Mario, I have the LV 6" fractional and have been very happy with it.
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Mario, I have the LV 6" fractional and have been very happy with it.
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No offense intended but there's always a few "wood machinists" around when talking about this stuff, isn't there?
I agree with Hilton. First of all the tolerances in ww'ing are to the 1/64th or 20 thou which is a gaping hole for a machinist.
Remember we're dealing with wood, which moves around, not steel so you don't need an expensive machinists type tool for woodworking, which is what Starrett, Mitituyo, etc. are for.
An Igaging digital caliper is fine. I've compared it to an expensive dial indicator and its very accurate.
In fact, its too accurate going all the way to 128'ths of an inch.
So most of the time I use the digital scale. It also does mm's which is handy sometimes.
Matter of fact, most of the time I don't care about the number I just want something that I can set for OD and ID for fitting purposes .... like tenons!
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I prefer a dial caliper in decimal inches. It's so easy to read that I don't see the point of having a digital readout.
Now vernier calipers are a different story. My first caliper was a fractional vernier and you needed pen and paper to take a measurement. It didn't last long.
I also don't care to use fractions smaller than 1/16 - if I need a more precise measurement I would rather switch to decimals.
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I use my calipers quite often on CNC router projects where the thickness of a piece needs to be consistent within 0.005" and that is waaaay more accuracy than what is needed for most woodworking projects. I have 3 sets of calipers. I have a 6" dial caliper from Brown and Sharpe which would cost in excess of $100 to replace, I have a 6" vernier caliper made by Starrett which was given to me by a technician who acquired new digital calipers and I have 8" digital calipers which I obtained from Harbor Freight for the princely sum of $16. I have had all three calipers for more than 5 years. By far, my favorite caliper is the Harbor Freight. If I use a Whiteside precision milled 1/2" brass setup block as a reference, I get better than 0.001" consistency between all three instruments. The vernier requires better eyesight than I have without my glasses to read. The dial caliper is easier to read but, as someone else already said, the number I get is harder to remember than in digital form. Especially considering that 1/64" (0.016") is an accuracy level that exceeds what most people need, I can't see spending a premium for a name brand set of digital calipers for woodworking purposes.
By the way, I have a cheapo iGaging brand digital height/depth gauge that reads the thickness of the setup block within 0.001" of the calipers. The reason it may be off by a thousandth is probably because I am not referencing off a precision ground granite plate.
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You mean like this? http://www.amazon.com/Anytime-Tools-...PK5MNYVGXF647BOriginally Posted by Lee Reep
Digital calipers make great Imperial to metric converters, and vice-versa. Try to do that on a dial caliper.
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No offense intended but there's always a few "wood machinists" around when talking about this stuff, isn't there?
I agree with Hilton. First of all the tolerances in ww'ing are to the 1/64th or 20 thou which is a gaping hole for a machinist.
Remember we're dealing with wood, which moves around, not steel so you don't need an expensive machinists type tool for woodworking, which is what Starrett, Mitituyo, etc. are for.
An Igaging digital caliper is fine. I've compared it to an expensive dial indicator and its very accurate.
In fact, its too accurate going all the way to 128'ths of an inch.
So most of the time I use the digital scale. It also does mm's which is handy sometimes.
Matter of fact, most of the time I don't care about the number I just want something that I can set for OD and ID for fitting purposes .... like tenons!
Hah, there is a lot that we don't 'need'.
IMO, there are often times when I prefer to be more accurate than .020". A sliding dovetail with .020" clearance is practically so loose it will come out of the receiver with a good pull.
Bumbling forward into the unknown.
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Just my take:
I have had Mito digital decimal - high quality tool. Sold it, in favor of my....
Starrett fractional analog dial caliper. Here's why:
I don't understand the whole "round stuff" you lathe guys do. My stuff is flat - more or less.
The rule on the TS, and the rule on the CMS infeed table [Biese], and the depth gauges on my fleet of PC 690 routers all have these little lines - "ticks" marking length, depth, whatever. Same with my Starrett combo and double squares.
Those ticks [ 1/32"] correspond directly to the little marks on the Starrett dial face.
So - I can think in terms of "one tick above 2-7/16", or "one-half tick below 4-4/16". I don't [generally] have to sweat out 32ds, 64ths, etc - it is sixteenths and ticks.
