Prometheus wrote:

We've got these buggers, with magnifying lenses mounted over the
scales.

http://catalog.starrett.com/catalog/...sp?GroupID=148


Yes, this would be the protractor I was referring to. 1/12 degree (5
arc minutes) is a far cry from 1/100 degree. And, both are "not nearly
absolutely perfect". It amounts to a little more than 0.007" on a 5"
sine bar. A machinist can do this with his eyes shut.

The standard low cost angle set (less than $50) is spec'ed at 30 arc
seconds (0.00015" per inch). It's what my angle blocks are spec'ed at.
Your average machine shop will use a standard gage block set with size
increments to 0.0001" to set a 5" sine bar (that's 0.00002" per inch or
about 4.1 seconds). If you don't mind the yield hit, it's just barely
adequate for making such angle blocks. You really need to follow the
10:1 rule here.

When I make my angle blocks, I use Starrett LM gauge blocks (grade 0.5)
to set my sine plate and sine vise. These have size increments to
0.000005" (yes, five millionths of an inch) which means I'm able to
adjust the setting by one millionth of an inch per inch (about 1 arc
second). It is, for all practical purposes, way below the noise level
of my machinery and measurment capabilities (which is where it needs to
be for the work that I do). I run batches with 100% yield all the
time.

Most machine shops won't attempt this sort of work. Even so, it's
still "not nearly absolutely perfect". I inspect my work with a
Starrett LM angle gage block set (AG16.LM):

http://catalog.starrett.com/catalog/.../4200/4153.pdf

At 0.25 arc secnd accuracy, these are "nearly" but not quite perfect.
A machinest knows from experience that nothing is perfect. Nothing is
"dead-on" accurate. There are only degrees of accuracy (no pun
intended).

You caught me being a buffoon there. I never really bothered to look
at the things all that closely- they're in a different area, and the
last time I really had to care about them was over a decade ago.

Ya, I kinda figured as much. Sorry about that but perhaps now you will
realize that I do know what I'm talking about and it won't be even
remotely easy to BS me. It seems so easy to just say things in a
newsgroup because there are so many people around who don't know any
better. But it isn't always the case.

I
run the breaks as a operator once in a while to help out when I have
time, but it's not my job.

For those who aren't familiar, a "break" is used for bending sheet
metal. It kind of explains the accuracy needs of your situation. Most
people would call this a fab shop, not a machine shop.

Laser cutting and manual milling on the
Bridgeport is, and I spend my time measuring in decimals, not minutes,
so that's what I pulled out of my ass. Like I said, in-process QC is
done with these squares.

Hmmmmm.......So, unless you are just an "operator" who loads parts and
pushes a button (pulls a handle, turns a wheel, flips a lever, etc.)
then you use indicators all the time, right? You have to align vises
on the table, tram the head, locate references, etc. So, I still don't
get it. You can't be a machinist using a Bridgeport type mill and not
use indicators all the time, for every single setup. It's another one
of these scenearios which sounds like it comes from a woodworker's
imagination.

http://catalog.starrett.com/catalog/...asp?GroupID=68

Yep, nice squares! Very pricey but worth it.

And, are you saying that nobody in this shop uses indicators on sine
bars or angle blocks? They just use this "adjustable square" to set
angles? And, never with an indicator? Frankly, I'm having some
trouble picturing this. I'm inclined to think that this "machine shop"
comes from the imagination of a woodworker.

Only for final QC. The parts have a wide enough tolerances that the
squares, mics and calipers work fine on the floor. Your inclination
is wrong, but only in that we've had experiences in shops with
tolerances that are obviously very different. As noted in another
post, we're much more likely to make a mount than a piston- other
shops with better equipment do that work, and I'm fine with that. I
use all the same G-codes you do, just while making less precise parts.
The customers still have a fit if the fit and finish is not perfect.

Hmmmm........So, as I picture it in my mind, you guys run a fab shop.
Basically, you assemble things - drilling holes or milling slots as
necessary. You bend up some sheet metal to rough angles - maybe some
welding too? The tolerances are a mile wide. I still don't get your
comment about the "G-codes". Is your Bridgeport a CNC machine?

You make it sound like if a part isn't within a .0001 of nominal, you
have to beat the damn thing into place with a sledgehammer.

No, that's not what I'm saying at all. This should be like second
nature to a machinist but let's take it from the top again. The "rule
of thumb" for achieving a desired tolerance is this: your measurement
devices used for setup and inspection should provide accuracy which is
ten times that of your tolerance. If your tolerance is 0.0001", then
you should be prepared to set up your machines and check the results
with instruments which can discern 10 millionths of an inch
(0.000010"). Otherwise, you will be swamped with all sorts of
uncertainty and guesswork which will result in poor fits and poor
yield.

