5C Step Collet Collars

[Boris Ludwig]

Hi fellas,

Another question I've noticed that its possible to buy 5C step collets which I think they are collets closing on the OD of work pieces in over size. From what I can tell they can be machined to the ID desired.
here's an example



But when I see the step collets for sale they never show, or offer, the collar that goes around the outside of the diameter of the oversize collet head to close it and hold it tight.
Here's an example





Does anyone know if such a thing is available for a lathe like Southbend, or will it be like the adaptor I have in my spindle with the needed size to encompass the step collet head?

Hers's the adaptor in my spindle that allows me to hold 5C collets.





Any help appreciated.

 

[kd4gij]

The collet in your first pic doesn't use a ring. The second one is a step chuck closer. I have used up to 2 inch with out the closer.

 

[Boris Ludwig]

Thanks KD.

So theoretically, If I'd have need for turning a brass slug at 1.57 - 2" I could do it without the need for a ring/collar. So how much collet would I need to leave on the outside of the work piece diameter if I didn't use a collar?

 

[Ulma Doctor]

the first picture appears to be an expanding collet, it grips on the ID of the part you are turning
the second picture is a 5C collet that has a collet ring. the collet pictured grips on the OD of the part you intend to turn.
if you are turning an emergency collet, you want the OD and ID dimensions to be as close possible without interference

 

[Boris Ludwig]

I found this which shows me something about what I was asking, not all but I can see a collar isn't always necessary ... but thanks for the info as it helped me learn what I needed. Cheers

 

[Jimsehr]

The first pic of collet is a step collet. It has 3 holes near the od for holding pins wen you are boring collet . Second pic looks like a Hardinge brand closer and matching collet. The closer screws on the spindle thread and then the collet is inserted and bored to size.
Then the link shows a inside collet holding a square part by the bore.

https://photos.app.goo.gl/PBcSdQjxffmAnatc2

 

[Boris Ludwig]

The first pic of collet is a step collet. It has 3 holes near the od for holding pins wen you are boring collet . Second pic looks like a Hardinge brand closer and matching collet. The closer screws on the spindle thread and then the collet is inserted and bored to size.
Then the link shows a inside collet holding a square part by the bore.

https://photos.app.goo.gl/PBcSdQjxffmAnatc2

Hi Jim,

By "inside" you mean it expands and holds the ID of the workpiece?

Thanks for clearing up the first picture and the holes.

 

[Jimsehr]

Hi Jim,

By "inside" you mean it expands and holds the ID of the workpiece?

Thanks for clearing up the first picture and the holes.

.


Yes the collet expands and holds the part from the inside. One side benefit of
Holding on the inside is you can hold dead lengths.

 

[Silverbullet]

Looks like your nose piece is missing the key ?

 

[Boris Ludwig]

Looks like your nose piece is missing the key ?

In that picture it is missing, it's an earlier picture, it now has a pressed fit pin.