Ball turning tool

[robwilk]

I am looking at buying a ball turning tool i have this Chester lathe with a 8mm quick change tool post.
http://www.chesteruk.net/store/conquest_lathe.htm

I have seen this one on eBay do you think it would do.?
http://cgi.ebay.co.uk/MODEL-ENGINEE...Home_Garden_PowerTools_SM&hash=item43a2267ce2
Does any body have one like it .?

I would love to get your comments.
Thank you
Rob.......

 

[GWRdriver]

Rob,
This ball turning tool appears to be based upon one designed and written up in ME some years ago by J.A.Radford (picture below), using a dovetail slide head on a rotating shaft, where the tool tip traverses the cut through the vertical plane. Some years ago I built one of these for myself based upon this same approach. I have turned a number of small radii on mine, and with enough care and fiddling it can do a very good job, however it does need care and fiddling and IMHO it should be limited to small radii. One problem with this design is overhang, the distance between the shaft bearing and the tool tip, which if too great will result in a lack of sufficient rigidity, ie, flexing of the tool, making nice clean cuts more difficult to achieve. The one you are considering appears to have more overhang than the Radford design and in either case the use of a tool bit held by a small pylon thing, or only itself, also adds to the potential for flexure. I made my BTT as rigid as I could but I still must rough all my radii and use it as a final finishing tool only. It balks at taking off more than a few thou' per pass but if the tool is set correctly and used with its limits it will produce a perfect radius and a beautiful finish. I can't tell the relative size of this BTT but with this design the maximum ball diameter is also somewhat limited as the further out the tool is moved the more moment (and therefore flexure) there will be in the tool so that eventually, although a diameter is with the physical limits of the tool, the rigidity has dropped off to the point where a good finish can't be produced.
I hope this is of some use.

 

[John Rudd]

Rob,

The guy selling the bt lives not far form me, not that I know him, but he sells quite a lot on Ebay..

As a good milling/turning excercise I made my own based on the design by Steve Bedair.. Just scale the design down a bit to fit the smaller machine..

If you dont have a mill, then milling can be done in your lathe with a vertical slide...

Cheaper than buying one...

 

[Blogwitch]

Rob,

That is an over the top ball turner, whereas most you see being used by the lads are side to side ones.

I cobbled my over the top one out of my mill boring head many years ago.

As already mentioned, I honestly don't think that this type (and even mine) is as rigid as the side to side ones, and so can't remove stock as well as the side to side units, which work on the same basic principles as normal turning.

The main advantage of the one you have shown is that it can be held in your normal toolpost, whereas the side to side ones are usually bolted to the saddle in some way. Plus the tool grinding is dead easy and should be able to be done by anyone.

I get great surface finishes with mine, but as I said, it can't get rid of a lot of metal in one go. But no worries on that score if you have a no rush attitude.


Bogs

 

[Lew Hartswick]

If you want to make balls on the end of a rod try these:


Ball turning, examples of.

I hope these saved IMG links work. (yep the link can be saved to a txt file and used)
...lew...

 

[robwilk]

Thanks for your advice i think i might keep looking on the net for alternatives. But i have a need for one soon to put a round on the end of a brass rod to fit inside a test tube for a Stirling engine i am trying to build .
So if i don't find one soon i might give this one a go until something else turns up.

As for building my own or making severe alterations to the tool i feel i am not to that standard yet and would find it difficult as well as time consuming with out a mill.

Thanks again

Rob.......

 

[cfellows]

If you want to make balls on the end of a rod try these:


Ball turning, examples of.

I hope these saved IMG links work. (yep the link can be saved to a txt file and used)
...lew...

Lew, what kind of tool did you use to turn these balls?

Thx...
Chuck

 

[Lew Hartswick]

Lew, what kind of tool did you use to turn these balls?

Thx...
Chuck

I actually built the whole tool but it is a "Horizontal" type with a rather "special
invention" type cutter holder. I think I've posted the pictures of the whole
device in the past somewhere. It wasn't difficult to build and anyone here with
a decent mill could duplicate it. It was made to fit a Clausing/Metosa lathe, I
think about 13" swing. I'll see where the pictures are and if anyone wants more
info I'll try to help.
...Lew...
edited: Here is a link to the entire tool set of pictures.
http://home.earthlink.net/~lhartswick/Ball - Radius turner/BallRadiusturner/index.html