Warco WM250 Colle set question 2

[John Hall 7Participant @johnhall7]

Im looking at getting a collet set for my recently aquired Warco WM250 lathe..

This is new to me…can anyone tell me the useage difference between ER and 5C collets…also the advantages/disadvantages of each one..Cheers..

[John Hall 7Participant @johnhall7]

[John HaineParticipant @johnhaine32865]

I don't know about 5C but they strike me as expensive and only suit one size per collet. Chucks also expensive. ER collets adapt over a 1mm range (0.5mm in smaller sizes) though worth buying a few imperial collets for in-between sizes such as 1/4". Accuracy is adequate. I use ER16 in my little CNC mill and ER40 on the Super7.

[SillyOldDufferModerator @sillyoldduffer]

ER were designed for tool holding but they're good for holding work too. As John says a big advantage of ER is the extended range of diameters that the collets can grip. Another advantage: I use ER32 collets on my lathe because that's what I have on my milling machine, which keeps the cost down!

BUT! Do you need collets at all? Their usefulness depends on the type of work you do, and they may be a waste of money. Most of my turning is 'general purpose' and it's done in a 3-jaw chuck. The accuracy of the chuck doesn't matter much because most cuts are close to the chuck. For practical purposes the turning accuracy is relative to the axis, not to the chuck.

With other work, the inaccuracy of the 3-jaw becomes an issue. When it does, I switch to my 4-jaw, which can be trued very accurately. The disadvantage of the 4-jaw is how long it takes to reset each time work is moved. Most of the time – for me – that isn't a problem. An advantage of chucks is that they can hold larger work than a collet system.

However, I sometimes tackle jobs where work is repeatedly taken on and off the lathe, in my case turn/mill/turn. Collets can save a lot of time because they don't have to be reset. Another time when collets are useful, is when you have to turn many examples of the same sort of item, like a stepped shaft, that can all be gripped by collets.

I over-estimated how often it's worth my while to fit the collet chuck to my lathe and I rarely use it. Before spending too much cash I recommend having a think about the type of work you expect to be doing. If occasional accuracy is all you need, then a 4-jaw may be enough. Collets are for when you need speed and accuracy and the type of work suits them. For example, I feel collets are better suited to clockmaking than building engines.

If money is no object, 5C.

Dave

 

 

Edited By SillyOldDuffer on 14/11/2018 11:31:17

[John Hall 7Participant @johnhall7]

Thanks …very helpful..

[Howard LewisParticipant @howardlewis46836]

FWIW

Agree with S O D comments. 3 jaw for most work; 4 jaw for accurate centering.

Although have the equipment, rarely use my ER collets in the lathe . (Useful if doing repetition work, but not my scene. Biggest quantity ever made; eight clamp screws for a 4 way toolpost)

Made a holder for ER25 collets for a Tailstock sliding Tap Holder.

BUT most often used on the Mill, to deal with different size endmills / slot drills, arbors for gear cutting, or for work holding, in Stevenson type collet blocks, or the Rotary Table.

Howard

[JasonBModerator @jasonb]

5C is nice for close work on small parts as there are no jaws swinging round,

5C Hex and square collets available and if doing a lot of square work you will grip it the same every time whereas a independant 4 jaw will not if two jaws are opened then closed.

5C have a larger capacity than ER32 and even ER40

5C will hold short work down to 1mm long

5C backstop available for batch work.

5C standard chuck key to tighten not two spanners

ER will grip odd sizes

ER can also be used in the mill for tool holding

3-jaw & 4-jaw Not good for thin wall parts which will be distorted

3-Jaw quicker to change sizes than collets and easier to insert long stock

 

I use the 5C a lot for small work even though my 3-jaw has less than 0.001" runout, 4-jaw occasionally where accuracy is really needed but most of the time it is only for odd shaped or large square work. I also have a 5C to ER 32 adaptor so can use the ER collets in the 5C if I don't have the 5C size needed.

Edited By JasonB on 15/11/2018 07:47:18

[John Hall 7Participant @johnhall7]

Thank you…very helpful..👍

[egaParticipant @ega]

Posted by JasonB on 15/11/2018 07:11:38:

…

5C will hold short work down to 1mm long

5C backstop available for batch work.

Thanks for your 5C/ER comparison.

There is an obvious temptation to grip work shorter than the collet in an ER chuck and I wonder how far this can safely be taken? Certainly not 1mm, but have you a helpful rule of thumb?

There is, of course, no reason why a backstop cannot be contrived for use with an ER chuck.

[mechman48Participant @mechman48]

Posted by Howard Lewis on 14/11/2018 22:28:25:

FWIW

Agree with S O D comments. 3 jaw for most work; 4 jaw for accurate centering.

Although have the equipment, rarely use my ER collets in the lathe . (Useful if doing repetition work, but not my scene. Biggest quantity ever made; eight clamp screws for a 4 way toolpost)

Made a holder for ER25 collets for a Tailstock sliding Tap Holder.

BUT most often used on the Mill, to deal with different size endmills / slot drills, arbors for gear cutting, or for work holding, in Stevenson type collet blocks, or the Rotary Table.

Howard

Virtually the same as I do apart from the tailstock holder which I have made a different type. I use my hexagonal Stephenson's block in my three jaw chuck for small work as I can get it to run more accurately than the small amount of run out the 3 jaw has. I also have a MT4 collet chuck to fit the headstock taper & find that this suffices more than adequately for my needs rather than buy a collet chuck & back plate, so I am well catered for.

George.

[JonParticipant @jon]

5C all the way no comparison to ER things.

5C were used on autos and capstans to great effect over many decades when Britain ruled the world. Theyre robust as well and dont flex like ER holding work and biggest clencher 5C have more holding power no slippages or job moving.

Gave my 5C chuck, drawbar with built in handle away to a mate many years ago. I had a 140 he still has the 11", reason for parting i didnt like the price of the collets and considering the amount i would need.

A note, you should always machine in one without removing job from any chuck/collet or expect problems.

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