4 jaw chuck selection--Self centering or individual jaw adjustment type

bobs7-62steamair · Feb 24, 2019

Just curious as to what experience has been with the self centering 4 jaw versus the conventional individual jaw adjustment type. most of my 4 jaw work involves irregular shaped and off center workpieces like cylinder castings and eccentrics. Unfamiliar as to how 4 jaw self centering are set up as I have never owned one. If they are like the 3 jaw self centering chucks you can't mount irregular shaped workpieces.
Currently considering purchase of a 4 jaw for my SC4 lathe. Any opinion and experience with both appreciated.
Regards.
Bob

Asm109 · Feb 24, 2019

Never used a scrolling 4 jaw chuck, never had a need either. 3 jaw for speed and low precision work, 4 jaw when it absolutely has to be right. Collets for in between.

bazmak · Feb 24, 2019

3 jaw s/c are used for round bar and hex. 4 jaw s/c are for round and square
4 jaw independent are used for irregular shapes,round and square and for offset turning
A general standard is to have a 3 jaw s/c and a 4 jaw ind to start and then build up to whatever else you need
I started with 3 and 4 jaw chucks.I also bought a 4 jaw s/c for my sieg sc4 lathe.Very useful as I tend to grip
square bar more than hex and they do give a better grip on round.I also used a
n old 3 jaw and fitted soft jaws.You can never have too many chucks

goldstar31 · Feb 25, 2019

As Barry( Bazmak) says 'One cannot have too many chucks'

Like him, I have a Myford-or 2 and a Sieg C4 but with a vertical mill drill attachment.

As far as I can understand the Sieg is a wee bit limited for accessories but I bought a couple of sets of soft jaws, a 4 jaw independent, a 4 jaw self centring chuck, a faceplate, and a fixed steady. However, with a bit of cunning, I can utilise the Myford bits using a proprietary Myford 'nose' and thus use my three sets of collets, a couple of catchplates and 3 sizes of faceplates.

I went a bit further and can use a Vertex BSO dividing head which goes onto the mill/drill, the Clarkson tool and cutter grinder, the 2 Myfords and the Sieg.

Really, it wasn't that expensive as the Clarkson cost a mere £100 and came with an electric driven chuck which will go on the milldrill. I don't go for all this E-bay stuff as I was warned off by my son who is a regional director of rather a large international transport firm who felt that I was too old to be capable of dealing with inevitable customs and security of money etc.

Whatever it is, I hope my comments are constructive though-- a little different.

Cheers

Norm

BaronJ · Feb 25, 2019

Hi Guys,

My take on this is the same as ASM109's post above !
However having used a six jaw scroll chuck, but I don't own one ! If I wanted a new scroll chuck it would be a six jaw that I would buy in preference to a three jaw.

If you wanted collet accuracy then Bazmak's adaptation of a three jaw with soft jaws, is the way to go !

My adaptation of soft jaws is far more crude, as the picture shows.

The reason that the pieces are cogged is because I parted them off from an aluminium toothed belt roller that I had laying around.

The way to ensure that the bore is accurately centred and parallel to the teeth. In this case, to have a bronze bush pressed into it as one part of a duplex drive gear. Replacing the moulded plastic one that got its teeth stripped off in my mill.

goldstar31 · Feb 25, 2019

I think that my Sieg ones were only £19 a set and were 'threaded' to fit the 3 jaw.

Of course, an alloy ring- split will hold discs and washers but Myfords DID a set of 3 bronze hexagons-------- at their usual very inflated price for what were really nuts

Cheers

N

BaronJ · Feb 25, 2019

Hi Norman, Guys,

Cromwell supply sets of soft jaws for the PB chuck as used on the Myford lathes.
I bought a set not too long ago, they cost me about £20 inc.

I drilled them and fitted aluminium blocks rather than actually machine them ! Cheating a little but it makes it more convenient and cheaper than buying new ones.

Mmm, I thought I had some pictures of them ! Seems not. At least I can't find them.
Sorry about that.

goldstar31 · Feb 25, 2019

Thanks for the information. I suspect that I have a couple of original Pratt Burnerd chucks.

Cheers

N

larryg · Feb 25, 2019

My opinion; if this is going to be your first or only 4 jaw then go with the independent unless you have a specific need/job for the scroll.

lg
no neat sig line

DJP · Feb 25, 2019

All of my old and useless 3 jaw chucks have problems with a worn scroll so I would stay away from a chuck with one more jaw to get out of sync with the other three. However a new 3 jaw chuck is fast and easy to use from almost all of my needs. My 4 jaw holds odd shaped work pieces or it sits in a drawer. Mostly it sits.

abby · Feb 25, 2019

Since buying a 4 jaw self centering chuck for a job requiring the turning of a large quantity of square bar the chuck has hardly been changed , I find that it does everything that I would use a 3 jaw for and more.

deverett · Feb 26, 2019

abby said:
Since buying a 4 jaw self centering chuck for a job requiring the turning of a large quantity of square bar the chuck has hardly been changed , I find that it does everything that I would use a 3 jaw for and more.

While I agree with what you wrote - and I also use a 4 jaw SC chuck, the OP is looking for advice on holding cylinders and eccentrics, i.e. irregular shaped objects. In this case it has to be a 4 jaw independent chuck that he should consider.

