Broken Protractor

[rake60]

I managed to break my Mitutoyo bevel protractor.
No shame to the tool, I bought it used in 1983.

All I used it for these days is setting proper angles on chamfer tools in the production
lathes at work and checking angles when grinding new tooling. That doesn't really justify
spending almost $300 on a new Mitutoyo tool.

So, I ordered a $42 import knock off from Shars this morning, This One to be exact.
When it arrives I will check it with my precision 45 degree gage and the comparator
to see how accurate it really is.

Review to follow.

Rick

 

[AussieJimG]

Looks like a useful tool at a reasonable price. I look forward to your posting on it. Thank you.

Jim

 

[mu38&Bg#]

I'd probably take my chances with a used Mitutoyo off thEbay knowing it lasted 30 years. They go for about the same price.

 

[rake60]

I did check the eBay buy it now listings this morning.
The least expensive complete Mitutoyo bevel protractor I saw was $125

The Shars protractor claims to read down to 5 minutes of a degree.
I'm working in tolerances 30 minutes or 1/2 degree.

We'll see what I get for $42

Rick

 

[rake60]

The protractor arrived today.

I can't really check it because my precision 45 degree gage is at work.
No matter, it will need to be verified by the Quality Assurance office there before
it can be used in the plant.

Most people who have bought this protractor complain that the magnifier is unclear.
When I opened it up I was a little disappointed to see a horribly foggy lens.
A few wipes with a disposable lens cleaning cloth fixed that.

Dragon grease. :

Now we'll see what the QA people have to say about it.

Rick

 

[rake60]

I did take the protractor in to QA today. She really didn't know what it was.
Machining is new to this plant, so I wasn't surprised.

I did check it with my precision 45 degree gage.

The zero is on the 45 and the 60 minute mark on the vernier is matched up spot on.
I'd call that a perfectly calibrated protractor.

Not a bad deal for $42.

Rick

(I just noticed the reflection of a bald head on the magnifier lens. Gezzzzzz. )

 

[kustomkb]

That is a chrome dome! And a pretty nice looking protractor.

40 bucks, that's crazy. How do the locking and fine adjustment movements feel?

 

[rake60]

No issues with the lock. The fine adjustment works well.
It is not near as smooth as a Mitutoyo would be but one would have to expect that.

Rick

 

[rake60]

For the gal in QA and anyone else who has never used a bevel protractor before,
this is a great tutorial video.

Embedding is prohibited, but clicking the "Watch on You Tube" will work.

[ame]http://www.youtube.com/watch?v=oJFUI_FHlio&feature=player_embedded[/ame]

Rick

 

[kustomkb]

Sounds good, thanks for the tool review.

 

[Blogwitch]

Rick,

I have been buying and using Chinese precision instruments for a few years now, for use in my shop, internal and external mics, precision mechanical protractor, height gauge, angle blocks, DTI's etc etc.

I could find no difference in the accuracy between the Chinese ones and my Mitutoyo, Moore & Wright and a few others. Maybe the good ones are a bit smoother to operate, but that doesn't bother me. So the good stuff now reside in the bottom of my precision tool cupboard, most probably to become expensive collectors items, and my shop gets to use these Chinese jobs.

I can buy a whole set of micrometers for less than the cost of one of the 'branded' names, and when one does get put through the wringer and get damaged, buying a new one doesn't cause you to cry.


John

 

[tel]

Couldn't agree more - for what we do, and the frequency of use, the Chinese stuff is more than adequate - and they keep improving all the time.

 

[arnoldb]

Rick, thanks for the link to that video :bow:

I lucked out about a year ago and found a Mitutoyo set in mint condition in a second hand shop locally; I paid about US$35 for it, so that must count as a heck of a bargain.

Anyway, I've been wondering what the sharp-pointed attachment was for and how it was supposed to be mounted, and the video describes it as an acute angle attachment and shows how it's mounted

And yes, I also have mostly Chinese measuring tools (DI's, DTI, Calipers, Mics); the only exceptions are the protractor, a 1-10mm DI and set of telescopic bore gauges (all Mitutoyo) and a 0-25mm Moore & Wright micrometer. The bore gauges also came from the second hand shop - at the princely sum of US$10...

Kind regards, Arnold

 

[Lew Hartswick]

That is a pretty good tutorial on the use / reading of a vernier for a beginner.
Now all that is needed is a bit more detailed one for the verniers with 10 25 and 50
divisions as used on height gauges etc. I liked the way he used the pointer technique.
...lew...

 

[Noitoen]

Just a little curiosity about the invention of the vernier scale. It was originally invented by a Portuguese guy that lived about 50Km. from where I live now :big:

The vernier scale was (re) invented in its modern form in 1631 by the French mathematician Pierre Vernier (1580–1637). In some languages, this device is called a nonius.

It was also commonly called a nonius in English until the end of the 18th century. Nonius is the Latin name of the Portuguese astronomer and mathematician Pedro Nunes (1502–1578) who in 1542 invented a related but different system for taking fine measurements on the astrolabe that was a precursor to the vernier.

 

[rake60]

That is a pretty good tutorial on the use / reading of a vernier for a beginner.
Now all that is needed is a bit more detailed one for the verniers with 10 25 and 50
divisions as used on height gauges etc. I liked the way he used the pointer technique.
...lew...

Actually this same man has a tutorial on how to read an Imperial vernier caliper.
The height gage vernier is read the same way. Using a metric vernier is exactly the same.

[ame]http://www.youtube.com/watch?v=ZRKFwJ1plwQ[/ame]

I am not a big fan of digital instruments.
I do prefer a dial caliper. (Bright orange face with white graduations.)
I still use vernier tools as well.

Rick

 

[Omnimill]

How does it compare in use to a Precision Universal Vernier Protractor, near the bottom of the page here:

http://www.arceurotrade.co.uk/Catalogue/Measurement/Squares-Angle-Gauges-Protractors

Vic.