Tag: Accuracy

Machining for Hobbyists-Getting Started

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Surprisingly complete and easy to understand book that can be used to supplement training on the job for beginners, and a nice reference for those with a year or so on the job. Machining and measurement principles and techniques clearly explained.

A nice easy to understand supplement for newcomers to machining.
A nice easy to understand supplement for newcomers to machining.

I was genuinely surprised  to find some really great nuggets like “the Basic Nomenclature of Measurement ” which clearly defines:

  • Nominal size
  • Allowance
  • Limits
  • Tolerance
  • Basic Size
  • Unilateral Tolerance
  • Bilateral Tolerance
  • Precision
  • Accuracy

…in just a little over a page.
Nice graphics, sample calculations, and well done explanations on how to read a micrometer, vernier, as well as tables with feed and speed data for various types of materials for specific machining operations. very focused coverage of the essentials of the topics.
Do not confuse this book for a hobbyist project catalog.
This is a very clear and understandable text that explains the “how, why, and what” of machining and the use of  tools of our craft.
Nice photos too.
What I like the most is how the author really distills the information down to useful essentials. And makes them understandable.
 

5C Collets Are Cool- Somma Tool

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In order to machine precision parts, you need to first hold the workpiece securely, accurately and precisely. 5C collets do just that.

5C collets are the result of 100 years of continuous improvement.

Work can be held using methods other than collets- 3 and 4 jaw chucks come to mind, as well as vises-  but for continuous high volume work with barstock, collets are ideal.

Here are 7 reasons Somma Tool says 5C collets are cool:

  • Collets are easier (and faster!) to set up than chucks.
  • Collets are more concentric. With chucks, tolerances stack up degrading concentricity.
  • Collets more affordably provide higher precision.
  • Collets more affordably provide higher accuracy.
  • Collets provide high holding force. As the collet is pulled axially into the bushing, the tapered sides compress radially generating static friction (holding force).
  • Collets are versatile- they can be made to hold over capacity stock; they can have steps built in; come in extra long sizes as well as have internal stops.
  • Emergency collets are available that can be custom bored to your exact need.

Hardinge invented the 5C collet back in 1901. It became a preferred choice for precision workholding in lathes, mills and grinders. Exacting standards, special alloy steel, heat treatment and spring tempering combine to assure accuracy and durability at low cost. The 5C collet became an industry standard. 5C collets range from 0.5 mm (thats 0.0196″ ) capacity to 1-1/16″  round; 5C collets hold up to 3/4″ square and and 29/32″ hex.

PMPA member Somma Tool sells 5C collets from Hardinge.

Thanks to Matt at Somma and Tom at Hardinge  for teaching this ‘steel guy’  7 reasons why 5C collets are cool.