Another more applicable example would be very good. Someone here said
that 1/64" is a good woodworking tolerance. Great. So, if you really
want to achieve this level of accuracy, then you should be using
instruments which can discern 0.0015" or better. Why? Because the
decimal equivalent of 1/64" is 0.015". The 10:1 rule would have you
use an instrument accurate to 0.0015". Therefore, your everyday
hand-dandy 0.001"/div dial indicator is the most logical and practical
choice. If, however, you choose devices which are only capable of
measuring to 1/64", then you will be swamped with all sorts of
uncertainty and guesswork. It's likely that you will spend a lot of
time doing test cuts and re-working joints by hand - which is what a
lot of woodworkers do (and they think it demonstrates an elevated level
of skill and expertise). I know it's a strong and blunt word, but do
you see why the average machinist considers this to be "ignorant"?

It would be asinine for me to apply at a place that requires that
level of precision, because that isn't what I've been doing for most
of my working life (though I don't imagine it would take much to learn
it from where I'm at). Like I said, I'm comfortable with that- lots
of things need to be made, not just TS-aligners and precision gears.
But simply because I do a different job than you is hardly reason to
imply that I'm only qualified to sweep floors and wish that I was a
spiffy as you.

But you are not working in a machine shop. You are not a machinist.
You are working as a machine operator in a fab shop. There's a whole
world of difference here. You guys don't do anything even remotely
near perfect. By machine shop standards it really is "half assed". I
agree, as fab shops go you are probably better than most (at least you
aren't using drafting triangles and protractors from the office supply
store). If you didn't go to a community college or tech school for an
associate degree then you would enter a real machine shop with a broom
in your hand. Yes, you would probably learn quickly and eventually
understand exactly what I am talking about. I don't say this to make
you feel bad. I say this to make you see reality.

Odds are fairly good you'd gunk up the works in my shop as well- a guy
that spent all day bitching about not having an optical comparitor
next to his machine or spending an hour adjusting offsets to within a
tenth (on a machine that is not manufactured to that level of
precision, no less) when a .003 tolerance is called for instead of
doing his work would be out the door there, too.

Well, not quite. I wouldn't think too highly of anybody who took more
than an hour to do a machine setup for any of the TS-Aligner parts
(including machine warm up and coolant transfer). A good machinest can
read the print, understand the tolerances, choose the right
instruments, fixturing, tooling, etc. and make the part to specs. The
reason why a guy like me wouldn't last too long in your shop is that I
would be running circles around everyone else making them look really
bad. Next thing I know is that my machines, tools, parts, etc. would
be getting sabotaged. The boss would be getting bad reports about me
(I don't play well with others, etc.). Before long I'm out. Been
there, done that, don't like it a bit.

I might, at that. But I'd certainly worry about trim nails pounded
into a block of wood being tweaked the first time you bumped them with
somthing, or busting that indicator if the jig fell on the floor.

Squares get tweaked too, and you'd notice it even less than a bent
nail. Things do happen to all precision instruments. A good machinist
knows to check the calibration of an instrument before using it (or at
least periodically). Always close the calipers to be sure that the
reading returns to zero (especially on digital calipers!). Always use
the micrometer standard. And Stoutman should always check the
calibration of his jig before using it. That's why I suggested he get
an angle plate to use as a reference. Using the jointer fence isn't a
good idea. But, as suggested by another, a self checking technique
(measuring both sides of the blade) is a great practice.

Look, Ed. I understand that you make a product that is very precise
for aligning table saws, and it's in your best interests to advocate
super precision when setting a saw up. I'm not demeaning your
product, or saying that it's valueless. From what I've seen here,
it's reputed to be a good product, and a lot of guys are getting a
decent value from it. It's not my intention to attack the way you
earn your living, or try and deny you sales.

I didn't say that you were. I did say that people who use precise
instruments to align and adjust their woodworking machinery are being
demeaned. Forgive me for being blunt, but it's a case of the ingorant
looking down on the intelligent. I'm just trying to point out, it
really should be the other way around (as it generally is in machine
shops). I'm doing my best to educate people so that they adopt more
intelligent ways of doing things. Sure, it's in my best interest to do
so but I am going way above and beyond what I will ever recieve in
return.

But the thread started as a way to align a table saw blade to 90*- I
use the positive stops in the saw, and a machinist square to double
check it. What you've effectively done here, unintentionally or not,
is to tell me that not only is that particular setup not good enough
for my hobby, but also that I am so poor at my day job that I am fit
for nothing better than janitorial work. It's really tough not to
just tell you where to stick it.

