> 95% of machine work, they work fine.
Please dont say that to a machinist (I am not, truly. Maybe a journeyman).
And note that the real guaranteed results are +/- 0.002" worst case, or
+/- 0.04 mm.
Making any kind of "mechanical" part to a print, with a 0.04 mm error,
is a reject for more than 90% of work.
Mechanical assy just dont work at that, even screw holes dont align, and
parts dont fit within each other, etc.
For a bracket, box, mount of course even a 1 mm error is usually
immaterial, but the whole idea about machine tools, for me, is trying to
make good stuff well.
If it works, looks good (shiny, stainless) and is better than store
made, then I am happy.
> If you are trying to make accurate cuts to press fit, you better be
> measuring with mics anyway.
Well- for me maybe, for most here possibly, for machinists, Absolutely not.
The reason for DROs is so that you can make accurate stuff *without*
measuring with mics, and so that bend, springback, slop, mounts, screws
and bearing errors are eliminated.
DROs are really good and useful, precisely because they allow one to
actually get to 0.01 mm accuracies, easily, fast, and without measuring
with mics.
The chinese scales, igaging stuff, and digital calipers are not proper DROs.
They just look like them.
I dont have DROs, yet.
When I get the money (february probably), I will install real glass scales.
I will get the more accurate ones, at 5 microns, as they are almost the
same price.
PS.
I make almost everything in stainless 303, 304 or 316L.
Given that it takes longer, costs more, and I need to spend the $ to
make the widget (as compared to store bought chicom junk), I want to
make it good, strong and shiny as well.
My inspirations are things like lee valley hand tools,
Hitachi Koke industrial power tools,
Haas indexers and mills,
and so on.
I have no interest in making stuff "almost as good" as a cheap chinese
cast iron piece, weak, light, less-than-very-good, rusting, from soft
cheese steel.
If I need a basic junky utility tool I just buy it from the nearest
chicom retailer, quite happily.
Example:
I will shortly be making wrenches.
Short, long, thin, and normal thickness.
My inspiration will be stahlwille.
My wrenches will be much stronger (by 50%), lighter (20%) and better
looking.
A full set (metric, imperial), in both slim and normal, long and normal
length will be about 12 pcs each, x 4, or 48 pieces.
Material will be billet titanium, and material costs will be about 1000$.
Note that equivalent wrenches woudl cost over 10.000 $, and the
Stahwille ones would cost over 4000$.
The wrenches will hang on my office wall, and will be used as a demo of
what I can make.
Accuracy will be to +0.01 mm - 0.00 mm,
And I will only measure the first few with mics (I will be using mills I
can trust for accuracy).
If the wrenches were to be off by 0.03 mm or an igaging/chicom scale
permitted error, they will round nuts, and will not work well.
I fully understand and support saving and very well understand the
reason people install igaging stuff.
Also, it makes it intuitively good and nice to see the "almost good"
results.
The problem is, that you then expect to get "real" accuracy (nothing is
accurate, truly) and expect to have DROs, when these are really just scales.
The most important point, imho, is that people will buy these without
actually knowing that they are NOT acccurate and you cannot use them to
make stuff to *size*.
So for those of us (minority, yes, but still) the money is totally
wasted, and the disappointment factor high, when yuo cannot really use
it for what you wanted it for.
I ahve a large 600 mm (20") chinese digital caliper.
It can be (by spec sheets and in reality) upto 0.08 mm off.
Totally useless for measuring size, in mechnical fab, with machine tools
I wasted the approx. 150$ it cost.
It IS however good for measuring relative size, in large pieces, to
about +/- 0.02 mm.
Thigs like measuring two like pieces for relative errors.
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