Emco Compact 5 headstock taper problem

[Nick anonParticipant @nickanon93441]

Morning lads, I've just bought a really nice Albrecht keyless drill chuck, the run-out of which I wanted to check with it inserted in the headstock of my Emco Compact 5. I took the chuck and back plate off, expecting to clean the bore and just tap it in. I've never used the morse taper sockets on this machine, apart from with centres, which worked fine. I tried the Albrecht and it bottomed out on the base of the chuck, before the taper mated. I thought, ok, try another chuck to see if it was the arbor. I tried 2 Rohm, 1 Jacobs drill chucks and 1 Emco collet chuck, all with crisp 2MT full length Arbors. Obviously the headstock spindle has too much material forward of the max Morse taper diameter, because the arbors will not seat and have some wobble.

Could I please ask if anyone has got an Emco C5, that they can try with a standard 2mt drill chuch arbor, to see if it is a standard characteristic on this machine spindle.

All the best, Nick

[Nick anonParticipant @nickanon93441]

[Martin ConnellyParticipant @martinconnelly55370]

Is it possible you have a number 3 taper? The gauge line diameter of 2mt is Ø17.78mm and that of 3mt is Ø23.83. Measure the inside diameter of the end of the spindle taper and it should be close to one of these values.

Martin

[Nick anonParticipant @nickanon93441]

No, I did wonder, but the first thing I did was measure the max D and it was roughly 18.5mm. I started to think that maybe Emco put in a plain bore in the Millenium LTD edition of the Compact 5, but that would be stupid.  You know the really silly thing, Emco sells a 2MT collet chuck, on an arbor from Promachine tools in Stamford. That shows that it was intended to be used with a standard long 2MT arbor. I'm really confused.

 

Thanks for the reply though.

 

Cheers, Nick.

Edited By Nick anon on 17/10/2016 15:55:35

[JasonBModerator @jasonb]

The spindle bore should be 16mm which is larger than the small end of MT2 at 14.52 so should not be a problem.

Is there a step from the end of the MT2 taper down to the 16mm spindle bore, if so it may need to be a short MT2 taper

[Tim StevensParticipant @timstevens64731]

I wonder if you are trying a taper with a tang (a flat extension to hold when used in a column drill)?

If your headstock has a drawbar (a threaded rod within it to screw into the end of the taper) then the tang will get in the way, and prevent the taper from seating.

Taper fittings come with and without Tangs, and with and without drawbar threads (and in some sizes with a choice of threads, Whitworth or Metric) so although you can get what you need, you must be careful to specify exactly what is required.

I hope this helps

Cheers, Tim

[Martin ConnellyParticipant @martinconnelly55370]

Tim, I thought something similar at first but rereading the original post the taper is going in until the back of the chuck hits the spindle so there is nothing on the taper hitting anything inside the spindle.

The next possibility is that someone has remachined the spindle taper, was it new when you got it Nick?

Martin

[mike TParticipant @miket56243]

Nick,

Unfortunately there is something odd with the way EMCO have machined the 2MT on all Emco Compact 5 lathe spindles. The taper is machined correctly for 2MT but the taper is located about 8 mm too far into the spindle; so any 'standard' 2MT drill chuck or 2MT ER25 collet chuck will not fit the lathe spindle. The back of the chuck always hits the spindle face before the taper can engage.

What Emco had in mind when they designed that feature is any ones guess. It has proved to be a source of annoyance for many owners. I discovered this oddity after waiting two weeks for a 2MT ER25 collet chuck to be delivered from China, I had to resort to that ungainly EMCO bolt on ER25 collet chuck.

Mike

[DrDaveParticipant @drdave]

Nick,

I have just taken the chuck off my C5 & tried some of my 2MT bits. My drill chucks fit, but my rotating centre does not: it fouls on the spindle Like yous do. It looks like Emco were a bit generous with the length when they designed the spindle.

Dave

[Nick anonParticipant @nickanon93441]

Thanks to everyone who replied, very much appreciated.

After further chuck tests, Mike's and Dave's reply and receiving a reply from Bryan at Barnac in Stamford, it is now clear that Emco, for some mad reason, decided to make a taper that was recessed in to the spindle bore. Whether this was to extend the between centers capacity or to force user to be loyal to their not inexpensive accessories, we'll probably never know.

Yeah I've also got the collet chuck, both bolt-on and 14mmx1 on a non-Emco 2mt arbor and they're a pain to set up, because you've got to take the chuck off.

The reason I need to put these chucks in the C5, is to check their accuracy. This in turn was in response to my new Wabeco drilling poorly from the tailstock, with visible wobble, regardless of drill size or type or if starting with a 10mm spotting drill. It's just one more nightmare in a long line with the D4000.

The tailstock drill chuck flexes by 0.25mm(two fingers on the chuck nose) and that's with the camlock lever and quill lever locked and a quality MT2 collet chuck seated well in the barrel. The arbor and bore are spotless, the ways are spotless and the chucks are a top end Albrecht and Jacobs that both show under a thou run-out.

I've clock the tailstock bore, a centre and a chuck with ground pin. One minute it is under a thou, then it's 7 thou low and 3 thou forward, then it's three high and 7 forward etc. Just driving me mad, because this Wabeco seems totally inconsistent in the tailstock alignment. A test bar shows that the tailstock is parallel and aligned to under 0.01mm. But it still won't drill better than a drunk Otter with a Lidl hammer drill.

Oh well, at least the Emco issue is identified, so I need extended arbors for my chucks in the future, at least that's an improvement. I think I'll either put the D4000 on Ebay or get a pro to set it up, just to find out why it is so poor at drilling a straight hole. In the mean time the Compact 5 will drill a great hole, so I'll just have to confine the new D4000 to polishing work, ha.

Thanks again for your help, cheers, Nick.

[Roderick MellottParticipant @roderickmellott71426]

I had this issue with a mt2 by 5/8"-11 adapter for a asian indexing head, and thought it to be odd. However, after measuring, it appears that some foreign/asian, non-imperial tooling, does not always comply with exact standards. I'm sure there may have been some reasoning at the time of design for the compact 5 spindle spec. or a oversight

The ability to turn and mill, just makes it an inconvenience to custom mate a part or tool. If thought out, its well worth spending the time on making or modifying one half of the mating peice to bring tooling to standard in some form.

i just purchased a new compact 5 head. Can anyone tell me the part information on the spindle bearings?

Thanks,

Rode

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