Thread: Cheap Live Centres

Gee, that's a lot of runout, even for a cheapie.

I've got two asian live centres and they have nothing like that degree of runout.

Rob

When cutting the 5MT for my ER32 collet chuck I was getting annoying chatter marks. The Brackenbury and Austin lathe is not normally prone to chattering. I checked all the usual suspects, gibs, headstock bearings etc. with no improvement. The last thing I suspected was the live centre, which had been used frequently in the past with no problems. However, as soon as I changed the live centre for a dead centre the chatter disappeared. I have used the live centre since on smaller workpieces and no chattering occurred. I can only assume that the extra weight of the larger than usual workpiece (for this lathe) was too heavy for the cheap live centre to support adequately.

Frank.

Martin If you don't have to check every diameter that matters for taper and make adjustments before finishing because your lathe is rooted, you've got it easy, so quit yer moaning.

Seriously, assuming your aren't using a sleeve, and that the parts are clean and burr free, I think your solution is about the only one - find the best position and mark it.

I've had a similar experience to Frank with a cheap live centre. Even my ' good' one has some runout so I tend to use deadies when it matters. And I have a couple of cheap MT sleeves that are out too.

I spent half an hour making a few pins out of 20mm bright round recently, it involved turning the end 60mm of each piece down to 12mm, nothing critical, 3 passes and you're done type of job. I used my Hafco live centre (came with the lathe) to support the end. The live centre certainly wasn't being overworked, but when I went to remove it from the tailstock at the end of the job it damn near burnt my hand it was that hot.

I know nothing of live centre temperatures as I usually use mine for just 2 or 3 minutes at a time. Is it normal for a live centre to get very hot? Is my live centre on its way to becoming a dead centre? Should I be considering CTC's offerings?

Have done some heavy machining with live centres that were none too large, and heavily loaded, and have never had one get noticeably warm. They have been around my shop for many years, so probably carry respected brand names, and i am surprised how well they have survived punishment. Suspect items that are of Asian origin are packed with whatever Yak fat they can obtain cheaply. If it's a recent purshase I would let H&F have it back again in exchange for a new one, possibly a different brand. Just my opinion, Combustor.

Originally Posted by bob ward

I spent half an hour making a few pins out of 20mm bright round recently, it involved turning the end 60mm of each piece down to 12mm, nothing critical, 3 passes and you're done type of job. I used my Hafco live centre (came with the lathe) to support the end. The live centre certainly wasn't being overworked, but when I went to remove it from the tailstock at the end of the job it damn near burnt my hand it was that hot.

I know nothing of live centre temperatures as I usually use mine for just 2 or 3 minutes at a time. Is it normal for a live centre to get very hot? Is my live centre on its way to becoming a dead centre? Should I be considering CTC's offerings?

Hi Bob,
I have machined for several hours using a live centre and mine never even got warm. On the other hand I've ruined a dead centre by overheating it. My fault entirely, I was that engrossed in what I was machining I forgot to keep lubricating it. I can't tell you what make my live centre is because there are no markings on it that I can find. All I can say is that its 2MT, 30mm diameter and thirty odd years old.

I bought a Skoda extended point about 8 years ago. It has done jobs where it has been running for hours and never gotten hot. I would say either it is poorly lubed or the bearings are overly tight.

BaronJ, i have clean melted the ends of a few dead centers, i forget the oil too, plus if the work gets hot and expands they get to much pressure on them and get even hotter.....

Ew

Bob Ward,
My Hare & Forbes live centre does exactly the same as yours, I now only use it for short jobs. I brought a CTC one and I have only done smaller jobs with it so far but it does not heat up, even on small jobs the Hare & Forbes on starts to get warm.
Bob

Originally Posted by krisfarm

Bob Ward,
I brought a CTC one and I have only done smaller jobs with it so far but it does not heat up, even on small jobs .
Bob

+1

My CTC one (morse 3) is about 7 years old and never ever, even gets remotely warm.

It has an adjustable tapered roller bearing as well, which is a very good thing.

Great live centre and no runout issues.

Most CTC stuff is good quality.

Rob

My hafco one used to get quite hot when i worked it hard at high rpm for several hours, until i opened it up, cleaned out the ###### grease it came with and repacked it with moly. After that it was fine to do heavy roughing between centers for 10 hours a day or more.Ive since bought the upmarlet hafco one, toolmaster brand. Rated to 5000rpm, it has a bigger dead center in it and a smaller body than my previous one, so it gets in the way less and can be used with bigger bores. Its really nice, expensive though...

Hello,

I have made crude live centres for my wood lathe and I had simply assumed that in 5 years time when I know what I am doing I'd be able to make live centres for my metal lathe too.

From what I read in these posts that not the case - everybody prefers to buy them.

So whats wrong with my thinking

a) Yes we could make them if we wanted to but its a boring dull tedious uninteresting task and its easier to pay some dollars and do something more interesting with our precious time

b) It far too difficult to make one even for us experienced machinists and we wouldnt even think about it

c) Other

Bill

I had a terrible Chinese live center that Ranout and got hot, After that I aquired a carbide tipped vertex dead center and skoda and piper live centers and have not had a problem since.

Originally Posted by steamingbill

Hello,

I have made crude live centres for my wood lathe and I had simply assumed that in 5 years time when I know what I am doing I'd be able to make live centres for my metal lathe too.

From what I read in these posts that not the case - everybody prefers to buy them.

So whats wrong with my thinking

a) Yes we could make them if we wanted to but its a boring dull tedious uninteresting task and its easier to pay some dollars and do something more interesting with our precious time

b) It far too difficult to make one even for us experienced machinists and we wouldnt even think about it

c) Other

Bill

Yes we could make them ! I don't think that its "boring dull tedious uninteresting" task, just that it takes skill and having access to the right bearing sets. I saw somewhere a detailed description of a live centre. It had three bearings two tapered one plain, an adjusting ring, a seal and cover plate. Then the point was hardened and ground. All on a hardened and ground MT spindle.

Your choice. I bought mine. But at that point in time I couldn't even grind a lathe tool properly either.

Originally Posted by BaronJ

Yes we could make them ! I don't think that its "boring dull tedious uninteresting" task, just that it takes skill and having access to the right bearing sets..

+1

I made a live pipe centre - same thing.

I just used a single tapered roller bearing, and this works fine once you put end load on the job (which you always have to do).

Very handy project which you can make as large as you wish - mine takes up to about 80 mm.

Rob