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11 Posts
I have read posts on the forum about rounding the (outer) edge of a disk. All good advice, so far. Concerns I have arise due to need to round over all edges of a square section ring to create a hoop; cfi curtain ring. My project, however, is not that simple: 1) it is not about making curtain rings per se. 2) there are 10 rings to make - all of different diameters; starting from about 0.75” bore to about 2.875” bore. 3) to create a circular section the internal bore edges, by definition, will need to be rounded as well. 4) earlier attempts to create these hoops on a wood turning lathe failed due to the hand held tools lacking the ability to reproduce - consistently - the order of accuracy demanded by this project; specifically and crucially in respect of the internal diameters and profile: these need to be accurate both in terms of internal diameter and radius. Perversely, the external profile only needs to “look” right!!
On the plus side, all the rings/hoops have the same circular section, which will be, of course, exactly two times the magnitude of the radius needed to turn the (already prepared) square section into a circular section. But this again poses it’s own issues: using a roundover cutter with a bearing results in there being no face to run the bearing against when the hoop is flipped over: making a “dummy” ring would be time consuming and waste material as the “dummy” disks would not profit any other projects or applications once discarded.
Using a ‘notched’ piece of (say) 3/4” ply to create a “nest” for the hoops whilst rounding the inter edges is a very good idea; it will need to be advanced/repositioned to cater for the different hoop diameters so a stop mounted on the router fence might suffice? But alignment and increment magnitude will need to be carefully managed. My solution would be to use the bearing as the initial setting stop - for each hoop - making sure the hoop is nested snugly in the notched plate. The notched plate, which should be in contact with, as well as guided and controlled by, the router fence at all times, must then be clamped firmly to prevent cutting forces displacing the hoop.
Biggest problem is, feeding the cutter: my router table is not in the least ‘user friendly’ and accessing the spindle adjustment and stops, underneath the table, is extremely difficult; with help I think adjustments could, in the event, be achieved. However, plunging a cutter (as in this case) into the workpiece could result in snatching. I don’t know how best to prevent or otherwise avoid this: the material is mahogany (of unknown pedigree) and could readily chip if not treated with respect. Flipping the hoop over also requires care as the router spindle will need to be reset to allow gradual advance of the roundover bit for this cut.
As there is not a great deal of purchase (grip) possible on the smaller hoops, preventing these from rotating, due to the cutter rotation, could prove very difficult so a positive means of safely preventing this - but at the same time allowing the workpiece to be rotated through the cutter - really is a must: I am, at this point, fresh out of ideas. A simple, manageable way of doing this safely and effectively would be a boon………..if anyone can help?
On the plus side, all the rings/hoops have the same circular section, which will be, of course, exactly two times the magnitude of the radius needed to turn the (already prepared) square section into a circular section. But this again poses it’s own issues: using a roundover cutter with a bearing results in there being no face to run the bearing against when the hoop is flipped over: making a “dummy” ring would be time consuming and waste material as the “dummy” disks would not profit any other projects or applications once discarded.
Using a ‘notched’ piece of (say) 3/4” ply to create a “nest” for the hoops whilst rounding the inter edges is a very good idea; it will need to be advanced/repositioned to cater for the different hoop diameters so a stop mounted on the router fence might suffice? But alignment and increment magnitude will need to be carefully managed. My solution would be to use the bearing as the initial setting stop - for each hoop - making sure the hoop is nested snugly in the notched plate. The notched plate, which should be in contact with, as well as guided and controlled by, the router fence at all times, must then be clamped firmly to prevent cutting forces displacing the hoop.
Biggest problem is, feeding the cutter: my router table is not in the least ‘user friendly’ and accessing the spindle adjustment and stops, underneath the table, is extremely difficult; with help I think adjustments could, in the event, be achieved. However, plunging a cutter (as in this case) into the workpiece could result in snatching. I don’t know how best to prevent or otherwise avoid this: the material is mahogany (of unknown pedigree) and could readily chip if not treated with respect. Flipping the hoop over also requires care as the router spindle will need to be reset to allow gradual advance of the roundover bit for this cut.
As there is not a great deal of purchase (grip) possible on the smaller hoops, preventing these from rotating, due to the cutter rotation, could prove very difficult so a positive means of safely preventing this - but at the same time allowing the workpiece to be rotated through the cutter - really is a must: I am, at this point, fresh out of ideas. A simple, manageable way of doing this safely and effectively would be a boon………..if anyone can help?