My S/H Chester Mini/Multi Lathe/Mill machine came with just MT1 taper drill chucks ' which I have been using for milling. Now I find that, for various reasons, these are not really appropriate for milling and I need to get a Collet Chuck. My web searches has thrown up that ER Collet chucks are the most widely used. But these come in various sizes. Bearing in mind the limited milling capacity of both the machine and my use ' i.e. I currently use end mills from 1mm to 5mm ' which ER Collet should I go for ER-8, ER-11 or ER-16 to have the best compromise solution. Or am I just going down the wrong path entirely.
As you probably also have quite limited space between the mill spindle and the work you may be better off using MT1 collets that fit directly into teh taper and will save you a couple of inches.
These are only suitable for nominal sizes eg 3mm, 4mm, 5mm (or 1/8" 5/32", 3/16" ) not a problem with milling cutter shanks but you would have to switch to a drill chuck for intermediate sizes when drilling etc.
The ERs will allow you to grip anything within each collets range so will save some time in changing between collet holder and drill chuck but at the cost of room not just the length mentioned above but also the dia of the closing nut can get in te way at times when using small cutters. I'm not sure that there are may MT1 collet holders about in te smaller sizes anyway.
I think Jason hit the nose on the head when he suggested morse collets. I have a dore westbury. It's morse 2 in a hefty spindle and that type of collet is the best option for a lot of work. I bought suitable metric and imperial collets because I like to buy bargains when they crop up.
I think you will find that standard shank diameters in your sizes are 3,4,5,6 and 8mm diameter. The actual cutting diameters at these sizes will vary. You will find that it's possible for instance to get 3mm cutters with a 6mm shank. The other smaller sizes of shank are more likely to be found on solid carbide cutters. You could get a better idea of the variations in this area by browsing ArcEuro's pages. They for instance only sell cutters with 6,10 and 12mm dia shanks.
ER collet holders sound very attractive but are just as much pain to change as a morse collet when a change is needed. I am not aware of any 1 morse versions anyway. I do use an ER16 holder at times because of the size of the quill on my miller ' they give more reach from the quill and also give me a better view of what is going on. The parallel shank ones are often used on "big" milling machines for the same reasons. My DW isn't big but is based on a Myford lathe spindle nose.
John
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Thanks Bob ' I read the wikipedia entry as well ' but it failed to explain why there were Brown & Sharpe, Jacobs, Jarno, Morse, B Tapers, NMTB tapers, HSK tapers etc. Providing the taper is big enough and man enough to cope with the different rotational forces encountered as the material size increases ' why so many variations. I appreciate quick release tapers (NMTB) or coping with high centrifugal forces (HSK) but beyond that ' why so many. It just strikes me as a similar situation to current USB plugs ' where everybody decides to create their own form despite the fact that the underlying reason and format is common and intended to do the same job. Fortunately, USB plugs/sockets appear to be converging to a common design. With the longevity of lathes and milling machines, I doubt that will happen ' although it seems that recent machines appear to be gravitating towards Morse tapers ' at least in the hobby/model area of machinery.
You missed Schaublin Colin ' sort of morse like. They chose to do that. Some of the various types will have been made for the same reason.
I'm not going to look at that lot, just general.
There are basically only 2 types ' locking tapers such as morse and ones which don't or shouldn't. A rule that is sometimes used for not locking under any circumstances is a 30 degree half angle. With oil I would wonder about that in terms of pulling it out.
Morse on cutting tools should really use a tang on the end to ensure it doesn't slip hence it's wide use on drills. A draw bar can also help.
For more information, please visit Milling Collet Chucks.
The various milling chucks are in one way or the other down to the the size of the machine particularly the size of it's spindle and the available motor power. The larger miller specific ones will generally lock into the spindle so the taper is more for accurate alignment. This can even extend to the collets used in them such as with clarkson auto lock. The cutters have a thread on the end so any slippage screws them in further until they can't go any further. The collet grip alone seems to be more popular these days but I don't know many people who have 5HP millers, not much idea how powerful they can get either.
