# Tool Makers calipers/dividers vs Spring calipers



## dzarren (Aug 6, 2019)

What is the difference between the tool makers dividers and the regular spring calipers?

From what I notice, the tool makers calipers never have a speed nut, just a regular nut. Perhaps the speed nut is less accurate? I dont really see why.

Also, i tend to see the ones described as tool makers calipers are typically round legged, as opposed to the regular rectangular stock "Spring Calipers."
I mean the tool makers calipers are also spring calipers..

Thanks!


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## 4ssss (Aug 6, 2019)

Any way you call them they are obsolete.


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## pontiac428 (Aug 6, 2019)

4ssss said:


> Any way you call them they are obsolete.


Not obsolete on my work bench. Useful on the lathe and for layout.


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## 4ssss (Aug 6, 2019)

pontiac428 said:


> Not obsolete on my work bench. Useful on the lathe and for layout.



Only if close enough is good enough


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## Flyinfool (Aug 6, 2019)

In the majority of cases close enough is good enough.


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## benmychree (Aug 6, 2019)

I, shamelessly still use calipers and dividers frequently; sometimes, more precision instruments will not physically fit into the space being measured; I do this for both wood and metal working, I am a journeyman machinist of over 55 years experience, both in industry and in my own business.
One example of the necessity to use calipers is measuring a hole over a line boring bar, or a recess in a hole.  I do like quick adjusting nuts on calipers, and would not think that they have any effect on accuracy.  The only time that they would be inappropriate would be in measuring a recess in a hole when the caliper legs are pinched together to remove the tool , then releasing tension on the legs to get the measurement.
Also, I agree with the above poster, that close enough is quite often, good enough.  Fits are often more important than sizes.  A practiced machinist can easily work within .005 of a nominal size with caliper and rule.
I do not think that the toolmaker pattern calipers/dividers are any more suited to accurate work than the flat leg variety, they just look nicer --- at least to my eye.


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## Technical Ted (Aug 6, 2019)

I agree with John 100%. I have a very wide selection of internal and external calipers as well as different types of dividers. There are a lot of times when it's all I have that will fit inside a narrow groove, thread, etc.. I guess it comes down to what type of work you do in your shop and what you need to measure. Mics and dial calipers are always my first choice, but sometimes you don't have much of a choice. 

Ted


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## pstemari (Aug 8, 2019)

Starrett used to make three styles of calipers/dividers for machinists:

Yankee: flat steel legs, about 1/2” wide x 1/16" thick, tapering in width towards the tip.

Fay: rectangular steel legs, about 1/2" wide x 1/4” thick, tapering in both dimensions towards the tip.

Tool makers: smaller sizes, with round steel legs about 1/4” in diameter tapering towards the tip.

Unfortunately, the Fay style was discontinued a couple years ago. I snarfed up all that I could find from Zoro and other vendors. They were rather pricey, and I believe the legs were forged.


Sent from my Pixel XL using Tapatalk


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## JimDawson (Aug 8, 2019)

4ssss said:


> Only if close enough is good enough



With a practiced hand, it's possible to do a lot better than ''close''.  I used to hold +/- 0.00025 on a bearing journal with flat leg calipers.  This was for a bearing fit that had to be a tight slip fit.  Each shaft had a matching bearing set.  I would ''measure'' the bearing ID with the inside caliper, then transfer that measurement to the outside caliper by feel, then turn the shaft to fit the outside caliper.  You can feel it when it's correct.  Did the final finish with 220 grit emery cloth backed by a file.  I made of lot of these, never had a complaint from the customer.

This was about 50 years ago, still have those calipers in my tool box.  Not sure I would have enough patience to do that today.


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