Thread: Extended live centres

Michael,

Piper make them. Lathe Centres from Piper Tools | Leading manufacturer of quality machine tool accessories for over 70 years

BT

Michael, Have a look here https://www.machineryhouse.com.au/C079 these are MT2, perhaps what you're looking for at $152.90 (expensive). Standard designs are also available with reduced diameter bearing housings. I have one that is a little over 1" diameter on an MT2 shank.

You could also take a standard one and make a new longer centre for it. Unhardened will give a decent working life and case hardening it shouldn't distort the centre by very much besides live centres aren't intended for high accuracy, use a dead centre for that. If you use a QC tool post or a 4 way turret the problem is common when turning slender work near the tailstock.

The lantern or American style tool posts are useful in this regard although not as rigid as a turret. A good design for a QCTP is a triangular section mounting block such that the right hand side slants away from the centre and reduces possibility of fouling.

Originally Posted by Michael G

One of the things that I would like to get for my lathe is an extended centre. The standard ones occasionally cause difficulty for access when turning small parts. The trouble is the tail stock on my lathe is only MT2 and all the ones I can recall seeing are typically MT4. I do have a live centre set with interchangeable tips, but don't know what the long term accuracy or durability of that will be.
I did buy one from Ebay that was MT4 with the intent of turning down the taper but the bearing assembly is big enough that it looks like it would foul the tool post. Has anyone ever seen (good quality) extended centres in an MT2 size?

Michael

(And if anyone is running a lathe with an MT4 tailstock and wants a centre, PM me...)

G'Day,
Had the same problem, made a live centre from scratch, runs in needle roller bearings with an 8 mm ball in the bottom as a thrust bearing, the inserts are 10 mm stainless steel, when they wear, I ditch them and make a new one.
Regards,
Martin

Hey tool man,

I like that. Any chance you could put up a drawing?

Does the 10mm shaft lightly press in and out? Do you machine depressions to hold the 8mm ball?

G'Day Brendan,
The insert is a Proctologist fit, the flats are to take a 9mm open end spanner to remove them, the ball seats are cut with a centre drill, the bearings are 2 x 14x10 mm needle rollers, no drawing I'm afraid . The Morse taper was turned with the compound set over then bored with a 5MT - 3MT sleeve in the headstock spindle ,the inserts are dialled in to dead nuts in a collet chuck to cut the point
Regards,
Martin

Very tidy. Thanks very much for that. Im definitely going to put it on my 'to do' list.

Toolman49: Nice! I'll be copying that too. Thanks for posting it.

Greg (also afflicted with a MT2 tailstock ram)

another great thread

Hi Michael
I needed one for a job last year and bought the set below from Ozmestore
eBay Australia: Buy new & used fashion, electronics & home d
They come in MT2 or 3 and with the 7 tips it will be good for a variety of jobs needing a special tip or cone.
The first one I received had a bit of run out, I contacted them and they paid the return postage and replaced it. The second one was spot on and I am happy with it.

Martin's centre looks good, someone on another forum posted up one with pictures of it dismantled (it could have been Martin's), I could chase it up for you if your interested in making your own.

Dave

Thanks Dave
I have a set like the Ozmestore one, but I find that I only use the extended centre and as these things are usually to a price I don't know how long it will last. A "proper" one would be preferred.
If you can find the reference for the made one you saw that would be of interest to both me and others here I think.

Michael

I just found an extended nose one on ENCO for $87.99

part 328-0164

(That's the web price, which less than the online catalogue price (??)

they'll likely have a 15% off coupon closer to Christmas too.

Apparently the extended nose centres are called "CNC centres"

Greg

ON EDIT: There are other models as well. The one I listed only has a 1.3" point length which does not sound too generous.

I'm not 100% certain that part number is for an extended centre Greg. Looking at the page there seem to be two brands under that heading. The "interstate" brand is the one you've picked out, but it's the "USA" brand that specifically mentions an extended centre.
There are some interesting things in the catalogue though - I keep meaning to add a (straight sided) spring centre to my list of wants. The other thing I've noticed is that no one looks to do a live centre with a tang on the back, so the automatic ejection on my tail stock won't work. Until it isn't there, you don't realise how annoying that can be!

Michael

Here's the one with the extended point.

Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies

I have the 3MT version of it and I like it a lot.

Ed

Michael you may be right. In any event there's another one on the same page for a bit more money, and the Royal on the next page for crazy money.
My bud with the Rivett 608 has a Royal centre...I am trying to steal it; it's that good. Silky does not begin to cover it.

I'll have to look at my unused centre...I have seen screw-in tangs to convert drawbar style to ejector-friendly style. On european sites I think, maybe elsewhere too.

Greg