# Pros and Cons of 3 and 4 jaw chucks.



## GummyMonster (Oct 3, 2021)

Afternoon,
 I'm stuck in the house with a cold/flu, so I've been reading a lot and watching machining videos until my brain starts hurting.
 I have what is probably a totally newbie, knows nothing question that popped into my head.
  I ended up with both 3 & 4 jaw chucks for my W210 bench lathe.
  Most of what I've seen says that the 4 jaw chuck is far superior than the 3 jaw.
 Should I just start using the 4 jaw, and save the 3 jaw for some project down the road? Like making a rotary table or dividing head for my mill?
Or are there times when the 3 jaw is preferable?
 Thanks for everyone's advice for all my questions. Truthfully, I haven't even started using my machines. The past 6-8 months have been rough. Too many bumps in the road that have had huge impacts on our family. None of them good, unfortunately for us.
Anyway, that's my concerns. 
Thoughts on the 2 chuck types?
Thanks,
Ken


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## 140mower (Oct 3, 2021)

In my opinion there's a place for both. If you can complete all of your operations without removing the part from the chuck, or its six sided etc., then the three jaw is the way to go, for speed and ease. If you are going to be removing the part from the chuck, or adding a feature to an existing part then being able to dial it in with a four jaw  is pretty much a requirement. 
 If you have both, keep 'em if you can, if you are only going to have one, the four jaw is the most versatile...


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## whydontu (Oct 3, 2021)

My $0.02:

3-Jaw - quick-n-dirty, easiest to use but tends to be inaccurate. Mine is about .002" off at some jaw positions. As 140mower says, good if you're not taking the workpiece out of the chuck, or if the workpiece doesn't need to be precise. 

4-Jaw - fiddly but best if you need real accuracy, or if you need to turn an eccentric like a crankshaft or offset bushings. 

If the budget will survive, get a collet chuck. Restricted in size range but super accurate and holds better than a 3-jaw.


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## Tom O (Oct 3, 2021)

Try dialing in a four jaw chuck and see how long it takes to get it in mind you you will get faster with time. I use the 4 jaw for odd shaped materials or offsetting from the center position but the 3 jaw is usually my go to.


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## YYCHM (Oct 3, 2021)

Tom O said:


> Try dialing in a four jaw chuck and see how long it takes to get it in mind you you will get faster with time. I use the 4 jaw for odd shaped materials or offsetting from the center position but the 3 jaw is usually my go to.



Yup... same here.


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## Tom Kitta (Oct 3, 2021)

Usually the 3 jaw is the default chuck as it is quick to use - cannot beat few seconds to load. It is as accurate as 4 jaw if you turn stock down and do not remove it. 

The 4 jaw independent is only accurate if it is quality chuck or you ground it - even then do not expect miracles. It is for non round stuff & for stuff where you need to position initially accurately. Also if you take stock in and out. It also places a bit less stress on stock if you want & holds more securely (if you want) vs. 3 jaw.

4 jaw ind. can do almost anything 3 jaw can.

collet chuck - can be quite accurate & fast but for set sizes only (combines 3 & 4 best things but for only certain range). There are many chucks for different collet systems.

soft jaws - if you need "collet chuck" for special size.

6 jaw - mainly for pipes and delicate stuff - but can be used for same stuff as 3 jaw (heck you can remove 3 jaws to make it into a 3 jaw). delicate and easy to break.

all chucks can be "set true". 

There is rare 4 jaw non independent as well as 2 jaw chuck.

Face plate is of use for very odd shapes. Dog driver is... to drive a dog.

For thin stuff you can mount a magnetic chuck.

It is true, but counter intuitive, that your 4 jaw should be more expensive then 3 jaw. Generally people have both plus face plate. Hope this helps.


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## GummyMonster (Oct 4, 2021)

Thanks for all the great input.
 I'll definitely keep both( and will confirm their both decent) and invest in a collet setup as well.
That should cover my needs for quite some time.
Ken


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## Degen (Jan 18, 2022)

It really cones down to a couple if things, Scrolling 3 jaws (or any scrolling chuck for that matter) for accuracy need to be ground on the lathe for accuracy (I've never done mine as I wasn't aware till recently....YouTube).

4 jaw independents (or any independent for that matter), accuracy is controlled by the user, this I knew.  Grinding to refresh the grip if needed is good but it does wear out your jaws, so my advice on independent jaw chucks is not to grind unless needed.  Watch a few YouTube videos for fastest set up. Typically it takes about me about 2-3 minutes to set up now (less if I'm doing it more often).

I use my 3 jaw mostly as it gives me the results I need, when upping the game I switch to the 4 jaw.

One thing I've noticed is the mistake most make is the chase of infinite precision and not accuracy.  Understand what you need as accuracy for your work and not what precision you can get.


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## Dabbler (Jan 18, 2022)

Most of the work I do never needs precision to the point of worrying about the inaccuracies of a 3jaw chuck.  From turning alone, Especially on lighter lathes) holding to .001 takes special care anyway, so the 3J doesn't seem to matter. 

+1 to all the advice above.


[edit]

The old school view  is that 6J are for pipes...  It turns out that that is based on some old school biases from 75 years ago. Many machinists use a  6J because of the better holding.  Tom Lipton did a video on this about 4 years ago.  Robin Renzetti has made similar comments. and Gotteswinter's old machine had a 6J on it for normal use.  I've never heard of a 6J breaking or wearing out prematurely, especially for a hobbyist.


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## whydontu (Jan 18, 2022)

don’t forget that the accuracy of a 3-jaw is irrelevant if you’re turning all finished surfaces. I often make punches and dies for sheet metal, and even if the chunk of bar in the 3-jaw is off center by 0.005”, the o.d. and i.d. of the fully-machined die is concentric once I part it off the raw bar.


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## Dabbler (Jan 18, 2022)

What separates expensive, precision chucks from cheap ones is the fitment of the jaws in their slots.  They should be very tight fitting without any wobble at all.  A real worn out chuck, even if it s good one will have a lot of wobble in the jaws.


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## terry_g (Jan 18, 2022)

I keep the 3 jaw on my lathe most of the time unless I have need for the 4 jaw.
I bought a Bison made in Poland 6" three jaw scroll chuck for my 10K Southbend lathe 
back in the mid 1990s. It is a very well made chuck or maybe I got lucky. When I sold 
the Southbend and replaced it with a 12"x36" Craftex lathe I kept the Bison chuck and put 
the new Craftex chuck on the Southbend. There is a "O" stamped beside one of the pinions 
for tightening the jaws that is supposed to be the lowest runout. Chucking a shaft 2" and under 
the runout is under .002"


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## thestelster (Jan 19, 2022)

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!!


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