New to vertical milling

Having just bought Centec 2B mill I now need to find some tooling. What
would be the best collet system to invest in and where is the cheapest
place to buy from? The mill uses 2MT tools.
cheers
Bob
Reply to
imagedude
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I assume you're thinking principally about vertical mode. Well, a friend and I both have 2Bs - he uses 2MT collets and I use ER32. The main advantage of the 2MT collets is that the tool ends up closer to the quill and so gives less overhang and more headroom: both good things. The main advantage of the ER system is versatility: both metric and Imperial sizes can be handled with the same set of ER collets. My friend built his 2MT set over time as he needed them, I purchased my complete ER32 set from RDG Tools - they had the keenest price and were made by Vertex. All in all I prefer the ER system.
Reply to
lemel_man
There are more drawbacks and advantages worth thinking about:
ER: - Isn't that stable as MT collets - very long tools (drills) can't be pushed in far enough sometimes (when you are going out of headroom). - not as precise as MT. There is an extra place for tolerance (ER in the ER holder) and the area of contact is smaller). + Takes less space to change the mill. There are situations where you don't want to move the table (or can't). + Cheaper collets + Often can be used on the lathe or rotary table
So what is better? Both! I'd first buy ER and then buy MT when a setup requires it. YMMV.
Nick
Reply to
Nick Müller
I would certainly add my vote for starting with the ER system. I bought a Vertex ER32 system for my small mill several years ago and have never felt the need to buy any direct MT3 colletts. While the Vertex system is superb I have purchased several additional colletts from ArcEuro Trade, RDG, JL and Chronos. While most of these have no manufacturers name they have all been fine. The flexibility is a tremendous asset and I have experienced no problem whatsoever with their accuracy.
Best regards
Keith
Reply to
jontom_1uk
Why do most endmills etc have a screwthread on the end, is this something I need to concern myself with?
Reply to
imagedude
In a word: Clarkson.
They brought the threaded endmill and holders to market a looooong time ago, so most end mills are threaded to suit their holders. Many copies out there, all pretty much equal.
Note that there are imperial and metric body/thread sizes and matching collets to hold them.
Peter -- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
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Reply to
Prepair Ltd
Yes and no. They fit into collets without problem. But if you are roughcutting, mills get pulled out of the collet and that is why some do have a flat or a thread. ER-collets can't clamp there, so you have to step back a bit and not make to hard a cut.
Nick
Reply to
Nick Müller
As Peter and Nick have said the threaded cutters were designed to stop any possibility of the cutter pulling out during a heavy cut. This was a particular problem as colletts became worn and cutting loads increased with better cutter materials. The ER design collett has more "splits" than the older designs which allows the internal part of collet to contract with parallel faces and it generates higher holding pressure on the cutter. While I know that it is possible to have a cutter pull out of a ER collett it is not a common occurance and rare in the home shop with normal HSS cutters. The ER system will hold, threaded, flat and plain cutters of both imperial and metric sizes, that's one of the major benefits of the system. The ER system is widely used in industry and known for long life and reliable holding.
Best regards
Keith
Reply to
jontom_1uk
The main problem that the OP has got is the 2MT spindle mounting. This severely limits the stiffness of any collet system that is mounted on it.
I would seriously suggest using 2MT collets if you are going to use 1/2" or 12mm cutters. This is based on my experience with a 2MT Vertex Pozilock collet chuck on a Myford ML7. The deflection was visible when pushing any cutter bigger than 1/4". I cured the problem by making a new collet chuck that screwed onto the lathe mandrel. This was _much_ stiffer than the original 2MT arbour and had less overhang. I don't think the Centec would have this option (could be wrong :-)
Of course, a 2MT head is probably going to struggle with a 5/8" or larger cutter, but a 5/8" roughing mill will chomp away on cast iron quite happily.
Mark Rand (this advice is worth what you paid for it :-) RTFM
Reply to
Mark Rand
Mark, excellent point I had missed the fact that it was 2MT. My experience is based on my 3MT Vertex chuck and like you on the lathes I use home made direct mounting chucks. I do remember when using Centecs years ago they needed to be treated fairly lightly, then again they might have been clapped out. Pity because the ER system is very flexible and my drill chucks are rarely used these days. Good job someone is awake.
Regards
Keith
Reply to
jontom_1uk
But this only helps, if you clamp something smaller than the nominal size of the collet. But then, ERs are really much better.
I have ruined quite some pieces when the rough-cutting mill was pulled out some mm. I use "softcut" mills. They cut so smooth and silent! The more feed, the more silent they get. You can really go to the limit of the mill. Diameter of mill 20mm, 20mm deep full cut. That's how they get pulled out. :-)
ACK
They more and more use shrink collets or hydro collets. Especially for HSC milling. Nothing else keeps the required tolerances. But that is out of reach for HSMs.
