Thread: Narex Paring Chisels - how flat should they be?

OK, let's cut the personal animosities at this point, they don't benefit the discussion, nor answer the original question, which was (paraphrased), 'how flat does a paring chisel need to be?'

IMO, dead flat at the business end, so that you can achieve as perfect sharpness as your methods & skills allow - paring chisels need to be sharp. I suppose an ideal paring chisel would be dead flat along the entire back, but that's a big ask of any chisel, particularly an inexpensive one. A concavity in the back is the most undesirable situation, I think, because it means it will want to dig in on a flat surface, and be hard to control, whereas a slight convexity, is easier to control. In fact, I have one of the LV 'cranked' chisels I often use for getting glue spots or other blemishes off the middle of wide surfaces (don't ask me how they get there! ) If I understood the description correctly, these chisels have a slight convexity to their backs, which is the better error to have if they are going to be used for paring....

Cheers,

I just tried to take pic just now of one sitting on a straight edge to show the light gap, but it's impossible with my camera.

It's concave on the back which means it will dig in. Flat for 25mm behind the edge, then dips sharply to 1mm for about half the length then comes back gently to the shoulder.

So you'd have to take off 1mm from behind the bevel - that's a lot of work - even with a diamond plate.

Originally Posted by FenceFurniture

...So you'd have to take off 1mm from behind the bevel - that's a lot of work - even with a diamond plate...

Sure is! My elbow aches just thinking about it!

What you described is the least-desirable of the possibilities, alright. They'll be ok for paring near edges, and on rounded surfaces, but not so good on a flat surface at full stretch.

If they were my chisels, I'd be sorely tempted to give them a couple of taps with a heavy hammer, to try & straighten them a bit. It could save a lot of lapping. Depending on their temper, they should tolerate a bit of straightening by force, but it's the risky approach. I have distinct memories of hitting a bent chisel that I had just hardened, but not yet tempered. It was just a light tap, I swear, and the chisel snapped like a fresh carrot!

So it depends on your attitude to risk - wearing them down is much safer.....

Cheers,

Originally Posted by IanW

If they were my chisels, I'd be sorely tempted to give them a couple of taps with a heavy hammer, to try & straighten them a bit.

Funny, I was wondering about the same thing. At $20 a chisel there's not a whole bunch of risk.

In Safety parlance, Brett, the risk is still the same for cheap or expensive chisels. It is the consequences that are different Sorry, couldn't help myself, a former safety officer in an electrical utility

Brett

Do you know anybody near you with one of these?

press.jpg

More gentle and controllable than hitting. However, sometimes the temper will not allow a shape to be "pressed" back. If you were a bit closer, I could help with this or you could post them on. Unfortunately, for you, there is no guarantee I would return them .

Actually a local garage might allow you to have a play with their press if you were a customer or on friendly terms.

Regards
Paul

I'd like to see a picture showing where the bend is located in relation to the handle. The edge need to be as flat as possible in order to get a good cutting edge. But in general the rest doesn't need to be all that flat... It's rare that the chisel would be laid perfectly flat on a surface for paring. But it all depends on just how bad the bend is, and where it is.. closer to the handle is not as big of a problem as close to the cutting edge.

If it's really close to the cutting edge, you could cut them shorter and regrind the bevel. That's going to happen one day anyway.

If you **really** want them flattened, I'd surface grind them... ( I seem to be doing a lot of that lately ) but it would probably cost more than the chisels themselves cost..

Ray

ImageUploadedByTapatalk1393051733.024641.jpg
This is a 26 mm bevel edged narex I got recently that has a discernible dish in the back about 10 mm back from the edge. Should I continue to flatten the back or given I have 10 mm of flat back to play with should I worry about it as it gets shorter with sharpening.

Lay on a sheet of optically flat glass. The pseudo woodworkers should be able to
get these to optically flat by watching the pattern of Newton's Rings.
Then, they can flatten wood so that it never moves except when someone breathes on it
(one end or the other, burp in your pants, no difference).
Involute sharpening on 36 grit at 40,000rpm will resoilve the connabulary.

Originally Posted by jimfish

... Should I continue to flatten the back or given I have 10 mm of flat back to play with should I worry about it as it gets shorter with sharpening....

I wouldn't worry too much about it. It's flat behind the cutting edge, which is essential, and there's a coplanar flat back just before the neck, so if laid flat on a board for paring, it shouldn't dig in. I'd say that for 99.9% of jobs, you won't notice it.

Don't worry too much about the flat area getting shorter as you use the chisel up, if you dress the back each time you sharpen, you'll most likely find the flat area keeps pace with wear, or actually increases.

Cheers,

Thanks Ian