If you regularly make fine turned finials or similar, then this is a useful addition to your toolkit, says Kevin Hanley
The Planet Finial Mandrel Kit in use
The finial mandrel kit is available in M1 and M2 versions and is available with a revolving centre (PHOTOGRAPHS BY KEVIN HANLEY)
Planet has long been known as manufacturers of specialised tools and equipment, including a comprehensive range of drive and rotating centres. New to their range is the finial mandrel kit which, while not suited to everyone, has the potential to be an invaluable aid in the production of fine finials, lace bobbins, thin goblet stems and other delicate work.
The finial mandrel is a Morse taper mounted - MT1 and MT2 available with revolving centre - with a difference. Instead of a point or ring centre, it has a 12mm diameter machined recess into which a hollow insert fits. Three inserts - made of an easily machinable nylon based compound - are supplied, pre-drilled to about 3, 4.5 and 6mm, but could, of course, be adjusted to suit your own specific needs, subject to maintaining the integrity of the insert.
The mandrel is machined out of top quality tool steel and incorporates free running twin race bearings. The inserts fit snugly and may need a knocking out bar through the hollow centre to remove them so, for added security, the bearing race is located with a circlip. The quality of the engineering is excellent.
Having mounted a piece of small square - ish - stock, I quickly realised that another live centre is needed to support the work, while rounding down. A pointed centre that fits into the mandrel's recess would eliminate this and, given that it would only ever be light/medium use, the absence of a thrust bearing should not be a problem and the same nylon type material should suffice. With the blank prepared, the top 10mm or so of the finial can be finished to completion and while part of this needs to be done without tailstock support, the bulk of the remaining blank provides sufficient rigidity for this purpose. Thereafter, the top of the finial is located in or against one of the mandrel's bushes and the additional support is immediately evident and confidence inspiring. The finial turns true with no flex and no risk of chatter, which means that much finer finials can be produced in safety. The additional support also means that no 'wobble' is induced when parting off.
If you regularly make fine turned finials - or anything similar - then this is a useful addition to your toolkit. It is designed for a specific task and it does that well. It also has the potential to form the basis of a multifunctional rotating centre system; additional inserts would be useful, but with a bit of ingenuity workshop turned alternatives such as ring/cup centres and point centres can be made.