Nick
Reply to
Nick Müller
Nick
I agree with most of your points when taken in a wider industrial context, however we are discussing the use on a Centec 2B in the home shop with as Mark rightly pointed out a 2MT spindle. I had also assumed that they would be used within their recommended range, silly I suppose as I should have remembered from my industrial experience that is never the case.
You are right to point out the dangers of the newer generation of milling cutters as they will eventually find their way onto our machines and this gives us an insight into just how far they can be pushed. I should have also mentioned the possibility when taking deep cuts in the more ductile materials. In my defence, I still cannot see a Centec 2B taking 20mm cuts with a 20mm cutter, however silent it is.
I also agree that industry is in the process of moving on with regard to tool holding but they always are. It's also true to say that much of smaller scale industry haven't even got as far as ER yet and I doubt very much they will make the jump to shrink or hydro colletts let alone to High Speed milling. As you rightly say I can't see machines with absolute minimum spindle speeds of 10,000rpm fitted with the best possible spindles that manage at most 4,000 hour lives, being widely adopted in the HSM. Then again with smaller cutters and more sympathetic feed rates just think how many pieces of scrap I could turn out in the hour.
I find this type of development very interesting and indicative of the increasingly inevitable demise of the remnants of British production industry. I suppose you could argue that by being slow to pick up these developments our industry will be able to "cherry pick" the best and miss those expensive "dead end" developments, a bit like telling the poor b*****s at Agincourt we'll skip the longbow and go straight for the ICBM.
Anyway, I digress, Nick thanks for your post as I think it's important to take us outside of our old machines and little sheds once in a while. Problem is it makes me depressed when I consider what I can do against what is possible. Just getting old I guess.
Best regards
Keith
Reply to
jontom_1uk
[rest snipped and ACK'ed]
I was getting off topic in discussing the differences and advantages of mill-holding systems. No insult intended.
Where can I get shink collets with MT2? :-))
Nick
Reply to
Nick Müller
Nick M=FCller wrote:]
None taken Nick, I do think it is good to see what real industry is doing with some of this kit that we play with.
Yes good, I don't think you should hold your breath though, I can't see a real commercial need particularly as they must easily outperform the holding potential of the MT taper in an old spindle?
Best regards
Keith
Reply to
jontom_1uk
I have one 9mm slot drill that I have mounted in a 2MT blank arbour by boring the arbour to a good fit, then removing another 0.002" in the middle part of the hole, then holding the cutter in with loctite 603. This is not quite as good as a shrink collet, but it's not far off. When the cutter is worn out, I'll heat the arbour up to 150 degrees or so and pull the cutter out.
One of my projects, once I've got the Beaver mill recommissioned, is to make some genuine shrink fit INT30 holders for some of the larger cutters that I have acquired. I can either use the shrink fit induction heater at work, or make my own for fitting and removing cutters.
... or I could go back to using the shaper
Mark Rand RTFM
Reply to
Mark Rand
Mark, given that blank 2MT arbours are cheaper than colletts that's a brilliant idea. Once fitted the cutters could be ground complete with arbour. The assembly would also increase available height table to cutter a real benefit on smaller machines. I suppose that I might worry if the cutter was too large so that the arbour rotated in the spindle rather than the cutter rotating in the work. What sort of interference/temperature rise do you think we would be talking about with a 1/2" cutter. Inspiring idea though.
Best regards
Keith
Reply to
jontom_1uk
I do that (without removing material in the middle) when I need long drills (small sized, about 2mm). Locktite centers the drill very well, so I just bore some rod with the drill that I want to glue in.
Pun intended? ;-)
Nick
Reply to
Nick Müller
Some of the Clarkson milling chucks had a screwed ring over the body that once the chuck was tighten in the taper the screwed ring was wound back to dear on the ends of the spindle to increase rigidity.
Not that I know anything about rigidity at my age -- Regards,
John Stevenson Nottingham, England.
Visit the new Model Engineering adverts page at:-
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Reply to
John Stevenson
Out of my depth here John but if we cut a thread on the outside of the blank arbour and made a matching sleeve nut, then when the arbour is tightened up we could load the sleeve nut against the spindle? Would that reduce the flexibility of the fairly small 2MT arbour that Nick was talking about before? Would it not reduce the holding pressue on the taper though, as I said I'm out of my depth.
Regards
Keith
Reply to
jontom_1uk
Yes - mine's like that. Advantage of the Clarkson over plain collet is that cutters don't pull out - ever. Disadvantage, on my 2A, is that the space between cutter and bed is reduced, so I can't get big items in.
For big items I fisit a friend, who has gone over to ER collets on his 3MT mill almost exclusively. He occasionally gets the cutter moving a bit, but usually when he's not tightened it enough. Really big advantage for him is that the ER system will also hold drills. So you don't need to keep swapping the Clarkson for the Jacobs.
Wilfrid Underwood
Reply to
tenacitygoogle

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