To Bob, yes a 4 jaw SC chuck is adjusted in the same way as a 3 jaw SC chuck. Good for holding round and square material. The extra jaw gives better holding power than the 3 jaw on round material.

Dave
The Emerald Isle

Jennifer Edwards · Feb 26, 2019

bobs7-62steamair said:
Just curious as to what experience has been with the self centering 4 jaw versus the conventional individual jaw adjustment type. most of my 4 jaw work involves irregular shaped and off center workpieces like cylinder castings and eccentrics. Unfamiliar as to how 4 jaw self centering are set up as I have never owned one. If they are like the 3 jaw self centering chucks you can't mount irregular shaped workpieces.
Currently considering purchase of a 4 jaw for my SC4 lathe. Any opinion and experience with both appreciated.
Regards.
Bob

Actually I use both an independent four jaw and a self centering version depending on the application. I purchased them from Arceurotrade for a very reasonable price.

I also have a set of collets that cover from 2mm thru 22mm that are great for turning round stock as well. They also interchange with my milling machine so they serve two purposes.

I find that the self centeting is super for chucking up square stock, and the independent for anything that needs an accurately located off Center bit of work like your cylinder castings and eccentrics.

Also I have a few flat cast iron “backing plates” I use in lieu of a Chuck for those jobs where the pieces to be worked need to be held outside the range of the chucks jaws or where a Chuck would be in the way.

I love them because I can easily drill and tap holes wherever I need to so I can either bolt the workpiece directly to the plate or bolt a clamp in place.

I spend a few hours almost ever day in my shop, and do not think I have mounted my three jaw Chuck once since purchasing the two four jaw chucks last spring.

I probably use any sort of Chuck maybe a third of the time, with collets being the most used method of holding stock in my lathe.

Hope this helps a little,

Jenny

abby · Feb 26, 2019

Dave , I believe my reply to this thread "Just curious as to what experience has been with the self centering 4 jaw versus the conventional individual jaw adjustment type." was exactly as requested by the originator.
I am sure that the originator is well aware that the term "self centering" means exactly that and that irregular shaped items cannot be held.
Incidently you may not be aware that there is such a thing as a self centering independent 4 jaw.
I had one made by "the original Knopfer company" or some similar name .This was a superb piece of (German , I believe) engineering but like a fool I let it go with a lathe I sold.
In use each jaw could be set independently to hold the irregular shape , then the setting could be repeated on subsequent parts using the scroll.
I have never seen another chuck like this and a web search has come up blank.
Dan.

TonyM · Feb 26, 2019

Combination chucks are still available but a tad expensive. https://www.pts-tools.com/search#/c...Combination Independent/Self-Centering Chucks

johwen · Feb 26, 2019

bobs7-62steamair said:
Just curious as to what experience has been with the self centering 4 jaw versus the conventional individual jaw adjustment type. most of my 4 jaw work involves irregular shaped and off center work pieces like cylinder castings and eccentrics. Unfamiliar as to how 4 jaw self centering are set up as I have never owned one. If they are like the 3 jaw self centering chucks you can't mount irregular shaped workpieces.
Currently considering purchase of a 4 jaw for my SC4 lathe. Any opinion and experience with both appreciated.
Regards.
Bob

johwen here. I have been using a 4 jaw self centering chuck for 40 years. They can hold concentrically all sections round, square and hex accurately. Can hold all these section in short lengths for cross drilling holes. Can also hold short length flat section for certain machining operations between the side faces of the jaws. Ten times more useful and accurate than the three jaw. Cannot hold irregular shaped pieces like casting though but are well worth the extra cost. Buy a good one though. Hope this helps John

Apprentice707 · Feb 26, 2019

I use a 4 jaw self-centering chuck as my default chuck since it gives a better grip on round stock than a 3 jaw sc chuck and will also deal with square stock easily. About the only time I use a 3 jaw sc chuck is for hexagon stock. My independent 4 jaw is not used very much and I also use Myford collets and ER 25s. The 6 jaw sc chuck I purchased sometime back gets used for thin wall tube and so not very often.

Keep on chucking

B

Hopper · Feb 26, 2019

^^^ Yes, when you think about it there is no reason that a three jaw should be the default selfcentring chuck. Probably just tradition based on economy of manufacture.

As you say, better grip with a four jaw and really, how often do you need to grip hex bar? And if you do you can grip it in the SC four jaw with a round split bush around it. I think next time I need to replace a worn out three-jaw I'll get a SC four-jaw.

bazmak · Feb 27, 2019

I bought a 5" 4 jaw sc chuck mainly for making turners cubes and now use as the default chuck
I still use the 4" 3 jaw for smaller compact turning etc

ki4byz · Feb 27, 2019

I have used 4 jaw scroll chucks on a regular basis for 25+ years. I like them, are they better? They will hold stock a little truer than a budget 3 jaw and they will hold square and hex stock. also rectangle with the right blocks in the chuck.

Repeatability and speed when running multiple parts just like a 3 jaw unless the part square. In the home shop? That is up to the individual 4 jaw independent chucks work great.

4 jaw chuck selection--Self centering or individual jaw adjustment type

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