Always been intrigued by ornamental turning, rose engines and holtzappfel lathes so when offered an opportunity to spend a day with Allan Joicey to test out his latest tools .... well it would be rude to refuse wouldn't it? So here is an overview of the first half of the day.
Whats in the box?
The tool in question is the JaHo attachment, this comes from a German company and is the brainchild of a dutch turner called Jan Hovens and it allows a painless entry into the world of ornamental work.
The system is made up of several components, the base unit is a compound slide (or table) which is attached to the bed with a piece of box section steel - these mounts are available in several sizes to suit a range of lathes. The compound table has a rotary index head mounted onto it and a nylon M33 boss is attached to the rotary head to allow a standard woodturning chuck to be attached to the index head.
A cutter head is mounted in the spindle taper of the headstock and is locked in place with a drawbar, two cutters are also supplied with the system to get the user started pretty much straight away. The cutter head is indexable to allow the cutter to be moved in a controlled manner and cutters can be mounted either inline with the lathe bed or at right angles to it - this last point is critical as it allows the user to carry out work on the side of objects such as boxes.
At any rate it is all good quality and well made, it fits and allows you to just get onto turning and using the system quickly.
For those of you already reaching for the credit card you can get one here:
Hopefully some of you are willing to read just a little more before buying yet another new tool....
Using the Jaho
Setting up the system is pretty straightforward, it all bolts together as it should and the parts appear to be well made, you do need to spend a bit of time making sure the centre of the indexing head lines up exactly with the lathe spindle centre. The centre of the work piece needs to align exactly with the lathe centre height or you may get some unexpected results, different mountings are available for a variety of lathes but even then it pays to check and if necessary use shims to get it right.
The workpiece in this case was a piece of Goncalo Alves, you are going to need to use a timber which is going to be able to accept detail easily so this means that you will most likely be working with exotic hardwoods quite a lot.
The workpiece in this case was roughly sized to be a box lid for a box of about 3 inches (75mm) in diameter, it was turned down from square, a spigot added, reversed into the chuck and faced off smoothly to give a good working surface. The chuck was mounted into the JaHo system with the workpiece still attached to it and a narrow pointed cutter was set into the cutter head.
The work was then advanced until it was about to touch the cutter and the sleeve on the index was set to zero, the sleeve on the other axis of the compound table was set to zero with the centre of the work dead on the centre height.
The cutter was then offset using the indexing on the cutter head and the lathe started up, it is critically important to make sure you have the cutter head secured by the drawbar - if you don't the cutter head may leave the lathe with somewhat unpleasant results!
The workpiece is then advanced onto the moving cutter slowly until you think the marking is deep enough, you need to make a note of the depth reading on the relevant index sleeve and then back the work out.
The workpiece is then rotated using the indexing head and the process repeated, I would think that on complex jobs you may need to keep a checklist of some sort as it would be easy to forget or become distracted by something and possibly make a mistake that would end up wrecking something which has taken a while to achieve.
Once the initial pattern was completed around the piece the cutter offset was altered and the workpiece moved in relation to the lathe axis and a new pattern created to intersect with the original.
It is also possible to decorate the sides of work by holding the work either parallel to the lathe axis or at an angle to it and inserting the cutter into the slot in the cutter head which is at 90 degrees to the lathe axis.
The possibilities are pretty much up to you.
The system is well made and easy to use, it is going to suit small to mid sized lathes, sadly not the RU!
The results are good and highly decorative, allowing the user to create an almost inexhaustible array of surface textures and patterns to enhance and decorate the surface of turned work.
If you are keen on boxes in particular then I would think this will keep you occupied for months on end!