D1 Style Lathe Chuck with 4 Pins?

[hudstr]

This chuck appears to have integrated mounting and it looks like it is D1 but it has 4 pins. Anyone seen anything like this before? My best guess is it is D1-5 but instead of 6 pins it only has 4. Disclaimer this isn't mine, it is an ebay listing I'm not affiliated with in any way, just window shopping.

 

[Dabbler]

I have seveeral D1-6 back plates with only 4 pins. It is very common for collet chucks and other low-power accessories. Measure across opposing pins to find out if it is D1-5 or D1-6. D1-6 is more common.

 

[ddickey]

Or just measure the pins.

 

[mmcmdl]

Spindle Type and Size Guide

It’s essential to know your machine spindle type and size when replacing or upsizing a lathe chuck on your machine. Use this guide to accurately measure.

www.toolmex.com

Ive seen three pins , 4 pins and 6 pins depending on the kind of chuck .