This blog will be a collection of technique notes, news and stories. I am hoping to persuade some woodworking friends to post articles, from time to time. Hoping that you will enjoy the content. best wishes, David

Here is the same 1 1/4" chisel back after about two hours of flattening work.

I tried several methods, coarse India oilstone, Shapton 320 grit glasstone and 800 grit waterstone. Progress was made but the amount of hard metal which needed removing was huge, due to the belly created by years of sharpening on a hollow oilstone.

I was reminded of how much I dislike oilstones. The oil migrated up onto the top of the shallow chisel cross section and made a good grip almost impossible. I did not feel that the very coarse waterstone removed metal faster than my favorite 800 grit King Stone, though it was much harder and did wear much less.

The whole sorry, frustrating business reinforces the good advice which I was given during my training. "Avoid bellied chisels like the plague".

So, as this Pattern Maker's Long Paring chisel has lots of blade length, I decided to solve the problem by shortening it by 5/8". This was done in a few minutes with a heavy duty cutting disk in a Dremel. I cut in from both sides and snapped off the offending end when about a third of the blade thickness remained. The good part of the blade is clamped between hardwood pads in a metal working vice. The exposed tip is covered in paper towel to catch flying splinters, and given a good whack with a large hammer.

The Dremel cutting disc worked very well indeed and created remarkably little heat, if used carefully.

This rather drastic remodeling has worked very well and I now have a chisel with a flat or slightly concave back which will sharpen properly. There is still plenty of blade length for another couple of lifetimes.

I wonder if anyone can suggest other solutions for the bellied back syndrome?

Best wishes,
David

Referring back to Flattening Traditional Oilstones on 15th Nov 07, here is a picture of the rounding or bellying of a chisel back, caused by many years sharpening on a hollow oilstone.



The dull gey area is the flat surface created on an 800 grit Japanese waterstone.

Now this chislel will not sharpen or function properly untill the flat area extends all the way to the tip, so there is a lot more metal to be removed.

Not only were the oilstones used not flat, it seems they might have been twisted as well.

This is one of the main hidden dangers of buying old abused tools, it is difficult to assess the amount of work needed to restore a flat back without careful checking.

I think it will be well worth the effort in this case as the chisel is a nice, bevelled edge, 1 1/4" Pattern Maker's long paring chisel, stamped Woodcock, Sheffield 1944.

The usable blade is 7" long, tool 14 1/2" including handle. The other crucial detail is that over its full length, the blade was clearly forged and ground with about 0.5mm of hollow in its length. A most desireable and essential feature, deliberately created to aid preparation, sharpening and correct support for the cutting edge.

So please remember to send those bellied new chisels straight back to the manufacturer if you are unlucky enough to come across them.

The rounding off near the tip suggests a less than meticulous craftsman.......

I will post more pictures as the work progresses.

There are still a few places for my short courses in January and February, if you would like to experience the revelation of working with properly fettled and sharpened tools! 28th Jan in particular.

best wishes,
David

I have been watching Larry Williams excellent new dvd on the making of traditional side escapement wooden planes, which has just been published by Lie-Nielsen

The working example is a matched pair, a round and a hollow.

He makes all the blades for his planes and has an interesting sharpening technique which I intend to try. He dresses and flattens the surface of his oilstones, both man made and Arkansas, with a diamond stone. The slurry is left on the stone.

I like to rub two 800grit stones together after flattening to ensure that they cut agressively from the beginning. (800 and 1200 work as well). If abrasive paper is used to flatten waterstones, they become glazed as the paper blunts. This means that they do not cut quickly in the beginning. After a few minutes of use the surface breaks down and fast cutting commences.

It seems likely that the slurry left on an Arkansas stone will overcome one of their main drawbacks, i.e. that they cut rather slowly.

Garrett Hack uses another cunning technique to combat this problem, he soups up the cutting action with a small blob of diamond paste.

Larry is in the business of making plane blades from scratch, and therefore does a great deal of back flattening and sharpening. He made a most significant comment about the speed with which Arkansas stones loose their flatness.

Best wishes,
David

There is a phrase which keeps cropping up on or after my short courses. It goes something like this;

"I wish I had come on your tool tuning and sharpening course 5, 10 or 20 years ago."

It is absolutely clear to me that many amateurs and a few professionals too, have been struggling with less than satisfactory tools for years. They assume that this struggle is their own fault, or lack of skill, when in fact it is not.

Many manufacturers of the last century supplied tools which were merely a crude kit of parts which did not work well. Bench planes are the best example of this unfortunate fact.

I also believe that sharpening is generally very badly taught and that the waterstones we have today produce a sharper edge, much faster and than oilstones. It is difficult to appreciate true sharpness untill you are shown it. How is an individual to know that his sharpening is not as good as his neighbour's if they do not compare and use each others tools?

The following quote from George Schumacher of Louisiana, is posted with his permission, a perfect example.

"After returning home and putting the techniques learned in Hartland into operation I discovered my work to have improved dramatically. Can you believe that I am, after 30 years of piddling with wood, now finishing projects with a hand plane, faster, and more efficiently than ever before! My goal of no more sanding dust is now secondary to the newfound thrill of working with sharp tools. Thank You David!! I wish I had attended your course 30 years ago."

The good news is that this revelation is available after a mere five days.

Best wishes,
David

I have been using the new Jet curved blade jig on my large Tormek, to grind the subtle curve which I find so useful in practically all my bench plane blades. The results are very pleasing indeed.

My old method of grinding an embryonic curve, was to exploit the slop in the standard blade jig. This technique involved pressing hard on one corner of the blade while lifting the opposite corner. The lifting finger was rather exposed and had to be kept well away from the surface of the grinding wheel! The results were never quite symetrical or balanced as the support points of the jig are off centre.

The plane blade can be centred over the pivoting point of the Jet Jig and the result is perfectly symetrical. The amount of curve is set by two limiting screws. (I don't think it will cope with scrub plane blades).

However for the subtle curves used on most bench plane blades it works perfectly.

Jet Camber Jig

The jig can be got from APTC in the UK