To use chuck or collets

[SteviegtrParticipant @steviegtr]

[SteviegtrParticipant @steviegtr]

I will soon have the Myford super 7 up & running if machine mart get there finger out, (3ph motor ordered since 31st Dec still not arrived). So the question is: When using the machine for turning round bar, would it be preferable to use a collet chuck or just the normal 3 jaw chuck. I know the Headstock is MT2 & only has a smallish bore. Thanks for any answers in advance.

Steve.

[OldironParticipant @oldiron]

I would say use a collet where possible.

regards

[Anonymous]

In order of usage I use a collet chuck, 4-jaw independent, faceplates and a 3-jaw chuck once in a blue moon. But I have a larger lathe that will take 38mm down the headstock spindle.

Andrew

[SteviegtrParticipant @steviegtr]

So I guess my next question would be are the Chinese Collet sets any good / meaning accurate.

[Stuart BridgerParticipant @stuartbridger82290]

Depends what you are doing and accuracy required.
If all operations can be completed without removing the stock from the chuck , then no harm in using a 3 jaw

[Thor 🇳🇴Participant @thor]

After I made an ER-32 chuck for my small lathe it get used quite often, if I can use the collets I prefer them instead of using my 3-jaw. My cheap Chinese collets have slightly more run-out than my Vertex collets, so when I buy new collets I try to get Vertex ones.

Thor

Edited By Thor on 10/01/2020 11:16:33

[HopperParticipant @hopper]

There is  nothing wrong with a good three-jaw chuck for general use. It is quick, easy and accurate enough for most work if used correctly. IE, don't expect it to hold things concentric to less than two thou or so and plan your work accordingly. Turn the job up in one setting, with a tailstock centre holding the far end if needed, so all diameters are concentric. Then part off the bit left held in the chuck. It is the standard go-to holding device for most lathe work. And it fits all diameters, plus holds inside jobs such as large diameter tubes, rings etc that collets can't.

That said, collets are nice if you have a full set to fit everything, metric and imperial and they are good quality without excess Chinese runout. But you have to change them with every diameter change rather than just twiddle the chuck key. Makes it easier to hold a finished diameter to run true(ish) without setting the jaws of a four jaw chuck. But using a collet to hold unmachined round bar is kind of waxing a dirt floor. The OD is not perfectly round and true so you might as well use the three jaw chuck. Keep your collets for holding precision machined surfaces when needed. I think the best type collet chuck to get is the flange-mounted type that bolts to a backing plate. You can adjust it for perfect concentricity, which you can't on the type that fits in the spindle's morse taper or screws on the spindle nose.

So if you already have a three jaw, and it's not clapped out like some old Myford junk is, use that to start with then buy a collet chuck if/when the need arises. Even if it is clapped, I would buy a new three jaw chuck before a collet chuck. Chuck will do more so if you only have one, that's the one to have.

Edited By Hopper on 10/01/2020 13:17:06

Edited By Hopper on 10/01/2020 13:42:07

[JasonBModerator @jasonb]

Really depends on the job in hand, not much point in saying it's preferable to use collets as that won't do you much good on a Myford for anything over 1" diameter, non round or eccentric.

I managed with 3 and 4 jaw for many years and now that I have a 5C collet chuck will tend to use that if I have several small parts to make but don't bother swapping chucks for just a single operation or part unless there is a specific need but my 3-jaw does run to 0.01mm tir

The 5C is nice for close or hand work as you are not going to do yourself damage but it does take longer if you are swapping between collet sizes and can be a paint to get a small part out of is not enough sticking out to get hold of, also putting long lengths of stock into a collet that is in the chuck needs a good long bed and no tooling in the tailstock.

I'd see how you get on with the 3-jaw and take it from there, set of soft jaws will be handy if you need concentricity when swapping parts end for end as well as thin discs.

[old martParticipant @oldmart]

For collets, you have a choice of MT2 using a home made drawbar, er 25 or 32 with exactly the same drawbar, or a screwed on backplate with an er 25 or 32 plate bolted on. The er 25 is generally limited to 16mm maximum collets, which may be enough for your requirements. The backplate method has no need for a drawbar allowing long stock right through the spindle, and also if the plate/collet register is left loose, you can fine adjust for zero radial runout on any critical work. 5C collet chucks are nice if the budget allows.

[Phil PParticipant @philp]

I have in the last couple of years managed to obtain a full set of genuine 2MT Myford collets.

They are not cheap, but having said that they are very accurate and I am now wondering why I left it so long to get them. I use these in preference to a chuck every time if at all possible. I do have a Harrison lathe with a 1.5" hole in the spindle as well for bigger jobs, 99% of the time I use Burned Multisize collets on that and only very rarely fit a chuck on it.

