Chisel Advice - Metric vs. Imperial

[Lance]

I am in the market for some decent chisels, and have been giving the new Narex cabinetmakers chisels a serious look. The one concern I have is that they only make metric sized chisels. How big a deal is it to have metric chisels, if most of my other tools are imperial?

I threw in a poll to get the general consensus, but it would be a huge help to me if you could share the "why" behind your vote.

For the “it depends” crowd :-) – I currenly use mostly galoot tools, bit & brace, grooving planes, etc. Also a cordless drill, a router, and a circ saw, and a few other power tools, mostly for DIY stuff. I don’t plan to do a lot of joinery with the router, but may hog out material with a brace or hand drill.

How bid a hassle will metric chisels be, if any at all?

thanks for the input!

-Lance

[PaulMarcel]

For non-mortising chisels, I don't think it matters much at all. If you are paring the bottom of a dovetail socket or the sides or cleaning the length of a mortise, all that matters is that the width is useful to the task. For example, if the bottom of a pin socket is 1/2" wide, you likely couldn't do a decent job cleaning it with a 1/2" chisel due to the sides anyway... besides, would you be dead-on 1/2"? well, if you used a router, but then you wouldn't be paring it now would you

For mortising chisels, I think you should get the size of the mortise widths you use the most. I'll assume you mortise by pre-drilling with the brace. In that case, a 3/8" auger will be better cleaned by a 3/8" mortising chisel at the ends, after using whatever (metric or imperial) to clean the long sides.

[Onboard]

I was looking at a set of mortise chisels in the following sizes: 6mm, 10mm, 13mm and 16mm. I was wondering how close to 1/4”, 3/8”, 1/2" and 5/8” they came. Here’s what I came up with. The calculated values are not exact, but very close. The question is: Are they close enough for mortise and tenon work? Of course I also wondered what the tolerance was on the millimeter sizes. I would agree with Paul-Marcel on this one.

6mm = 0.236” or ~1/4” // 0.236” is ~15/64” (1/4” = 16/64”) or -1/64”

10mm = 0.394” or ~3/8” // 0.394” is ~25/64” (3/8” = 24/64”) or +1/64”

13mm = 0.512” or ~1/2” // 0.512” is ~33/64” (1/2” = 32/64”) or +1/64”

16mm = 0.630” or ~5/8” // 0.630” is ~40/64” (5/8” = 40/64”) Actually +1/128”

[mikem]

I have a set of Pfeil chisels, which are all metric, and have used them to make mortises at imperial measurements. I think what is more important is getting good layout lines using a marking gauge, and working of that.

[thewoodwhisperer]

I really prefer metric for standard bench chisels. The reason is because I am often "cleaning up" after some machining task. Most of my machines are imperial and the resulting joints are in imperial increments. With metric, I am usually able to use the closest size and its typically just a hair under. I like having that little bit of extra breathing room. A good example is a stopped dado. I may plow the groove with a router but when I need to square up the end, I go to a chisel. With a perfect 3/4" or 1/2" chisel, I would most likely overshoot my borders. But if the chisel is just a hair undersized, I have some room to work with.

[wilburpan]

Pretty much the only time you need a chisel to be exactly a given width is if you need to chop a mortise in a groove. If you do a lot of this, then you need your chisel to match your router bit/plow plane/whatever other tool you used to make that groove.

Beyond that, the exact size of the chisel doesn't matter. If your plan is to make a 1/4" mortise, and you use a 6mm chisel to make that mortise, the strength of the joint won't be affected. A much bigger factor in the strength of that joint will be how well you fit the tenon to your mortise.

This also is really much more a matter of convenience. If you made, say, a 1/4" groove and chopped a 6mm mortise in it, it would be trivial to pare away the 1/64" of wood that would be left to bring that mortise up to 1/4".

What would be more important is that you get a spread of sizes in your chisels that gives you flexibility in picking which one to use. 1/4", 3/8", 1/2", 5/8", 3/4", and 1" (or 6mm, 9mm, 12mm, 15mm, 18mm, and 24mm) would be a good starting set, and you could skip the 5/8" chisel.