I don't have to translate decimals to fractions, my mind is trained to always think in 16ths [notice I did not say 4-1/4" above] and the ticks are an analog visual representation of the teensy fractions used in wood stuff. My notes for the above dimensions would say "2-7 +", or "4-4 -1/2",
The ability to visually recognize and transfer dimensions is something I find very efficient.
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.
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It'snot just woodworking that this arises in, i remember way back being bemused at fractional inch engineering drawings (with tolerances added in thou) issuing from the design office of a US corporate i worked for at the time. Down to /64ths which while i could sort out by maths and convert to decimal were on first sight meaningless. As before it's all a matter of what you are used to.
I don't think woodworking and engineering are as different as many perceive. It's for example common enough to see fabrications and castings for example quite loosely dimensioned (possibly covered by a general tolerance), but the tight tolerances emerge immediately in situations where parts have to fit closely together.
Woodworking (as Brian) is little different - a properly fitting dovetail, or a mortise and tenon, or even two faces forming a plane surface are likely fitted to within a thou. Try a 0.010in gap at one end of a joint, or as clearance in a joint...
The change to working from dimensions came when the need for parts made in differing locations, or at different times to fit together. Especially volume produced standard parts made in multiple locations over extended time periods. Traditional custom production for example permits a story stick to be used to manage the dimensions of a single cabinet (to be silly - you'd have to mail the stick to China to get cheap drawers made), but even in the case of this single custom product the joints are typically very tightly fitted. To each other though by craft means, as opposed to cut to specified dimensions.
This actually was the way that engineering worked too until the advent of mass production. Early cars from a single factory certainly looked the same, but the parts were in fact generally custom fitted to each other (hence the term 'fitter' used over here for a mechanic) and not interchangeable between individual examples of the same car...
Last edited by ian maybury; 03-30-2015 at 11:02 PM.
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Pat Barry, ah the joys of mixed fastener systems in the same vehicle. My 1972 (?) Ford Pinto...USA vehicle, assembled in Canada with the German-made 2.0L SOHC engine and Northern Ireland-made carb. Virtually everything under the hood was metric, and the rest Imperial.
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Don't want 1/128ths . . . don't need 1/64ths . . . 1/32nds rarely used ?
Have you seen . . . are you aware of . . . this ?
Increments of 1/16th.
There are a few different ones.
Personally I need more of a friction thumb brake or locking screw to prevent the setting from changing . . . I have never really made friends with this little caliper but it may be all you need from what I am reading here.
Shallow jaws though.
Sharpening is Facetating.Good enough is good enoughButBetter is Better.
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If someone could make a fractional digital caliper that had a line on bottom or top of display, taking full width of LCD, with 128 pixels, representing an inch, and tick marks in 1/16 increments, then you could have a visual cue where your measurement is in relation to importation fractions of an inch rather than doing all the juggling with 1/128.
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Reminds me of this one I bought from Lee Valley. I keep it in my pocket when out shopping for hardware.
No locking mechanism or other fancy tricks but will quickly tell you the size of a drill bit, masonry plug or bolt, be it Imperial or Metric. Less than $6.
24n0655s4.jpg
"If you have all your fingers, you can convert to Metric"
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That’s a very cool idea.
The open hardware folks have been doing some neat stuff --- apparently the digital calipers can communicate w/ other tools: http://concifederico.blogspot.com/20...nterface.html#!
So it should be possible to add a new display and firmware so as to make that happen.
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I have a metric mitutoyo vernier caliper. It's superb and reliable, I have a digital one that goes between metric and imperial (in decimals, I don't understand fractions) which is also useful, and its battery doesn't run out when not in use, or at least it takes a while, 2 years or more between battery swaps. Brand is toolmate and it was a birthay gift I remember many years ago.
I'd like a dial caliper because they look nifty and I think the dial comes in handy sometimes. I have a real dial indicator though which also works.
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Really? If there's a 1/64th gap I submit you will have a snug fit, so how can .020 be that sloppy?
1/64th = .016, so for the sake of argument, permit me to revise the .020 figure.
I mean, you have to have some room for the glue, don't you?
My point is, we are woodworkers, not machinists.
Our building material is alive and moves and shrinks and expands, so cutting and fitting beyond 1/64 is a waste of effort.
As to your example, you wouldn't have the issue with a tapered sliding dovetail.
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