The backs of paring chisels

[MarcW]

Hi all,

Yesterday I was putting to work a 19 mm paring chisel from Crown, kind of flattening the back, grinding a lower angle and so on. While making a break I checked the back for flatness. Well a little disappointment caught my face as I measured a belly on the length of the blade: 0,2 mm on more or less 20 cm. Now is that a problem or isn't it? My seller says it isn't, because all of those western paring chisels don't have flat backs due to the hardening process of the metal. The length is responsable for the warping during the process. What do you think about? :? What's with your paring chisels? And is a belly preferable to its opposite i.e. a hollow over the length as it behaves with plane soles - digging in the wood?... For the sake of the tool, I just tried it, but it feels a smallish bit awkward, hm.

BTW I checked the skew chisels of the same maker and yes they have a belly too. :shock:

Marc,

Now paring with japanese chisels a little bit too short

 

[David C]

I would much rather have a hollow in the length of the back of any chisel than a belly.

This logic is mainly about the reliable sharpening, i.e. polishing off of the wire edge when sharpening, of chisels, and is concerned with the front 3 inches or so.

In use I rarely pare over a length of more than 1". From the point of view of use, the belly on a long chisel may not matter.

I was taught 30 years ago to reject bellied chisels. I think it is mainly the owners and sellers of bellied chisels who disagree?

However there are some esoteric and and no doubt practical reasons why the users of framing slicks quite like a belly. Not being a timber framer I am a bit unclear on the details.

David

 

[David C]

P.S. Stanley bench chisels were almost always rather well ground with a slight hollow in length. This makes the polishing of the tip much quicker and easier.

David

 

[Alf]

Marc, I honestly can't make my mind up about it; whatever position one takes someone always seems to come along with a good argument as to why it isn't so. fwiw, I agree concave is usually more desirable than convex if you want to flatten, 'cos it'll sit on two points rather than rocking on one. Not having flat paring chisel backs from the manufacturer isn't a new phenomenon either - I've told this one before, but the son of a planemaker at Greenslades in Bristol told me how, as the useable length of a paring chisel started to get near being too short for the task, the worker'd buy the replacement and start working on the back to flatten it. A little every day for months...

What I find more frustrating than a belly along the length is one across the width. The Henry Taylor I bought before I knew better was so buffed as to be noticably convex across the width, meaning an awful lot of metal removal to get the corners of the edge doing their job. Henry Taylor apparently believe that the demand is for polished chisels and don't seem to want to even entertain the idea of offering them unpolished. I fear their market must be with folks who buy hand tools simply as decoration to put in the tool cabinet they made to Norm's plans using the tablesaw and biscuit jointer. :roll:

Cheers, Alf

 

[Chris Knight]

Marc,
I'm not sure if I read your measurements correctly but zero point 2 millimetres on a length of twenty centimetres sounds very flat to me!

 

[Anonymous]

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[MIGNAL]

Also - by "back" does everyone mean what I'd call "face"? i.e. the cutting edge being at the join of bevel and face - the "back" being the top - the side with the bevels on.

Now you have really confused me! Yes I call the back of the chisel the side you have to flatten and mirror polish. The front or face is the side with the bevel grind on it. I hope that's right.
I don't think 0.2mm is a great deal, not enough to worry about IMO.

 

[Alf]

I'm confused here Alf - are you getting concave/convex wrong way around?

Nope.

Also - by "back" does everyone mean what I'd call "face"? i.e. the cutting edge being at the join of bevel and face - the "back" being the top - the side with the bevels on.

Erm, now I'm confused... The back's the side that doesn't have a bevel on it. The side that meets the bevel to create the edge.

FWIW I think a concave face is undesireable cos it could lead to the (paring) cutting edge taking a dive into the wood, whereas convex allows you more control as you pare - lifting or dipping a gnats to control the cut. So concave - you do need to flatten ; convex - don't bother; flat - best.

I agree, which is why I said concave was desirable if you want to flatten. If you don't, then it's potentially a 'mare.

Cheers, Alf

 

[MarcW]

Many thanks to you all for your input,

While grinding and grinding and... a lower bevel on the chisel, I had time to bother about my poor tool, polished metal - burrgh - 25 ° bevel on a paring chisel and laqueered wood . I surrended and gave Mike Hancock a call for a Sorby pendant. Definitely I got a hint of cleverness and first asked him at which angle it's ground and guess, yes, they do it at 20° \/ and not polished \/ and smart boxwood handles \/ . Fine, I ordered and let him join a 50 mm bevel edge chisel to the parcel. I was happy and confident to solve my problems and so finish the work at least during the weekend.

After having my dogs a go, brain cleared again, I looked at my work and my test scrap, marked a joint (well it isn't a joint more of a kerf on a style in order to put in a batten that will support a shelf board), chopped out the waste and grabbed automatically a chisel plane. #-o Yes, I do have one and even dull it performed like everyone would expect very well and exactly.

So thank you again, now down in the shop and sharpening a plane blade :lol: ,

Marc