Thread: copying and ball jigs cutting without tearing

I had a similar contraption many years ago and it was a total failure - it took more time to cleanup the torn fibres than it would take to turn the piece with appropriate gougesl The unit I had used metal cutting tips which were ineffective when turning wood, although I recall that a piece of jarrah wasn't too bad. The other problem was that the only cutting method is essentially a plunge cut at 90 deg to the axis of the piece being turned.

I had a couple of 'lessons' from a more experienced turner who showed me how to correctly markout the piece and to set the key diameters - tops of beads, bottoms of coves, etc and how to blend these together to form the beads, coves etc.

I can now make a reasonable good copy much quicker and with a better finish than I would ever have achieved with the 'copy' tool.

Bob

wood copying lathe

Found this idea at the thread above

"A slow-turning router lathe (with high-speed router) could reduce the finishing problem and eliminate the need for a steady, but with additional engineering needed for template following."

This is not going to be the advice you want to hear, but after looking at copy lathes and other attachments it really did come down to learning the skills.

It doesn't take long to be decent. One doesn't even need to be great or even good, just patient. Practice beads and coves, beads and coves..... Beads and coves.

This guy has a Facebook page where he posts excellent videos of how he turns: http://thewoodturners.com he doesn't want people to use them as instructionals, but they are some of the best videos I've ever seen on skew turning by a real life production turner.

When I first started I wanted to do eggs and spheres too. They seemed daunting and needing of jigs, machinery and attachments - but you need exactly none of them. Once you practice a few you can really pump them out.

Ill post some pictures and links on how it's done.

We were given one of these at the mens shed and we asked our most competent turner (who also said he had used one before) to refurbish it but I have to say I was less than impressed with the results. Eventually we gave it away to a member who reckoned they could make use of it.

Thanks for replies.

Lets change the question

Has anybody anywhere used these copying things or a ball turner and also achieved a good finish on any sort of timber ?

Bill

Originally Posted by steamingbill

Thanks for replies.

Lets change the question

Has anybody anywhere used these copying things or a ball turner and also achieved a good finish on any sort of timber ?

Bill

Bill, I have my own shop made ball turner and I use a bowl gouge in it, almost turned on its side and it gives a very good finish.
Rgds,
Crocy.

Originally Posted by Old Croc

Bill, I have my own shop made ball turner and I use a bowl gouge in it, almost turned on its side and it gives a very good finish.
Rgds,
Crocy.

............ Clever ....... Thankyou ............. Was beginning to think these ball turners were a big con.

Bill

Yes, I have used the Vermec ball turner, and highly recommend it.
My mate does demos of it and the finish is excellent. I reckon simple to use too, especially after a little bit of trial and error
Cheers
Willy

Originally Posted by Willy Nelson

Yes, I have used the Vermec ball turner, and highly recommend it.
My mate does demos of it and the finish is excellent. I reckon simple to use too, especially after a little bit of trial and error
Cheers
Willy

I also have the Vermec Sphere Jig and likewise I would recommend it over others BUT like all tools it has a learning curve and requires some experimentation to achieve optimum results. The cutter does a great job on most timbers and will give good results if you play with the presentation angles. I also hand turn spheres and eggs. The jig is great if you want to do a production run of spheres without having to cope with the concentration levels required for skew or detail gouge turning.

To avoid torn grain you need sharp tools and often TC inserts just aren't sharp enough, even when new. I would prefer a HSS tool in this situation. Also, fast spindle speed and working with the grain will help considerably. With a sphere jig you need to work from the equator to the pole to cut with the grain. The last facor to consider is choice of timber. The sphere jigs and copy attachments rely on the tool scraping rather than cutting so a hard, fine grade timber will help.

Originally Posted by brendan stemp

To avoid torn grain you need sharp tools and often TC inserts just aren't sharp enough, even when new. I would prefer a HSS tool in this situation. Also, fast spindle speed and working with the grain will help considerably. With a sphere jig you need to work from the equator to the pole to cut with the grain. The last facor to consider is choice of timber. The sphere jigs and copy attachments rely on the tool scraping rather than cutting so a hard, fine grade timber will help.

I agree although there now some very fine grade tungsten available. But at the end of the day your HSS is capable of a finer edge. In fact I have a 10mm bowl gouge made from Silver Steel which is high carbon steel. Its kept for the really difficult tear out problems. Its edge is finer than HSS.

You really need to go from high point to low point.
All newel posts I turn with balls are free hand with skew chisel.
The only good finish I have seen is from centruo copy lathes with plunge cutters!

I have never used a copy lathe but do have a ball turning jig. Mine is home made but basically a Vermec look alike.

I have seen many a turner use jigs and indeed TCT just turning by just plunging them in. This is fine for roughing out stuff but you tear the crap out of the grain in the process. If you want a good finish fine cuts are essential but I also turn the TCT at 45 degrees as a shear cut too. The TCT cutter does need to be sharp as Brendan suggests and grain orientation is also critical regarding the cutting direction.

Originally Posted by dai sensei

If you want a good finish fine cuts are essential but I also turn the TCT at 45 degrees as a shear cut too. The TCT cutter does need to be sharp as Brendan suggests and grain orientation is also critical regarding the cutting direction.

I find it is more important to regulate the depth of cuts than it is to "turn the TCT at 45 degrees as a shear cut." Turning the TCT is fine in one direction but is less helpful in the other as it is actually burnishing the cut.

If you rotate the Vermec TCT say 45 degrees to the right (facing tailstock) then that works very well for cuts from the equator of the sphere to the pole at the tailstock end. However when you make the cut from equator to headstock the back of the cutter makes first contact with the wood to be cut. It is almost like cutting the grain uphill. I have found it to be more efficient and less resistance in the cut to use a 15 or 20 degree inclination (thereabouts) to the cutter. I discovered this while turning spheres from very old 100mm SQ Hoop Pine posts. When the TCT was rotated 45 degrees the cut to the headstock was always more burnished than the other hemisphere.