Official Luthiers Forum!

Maybe I'm making too much of this but I cannot find an accurate rule longer than 6" (from Stew-Mac). Is there a good source for this type of thing? Alternatively, what does everyone do about this. The question occurred to me yesterday as I was measuring heel block spacing on several necks. It just makes me nervous using a $5.00 tool for a million dollar job! well... maybe not quite

Also, O'Brien uses a nifty protractor (a locking style, I believe)in his DVD. Does anyone know a source for this or something better?

Believe me, I do search before I ask these questions but with a term like rule or measure, you get 100,000 responses.

Regards, Steve Brown

Steve,

I have a couple of stainless steel rulers I got from Woodcraft. One is a 12" and the other is a 24" center-finding ruler that I find indespensable. I've also got a few of the 6" stainless steel rulers made by General that I got at HD.

_________________
Jimmy Caldwell
http://www.caldwellguitars.com

Woodcraft! Why didn't I think of that. Thanks

Steve

Starrett, As good as it gets. you can get them from McMaster-Carr or a machiest supply house. The ones from Stewmac are good though 1/64 but if you want accurate though 1/120ths get a Starrett. Hold on to you wallet though. I got mine a couple decades ago 24" 4r grauation
I think I paid $50 back in the late seventies still as straight as the day I bought it. I found my wife using it once as a straight edge to cut fabric. That is my ex wife I mean MichaelP38460.7030555556

Oops,

I heard I was supposed to LET MY WALLET GO!

starret rule Click on the catalog page and you will see all the rules that MSC carries. Didn't want to have that as the link since it might take forever.

Someone I know bought a measuring tool from Starret and it hadn't been fully machined, so it was clear that it never worked and hadn't been inspected. The consumer called Starret up and actually talked to Mr. Starret, who said it was cheap and that's what you should expect. My suggestion is to buy Mitutoyo.

here is the rule catalog page

I use one sort of like it. It does on one side .050 and .100 and the other 1/32 and 1/64 increments. 1/4 wide. At school basic same thing as mine but 1/2 wide. I don't use the fraction side much. Never use mm and so most of my use is in the decimals.

[QUOTE=MichaelP] Starrett, As good as it gets. you can get them from McMaster-Carr or a machiest supply house. The ones from Stewmac are good though 1/64 but if you want accurate though 1/120ths get a Starrett. Hold on to you wallet though. I got mine a couple decades ago 24" 4r grauation
I think I paid $50 back in the late seventies still as straight as the day I bought it. I found my wife using it once as a straight edge to cut fabric. That is my ex wife I mean [/QUOTE]

Does she still have hands or is that why you had to cut her loose. I know bad joke

_________________
Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

I have never bought a cheap Starett scale so I don't know about ther second line products but the one you linked to is a good scale. Mitutoyo are equally as good. I have several Starett's and a couple smaller Mitutoyo and I belive I have a General tool. I have been in the Machine and manufactureing indusrty for 30 years now 90% of our QC tools are Starret. never had an issue.

Well, For the time being I settled on a 24" Woodcraft brand rule (has some kind of guarantee as to accuracy), a "mini-T" from Incra (I have one of their other products and it is spot on!)and a 6" rule. This shopuld get me by for a while.

I can't believe I forgot about Woodcraft!

Thanks for the help. I was trying to arrange going there tomorrow but it isn't going to work. I have too much else to do.

Regards to all, Steve Brown

you can get them in all lengths 6"-48" from enco accurate to 0.01", and much cheaper than starret!

Crazy Mike...One-hundredth ain't good enough!

Steve...The key to accuracy is this: All the tools with which you measure should agree with each other (compare 'em). Use only those to measure, and you can't go wrong! Several years ago, I found a 6" Starrett rule and a Starrett 4" double square at a hardware store's going-out-of-business sale. They both spot-on agree with each other. Then, I got a set (1 meter;2 ft.;1ft.;6") of rulers (I think, from Garrett Wade) made by Rabone, a British firm. They all agree with each other, and with the Starretts! The Rabones were quite inexpensive, as I remember, certainly much less than the Starretts, AND with the same accuracy!

Carlton

i know can't mark wood with a rule by hand more accurately then .01", and don't know anyone whom i would believe who claims they can.

i don't know of a starret rule or square, and i have checked the starret catalogue on my shelf, that is graduated finer than .01".

The wood probably moves a good deal more than .01" with temperature and humidity swings. Now, in the shop, they shouldn't be around. But as soon as it leaves the shop, all bets are off..

Starrett has been the machinist's standard for more than a century -- but
your eyes are better than mine if you can precisely read 128ths! That's
why they invented digital calipers ...