I'm sorry that you've taken it that way but I suppose I shouldn't be
too surprised. I didn't say that your way wasn't good enough for your
purposes. This was a conclusion that you created all by yourself. I
said that *I* didn't like it for *my* purposes. I said that Leon's
"test cut method works and is very accurate when done properly" but
that I still prefer accurate instruments over test cuts. I said that
using an accurate instrument like Stoutman's was easier, faster, and
more accurate. The suggestion from myself and Stoutman is that people
should try it before jumping all over us for suggesting it.

I also didn't say that you were poor at your day job. What I did was
to challenge what you said about your job. You were claiming to be a
machinist who worked in a machine shop. Unfortunately, all your facts
and figures were so screwed up that it's was very obviously a load of
bovine fecal matter. You are really a machine operator in a fab shop.
I did it in a pretty polite way but honestly I believe that someone who
would try to pass off such obvious nonsense should be just a bit
embarrassed about being caught in the act. It's a little disingenuous
to be indignant over being caught in a blatent lie, don't you think?

Most of the folks here have a *hobby* woodworking. In my case, I make
a lot of sort of fancy end tables and vases on the lathe. The tables
end up scattered around my house, and are there for my enjoyment and
use, along with the other stuff I make. I don't care to be bullied
and told that because I'm not using a sine bar and dial indicator,
optical comparator, or a laser measurement system to set up my
contractor's saw to make those projects, they're fit for nothing
better than firewood (which is what I'm getting from your attitude
about the subject.)

I never said anything even remotely resembling this. I believe that
you have things turned around a bit. It was you that jumped all over
Stoutman (and me) about using a dial indicator jig. I am just
defending my (and Stoutman's) position. And, if my defense makes you
feel like your technique is inadequate and that the resulting work is
inferior, then it's time for a bit of retrospection, not recrimination.

If I was running a cabinet shop, I'd probably buy
your alignment tool- but I'm not. And neither are most of the people
on this group. There's a good deal of sense in buying tools with good
motors and careful construction from decent materials, but when it
comes time to rip a board, I'm just fine with using a square to set
the blade angle, and a cabinet maker's rule to check that the fence is
parallel to the blade, and get on with actually making something-
there's never been any fiddling around or wasting time involved in it.

Fine. Then there really was no need for you to jump all over Stoutman
for his idea or to present lies about your job in order to try and make
it sound like you were an authority on such matters when you really
aren't.

It's just a constant drone on some of these threads about how
everything has to be expensive, precise, and robust to do any goddamn
thing.

Stoutman's jig is probably a lot less expensive than your square. The
"drone" here seems to be about a bunch of people who feel so insecure
about themselves that they need to ignorantly attack what is a very
good, well designed, low cost, and accurate jig.

's the wrong impression to give someone who is just starting
out and checks out this group because they'd like to make some plywood
cutouts of an old lady's butt to put in the garden, or a desk for
their 4 year old to color on. If I'd have listened to too much of
this crap when I was first starting to putz around with woodworking, I
still wouldn't have ever even attempted anything more difficult than
rough house framing- but maybe I could have saved up enough money to
get a 5hp Unisaw and a phase convertor that could sit alone in my
basement by now. Then maybe in a year or two later, I could buy a
router- and ten years from now, a jointer. Boy, I bet I'd be almost
ready to make a birdhouse by 2025.

Just a bit over the top, don't you think? Here's what I think:

If the beginner were to learn about how to properly align their
machines using instruments which provide the proper degree of accuracy,
then they wouldn't agnoze over all this stupid BS that you seem
paralyzed by. Imagine spending $15 on Stoutman's jig so that you can
know for sure that the machinery you have is perfectly accurate, well
aligned and precisely adjusted for all the work that you want to do.
No guess work required - no uncertainty. Nobody saying anything about
lasers or millionths of an inch in any newsgroup would ever be able to
rattle the confidence you had in your machinery or the work that you
produce. Your knowledge and expertise would prevent you from becoming
defensive whenever a new idea comes along. Instead of attacking it out
of ignorance you would be able to evaluate it and decide for yourself
if it had any merit.

The nonsense about always having the best is just that. Try walking
into most any job shop, and demand that they buy you all new
top-of-the-line consumables before you get to work and see how long
they laugh at you before they show you the door. The best serves a
purpose, and it's nice to have, but you don't need it to do good work.

I agree, it's nonsense. And only an ignorant person who refuses to
educate themselves about the basics of Metrology, machinery alignment
and adjustment would be rattled by such stupid nonsense.

Do you really want to know what is so frustrating? Just ask.

Ed Bennett

http://www.ts-aligner.com