Live centre suggestions

[Stigmorgan]

So today my Charnwood live centre decided to snap while I was roughing down a branch approx 150mm across and 450mm long, now I have no way to support the tail end of anything I make so need to replace it, I'm going to ail Charnwood as I only bought it at Xmas, do any of you guys have any suggestions for a replacement?

 

[Tris]

I'd be tempted to take the pin out of the centre, pop a bar through the hole and drift the rest of the Morse taper out. Once you know it's width you can order a new one from places like Chronos or RDG for less than a tenner. I'd guess it'll be mt2-jt3? but there'll be more knowledgeable people awake tomorrow. Can't find the link ATM but someone recently posted a page from Zoro tools with all the dimensions for Morse taper chuck arbors

 

[Dalboy]

I'd be tempted to take the pin out of the centre, pop a bar through the hole and drift the rest of the Morse taper out. Once you know it's width you can order a new one from places like Chronos or RDG for less than a tenner. I'd guess it'll be mt2-jt3? but there'll be more knowledgeable people awake tomorrow. Can't find the link ATM but someone recently posted a page from Zoro tools with all the dimensions for Morse taper chuck arbors

I think you will find the end in the centre is a straight piece as it needs to fit into bearings. It may not end there as it could also have a groove for a circlip of similar you can buy blank end MT arbours which possibly need turning down to size so may make it cheaper to buy a new one, that is if it is not replaced FOC as it is only 5 months old

 

[Stigmorgan]

Emailed Charnwood with a pic of the broken live centre and description of what I was doing when it broke, got a call from Dave who is sending me out a free replacement, he was a delight to deal with, will 100% be buying from them in the future.

 

[Stigmorgan]

So my 2nd live centre just broke in the same place as the previous one, what could I be doing wrong? It's only been 8 weeks or so.

 

[Sandyn]

I think the only thing you are doing wrong is using it. If you leave it on the shelf it probably won't break. It must be a poor design. I would be back to Charnwood and see what they say and see if they can offer a different live centre. I have had my live centre for 30+ years I use it on the wood and metal lathe, still going strong.

 

[Richard_C]

Could be that Charnwood had a faulty batch, not just a faulty one-off.

 

[Stigmorgan]

Possibly, I just wonder if it's something I'm doing, tightening it too much when roughing out maybe?

 

[Tris]

One thought occurs, if you are using a record lathe with the twin bed bars, are the bars parallel and level both ways? If not it is possible the live centre is under a lot of stress. There doesn't look to be much 'meat' at the point of failure so perhaps it has an inherent manufacturing fault. If you've still got the old one I'd dismantle that and see about a new Mt.
Otherwise it a case of upgrading, I've had an Axminster live centre for about 18 years, no problems yet

 

[steve355]

I was thinking the same as Tris above, basically that the tailstock isn’t aligned with the axis of the lathe. But on the other hand, live centres are perfectly ok to be used for turning tapers on a metal lathe using the “offset tailstock method” so that should be fine.

One thing I’d imagine could cause it is if the centre of mass of the workpiece is significantly to one side, such as you'd be likely to get with a small log. That could have the same effect as breaking a copper wire by wobbling it.

 

[Stigmorgan]

One thought occurs, if you are using a record lathe with the twin bed bars, are the bars parallel and level both ways? If not it is possible the live centre is under a lot of stress. There doesn't look to be much 'meat' at the point of failure so perhaps it has an inherent manufacturing fault. If you've still got the old one I'd dismantle that and see about a new Mt.
Otherwise it a case of upgrading, I've had an Axminster live centre for about 18 years, no problems yet

Thanks Triss, I hadn't thought of it being out of level, it was level when I set it up but haven't checked it since.

 

[Fergie 307]

Being slightly out of alignment shouldn't have any effect, they are often used for taper turning as steve355 says. I think it's just badly made, my guess would be it's possibly been over hardened, making it brittle.

 

[Phil Pascoe]

Or Chinesium, making it cheese like.

 

[okeydokey]

Have you tried checking that the spindle and tailstock are in good alignment no harm in having a swift check.
I assume the tailstock itself is not loose on the bed

 

[Phil Pascoe]

1/ It shouldn't make any difference.

 

[Shan]

Thanks Triss, I hadn't thought of it being out of level, it was level when I set it up but haven't checked it since.

Stig. I might be slightly wrong in my detail here but if you're piece that you screw the live centre isn't flat it tends to put stress on the live centre but out of balance. Might be worth checking out because I remember a blank that I was working on and the live centre didn't engage in it completely flat and I might not have had the tailstock screwed up tight and the live centre started to wobble slightly. When I clocked it I noticed that the whole live centre was starting to grind it's way around in the tail centre. Fortunately didn't cause too much havoc but made me aware of the risk.

 

[Sideways]

I'm trying to figure this thing out.
From the description it's a live centre for the tailstock with ball races inside.
But it's serrated like a Sorby steb centre. That's a headstock drive thing, an update of the 2 and 4 prong drive centres. I can't see any point in having serrations on a free spinning tailstock centre. Just use a point, or if you're worried about splitting the timber, a smooth ring live tailstock centre.

What am I missing ?

This looks a bit feeble. There are much stronger cheap live centres for model engineering that would work fine in a lathe tailstock and Axminster et al do live tailstock centres with interchangeable points, cones and rings that are stronger than this.

 

[Stigmorgan]

I'm trying to figure this thing out.
From the description it's a live centre for the tailstock with ball races inside.
But it's serrated like a Sorby steb centre. That's a headstock drive thing, an update of the 2 and 4 prong drive centres. I can't see any point in having serrations on a free spinning tailstock centre. Just use a point, or if you're worried about splitting the timber, a smooth ring live tailstock centre.

What am I missing ?

This looks a bit feeble. There are much stronger cheap live centres for model engineering that would work fine in a lathe tailstock and Axminster et al do live tailstock centres with interchangeable points, cones and rings that are stronger than this.

You're not missing anything, I bought it because it was within the budget I had, another member has messaged me offering to make me new tapers and to see if they can see why they broke so I will be sending them out this week.

 

[Robbo3]

I'm trying to figure this thing out.
From the description it's a live centre for the tailstock with ball races inside.
But it's serrated like a Sorby steb centre. That's a headstock drive thing, an update of the 2 and 4 prong drive centres. I can't see any point in having serrations on a free spinning tailstock centre. Just use a point, or if you're worried about splitting the timber, a smooth ring live tailstock centre.

What am I missing ?

The revolving or live serrated centre was good for off centre turning. Much like the ring centre it tended to not to move or enlarge the divot especially when near the edge of the work piece. Often used with a matching drive center so the work could be swapped end for end.