There are a lot of companies making good, ruled straight edges including
Starrett, Mitutoyo, Browne & Sharp, and others. For good bench tools, I'd
suggest going with an identifiable brand rather than a special-labelled
tool from a hobbyist supplier. After all, you wouldn't have written if you
just wanted an average tool, would you?

I really like the Incra perforated rules but I've found the T-square isn't
predictably square and I don't trust any of them to be really straight. For
linear measuring they are really nice, making it virtually impossible to be
off by more than .005".

I don't know which protractor you've seen, but locking protractors are as
old as dirt (and just about as common) and are available from
industrial supply and machinist's tool companies. Starrett has several with
vernier scales. For coarser measurements, there are Asian versions for
very little money.

[QUOTE=crazymanmichael] i know can't mark wood with a rule by hand more accurately then .01", and don't know anyone whom i would believe who claims they can.

i don't know of a starret rule or square, and i have checked the starret catalogue on my shelf, that is graduated finer than .01".[/QUOTE]

We're not talking about the accuracy of the woodworker, but the accuracy of the ruler. I want my measuring tools to be on the money, at least with each other. If you've got one tool accurate to .01" and another rated the same, you've got a possible discrepency of .02". If you switch between them for various tasks on your instrument, you've got potential problems. On all the measuring tools you've got, you want those inch marks to match each other!

Carlton

charlton,

please tell us how did you made your determination that your various rules:

    1) are manufactured to the same tolerance, since they     
       since they were manufactured to different
       standards, i.e. asa and us govt vs. bs, and
    2) agree with each other, particularly since one is     
       metric and the others are imperial.

do you have access to a standards laboratory?

the accuracy of a rule is determined by its capability of measuring an actual length, and thus is limited by the smallest unit you can measure with it.

the manufacturing tolerance is a different thing. quality rules, and here we are talking about starrett, brown and sharpe, mitutoyo, and also the relatively inexpensive pec brand i refered to above sold by enco, etc., are all made to the same relevant asa and us govt standards, and the deviation permisable is so small as to be totally undetectable for practical purposes, and of utterly no consequence whatsoever in the work we do. the british rules of similar quality are made to bs. these are machine room standard rules, not the aluminium big box store stuff sold to carpenters. rules made for general woodworking are also not in the same class.

while i grant that a given sample of starret rules may be expected to show less deviation one to the next within the acceptable range of manufacturing tolerance under the applicable standard than a sample from a less expensive brand, but any detectable measuring error resulting from the use of any rule of this standard will, in my opinion, overwhelmingly more likely be as a result of the quality of work done, rather the difference between the manufacturing tolerances of different manufacturers. to believe otherwise is mere delusion. afterall, we are working with wood.

as i said i know of no starret rule that is graduated finer than .01". the 4r starret square and rule you refer to above are only graduated to 1/64", and hence can measure accurately to no smaller increment. the 16r incremented in .01" is more accurate.

if you're are building in imperial units, a 16r 36" rule which is graduated to .01" on one side and 1/64 on the other is the trick for laying out any scale lengths, compensation, etc. which are commonly measured in decimal increments of an inch on many plans, the other side of a 16r, or 4r rules of various lengths are ok for general layout and gibson type plans where scale lengths are measured in fractions of an inch.

if you are working in metric this quality rule is graduated to .5mm.

tell me, as a practical matter, unless you are building only ukes, mandolins or other short scale instruments with scales measured in fractional inches, how are you going to accurately lay out guitar scale lengths measured in inches with your 24" 4r rule, or your metric rule? crazymanmichael38461.3392476852

Actually, my all-time favorite tool is the lowly 6-inch machinist's scale. One of the wizened old guys I apprenticed with could routinely hold tolerances of plus or minus .003 with a scale that was graduated in .01 increments.

When I asked him how that was possible he told me it was no great trick eyeballing half or even a quarter of the space between those .01 divisions -- especially if you cheated and used a pocket loupe.

He used a Starret as I recall. Starret was too pricey for me at the time, so I bought a Mitutoyo and kept it in my apron pocket at all times. I quickly became proficient in its use for measuring things, though I never achieved the same skill level as my mentor. The flexible little scale was pretty handy for other tasks, too, such as swatting flies, stirring coffee ....

_________________
D..

[QUOTE=Rick Davis] I don't know which protractor you've seen, but locking protractors are as
old as dirt (and just about as common) and are available from
industrial supply and machinist's tool companies. Starrett has several with
vernier scales. For coarser measurements, there are Asian versions for
very little money.[/QUOTE]

I actually found the one I was looking for. Its advantage is that is uses cantilevered bars to take lay on the angle as opposed to one edge of thee protractor. Easier to use and greater accuracy.

Regards, Steve