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Post by Tom Gensmer on Feb 25, 2018 17:39:20 GMT -5
Alright folks, I stand at a precipice: As I consider buying a Incra router table, do I opt for Imperial or Metric Incra racks and tooling? As a general rule, I've tried to remain system-agnostic. For instance, for most "rough" work (framing, roofing, etc...) I still use Imperial measurements since that is how framing is laid out in North America. However, for shop and precision work I've transitioned to Metric, for a few reasons: 1. 1mm increments are finer than 1/16" while still being pretty easy to see with standard measuring techniques 2. The math is SOOOO much easier dealing with metric versus imperial, particularly when getting down into 1/32's, 1/64's, etc.... 3. Most of my tools (Mafell, Festool, etc...) come with Metric scales on the tools As noted in another thread, I am looking at purchasing a Incra router table (this is my primary concern for this thread), and am also considering integrating a LS Positioner into my Erika 70 setup. In the interest of avoiding a thread that might veer away from it's intended purpose, I pose the following question: Am I better off getting an Imperial or Metric LS Positioner for a Incra router table?Here's an example of the table I'm looking to set up: www.incrementaltools.com/ProductDetails.asp?ProductCode=RTCOMBO-3-TWHere's a detail of the Incra LS Positioner: The Imperial version locks in 1/32" increments, with micro-adjustments. The Metric version locks in 1mm increments, with 1/20mm adjustments. So, both versions lock in fine increments, and micro-adjust to extremely fine increments. My gut tells me to get the Metric version, but I wonder if there's something I'm missing? The biggest hiccup I see is working with straight router bits, most of which come in imperial diameters. This isn't necessarily a problem, since I'll just convert them to metric decimals and do the math from there. I'm just wondering if I'm overlooking a glaring reason why I would want to consider Imperial over Metric, knowing that most of my other work flows already operate in Metric? Thanks for any input you may have to offer!
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Post by kraftt on Feb 25, 2018 19:29:52 GMT -5
As I read and got caught up in the other thread and looked into all these products I also pondered mm or inch.
I might contact Incra and ask if the threaded rod and locking ’nut’ for both metric and imperial are interchangeable and sold separately - that would cinch it for me because I could always convert back it if it bothered me.
( edit: .... and I see they do after I followed one of your links to metric accessories / conversion kit, around $80 depending. )
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Post by kraftt on Feb 25, 2018 19:43:06 GMT -5
The only other thing that comes to mind, if there’s even any logic to it, is that while imperial may not be forward thinking the built in gross adjustment scale of 1/32" is a hair finer/tighter than 1mm.
(1mm).0393 - (1/32 in.).0313 = .08
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Post by Tom Gensmer on Feb 25, 2018 20:43:52 GMT -5
Hi Kraft!
Incra offers kits to convert Imperial LS Positioners and saw fences to Metric, and I'm sure they can convert from Metric to Imperial as well. My understanding is that the extrusions are identical, the difference is that the LS Positioners use different threaded rods and associated parts/scales. The miter gauge fences are the same, where the black plastic Incra blocks are 1/32", while the red plastic blocks are 1mm.
I agree that 1/32" is finer than 1mm, but since both LS Positioners offer fine adjustment above and beyond 1/32mm / 1mm, so I'm not very worried on that account. For example, I believe that the Metric LS Positioner fine adjusts in 1/20th MM adjustments, so 0.05mm increments(!!).
My inclination is to go with the Metric, and if I realize I've made a terrible mistake I can always retrofit to Imperial....
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Post by kraftt on Feb 25, 2018 21:53:27 GMT -5
(...would be cool if they integrated both threads into same system with a disengagement lever to choose from) I saw this: pyRouterJig
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Post by bicycleclip on Feb 26, 2018 4:44:26 GMT -5
Metric vs Imperial Tom Gensmer ? It's complicated. I was of the UK generation schooled in the 1970s and 1980s who were educated using both metric and imperial. I've seen it written elsewhere that Metric excels for small precision measurements, Imperial is useful for conceptualising large measurements (feet etc.) I basically agree with this. With the view that an Erika/Incra set up is going to be more geared towards using small precision measurements, I'd say that Metric wins hands down based on likely output. For example cabinets using the 32mm system, metric wins. Any construction using the Mafell DD40 fence, metric wins. In fact even when I've attempted complex scarf joints in framing, I revert to Metric, since I find that I can do calculations easier. It has to be said that the UK is pretty much set up for Metric. I'm sometimes frustrated when I can only get woodworking plans in Imperial, and I usually convert them to Metric before I start working so I can reference off of my Erika and KSS. It's worth noting that America leads the world in recreational woodworking, and so most plans out there are published in Imperial. In the UK we still hybridise the two systems here. For example, router bits here come in 1/2" or 1/4" shanks as standard, but with metric sized heads. This probably originates from the fact that our first routers were US imports and the metric cuttters were produced to be backwards compatible with these. If I was planning to go metric, I would start looking at Freud who do metric cutters on Imperial shanks, or UK router makers, e.g. the Wealden Tool Company. I suppose some cutters, especially straight and bevel edged ones, would be system agnostic in a router table. Round-overs and perhaps box-joint cutters might be complicated though. I developed an aversion to imperial/metric conversions after having to convert a complete set of aerospace drawings from metric to decimal inch fractions. They were from a UK developer to US Lockheed Martin, who wanted precision to four decimal places. So 2cm became 0.7874". The results made my head hurt just looking at them.
