A few weeks ago at a auction I got some Hardinge collets in a Myford box. I don't have a Myford lathe but they looked pretty close to the diameter of 4c collets that my Rockwell uses. For the price I got them for it was worth a gamble. What I discovered is if I grind a notch in the back of the collet and use my homemade closer they seem to work just fine. I have only notched one of them so far.
4c collets are hard to come by but can be had for a premium. I have not found much information on these but they appear to be just as rare and costly as 4c collets.
If they are rare I hate to deface these by grinding a notch in them.
If they are hard to get then I need to decide if I want the hassle of re-selling them than finding and buying some 4c collets.
If they are not rare then I don't have an issue. I will just keep them and use them.
The collets and my closer.
![IMG_0375.JPG IMG_0375.JPG](https://www.hobby-machinist.com/data/attachments/84/84150-08757a2ef17461d3aab4031558849c48.jpg)
A single collet
![IMG_0376.JPG IMG_0376.JPG](https://www.hobby-machinist.com/data/attachments/84/84151-266b0f6db0c67f48448a8f3d688a1f8f.jpg)
Top view of collet
Here is what a 4C collet looks like showing the notch.
![IMG_0378.JPG IMG_0378.JPG](https://www.hobby-machinist.com/data/attachments/84/84153-025d3d448da05d590065d1a9b58588fb.jpg)
4c collets are hard to come by but can be had for a premium. I have not found much information on these but they appear to be just as rare and costly as 4c collets.
If they are rare I hate to deface these by grinding a notch in them.
If they are hard to get then I need to decide if I want the hassle of re-selling them than finding and buying some 4c collets.
If they are not rare then I don't have an issue. I will just keep them and use them.
The collets and my closer.
![IMG_0375.JPG IMG_0375.JPG](https://www.hobby-machinist.com/data/attachments/84/84150-08757a2ef17461d3aab4031558849c48.jpg)
A single collet
![IMG_0376.JPG IMG_0376.JPG](https://www.hobby-machinist.com/data/attachments/84/84151-266b0f6db0c67f48448a8f3d688a1f8f.jpg)
Top view of collet
![IMG_0377.JPG IMG_0377.JPG](https://www.hobby-machinist.com/data/attachments/84/84152-ca247e562bc30aaedf21fa311ee774fc.jpg)
Here is what a 4C collet looks like showing the notch.
![IMG_0378.JPG IMG_0378.JPG](https://www.hobby-machinist.com/data/attachments/84/84153-025d3d448da05d590065d1a9b58588fb.jpg)