Dial Test Indicators

Loading thread data ...
Hi Randy,
Suggest don't encourage him--next thing you know there's gonna be another damned 6 kb rant !!
And to Kirk :
In our shop, we only use test indicators for comparative readings anyways...
Reply to
PrecisionMachinisT
I have a Browne & Sharpe BestTest 7034-5.
Nice half-thou marks, 0-10-0 on the dial that goes around the same way regardless of which way the needle is pushed, the dial diameter is small enough to fit into tight spots, the long needle is a benefit more than it's a hindrance, and when the spindle button was inadvertantly pushed one day it withstood being launched into the side of the machine enclosure. Replacement needles cost coworkers around $45.00 with shipping, and they're easy to replace.
Later,
Charlie
Reply to
Charlie Gary
[snip]
I don't know what I was thinking. I shouldn't post when dead dired. I ment to post a 'nevermind' doh message.
Mine goes clockwise for deflection in either direction from the at rest position of probe. Nice and logical. I've seen a few that don't and that would drive me nutz. Righty tighty.
Thanks,
Wes S
Reply to
clutch
check your work with MY
Kirk:
Given two .0005 indicators (say an Interapid 0-15-0 and a Brown & Sharpe Bestest 0-10-0), with the same dial diameters of 1.5" which do you think would be more accurate - the Interapid with .030 per revolution of travel or the one with .020 per revolution of travel (which equates to 30% WIDER spacing of the marks)? Or take two .0001 indicators (say an Interapid 0-4-0 & a Compac 0-2-0), with similar dial diameters (the Interapid being 1.5" & the Compac being 1.575"), which do you think would be more accurate - the one with .008 per revolution of travel, or the one with .004 per revolution of travel (which equates to DOUBLE the width spacing of the marks). Eh?
Reply to
BottleBob
About 90% of the time I use a Blake Co-Ax because everyting is fixtured with a locator hole. Interapid or BestTest if I need them. Reason? well you CAN fuck them up, but you have to be really trying!
Cheers! Dave G.
formatting link
Reply to
Dave Gee
check your work with MY
Bestest 0-10-0), with
the Interapid with
(which equates to 30%
0-4-0 & a Compac
being 1.575"), which
travel, or the one with
the marks). Eh?
The more accurate indicator, obviously, would be the one with the best quality bearings, the smoothest and most consistent engagement between the gears, and the best designed ratio of point length to gear ratio to spring rate. And, if you really want to do it right, you'll use a spring that exerts almost exactly the same force at pretty much any displacement.
It would also help if the whole thing was made of materials that resist wear, and was built so that dirt, dust, and other crud couldn't get inside, or into the point bearings, to make it stick, or make it vary even a little bit in the force required to move through any increment. A perfectly polished, extremely round ball on the point helps too. It can reduce friction, and avoid false readings from off-axis motions.
After you've made sure about all those things, then a little extra spacing between the numbers might be nice - especially since my eyes aren't what they once were. But you could make the spacing bigger with just a magnifying glass, and the basic instrument wouldn't be any better.
Interapid is my choice. New, or 35 years old. It's still the best I've ever found.
KG
Reply to
Kirk Gordon
I wear both kinds of hat, depending on what's needed, and who else is involved. But if a piece of work is going to have my fingerprints on it for any reason, then I want it to be right. And if getting it right requires an indicator, you can bet I'm gonna be real fussy about what kind it is, how it's used, and everything else about it, too.
I'm kinda strange that way.
KG
Reply to
Kirk Gordon
[...]
I concur.
Who uses a test indicator for anything besides a comparison tool anyway? I surely don't, there are better tools available for making fine measurements. That makes any perceived inaccuracy or accuracy of test indicators irrelevant. What matters is repeatability and dependability, and in that regard it's pretty tough to beat an Interapid.
Reply to
Black Dragon
I was going o point that out. These things really aren't measuring tools per se. The only number I really care about being able to read on this type of indicator is Zero. Other than that it's a "split the difference" to find zero tool and sensetivity and sticking are the issue. BTW, I "tool changed" one of my Interapids at one this morning by accident and it survived the ordeal unscathed. Wish I could say the same for my shorts. LOL
Reply to
John R. Carroll
There was this night when I forgot to use G53 and sent Z to zero on a VMC. Somehow I missed the 12" cylindrical square, the fixture, and my indicator. The magnetic indicator stand needed a bit of work though.
The Mitutoyo indicator was and is still fine.
I think I used up my lucky break for this year.
