Bubostyl Reverse Bowl Chuck
Reviewed by Neil Turner
On a recent visit to France to teach at the Escoulen School in Aiguines, one of my students was selling a reverse bowl chuck, the likes of which I had never seen. The chuck is based on the Longworth system and made of acrylic. What really attracted me was the quality (it is all laser cut providing superb accuracy) and the flexibility (any thread size can be fitted to the chuck to suit most lathes).
Two size options are available and shown above; an outside diameter of 295mm (with a 105–246mm holding capacity), or an outside diameter of 400mm (with a holding capacity of 165mm to 345mm). Seeing the benefits I ended up buying both.
The maximum speed of rotation when using the chucks is 1000rpm, however it is recommended to start slow and then increase to the desired speed (somewhere between 600 to 800rpm). The rubber holding buttons are round, so the chance of catching yourself during the turning and sanding process is minimal, however you still need to be mindful of the potential risks they pose.
When the chucks arrived I was keen to see how they performed. With two 270mm diameter plates and a maple bowl 280mm diameter and 120mm deep to finish, I had the perfect opportunity to investigate how the chuck operated when working at different distances from the faceplate and whether the black stoppers would mark light coloured wood.
Set-up entails undoing the holding nuts on the back of the disc – I found these easy to hang on to and turn. This allows the two discs to move independently and freely without restriction. Using the tailstock to hold the plate in position I rotated the two
discs in opposite directions (using the holes on the outside of the disc). This gave enough gripping friction to hold the plate in position when all the nuts were tightened on the back of the disc.
To get some more pressure on the rubber buttons I locked the headstock and only had to rotate the outside disc to tighten the buttons onto the plate. This was easier as it freed up one hand to tighten up the locking nuts. The holding bolts are recessed into the rubber buttons and have an Allen key recess for extra tightening if required.
I was able to remove the waste where the tailstock centre had been cutting with the grain and then sand to finish without any problems.
Moving on to the deep maple bowl, I kept the tailstock in place for as long as possible until I finished turning the
base of the bowl. My preference is to do as much turning and sanding with the tailstock in position. Then with the tailstock removed, I turned away the remaining timber (cutting with the grain). Working 120mm from the face of the chuck I expected some problems, however with the bowl rotating slowly the remaining timber was removed easily with light cuts.
Overall I was very impressed with the chucks and the results achieved. The discs rotated accurately and the holding buttons ran true. It was able to hold the plates and bowl securely even when working a long way from the chuck’s faceplate, and there were no visible marks from the buttons. I highly recommend this product as a great addition to a turning workshop.
Available from www.bubostyl.fr
Neil Turner is a wood artist who lives in West Australia. See www. neilturnerartisan.com.au