3-jaw. They are self-centring, convenient, easy to use, and good for 80% of 'beginner' turning jobs (ie gripping round or hexagonal objects with reasonable accuracy).

A 4-jaw can can grip a much wider range of shapes BUT it isn't self-centring. Setting them up has to be practised and you need a Dial Test Indicator with Stand to do it. Well worth it, but the purchase can be delayed until you know why it's needed!

In theory you can do everything with a simple backplate. In practice people seem not to, usually starting with a 3-jaw, then 4-jaw, and perhaps progressing to a collet chuck.

Dave

used only on certain jobs.

Maybe, but if you intend to remove and re-chuck a part, the 4 jaw is by far the better choice for concentricity on remounting – if one can master the technique easily or have the time to fiddle until it is right.

So it depends… I would say start with a good 3 jaw if your needs are simple. Otherwise, you will find, as many have, that the 4 jaw independent is often the choice (mine is – because it is there ready and waiting. By the time I have changed chucks, the part is centred adequately).

As above, re historical operations – turning cylindrical items was often done between centres for best concentricity, particuarly if removing from, and refitting to, the lathe. But fallen out of use for various reasons (modern chucks are better than a worn out old 'un, no spinning drive dogs to keep away from, etc.).

I bought a 4 jaw self centering chuck, as well (for the rotary table). But I would not go out and buy another – they will only chuck properly on perfectly round bar, per eg.

Join your local Model Eng. Soc. and practise with a 4 jaw independent, if you have the opportunity or time. Hands on experience is worth far more than a forum reply.

If I now had a choice of only one chuck, it would be the 4 jaw independent variety. But that is after 20 years of tinkering.

If only one chuck it is a three jaw for me, easy to hold hexagon stuff not so easy in a four jaw. Using a three jaw it is easy to make a split bush to grip across the corners of square bar so not that limited. Save up for a four jaw when you need one.

I would suggest that you learn to use a 4 jaw chuck ,it will be far more versatile.If you remove work from a 3 jaw chuck it will not be accurate if you replace it,but replacing in a 4 jaw it can be clocked dead true.

Frank

Only a hobby metal turner myself, but back in the day I would wander about University workshops waving an envelope with my latest scheme on its back. Mostly the lathes I saw were set up with 3-jaw chucks, the only times I saw 4-jaws were when there was work in them which obviously needed one. The workshop guys had to make one-off weird and wonderful things for research, and it was obviously their go-to chuck. Machines in the postgrad training shops were also equipped with 3-jaws. So my 2d worth would be to go for the 3-jaw until you actually need a 4-jaw. Though I accept that the 4-jaw is more versatile, my limited real-world experience tells me that 3-jaws are the norm for general turning.

Rob.

Edited By Robin Graham on 21/05/2017 20:15:46

Has to be the 3-jaw for me, I seldom find the need to use the 4-jaw to do second ops on work to get things concentric enough. I'm sure you have all seen the number of engines I have made and they all seem to run OK so why spend half your time setting up work in a 4-jaw when a 3-jaw will do the job. Maybe others feel the need to work to 10ths or better.

I only tend to use the 4-jaw when a round item is too large for my 3-jaw or of a shape that won't fit in the 3-jaw eg square, rectangular, eccentric or an odd shaped casting.

I would say my usage for making models both large and small is something like:

50% 3 jaw

35% Collets

14% 4-jaw

1% Faceplate

Before I got collets a couple of years ago that would have been more like 80% 3-jaw, 19% 4-jaw 1% FP

If you have the option of a 3 jaw with soft jaws as well they can be very helpful for some jobs. You may not need them for a while but if you do then you may find yourself buying a second 3 jaw chuck if the first one does not have them as an option.

Martin C

Did anyone mention that the four jaw independent may well have greater capacity than the corresponding three jaw SC? So, less temptation to overstretch the chuck.

Individual usage patterns are interesting but not necessarily helpful to a beginner who may not know what he wants to do.

A DTI is really for secondary operations or tapers for me

Only because you never re-chuck anything, Ady?

I would suggest that 3 jaw chucks are supplied as standard (generally) because it is convenient for those that don't know the limitations, they are cheap and t

he puchaser will likely need to get a 4 jaw independent fairly soon (extra sale) if they need to do anything other than basic turning.

My advice might be to check the individual chuck prices and go for the most expensive one to buy separately, if the price of lathe and one chuck is the same for either combination!

One might ask the question in a different way. Like… Which would you buy if you were starting again and could only have one chuck? Or … Which is more useful – a 3 jaw or 4 jaw independent? Or… What did you start with? Or… How soon did you need another chuck? Or … Does it make a difference whether a quick change chuck or a bolted on variety?

When I was at school in the early 1960s, for the first 2 terms in the machine shop we used only the 4 jaw independent chuck, or did our turning between centers, in the 3rd term, after we had mastered(?) the 4 jaw, we were allowed to use the 3 jaw chuck. We were using were old Harrison lathes driven from line shafting as workshops of 100 years ago would have had, although the steam engine that drove the school workshop had been replaced with an electric motor.

My vote, four jaw first, then three jaw, it will take a little time at first, but with practice you'll soon speed up.

Ian S C

I wonder if this is where the two different opinions come from, several posts by people who went through an engineering apprentiship seem to be advocation the 4-jaw approach. Where those like Neil and myself who have no engineering background (maybe a bit of metal work at school) and are just hobbiests favour the 3-jaw as the first buy for a fellow hobby turner.

I seem to remember Brian John only has a 3-jaw on his little Optimun machine which is a similar size to what teh OP is looking to buy yet he has managed to make several engines on it.

J

where those like Neil and myselW

Put me in that bracket, too. I bought a lathe with a 3 jaw chuck. But in hindsight, I could have done better with the 4 jaw independent from the off. Most certainly able to use a dti, so perhaps ahead of you two at the starting point, but the 4 jaw chuck is far easier than working round not being able to remove the item from the chuck (until all turning is completed). Unbolting and bolting on chucks is a pain (yes, I will put up with not being able to turn with the lathe in reverse).

for size aren't 3-jaw chucks more expensive than 4-jaw chucks?

They may be offering a smaller or larger 4 jaw than 3 jaw – we don't know. There may be a quality difference, as well.

Only one set of jaws needed for the independent chuck is yet another plus for the 4 jaw, too. The first time anyone re-chucks a part they will wish they had a dti! That is if they notice the problem, of course….

It is somewhat a revelation that the lathe is actually being offered with a choice of chuck.