What to do,what to do.

I bought one last year (and three sets of soft jaws.....). Its been useful, but to be honest, I could live without it!

But, if you need one, you need one.

Jim

I'd buy something else being as you already have a independent 4 jaw chuck. I've an ER32 collect chuck for my lathe and love it, gets a fair bit of use. I also have a really, really nice independent 4 jaw that's a tad big for my lathe so will be downsizing. Once I've done that I can't see my using my 3 jaw on the lathe again. I've currently got the poor mans DRO of a dial indicator and caliper on the lathe but really tempted to go for a proper DRO after having a play on a lathe with one fitted, really makes things so much easier and quicker. I'd definitely consider a DRO if I was you.

I have one and find it handy making clevises and so on, it will grip round of course, but not hexagon. A lot will depend on what you make, if you work with square a lot, then it will save loads of time faffing about with an independent jaw chuck. I often use mine to make rod ends that need to be rectangular in section, I do all the turning and cross drillin and so on, then mill the square to a rectangle.

Chris Gunn

I’ve often thought a 4 jaw SC would be very useful.

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Read this, and be happy Chris: **LINK**

https://www.hobby-machinist.com/threads/4-jaw-self-centering-chuck-question.35560/

MichaelG.

MIchael, I read it, but not 100% convinced by the drawing. I will have a go when I get a minute and report back.

Chris Gunn

4 jaw sc chucks hold hex stock just fine.

I have one, but the ER25 is used most often, followed by a 3-jaw SC, then 4-jaw SC, finally, way down the list, a 4-jaw independent. I rarely machine from castings, thus the SC and ER chucks are most used.

Here's a pic (posted before) of a 4-jaw SC holding hex:

4 jaw SC chuck - i'm with the majority on this one - can't see the point.

If you fancy having a play with a SC 4-jaw then, what the heck, buy one. It's really the only way to find out if it was worth it to you. Or... you list all the other related toys around that value that you fancy and see if there's any other suspects.

However you wrap it up, for most of us this hobby is 'playtime' and doubtless if the new toy proves worthless (to you) then some funds can be recovered by reselling it. If you were running a business then the decision would be based on different parameters but even then it's sometimes a gamble that a new item of kit will open up more economic (faster) ways of doing a job or widen the range of jobs.

I'm sure we've all made a gizmo that looked fun or cool and it sits in the cupboard unused and we've all made one that gets used more than we expected.

Maybe I've been depriving myself over the 25 odd years that I've had lathes, but 3 jaw SC and 4 jaw Independent, plus ER collets have done all that I need.

But it maybe that I have yet to come across a job that NEEDS a 4 Jaw SC.

Yes, and i have a Tailstock Turret that is still waiting to be used. "Seemed a good idea at the time" category!

I would be inclined to see if there was anything else that appealed more.

Howard

4-jaw SC is one of those things you don't need, but is rather wonderful to have.

Neil

Thanks JAS for showing practically that a hexagon can be held in the 4 jaw self centering chuck, that will save some time in the future. As said before I used it a lot building my 4CD for all the clevises and rod ends from square stock, and am using it quite often right now on the 6" Ruston proctor I am finishing for the same purposes. Once one has such a chuck plenty of items are easier to make from square stock rather than round, but it depends what your interest is.

Chris Gunn

I bought a 4 jaw scc chuck many moons ago, but to date it is still sitting in its box waiting for a backplate, which I doubt I will ever make. Never really found a job to justify setting it up. I do use my 4 jaw independent chuck quite a lot and can set it true fairly quickly with the clock.

So perhaps you might be better off to spend your money on something else

PS Just be careful who you buy from, see above Post re "Suppliers".

Perhaps the mounting makes a difference? My son's Chester has the same collar arrangement as the Sieg SC4, so it takes less time to change chucks than to clock square bar in the 4-jaw, making the self-centring chuck a worthwhile time saver. The mini-lathe is another matter though.

Brian

Hi,

I can’t answer the OP without knowing what he might want to use or expect a 4 Jaw SC to give him that he doesn’t already have.

Something not yet mentioned in the thread as I can see, is the facility a 4J with soft jaws can give you to have no run out repeatability for small items that you can get exactly square in the Chuck without parallels, say for a second operation where you are machining the backside of a number of parted pieces to bring to thickness.

Obviously you can do this with a 3 Jaw with soft jaws also but it is much more difficult to measure the diameter when boring the soft jaws to size.