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Thread: Metrology for the cabinetmaker

  1. #31
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    Brian what are those vice jaws called? they are not 123 blocks and they are not a sine plate. I need to make a accurate 30 degree taper for a saw arbor and I am having a time getting it correct. I have swung the compound to 15 degrees and it is close but needs more test cuts. I think I need to mount a test indicator and look for zero deflection on the existing one I am trying to copy.
    Bill D.

  2. #32
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    I hope no absolute beginner gets the false impression that this sort of measurement accuracy and instrumentation is necessary for doing first class woodworking.

  3. #33
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    Quote Originally Posted by Bill Dufour View Post
    Brian what are those vice jaws called? they are not 123 blocks and they are not a sine plate. I need to make a accurate 30 degree taper for a saw arbor and I am having a time getting it correct. I have swung the compound to 15 degrees and it is close but needs more test cuts. I think I need to mount a test indicator and look for zero deflection on the existing one I am trying to copy.
    Bill D.
    Bill, they are Kurt 3 in one vise jaws, they could certainly work for you if you have a Kurt vise.
    Last edited by Brian Holcombe; 08-01-2019 at 6:30 PM.
    Bumbling forward into the unknown.

  4. #34
    In case there is any interest in old machinery, here's a photo of my old Index mill and the rotary table I used to create the boom end fitting.

    "Anything seems possible when you don't know what you're doing."

  5. #35
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    Nice!! I've seen this photo before on another thread about planers.
    David

  6. #36
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    Nice setup, Andy!

    Isn't it amazing how many tool chests one winds up with after a while?
    Bumbling forward into the unknown.

  7. #37
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    Quote Originally Posted by Art Mann View Post
    I hope no absolute beginner gets the false impression that this sort of measurement accuracy and instrumentation is necessary for doing first class woodworking.
    Good point Art. While I do love some fine measuring tools and dabble in the automotive world building engines, body work, and welding, I have not had the chance to do much machine work, though my day job does have me working on the design and fabrication side and communicating heavily with machine shops. There definitely is plenty that can be gained from this sort of work in woodworking.

    I do however believe it is very easy to get caught up in the precision of it all and many woodworkers I speak to get obsessed with measurements, settings, and details they loose track of the right brain side of woodworking. "I cant use this that or the other because its out by .001". My favorite person to talk about when things start getting to heavily into the "machinist side of things is Andre Charles Boulle. A French guy from around 1700 that created some of the most amazing woodwork ever created, combining brass, tortoise shell, and ebony... and I doubt he owned a caliper.

    Andrew Gibson
    Infinity Cutting Tools

  8. #38
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    Part of learning a craft is learning when to do so and when not to do so. Learning when to do by hand and when by machine, learning when to take fine measurements and when not to.

    This is something that must develop over time, but in my opinion having a wider range of information available is not a bad thing. There are plenty of times when I read back through advanced level info and have a 'got-it' moment that didn't occur to me at the time. Should I have been kept from that information because I did not understand its purpose years ago?

    More to the point, should we stop discussing industrial machine tools because someone may interpret them as necessary? Should we also stop discussion fine hand tools because they may also be deemed necessary?

    Perhaps we can produce information and simply let people interpret it as they will and consume it as they may using it to their benefit when it becomes beneficial to them.
    Bumbling forward into the unknown.

  9. #39
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    Brian,
    thank you for posting this. This is very thought provoking and has caused me to review my metrology methods and how they apply to my woodworking. No time to post right now but add my thoughts about this when I have some time.

  10. #40
    Quote Originally Posted by Andrew Gibson View Post
    I do however believe it is very easy to get caught up in the precision of it all and many woodworkers I speak to get obsessed with measurements, settings, and details they loose track of the right brain side of woodworking. "I cant use this that or the other because its out by .001". My favorite person to talk about when things start getting to heavily into the "machinist side of things is Andre Charles Boulle. A French guy from around 1700 that created some of the most amazing woodwork ever created, combining brass, tortoise shell, and ebony... and I doubt he owned a caliper.
    I think this is a valid point. Like all things, this subject is personal, which is to say if one is wired with a machinist's or engineer's mentality, I can see where it would be rewarding and maybe even comforting to pursue super high levels of precision.