[Lance]

Thanks, guys, the info is very helpful, and alleviates my concerns. Even the "mortise in a groove" scenario seems easily manageable with the work I am likely to do.

The new narex chisels arrive at Lee Valley next week, and I will be ready to make my purchase...investment.

Also, I find it fascinating that the responses have been either purist or ambivalent. No one went the premium route so far. (e.g. I think the new stanleys are about on par with the Narex, but are 30-40% more for an equivalent or smaller set.) No metric votes. Have our non-US/UK woodworkers not chimed in yet?

[woodcanuck]

No metric votes. Have our non-US/UK woodworkers not chimed in yet?

Ok....Canada is officially metric....and yes, I have the Narex chisels in metric...EVERYTHING else I have for woodworking in based in inches. I actually think that imperial is easier to use when you're doing woodworking, at least as far as marking and measuring goes. If you're looking at things in 1/8" increments on a rule you're not too worried if you're off by 1/32", it's close enough. If you have to mark things in millimeters, I think you're at risk of developing OCD....1mm is not far off 1/32" and I doubt too many people go to that degree of accuracy in regular woodworking tasks.

Now, if you want to talk doing mathematical calculations, I make more mistakes multiplying and dividing imperial measurements...and I've got a CS/Math degree!

Having said all that, I am proud to say that I'm passing along my bastardized measuring system to my kid. WWing is in inches, feet, board feet - height in feet/inches - weight in pounds - math in metric - distances in KM - and though not really metric, temperature in degrees C.

....now, back to my poutine.

Ian

PS...I like the Narex chisels a lot, both bench and mortise chisels are a great deal for the money.

[wilburpan]

No metric votes. Have our non-US/UK woodworkers not chimed in yet?

Okay, I voted for metric only, but not for the reason you might think.

I voted that way because Japanese chisels only come in metric sizes, and I use Japanese chisels.

(Actually, even that isn't exactly true. Japanese chisels and tools are sized on a different, traditional measurement system than metric or imperial, but it's so close to metric that they are practically equivalent.)

[PaulMarcel]

Ha! I was going to ask if New Jersey is now non-US

[Tobbe Arnesson]

Have our non-US/UK woodworkers not chimed in yet?

I work only in metric, Sweden has had that since 1860. So I figured my opinion is not valid in your case.

As a side note I was cutting stock to 2150.0 mm yesterday, I'm building a small pier so I better be precise.

[Bob Rozaieski]

I don't think it really matters. I like my tools to be all the same system just for consistency and efficiency, because I use my chisels for more than just chopping and paring. I think it's more important that your tools match in size and not so important what the actual size is. I don't care if my 1/4" chisel is exactly 1/4" or if it is a hair over or under 1/4" or if it is 6mm or 6.5mm, etc. But I do want my ~1/4" bench chisel to be the same width as my ~1/4" mortise chisel and my ~1/4" plow plane iron, etc. Having the tools be the same width makes slaving easier. This can be worked around, but doing so is just not as effecient or precise.

[wilburpan]

Ha! I was going to ask if New Jersey is now non-US

Many New Yorkers seem to think so.

But then again, I've been asked in all seriousness by New Yorkers who learn that I'm originally from Chicago if Chicago is on the west side of the Mississippi.

[Southwood]

Wilbur, I have heard that Illinois is in Chicago, any truth to that?

As far a chisels go, I just use imperial. It's what I have so it's what I use. Cleaning out a stopped dado, I just use the next size smaller.

[Lance]

Everyone,

I just wanted to thank you all for contributing your opinions. For a first time poster in here, it is really valuable to get that kind of feedback.

And Marc, Nicole, et al., I love being able to add the poll. It makes it so much easier to get more opinions, without people having to take the time to write a full reply. Great, fun feature!

-Lance

[nateswoodworks]

I have both imperial and metric and it don't matter to me one bit, I can see where Marc is coming from with it being nice with the metric being a hair smaller but it wouldn't sway me either way when it comes to purchasing. I really like my Narex and if the only made them in imperial I guess I would have another set of imperial chisels!

Nate