I'm glad you realise that cutting torque matters. Just because some on sells a morse 1 ER collet holder doesn't mean it's a sensible thing to use. People have been known to bend even MT3 arbours on millers. Any morse fitting collet holder extends significantly out of the spindle ' morse collets don't so less leverage is applied. You have a fairly light weight machine so personally I would be inclined to bear that in mind.
John
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Edited By John W1 on 01/06/ 13:35:24
Colin the quick answer to "why so many" is probably histrory. Back when machine tools were being invented and developed there was very little if any likelyhood of a milling cutter made in America being used in a milling machine made and used in the UK. So while both America and the UK thought that a standardised taper would be a good idea, in their own countries, there was no need for them to have the same taper as each other ' even though the mechanics of the situation would dictate that they would inevitably be very similar. Now apply that same logic across the rest of the world and you can see where so many different but very similar National and Manufactures Association standards come from. It is probably only from the late Victorian era that international trade in machine tools got going and then only on "high-end" machines which would be almost one-offs, so the machine builder could put whatever taper the customer demanded on the machine. Now-a-days markets are global and machines and tooling are often built and produced in different parts of the world. New machines will have the more widely accepted international standards but there a still a heck of a lot of older machines around that need tooling to the old standards. USB plugs and computers have come from a different direction in that global markets were already well established and standardisation was an obvious thing to do.
A good example of how multiple standards come about is the electric vehicle market. The large car makers all develop their own take on the vehicles and systems ' partricularly the charger connection ' result was that you couldn't charge say a Ford from a Peugeot charger even though the voltage etc was right ' the plug didn't fit! I pointed this out about 20 years ago at a conference and suggested that since petrol cars could all go to the same pump for a refill as the nozzles were all the same size wouldn't it be a good idea to use the same logic with the electric cars and standarise on "refill" connectors ' didn't get a good reception for some reason! I note that mobile phones are now or are to be being fitted with a standard charging connector ' about time!
Edited By Keith Long on 01/06/ 13:49:56
Posted by John W1 on 01/06/ 13:33:58:I'm glad you realise that cutting torque matters. Just because some on sells a morse 1 ER collet holder doesn't mean it's a sensible thing to use. People have been known to bend even MT3 arbours on millers. Any morse fitting collet holder extends significantly out of the spindle ' morse collets don't so less leverage is applied. You have a fairly light weight machine so personally I would be inclined to bear that in mind.
John
I think you would be hard pressed to bend a MT3 ER collet without some kind of mishap/mistake on the part of the operator or any other tool holder if it comes to that, so I think the comments are unreasonable. I have been using ER collets for several years both on the milling machines and the lathe, never bent one, broken a few tools but the collets have been fine and have not had a tool move in them.
Small machines are not going to be capable of large cuts and large cutters are probably not advisable, one has to work within the constrains of the machine.
Bob
Posted by Bob Brown 1 on 01/06/ 14:00:26: Posted by John W1 on 01/06/ 13:33:58:I'm glad you realise that cutting torque matters. Just because some on sells a morse 1 ER collet holder doesn't mean it's a sensible thing to use. People have been known to bend even MT3 arbours on millers. Any morse fitting collet holder extends significantly out of the spindle ' morse collets don't so less leverage is applied. You have a fairly light weight machine so personally I would be inclined to bear that in mind.
John
I think you would be hard pressed to bend a MT3 ER collet without some kind of mishap/mistake on the part of the operator or any other tool holder if it comes to that, so I think the comments are unreasonable. I have been using ER collets for several years both on the milling machines and the lathe, never bent one, broken a few tools but the collets have been fine and have not had a tool move in them.
Small machines are not going to be capable of large cuts and large cutters are probably not advisable, one has to work within the constrains of the machine.
Bob
I sold a sensitive DTI to some one after finding I had 2 some how or the other who had done just what I said and wanted to straighten it. I have also seen bent 3 morse milling collet holders in used machine tool sellers stock. Much depends on the power of the miller and the size of the cut and cutter it will take but by all means use what ever you see fit to use. Really there is no point fitting a collet holder that can take bigger cutters than the machine can usefully use. A rough metric for that is a depth equal to the diameter with some care. Light cuts with face and fly cutters are a different matter.
John
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Edited By John W1 on 01/06/ 15:15:04
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