    I think it's important to note, that working this way is a matter of personal preference, not necessity.

    After all, traditional methods of woodworking have not required the types of super high precision being discussed here. I like to remind myself that the average human hair is about .004. So working to thousandths is basically working to a fourth of a hair. Plus wood is an organic ever moving material. Plus we don't work in clean rooms, so there's that little bit of sawdust that enters the picture.

    But if a person enjoys the machinist approach to the craft of woodworking, I say by all means have at it.
    For me, I'm willing to go partway down the metrology road, but too far gets me into the law of diminishing returns maybe because I'm not working in volume and partly because of my own inclination. It's very interesting though and thanks for sharing.

  11. #41
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    Glad that we’re continuing an interesting discussion and glad you guys are getting something out of this. I felt I should do a deeper dive because the basics are already out there. I wanted to scratch below the surface.

    A note on Boulle and cabinetmakers of that era, ‘a French guy’ does not describe that operation. He was running one of the most famous shops working on royal commissions, not a one man shop. They had staff that were highly specialized, so apprentices for basic joinery work, joiners for prep and advanced joinery work, highly skilled workers for veneer, shell and brass individually. All that comes together in a way that is near impossible to reproduce. I’m sure they actually did own vernier calipers, which were invented in 1631 in France and would be very relevant to veneer making.
    Bumbling forward into the unknown.

  12. #42
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    Quote Originally Posted by Brian Holcombe View Post
    Part of learning a craft is learning when to do so and when not to do so. Learning when to do by hand and when by machine, learning when to take fine measurements and when not to.

    This is something that must develop over time, but in my opinion having a wider range of information available is not a bad thing. There are plenty of times when I read back through advanced level info and have a 'got-it' moment that didn't occur to me at the time. Should I have been kept from that information because I did not understand its purpose years ago?

    More to the point, should we stop discussing industrial machine tools because someone may interpret them as necessary? Should we also stop discussion fine hand tools because they may also be deemed necessary?

    Perhaps we can produce information and simply let people interpret it as they will and consume it as they may using it to their benefit when it becomes beneficial to them.
    How does the old saying go? Knowledge is knowing what tool to use, wisdom is knowing when to use it.
    Years ago when I started down the path of building instruments my biggest fear was, can I build to the necessary level of precision. Highly accurate measurements are absolutely necessary. Execution is absolutely necessary and for me required a mix of machinery and had tool skills. Knowledge of the material and the way it behaves is absolutely necessary. If you are missing any of the three the end result will suffer.
    Instrument work for me is very enjoyable because it pushes me in opposite directions of artistic and technical at the same time.
    With everything we make the concept of tolerance is key.

    Brian, this is a great thread and a very enjoyable and thought provoking for me.
    Andrew Gibson
    Infinity Cutting Tools

  13. #43
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    Quote Originally Posted by Brian Holcombe View Post
    Glad that we’re continuing an interesting discussion and glad you guys are getting something out of this. I felt I should do a deeper dive because the basics are already out there. I wanted to scratch below the surface.

    A note on Boulle and cabinetmakers of that era, ‘a French guy’ does not describe that operation. He was running one of the most famous shops working on royal commissions, not a one man shop. They had staff that were highly specialized, so apprentices for basic joinery work, joiners for prep and advanced joinery work, highly skilled workers for veneer, shell and brass individually. All that comes together in a way that is near impossible to reproduce. I’m sure they actually did own vernier calipers, which were invented in 1631 in France and would be very relevant to veneer making.
    I meant this as a bit of hyperbole. I have always seen the work of Boulle as an inspiration simply to do better work and stop making excuses.
    Andrew Gibson
    Infinity Cutting Tools

  14. #44
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    Those that come from the metalwork and engineering world have mindset and tool set that they bring with them into woodworking.

    Metalwork and engineering is about measurement. It is all about numbers. Numbers are specified, parts are measured and verified.
    Woodworking is about fit, not measurement*

    *Woodworking is a different world, at least the kind of woodworking that I do.
    For reference; I made furniture, tables chairs, cabinets etc. I did lots of nice joinery work. I worked a combination of hand tools and stationary power tools,some automatic, like mortise and tenon machinery.

