honed square, not cambered - Rob

 

[Karl]

If you want to use it on the shooter then the blade ideally has to be honed square, not cambered - Rob

Which of course means that you need two planes........... :lol:

Seriously, if you have a small camber on your blade, then it's not a problem. Just use the lateral adjuster to level the centre of the blade with the centre of the workpiece on the shooting board. If however you have a good camber on the blade (ie jack plane camber) you may need another blade for the plane, sharpened with a straight edge as Rob says.

Cheers

Karl

 

[woodbloke]

Karl of course, is quite right...a small camber on a blade doesn't make a huge amount of difference, a quick tweak of the lateral adjustment lever will give surface off the 'shooter which is as square as makes no odds. A square blade is best, but a cambered blade on a 'shooter can be made to work equally as well - Rob

 

[Mr Ed]

I tend to camber my blades using the David C method of tipping the Eclipse guide a bit. I believe this is only really affecting the edges of the blade and the middle remains substantially straight. Consequently I have never had any concerns using blades sharpened in this way for shooting. Would be an issue if the work was thick, but mainly material is 1" or less, with a 60mm blade in a 5 1/2 there is enough straight in the middle to do the job.

In my view, for most day to day usage the camber you want on a bench plane is very very small

Ed

 

[woodbloke]

I tend to camber my blades using the David C method of tipping the Eclipse guide a bit. I believe this is only really affecting the edges of the blade and the middle remains substantially straight. Consequently I have never had any concerns using blades sharpened in this way for shooting. Would be an issue if the work was thick, but mainly material is 1" or less, with a 60mm blade in a 5 1/2 there is enough straight in the middle to do the job.

In my view, for most day to day usage the camber you want on a bench plane is very very small

Ed

Agree Ed, this is the way I used to do it to get a cambered blade. However a small bit of uneven pressure on one side or t'other will result over time in a cambered edge which is unintentionally skewed a fraction. This then has the consequence of not then being able to close the mouth up really tight, which is a pain in the arris - Rob

 

[graween]

Hi.

Thanks Matthew for the advice. Will think about it. Although I'm trying more to do the same process as Ed.
Woodbloke, to correct the problem you just have to get back sometimes to a coarser stone.

I don't really understand Alf about the scraping action of the corner. I'd be interested in understanding it.

I'll definitly have to watch DC videos (must buy them before tough :wink: ). Maybe that would be a Christmas gift !

Have a nice sunday.

 

[woodbloke]

Hi.

Woodbloke, to correct the problem you just have to get back sometimes to a coarser stone.

I don't really understand Alf about the scraping action of the corner. I'd be interested in understanding it.


Have a nice sunday.

I've gone back to regrinding blades square on the Tormek and then using a Kell III honing guide which is guaranteed to give a square edge provided it's set up correctly.
To knock of the corners, just hold each corner in turn at 45deg to a fine stone and make a couple of passes. This just has the effect of rounding the otherwise 90deg corner - Rob