Chisel and plaine iron width variance

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  • #675886
    Jukka Huuskonen
    Participant

    Hi,

    I just got a 6mm Veritas router blade. After I started to use it, I noticed it seemed a bit narrow and comapred it with my Narex 6mm chisel. It was noticeably narrower. I took out my vernier caliper and measured both blades and results are these:

    Veritas 6mm plane iron: 5.80 mm (+/- 0.02mm)
    Narex 6mm chisel: 6.1mm (+/- 0.02mm)

    Especially that Veritas blade 0,2 mm variance seems quite big.

    Is this variance normal or should those widths be much closer to their nominal widths?

    In this pic you can see the difference in width with these 2 blades, just zoom in.
    Veritas iron on top of Narex chisel

    -Jukka

    #675908
    Selva
    Participant

    Their 3mm blade is the same as 1/8″ so sizes are not really precise.
    In fact their online description says sizes a nominal .
    Have you asked Veritas (lee valley)? They are generally very good at responding to such questions.

    Selva

    #675939
    Jukka Huuskonen
    Participant

    Hi,
    just got a reply from Veritas. They have 0.25mm tolerance. So that iron is near lower tolerance limit.

    -Jukka

    #675989
    Larry Geib
    Participant

    Do you woodwork with a micrometer?

    #676029
    Jukka Huuskonen
    Participant

    Do you woodwork with a micrometer?

    No I don’t, the difference can clearly be seen by your eye, if you check the pic I posted. And I was talking about a caliper, not a micrometer. The caliper is a very useful tool in woodworking, even though it’s accuracy is usually much greater than is needed, but you you can eg. transfer measurements and check mortices/tenon sizes easily.

    In any case, I’ve seen eg. Paul Sellers use chisels width to measure widths of mortices and tenons and thought those tolerances would tighter. Of course, he was just using the same chisel for both. Then they are the same width and it doesn’t matter if those tolerances are greater.

    In my case I was starting a long dado with 6mm chisel and finishing the depth with router plane and just noticed how much thinner the router iron was. Had those tolerances been other way around, it would have been impossible to finish the dado of that width with the router plane.

    I do have experience in machine design and in there tolerances of machined parts (like that chisel) of that size (chisels width, 6mm) would easily have tolerance of a few hundreds of a millimeter. As that chisel and router iron are comparable to machined parts, I just assumed the tolerances would be tighter. Of course, now that I thought about how that router iron is manufactured with its narrowing blade, it’s quite understandable that achieving tighter tolerances would harder than with the chisels.

    #676043
    Sven-Olof Jansson
    Participant

    Veritas offers some tools, e.g. plough planes, in pairs of left hand and right versions, with the supposed benefit of one of the planes to be used with the grain. It’s of course not uncommon for grain direction to change, which would call for first using one of the planes and then the other. If tolerances are ±0.01″, then it’s perfectly feasible to have quite the discrepancy in width of a groove where the planes meet. Running a 6.2 mm left replacement blade into a more narrow part of a nominally 6 mm wide groove, resulted for me in bad spelching. Being by myself fairly good at generating imperfections, there is no need for the tools to add any.

    Thinking that the 6.2 mm one was just bad luck, and not completely without merits for fitting 6 mm plywood (seldom 6 mm), I ordered a new one, and was apparently in luck, as it actually is 6 mm. Then, after having read this exchange, I measured the widths of all my 26 plough plane blades. The ones coming with the planes were, perhaps not very surprising, ¼”. The 10 mm ones were 10 mm; all the other blades were off, with one deviating by 0.23 mm. Thankfully the discrepancies were consistent within the pairs. The metric blades were all above their nominal widths, with opposite for the imperial ones. The wide blades 10, 12, 16, and 18 mm were all very close to nominal values. Finally, all left hand metric blades came in small plastic bags, while all imperial and some right hand metric were neatly wrapped in little paper envelopes – acknowledging the company’s awareness of its bread being mainly buttered on the transatlantic side.

    Those who, like me, have multiple chisels of the same widths, to be able to change when one loses sharpness, might wonder if a tolerance range of 0.02″ really leaves sufficiently accurate mortice holes.

    In a rather hagiographic blog post of some years, Mr. P. Sellers describes the detail into which Veritas go in order to achieve accuracy and precision (plane soles for instance), which begs the question: why not plane blades? Particularly since there’s a company not that far west of Toronto, capable of the most laudable accuracy and precision.

    Finally, and please forgive me Larry, but isn’t the comment on a micrometer just the teeniest tad of rich, coming from someone who allegedly milled his own set-up blocks.

    Cheers
    Sven-Olof

    Sven-Olof Jansson
    London, UK; Boston, MA

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