what i am trying to avoid is the conversion to metric and staying in one at time, considering my beloved festool is metric.I am trying to also not have the rounding error that tends to be required when going from fraction do decimal. i sure do not want to try 1/2 to1/3 mm defeats the idea. [crying]
a new metric discussion
- Thread starter tallgrass
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tallgrass said:
As 1/64" is the smallest practical graduation used on Imperial scales & rules, the 1/2mm is on metric rules. 1/2mm is about the thickness of a sheet of paper greater than 1/64 of an inch. The same techniques that you use to mark or adjust increments that are less than 1/64" can also be used to adjust increments less than 1/2mm. Of course for even finer resolution decimals work for either system.
Deansocial
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Eiji Fuller said:
but if you have a .5mm gap you have marked and cut it wrong havent you
Yes, a .5mm gap is huge because obviously there would be no gap. What i meant is when measuring the length or width ect then .5mm is acceptable. If anyone thinks they can mark & cut i piece of wood to .2mm then they are just kidding themself. Either that or they have the eyes of a Hawk [tongue]
Woodguy.
Woodguy.
mouppe
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My Incra rulers can measure and mark up to 1/64" and .25mm. I don't think I have ever used them to that degree of accuracy, but it is helpful to know they are there. If I can get to within a millimetre, I know that light sanding or planing will get me flush.
Having grown up in England but lived in North America for the last 10 years, I am comfortable with imperial and metric measurements, and I use both when woodworking. It depends on how the tool is calibrated, how the plans are drawn up, which ruler is closest to hand, etc.
What I would like to see- and perhaps it is there but I just haven't found it- is the ability to convert entire plans from imperial to metric and vice versa in one go in sketchup.
Richard.
Having grown up in England but lived in North America for the last 10 years, I am comfortable with imperial and metric measurements, and I use both when woodworking. It depends on how the tool is calibrated, how the plans are drawn up, which ruler is closest to hand, etc.
What I would like to see- and perhaps it is there but I just haven't found it- is the ability to convert entire plans from imperial to metric and vice versa in one go in sketchup.
Richard.
Jesse Cloud said:I'm doing more and more of my work in metric and enjoying the easy math immensely. What I don't understand, though, is why woodworkers in the US insist on using non-decimal fractions for measurements. (I presume it is historical, that when the craft took its current form it probably wasn't feasible to make an affordable ruler marked in 10ths and 100ths.). Most of the things I see relating to metal use decimal fractions, e.g. 1.5 or 1.625, why can't we do that with wood? It would make the math so much easier.
As to the degree of precision required for woodworking, I make high end furniture like chairs and drawers with hand cut dovetails. I almost never measure anything smaller than 1/64th and if I did the measurement would darn well be in decimal fractions instead of some silliness like 53/128ths.
When high levels of precision is required, I never rely on the gauges built into tools. With a router, I always measure the travel distance between the stop and the depth adjustment rod with a caliper, rather than trusting the guide. Same principle with saws, etc. If precision is vital, I always make a test cut on scrap to ensure the setup produces the desired result.
So, I can go either way - imperial or metric. I think the main thing, though, is to pick a measurement system for a project and stick with it. Using some imperial dimensions and some metric ones is just asking for trouble.
Most of all, I never measure unless I absolutely have to. Most of the time in woodworking the key is making two or more pieces the same length or width and the actual length is immaterial. When I'm making furniture, I often do a full sized drawing on a thin piece of mdf and erase and redraw until it looks right, then cut out the shape and fair it. Then I have a template to mark wood with and to compare the current shape of the wood to its intended shape. I have no idea how inches or meters tall my chair is or how many degrees the legs splay, but each one is exactly the same as the others and they are all as long as they need to be.
The virtue of high end tools such as Festool is not so much that they measure something accurately, but that once they are set, they keep their settings long enough to produce consistent results throughout the project.
Sorry this is so long, must have 'pressed a button' for me.
