Pros and Cons of 3 and 4 jaw chucks.

These are my lathe chucks. 14"-4 jaw, 8"- 3 jaw, 10" 3 jaw converted to hold ER40 collets, and ER11 collet holder (which is held in the larger ER40 collet chuck).
90% of the time the ER40 chuck is on the lathe. Nothing beats a collet for rigidity. You can turn parts that are almost double in length without chatter compared to a 3 jaw. Parting has less chatter and is more rigid. The collets will also hold parts that are plus or minus 1mm, so you can use parts that are oversize or undersize without issues. There are only two downsides with the ER system: 1. is that it has a maximum hole through dimension. So for instance, if I want to hold a 1" round stock, it will only go in about 4" into the chuck, versus 5C collets where you can put a whole 6 foot shaft in if you wanted. The other is that the collets are designed to hold the part over the whole length of the collet. So you should have parts that are at least 3/4 the length of the collet. The next most used chuck is the 4 jaw. I use that for holding anything that I have to turn an outside dimension be perfectly concentric with an internal bore, (i.e. rifle barrels, rifle receivers, collars, bushings, etc.) The 3-jaw I will use when turning parts that are larger than 1", and I don't want to have to dead lift that 14" 4-jaw, which weighs 100lbs? (Next big purchase will be an 8" Bison 4Jaw)

You can see in one of the pictures the griping sections where the collet has the greatest gripping forces on the end mill holder.

The other great advantage for using collets, is that I use the same ones on the milling machine.

Finally, on the lathe or milling machine, with the ER11 collet chuck held in the ER40 collet chuck, I can hold tools or parts ranging from 1mm-26mm!!

Link to DRAKE

Want more information on 3 jaw chuck for milling machine? Feel free to contact us.

Adding to AJSakowski's statement a 4 jaw chuck can be used to fabricate cams, and bore off center holes. I just finished 2 sets of cams for a sheet metal brake. One set was to make fine adjustments on the grip of the upper platen, the other set were the ones used to open and close the platen. Both sets required a 4 jaw independent chuck.

As for taking more time to dial in a 4 jaw, I would agree that in the beginning it will take considerably longer. However the more practice you get the less time it will take. After many years of practice I find a 4 jaw independent more often than not the go to chuck. It generally takes less than a minute to dial a 8" or 10" 4 jaw to within .001". That's close enough for most work. It can get tedious to dial into .", but then again I don't know of a 3 jaw scroll chuck that's capable of that close tolerance.

For more information, please visit Power Chuck Exporters.