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.

Listen! There is a reason they have canaries in the coal mine.

As a steel company Metallurgist and Quality Director, I was the guy who got the call to visit a shop because the material we sent wasn’t machining right.
“This stuff won’t drill! Help!”
“This stuff is killing my OD form tool. Can you check the steel?”
“This steel you sent is acting crazy. It machines fine on one machine, but not on the other one.”
As the fellow responsible for the processes and quality system that produced the bars, and having visited my hot mill upstream suppliers, I was always confident that I had provided conforming product.
But how could I make sense of the problems reported?
My solution was to always look at the wrong tool- first.
If they complained about the drill, I asked them to show me the cut off tool.
If they complained about the rough, finish form, or shave tool, I asked them to show me the cut off tool first.
They said “Hey Mr. Free you aren’t paying attention. I said the drill is giving me trouble, not the cut off tool.”
To which I  cheerfully replied “Yes?”
After letting that sink in for a bit I would ask the following appreciative inquiry type of question to lead their thinking:
If the cutoff tool sees every aspect of the steel provided-  the very surface of the outside diameter (OD), the sub-surface, the mid-radius, the core, and it does not have any abnormal issues resulting from this material, what is there about this material that you think would allow it to affect this one tool, but not the cutoff?”
Then we focused on the aspects of the operation that inevitably were found to be the cause.
How does the steel know to only interfere with the drill, lets say? Or the the finish form? While leaving the cut off tool unscathed?
While there can be material conditions that are specific to a certain zone in the steel and thus would manifest on a particular tool, that conditon would also have an impact on the cut off.
 If the cut off  tool is A-OK, it’s probably not the steel.
This is the tool that will tell the tale.

It may not look like a canary, but a cutoff tool can sing a song about your process, if you can listen with your eyes.