    Woodworking / furniture making, has no specifications demanded by customers. No customer ever asked for + or -0.001" tolerance on a mortise and tenon joint, or even demanded a mortise and tenon joint in the first place. No customer ever pulled out there micrometer to check the table leg size.

    While metalwork is governed by specifications and function, Woodworking is a fashion industry governed by the whim de jour. What tolerance you work to is it is pretty much all up to you. Your customer wont request or check your joinery work.

    Although "high precision" is not necessarily a requirement in woodworking, it can be a big help in getting complex assemblies completed without any problems and can make for a very high quality product and of course give the maker a lot of personal satisfaction.

    For those that want to do high end work with the finest joinery work and the tightest tolerance, it can pretty much be achieved without measuring anything.
    There are many ways to do things and it helps if you have a broad scope to choose which way and when.
    I have a lot of measuring tools, micrometers, camel back straight edges and granite surface plates etc.
    But i did't always, i learned to do without all of the fancy measuring equipment.

    Woodworking is about relationships; and when you learn to understand them and apply them, you can achieve as high a degree of precision as anyone, anywhere.
    Doing high end work is not just about the tools. It is a mindset, its about thinking and visualizing in three dimensions, its about understanding the relation ships between parts and referencing, its about developing a system, and project management. It is about personal training, patience and discipline to follow every step of the process. every time.

    As an example; when i make mortise and tenon joints with, lets say, my slot mortiser i choose the mortise bit, lets say 1/2" bit. I will cut the mortise in a scrap piece. then set up the tenoner and cut a scrap test piece to test the thickness fit only, when i have the thickness a smooth fit, i then set the tenon width to be a tight fit on the ends or the mortise. The reason i do the mortise first is simple; it size is governed buy the bit diameter. When i cut the tenon, i check one dimension at a time, so i can feel the fit of each, I don't want the tenon too tight in thickness as it can split the grain, but i want it tight on the end where it wont split. What the actual sizes are i don't know or care, but i bet they are as close or closer than any would get with working from calipers. The quality of your joints is a lot dependent on the quality of you machinery, its ability to do accurate and repeatable work, and also the tooling being the correct geometry and properly sharpened.

    Measuring and measuring tools are an important part to learn to understand and use (but just like starting off with hand tools, i now understand the machinery that i use a lot better) i believe that you should first learn without measuring equipment.
    I have seen many examples of people with high end measuring tools struggling to set up a machine because they cant "see" the relationship of the parts and geometry of the planes and axis. Developing the mindset is critical.

    Once you learn without measuring tools your mind thinks in relative terms. Then add the knowledge of measuring tools and you will understand how and when to apply them.
    Metrology is fascinating and another part of the education of a woodworker and we are lucky to have Brian contribute his knowledge to the collective.
    Thoroughly enjoying the discussion.




    Quote Originally Posted by Andrew Gibson View Post
    Good point Art. While I do love some fine measuring tools and dabble in the automotive world building engines, body work, and welding, I have not had the chance to do much machine work, though my day job does have me working on the design and fabrication side and communicating heavily with machine shops. There definitely is plenty that can be gained from this sort of work in woodworking.

    I do however believe it is very easy to get caught up in the precision of it all and many woodworkers I speak to get obsessed with measurements, settings, and details they loose track of the right brain side of woodworking. "I cant use this that or the other because its out by .001". My favorite person to talk about when things start getting to heavily into the "machinist side of things is Andre Charles Boulle. A French guy from around 1700 that created some of the most amazing woodwork ever created, combining brass, tortoise shell, and ebony... and I doubt he owned a caliper.

  15. #45
    Quote Originally Posted by Brian Holcombe View Post
    Nice setup, Andy!

    Isn't it amazing how many tool chests one winds up with after a while?
    Thank you. Especially in precision machining the amount of tooling and instrumentation required seems never ending.

    Regarding the varied need for precise metrology in woodworking, it greatly depends on the type of woodworking. Some, like carving for example, may be done entirely by eye. Other types might require a high degree of interchangeability in very complex assemblies. I regularly use dial calipers in my woodwork, but I also get a lot of use from a tiny 10' tape that is always with me.
    "Anything seems possible when you don't know what you're doing."

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