5C Emergency Collet Question

[7HC]

On a 5C Emergency Collet there are three pins inserted into the splits in the machinable face.

It's often stated that "Three dowel pins are supplied for accurate machining."

Are they there to hold the sections open in a fixed position while the collet is machined, and if so, presumably they should be removed afterwards?

I'm guessing that if the collet was machined without them it would be less able to contract when installed?

Thanks for your patience,

M

 

[7HC]

7HC Your right the pins are inserted so that the collet don't close plus to have a ridged surface to machine. It's similar to machining soft jaws in a 3 Jaw chuck. After your size has been machined remove and save the pins. Your ready to chuck your work! Saving the pins will let you re-bore the collet in the future to another size.

Frank

Thanks, I've got a 5C spin index coming and an emergency collet seems like a good start.

M

 

[7HC]

Hi 7HC
Do you have 5C on your lathe? How do you plan to machine the collet?

Frank

No, I don't, but a have the use of a lathe larger than the 7x10 I own, and a larger mill too.

I think the main body of the 5C is parallel as well as internally and externally threaded, so if I can't chuck it for some reason I should be able to make a mandrel to hold it.

M

 

[DaveD]

You can get inexpensive collet blocks from places like Shars, Enco, and even EBay. Usually comes as a set of two. One 4 sided and one 6 sided. Around $30 if i remember correctly.They have the 5c taper and a nut to hold the collet in the block. Then you can chuck the collet/block/work piece in a 3 or 4 jaw lathe chuck and have at it.

Then there is the kind, for a few hundred $ that has the threads and gearing built into it so you can chuck the round adapter in the lathe and then tighten the 5c collet in the adapter with a hex/square key. That saves you time if you have multiple pieces to turn because you don't have to take the adapter out of the lathe chuck for each iteration.

 

[7HC]

You can get inexpensive collet blocks from places like Shars, Enco, and even EBay. Usually comes as a set of two. One 4 sided and one 6 sided. Around $30 if i remember correctly.They have the 5c taper and a nut to hold the collet in the block. Then you can chuck the collet/block/work piece in a 3 or 4 jaw lathe chuck and have at it.

Then there is the kind, for a few hundred $ that has the threads and gearing built into it so you can chuck the round adapter in the lathe and then tighten the 5c collet in the adapter with a hex/square key. That saves you time if you have multiple pieces to turn because you don't have to take the adapter out of the lathe chuck for each iteration.

You can get the set for around $60 shipped: http://www.ebay.com/itm/5C-COLLET-B...8?pt=BI_Tool_Work_Holding&hash=item1c1c51e82c



However as it will be mostly used with a mill, I decided to go with a more versatile, 5C spin index which allows you to rotate the collet in one degree increments.






M