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Post by holmz on Feb 26, 2018 9:06:26 GMT -5
Tom,
I am pretty hard over on metric, but I have relatives N-NE of you so I understand the territory a bit. And you seem like a wise fellow... so I doubt it matters a whole lot.
If your gut tells you metrics, then I assume that you will be able to "calculator your way" to a solution... much in the same way the astronauts who believed that they were not trending towards motion sickness did not get motion sickness, and those that believed that they were prone, seemed to be prone to it.... so if you are predisposed to be metric tolerant, then you are 80% of the way there. (IMO)
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Post by huntsgemein on Feb 26, 2018 9:24:51 GMT -5
What are you personally set up for? The emphasis on the PERSONAL: i.e. where's your head at? I'm a child of the late 50's, so my education (60's-70's) started off with imperial before we "decimalised" on Valentines Day '66. These were the days of longhand division, laborious log tables & those diabolical centre slide & circular rules. I can recall when one of the more "indulged" kids @ school turned up with a simple, primitive neon display Sharp calculator.... & everybody else was at first absorbed & fascinated, then jealous as buggery, & finally gleefully awash with "schadenfreude" when it was banned from the Physics classroom.
Anyway, long story short I endured too many years of imperial/fractional torture. More than enough time to develop a deep-seated, lifelong, abiding loathing for the system. For me, any system of unitary division not decimally based is ridiculous, anachronistic & crude. Anything other than SI is just inappropriate for both the academic Arts (calculus, algebra, & yes even the [non-metric] discipline of geometry) & sciences (physics, chem., etc.). Yet it works; sufficiently well for the truly herculean and nation-defining task of landing man on the moon - arguably that particular nation's (maybe even mankind's) single greatest achievement. All done with those same slide rules & medieval measurements that so tortured my own youth.
My father, his twin brother & their younger twinned siblings (born in 1908 & 1909 respectively) rejected all but the inescapable metrication of currency. They collectively concluded, as did I'm sure all of their generation, that it was just "too much" new knowledge to adopt. To change so radically & comprehensively requires an element of neuroplasticity that doesn't come readily or easily beyond a certain age. I understand only too well their reluctance, as I myself struggle to adapt to the CAD & 3D modelling software required in contemporary architectural design.
I personally reject almost all imperial measurement instinctively, with an almost visceral aversion. Yet it still sneaks in, as a vestigial remnant of a bygone age. I still put PSI in my tyres (WTF is a Hectopascal anyway?), my fuel consumption is best visualised in MPG, despite what my onboard computer says, & I sometimes catch myself mentally calculating intermediate distance in chains (serendipitously with a comfortable metric equivalence of approx. 20m).
Which is the heart, or crux, of your dilemma. With which system of measurement are you spatially & volumetrically fluent? How do you visualise dimensions? Do you subscribe to Fahrenheit or Centigrade? Do you drink fluid ounces or centilitres? Do you weigh Stones or Kilograms? Is your house block/back paddock in Roods & Perches or square Metres? Forget what others may say or recommend, just go with your gut. If you have to mentally reconvert as a matter of course, then you've obviously chosen inappropriately. The relative "age" & adaptability of your brain should dictate which system you feel fits you best.
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Post by kraftt on Feb 26, 2018 20:10:46 GMT -5
I know, I'll just get both imperial & metric carriages and only engage the one I need to use: imgur.com/a/6kUhG
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Post by Tom Gensmer on Feb 26, 2018 21:16:09 GMT -5
I know, I'll just get both imperial & metric carriages and only engage the one I need to use: imgur.com/a/6kUhGHah-hah, I love it!! It took me a sec to see the extra bit sitting next to the riving knife. Thank you all for your input!! I'm pretty certain that when I acquire the setup it will be with Metric equipment (LS Positioner and router lift). If I decide later that I've made a terrible mistake (not likely) it looks like things can be retrofitted to Imperial. Thanks again, and be safe out there!
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Post by GhostFist on Feb 26, 2018 23:49:09 GMT -5
I remain pro imperial for woodworking. Fractions, ratio, proportion all related and in turn the language of design. Math is math and these days everyone has a calculator for the fun stuff. imperial is based off of proportions of the human body and our body relates to what what we build.
metric is best for temperature and is no more accurate.
this discussion will continue for eternity
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Post by yetihunter on Mar 5, 2018 21:17:49 GMT -5
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