Jesse, you hit it right on the head. The only time "accuracy" (meaning absolute correctness) is important to woodworking is if two parts are measured and made separately and then need to match later. But "precision" (meaning repeatability) is always crucial. If you make two door rails, you want them to be spot on the same, even if neither of them is exactly 12 inches or 30 cm or whatever. If the fit isn't perfect one usually has to shave something down a bit until it matches, so where's accuracy then?
The point of this rant is that it doesn't matter much to me what units are used for the measurements since I make jigs to make sure all significant parts match and plane or otherwise adjust parts that need tweaking. If something calculates to 57/64 inch, I just round to some easier unit, since I generally can't see those tiny gradations on the rule anyway! I use measurements mainly to get the relative proportions according to the design; sometimes a surprisingly small change can have a large impact on appearance. But then I jig or mark one part from another and cease measuring.
The beauty of Festools and systems such as Incra is that they offer high precision in portable tools.
So, use metric or imperial based on what is comfortable to you and get on with making sawdust!
Steve
it seems like many people do not measure but "fit" their parts. I agree with the importance of "exact sameness" and making jigs to give repeatable parts. I come from a ME and metal working background so i think that colors my building process. It also seems that the relative fitting of batch parts makes the measuring system's unit size makes no difference, since people seem to be fitting their parts as apposed to making parts to a tolerance. I think it is my process that is having problems. My ability to resolve easily that which is smaller than the mm. it also seems that the mm is the hash mark of "that will do"in wood working. I guess glue sandpaper and clamping pressure is the general cure. I guess i should just get used to it. It is not metal.
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I'm assuming you were asking me?
There's an adjustment on the depth gauge.
Tom
Brice Burrell
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Tom Bellemare said:
My first though after reading this was that depth scale could be adjusted and that's not the case (at least I'm not that I'm aware of). There is a set screw on the depth adjustment knob. This set screw can be adjusted to fine tune the depth setting.
I found out from my visit to the the advanced router class in April that the routers also have a set to perfectly zero out the depth setting.
Michael Kellough
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tallgrass said:
Build to fit or build to plan....
If building to fit you scarcely need a measuring stick, just a story pole and a marker.
If building to plan you need a very fine measuring stick but if you control the plans you can make adjustments
that reduce the need for increment division. Plan for the joinery to be whole mm and let the outside dimensions
be whatever. Rounding the outside to the nearest mm will be an insignificant change to the whole but make part
fabrication much simpler.
Rob-GB
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tallgrass said:
I think Tom is just trying to be clever [huh].
From the TS55 Manual:-
4.2 Cutting depth
The cutting depth can be set at 0 ? 55 mm:
- Press the cutting depth stop (2.3) and move it to
the desired cutting depth (the values specifi ed
on the scale (2.1) apply to 0? cuts without guide
rail),
- Release the cutting depth stop (the cutting depth
stop notches along in 1 mm-steps).
The sawing unit can now be pressed down to the
set cutting depth.
17
A grub screw (M4x8 to M4x12) can be screwed into
the hole (2.2) on the cutting depth stop. By turning
the grub screw, the cutting depth can be set even
more exactly (? 0.1 mm).
So yes you can do it, but it is not a standard factory fit, it is fiddly, and as it is an alteration to the tool it may be deemed as voiding the warrantee!
Rob.
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You're right, Rob - to a degree...
That screw is designed for calibrating the saw depth.
I, personally, don't very often need to adjust depth in less than 1mm increments and if I did, I would use that adjustment.
You're right also, tallgrass - it isn't something that I would want to do very often but it can solve a problem in a pinch.
Tom
That screw is designed for calibrating the saw depth.
I, personally, don't very often need to adjust depth in less than 1mm increments and if I did, I would use that adjustment.
You're right also, tallgrass - it isn't something that I would want to do very often but it can solve a problem in a pinch.
Tom
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