Wes S
Reply to
clutch
check your work with MY
Bestest 0-10-0), with
the Interapid with
(which equates to 30%
Interapid 0-4-0 & a Compac
being 1.575"), which
travel, or the one with
of the marks). Eh?
quality bearings, the
designed ratio of point
you'll use a spring
Kirk:
Now all that certainly SOUNDS reasonable, BUT unless you dismantle numerous different types and brands of indicators and have the instruments and skill level to be able to determine which indicator is superior to another as regards smoothness, bearing quality, consistent gear engagement, etc. then you don't have direct experimental knowledge of which one might, or might not, be superior. Again, here is what Long Island Instrument has to say about the indicators in question:
================================================================================== In Brief:
The best dial test indicators are Swiss made. You have 4 commonly available brand names to choose from: Bestest, Compac, Interapid, Tesatast. All of these are made by the same manufacturer in Switzerland. There's nothing better on the market, in our opinion. ==================================================================================
Now Interapid visually seems to be the superior indicator as regards the ruggedness of external construction area, but that doesn't necessarily equate to automatic superiority in the construction of it's internal components. And since all the indicators listed above are made by the same manufacturer the quality might in all probability be similar. Now it "could" be that one or more of the indicators gets the best most accurate parts, and that the others are using "seconds", but we have no way of telling if that is the case here, short of getting inside information from someone within the indicator manufacturer itself.
wear, and was built so
bearings, to make it stick,
increment. A perfectly
friction, and avoid false
between the numbers
You could use the same magnifying glass on a Compac or Bestest and STILL retain your 30% width advantage in the case of the Bestest and 100% advantage of the width spacing on the Compac. LOL
And about your original comment about checking someone else's work... If I were taking over a job that someone else set-up with an Interapid .0001 indicator and it needed to be as accurate as possible, *I'd* recheck it with my Compac. LOL
Reply to
BottleBob
My half thou Interapid survived a 3K launch better than the Indicol it was mounted on did. It stayed in the machine, the Indicol came out after me in a few pieces. Almost getting impaled by my own absent mindedness I was too stunned to shit myself. :-/
The only thing wrong with it was the bezel was cracked. Sent it out and paid $60 for a new bezel and a tune up and it came as good as new.
Reply to
Black Dragon
Dan,
"As far as how to hold it... Well, I've amassed a collection of odds and ends over the years. In one desperate situation, I held a DTI with a very small Starrett surface gage that I have. I clamped the surface gage to the sub spindle with a large hose clamp. It wasn't pretty, but it worked."
Would it be fair to interpret this as one needs a variety of holders and indicators to deal with the many different situations that a machinist doing a wide variety of work encounters? If so I agree. I have never seen anyone use this Zero It deal in my 12 years in the field. I love the Zero It as it solves a lot of situations that were taking me too long and frustrating me. Still... the Zero It is not right for every situation. Also, I prefer to use my Brown and Sharps with the Zero It rather than my Interapids which IMO don't work very well with the Zero It.
Where is Cliffy in this tread? This is just another example of Cliffy having no experience with holders / indicators and the variety of situations a machinist (something Cliffy clearly is not) encounters.
Jon "The Jew" Banquer Phoenix, Arizona
Reply to
jon_banquer
Jon:
Zero-it type holders have limitations (just like everything). If you have to get down inside a small dia. area the Zero-it might not fit and you'll have to use something else (I have a number of other indicator holders store-bought, modified, and made from scratch for this purpose). If you have to indicate something with a large dia. like say 30" then the normal Zero-it won't extend that far so you have to use something else (I have a 5/8" dia. rod that mounts to a tool holder that I can use for that).
I've got him busy responding to physics posts, it keeps him out of trouble. LOL
Reply to
BottleBob
"About 90% of the time I use a Blake Co-Ax because everyting is fixtured with a locator hole."
What do you use for a stop for your Blake Co-Ax? Do you ever hold it by hand? Does holding on to the Blake Co-Ax by hand decrease accuracy?
Jon "The Jew" Banquer Phoenix, Arizona
Reply to
jon_banquer
"I'm kinda strange that way."
IMO that would be one of the least "strange" things about you.
Do you have the opportunity to learn SolidWorks, SolidEdge, Inventor or god forbid Alibre in your new job? If so I wonder if you will try and make use of design intent / top down design rather than create dumb models like you use to do in AutoCAD.
Jon "The Jew" Banquer Phoenix, Arizona
Reply to
jon_banquer
"My half thou Interapid survived a 3K launch better than the Indicol it was mounted on did."
Indicols while useful / invaluable in many situations are my least favorite way to indicate something.
Jon "The Jew" Banquer Phoenix, Arizona
Reply to
jon_banquer

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.