live centre construction

[BrokenBiker]

i fancy making a live centre for my newly acquired lathe. I have reasonable amounts of scrap than need using too so it seems like a good idea. The tailstock has a mt1 and i have a blank mt1 but the od of the blank is too small for the inner race of the bearings i have.

does it sound feasible to make a steel bushing to press into the inner race then press the blank into the bushing?

then make the point of the centre so that it will press onto the outer race?

bearings are good for around 3000rpm so they can cope quite easily with the task at hand

 

[MattF]

Should work, but I wouldn't bother making one, to be honest. For what a 1MT live centre will cost, just buy one. If you're even a gnat's off in any respect when turning up the bits for one, it'll be useless.

 

[Fazerruss]

Have a look at rdg tools. They do some decent stuff for the price

 

[BrokenBiker]

ive bought a few in the past, i think my mt2 drill chuck came from rdg tools. Just thought i would have a go.

i have clocked the chuck and a bar that i know to be perfectly round and there is only 1thou runout so it should be accurate enough.

my main concern was making a bushing to fit the bearing as ive never put a bushing in a bearing before so wasn't sure if it would affect anything

 

[doubleboost]

Be good practice to make your own
If you mount your morse blank in to the head stock taper (using a suitable morse adapter)
You will be able to make it run true
Old morse drills (from car boot sales) are a good supply of mandrels

 

[BrokenBiker]

the Morse blank is already the same as the headatock from what i can find online but i haven't taken the chuck off yet

 

[gordon stephenson]

Will the bearing you have take both radial and axial thrust?

 

[BrokenBiker]

not sure. I have about 40 bearings, most are all different as they were taken after clearing out a stores in work for demolition. Apart from dimensions the only other thing i know is the smallest of them is rated for 3k rpm

 

[Lawnmowerboy]

Live centers work on a taper roller bearing.

 

[BrokenBiker]

not all of them. We have a few broken ones in work that run on 2 bearings similar to mine and im sure ive seen one with a phosphor bronze Bush in place of a bearing that was used on a large dean smith and grace cnc lathe for turning 14" tube

 

[Lawnmowerboy]

Using just a standard ball race would surely try and just pop the inner out?

 

[BrokenBiker]

that is part of why i want to make one, to find out. If the first fails it will be modified to suit, if that fails i will buy one and admit defeat in light of not wanting to waste any more material proving a bad design.

i have also seen delrin centres for machining soft plastics that need to have soft jaws in the chuck

 

[aametalmaster]

I made a bull nose center a few years ago. I use it for smaller pipes and to line up my tap handle when threading short threads...Bob

 

[Pete.]

Normal ball bearings actually do take quite a bit of thrust, we have a drilling machine at work that just uses a pair of standard deep-groove bearings and all the load is axial. angular contact bearings would be even better.

If I was going to make a live centre I would take the MT1 arbor, put it in the headstock taper, turn the end down to accept two bearings. Then I would turn up the revolving centre in some scrap steel, reverse it in my 4-jaw, dial it in as close as I possibly could, bore it out for a light interference fit on the bearings and press it onto the arbor. Lastly I would mount it in the tailstock nice and secure then cobble up a flat belt/o-ring drive to spin it with an electric drill or something then take a light skim pass with a sharp hss tool to make the taper run true right down to the point.

 

[doubleboost]

I have made 2 using standard ball races (2 bearings back to back)
They have given no problems at all.
I will get a picture later

 

[mfletch]

I made my own and it is a good project made mine out of stainless steel but had to make a taper attachment first for the mini lathe all good fun used 2 bearings and made different sized tips

 

[BrokenBiker]

cheers for all the pics lads. Gives me alot of faith. I think i am going to use two bearings as i have two that match so it makes sense really.

 

[lshigham]

My suggestion would be angular contact bearings, preloaded taper rollers would be ideal but more work

 

[Pete.]

Angular contact bearing pairs would need a pre-load. One angular contact bearing and one standard bearing would be ideal.

 

[aametalmaster]

I made my own and it is a good project made mine out of stainless steel but had to make a taper attachment first for the mini lathe

Nice work. Thats one problem i have as i have to make another project to build the first one i had in mind. Oh well that is why we have machines...Bob