Indexing wheels (also known as an division plates or a indexing plates) get used for a number of operations on the rose engine. As with traditional lathes, indexing wheels are used for cuts which need to be at set angles around the circle : say, every 15°.
A common use for indexing wheels in ornamental turning is for phasing. Phasing is changing the relationship between the rosette and the object being turned. For example, to make a basket weave pattern:
- the ornamental turner cuts a pattern on the object, one complete revolution.
- the ornamental turner then rotates the object some pre-determined direction and number of degrees (say, 15° clockwise)
- the ornamental turner repositions the cutting head a pre-determined distance (say, 0.050" towards the lathe headstock)
- the ornamental turner then cuts the same pattern on the object, one complete revolution.
- Steps 2-4 are repeated until the object is completed.
Indexing wheels like the yellow one shown to the right can be made with 3D printers, or they be purchased. I purchased an aluminium one from Alisam Engineering.
- Phasing Fundamentals by Jon Magill describes phasing in better details. American Association of Woodturners' magazine, "American Woodturner", Fall 2008, pg 62.
- Spiral Fluting an Ornament on a Rose Engine, by Gary Miller. This YouTube video shows a number of things, including the use of an Alisam index wheel (around 2:35 into the video).
Disclaimer: eMail comments to me at OTBookOfKnowledge @ Gmail.com. The process of woodturning involves the use of tools, machinery and materials which could cause injury or be a health hazard unless proper precautions are taken, including the wearing of appropriate protective equipment.