Al Capwn

Tips to remove use of trivial math?

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Short Version: What tips/tricks/tools/jigs, etc. do you use to skip unnecessary math/measuring?

Long Rambly Version: Ok, so I know that this may be controversial or somewhat unavoidable, but I am wanting to remove trivial math from my workflow when possible. What I mean by that is constantly having to do mental juggling with the imperial system to cut parts: I.e. "Width is 28 5/16th, but I have two dados with a depth of 1/4 each, so the shelf will need to be...blah blah blah..."

I much prefer using referential measurements, geometry and ratios. I picked up the Veritas bar gauge, and so far that has been fantastic. Because I can accurately measure my existing dimensions (internal/external) and transfer them over as needed. Make a drawer box, measure the inside groove for the bottom, cut it out. Done.

Or, when I was cutting out a mortise and tenon by hand, I just set the marking gauge into rough "3rds" and scribe out my mortise and matching tenon - done.

I know that in some cases and circumstances, mucking about with measurements will always be needed, and I am not pitching my tape measure and adjustable squares anytime soon, but any "shortcuts" to "make these parts like (or fit) the other parts" without busting out a calculator would be welcome.

I know of story sticks and bar gauges, but if there is anything else I am missing, I would love to hear it.

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This may be the biggest reason to go metric. I see any measuring as a preferential choice and so do not leave Empirical, but for simple math's sake doing subtraction in pure millimeters has appeal. This I picked up from listening to Don PB may he retire in peace. 

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If imperial in particular is your enemy, go metric.  I have worked in octal, decimal and hex for 30-odd years and LOVE using imperial in the shop.  It must engage some other part of the brain because I find it relaxing.

If measuring in general is your enemy, you are already on the road.  Measure the things you have to and measure everything else off of the project as it goes.  I use SketchUp and get pretty specific measurements for critical pieces and joinery.  Once I am rolling along though I definitely will take the measurement for a panel or drawer bottom off of the carcass or the drawer box as opposed to off of the plans.

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Yes I agree with Gee Dub. Try metric - it might work for you. I use both imperial and metric but was brought up with both from an early age just as England was going over from Imperial to metric in the late 60s early 70s.

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This won't be much help but I kind of enjoy the ciphering. In the days of computers and tablets I like figuring stuff out. I'm in my 60's now and hope this keeps my brain working and sharp. I did enough damage back in the sixties and seventies so I need all the help that I can get. I guess I'm getting to the point where it more about the journey. I can say a centering ruler comes in handy. 

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I use dividers a lot.  On a recent shutter job, I started with the overall width and height measurements that fit the windows, then used dividers to space out proportions on some brown builders paper, with pencil and framing square (what I had closest at hand at the time), and when it looked right, I measured what the stile width (1/6 stepped off with the dividers looked good, and turned out to be 3-7/16), and panel reveal measurements were, and went from there.  I never had any plans beyond the width and lengths of all the parts from that few minute session.   Not much math involved in that job other than being able to read a tape measure and ruler.  That was about a $30,000 job, and anyone who has commented on them says that they look great.

 

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Ever use story poles @Tom King? I used a story pole similar to your use of dividers when laying out siding courses etc. I am not sure the value with furniture's tight tolerances. 

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@Janello - I do have a pair of digital calipers, and I should use them more to be perfectly honest. I just frequently forget about them.

@wtnhighlander & @woodbutcher74 - Center finder sounds useful; is that something shop made or some whiz-bang gadget that someone sells nowadays? I was just thinking about this today "If I want to center a mortise quickly, say with a router, how would I go about finding the center quickly..."

@micks - You know...that is actually pretty genius. I am sure I could have Google do the math for me as well. As a computer nerd I am not sure why I didn't think about that. In the cases where I must crunch numbers, I will try to keep that in mind.

@K Cooper - Yeah, I uhh, do the same thing too. Especially with things like table legs.

@Tom King - Makes sense, and I was thinking about that for finding the center points of locations (see above pondering in regards to centering a mortise). I figure I already have those for laying out things like dovetails, but they can do much more. I have been reading a bit of By Hound & Eye, and that is what also got me started thinking in terms of ratios (which then can be built out to scale). One of the tools they mentioned was a Sector, to be able to divide out parts evenly. Seems like a handy shop-built layout tool as well.

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1 minute ago, wdwerker said:

I've had several of the Veritas bar gauges and as they get longer the wood gets kinda wobbly. Then Rockler put their version on sale. Flat tips for inside measurements, pointed tips for diagonals and a compass pivot & pencil holder to draw circles plus the 2 blocks that clamp the 3/8 rods it uses. I got 6 Aluminum rods & 3 sets of the kits. I cut a variety of lengths so I can measure/copy anything from 9" to 68" wide. And if I add a extra block & rod it extends to over 102" . The 3/8 aluminum is quite stiff.

Multiple sets lets you copy both dimensions of an opening.

I could see that; I haven't used the super long rods in the Veritas kit yet. Keeping that in mind, I'll save the Veritas set for the smaller work, and either make my own or get the Rockler kit for stuff over 36" if the rods get a little squirrely on me.

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I had the earlier Veritas set that you made your own 1/4" x 3/4" sticks to use with. The newer Veritas set w rods that thread together looks pretty useful but 2 or 3 sets was to much $

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1 hour ago, Janello said:

Never measure a board width. Set fence and rip!

John, please explain the never measure a board width. 

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I will never for the life of me understand why people insist on thinking that metric is somehow better or easier. 

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2 hours ago, K Cooper said:

My rule (no pun intended) of thumb is if there are four pieces that need to be the same length, I will measure each piece twice before cutting. Then I will recut the three longest ones to match the shorter one. Not scientific nor does it work very well either.

I'm with you, in principle.  The measurement of a chair or table leg is important - plus or minus an inch (or a few cm.)  What's more important is that they are pretty much the same length.

I measure the first leg, with a stop block, and use the stop block for the other three.

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A millimeter is a little over 1/32 and far easier to count. This makes metric useful for accuracy. Another good thing it it's different and that makes you pay attention a little better. Math is far simpler too. 

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The centering ruler I spoke of is a scale with the zero in the center and is marked out on both sides. If your looking for the center of a board just check both ends, if they match the center is zero.

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10 hours ago, micks said:

Slightly off-topic, but sometimes a little math is unavoidable. I put an Amazon Echo in my shop. She does much of the math for me. Alexa, what is 7 9/16 - 3/32?

I did the same thing.  I always try and do the math in my head, keeps my brain active while working in the shop but sometimes I just have a brain fart and ask Alexa.

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I use a fractional inch/foot calculator.  I picked up a good one at Home Depot for a couple bucks a while back, and it's saved my butt a few times. 

 

16 hours ago, gee-dub said:

If imperial in particular is your enemy, go metric.  I have worked in octal, decimal and hex for 30-odd years and LOVE using imperial in the shop.  It must engage some other part of the brain because I find it relaxing.

 

I'm assuming you are refering to Octal and Hex in a coding sense, which I completely understand, and have used a few times myself.  But at first, I was trying to imagine a tape measure that uses inches as it's ujnit, but counts in Hex.  9, 10, A, B, C, D.  Wait wut?   Of course, your studs being one Hex on center is kinda a nice unit to use.

Reminds me of the time I was teaching a coworker binary, and then other number bases.   I had hm count out loud in binary, trinary, etc.   Then we hit base 11, and I truly got to see his mind seize up as he tried to vocalize a word for a value that doesn't exist in his mind. 

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