Actually I think I am a "Colletaholic"

Phil

[Anonymous]

Posted by Phil P on 10/01/2020 14:42:23:

…..99% of the time I use Burned Multisize collets on that and only very rarely fit a chuck on it.

That's what I use too. May be not quite as good as fixed size collets, but way better than my 3-jaw chuck.

Andrew

[Douglas JohnstonParticipant @douglasjohnston98463]

The real pain is chuck changing. If you have the collet chuck fitted, chances are you need the 3 or 4 jaw or vice versa. There is no decent answer to this problem apart from muttering some favourite oath and getting on with changing the chuck. The collet chuck is more accurate but also more limited, so I would always go with a 3 or 4 jaw chuck first before buying a collet chuck. When you have all three it just increases the chuck changing problem, you just can't win!

Doug

[Anonymous]

Posted by Douglas Johnston on 10/01/2020 15:17:41:

The real pain is chuck changing.

Depends on the fitting. With Camlock it's simple and quick. A bigger problem is the large chucks and faceplate seem to be getting much heavier as I get older.

Andrew

[Bob Brown 1Participant @bobbrown1]

You can get a collet chuck with a Myford thread as I have one on my Dore Westbury milling machine Also have an ER40 on a back plate on my Boxford which I tend to use over a 3 jaw chuck with round bar.

[SteviegtrParticipant @steviegtr]

A bit confused & forgive my ignorance but someone said using a drawbar. I thought a collet chuck with an MT2 taper just tapped into place on the myford. Are they saying I need to pull it into place with a drawbar down the centre of the head stock.

[Phil PParticipant @philp]

The Myford collets are pushed into the taper using a special nut on the chuck thread, the same nut also withdraws the collet from the taper using a locating groove on the collet nose.

This means a long workpiece can pass right through the collet and spindle up to the max diameter of 1/2" (13mm)

Phil

[Paul LousickParticipant @paullousick59116]

Steve,

If using a collet chuck in a morse taper, you will need a drawbar to hold it in place. Unless you are also using a centre in the tailstock. Side forces on the work could rattle it free.

Paul.

 

Edited By Paul Lousick on 10/01/2020 22:58:51

[SteviegtrParticipant @steviegtr]

Does that mean a special type for the Myford has to be purchased or would any MT2 one do.

[Paul LousickParticipant @paullousick59116]

Not sure about Myford, I have a Southbend with a 3MT taper in the headstock. But any adaptor with a MT2 taper should fit into a MT2 hole. The drawbar can simply be a piece of threaded rod with a nut on the other end.

The Southbend with a 3MT taper also uses an adaptor to take 3C collets and is clamped with a hollow drawbar which allows 1/2" dia rod to pass thru it.

Paul

[Phil PParticipant @philp]

I thought you were just talking about 2MT collets sorry.

If you want to fit something like an ER milling collet chuck to the morse taper then yes you will need a drawbar to hold it in place and yes any make should work so long as it is 2MT.

However you would be much better off using one of the type that has an adapter that screws onto the spindle nose in place of the chuck, those are much more rigid and you still have the benefit of a full through bore up to the spindle bore diameter depending on the collet used.

Phil

[Paul LousickParticipant @paullousick59116]

My mill, lathe and rotary table all have 3MT tapers and can share the same tooling. Very handy to take a job from the lathe and put it in the RT without losing its centre position.

My main problem I had when using the ER adaptor in rotary table was holding the cutters in the mill and had to buy a second 3MT/ER adaptor.

Paul.

[duncan webster 1Participant @duncanwebster1]

Myford type collets, or any MT2 collet with a drawbar need material which is close to nominal size, no good at all for black bar or odd size stuff. If using drawbar type be very careful you don't overtighten the drawbar or you will have a devil of a job releasing it. Don't ask how I know. I've got an ER set up for my 254, but I hardly ever use it, most of the time I use the 3 jaw, if the 4 jaw is on I just use that, yes I've even set up hex bar in a 4 jaw, one of my irrational pet hates is swapping chucks

[SteviegtrParticipant @steviegtr]

Posted by Phil P on 10/01/2020 23:15:33:

I thought you were just talking about 2MT collets sorry.

If you want to fit something like an ER milling collet chuck to the morse taper then yes you will need a drawbar to hold it in place and yes any make should work so long as it is 2MT.

However you would be much better off using one of the type that has an adapter that screws onto the spindle nose in place of the chuck, those are much more rigid and you still have the benefit of a full through bore up to the spindle bore diameter depending on the collet used.

Phil

Thanks for the reply. Once I get set up I will have to purchase one of these sets. Trouble is once the weather gets better I start spending money on the motorcycle.

[Phil PParticipant @philp]

Me too

Phil

PS Where in West Yorkshire are you ?

Edited By Phil P on 11/01/2020 00:21:20

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