Anybody know of a source for a roundover bit that does the rounding on the top of the material with a bearing that rides on the edge of the underside? I picture it looking like this. It would be used in a router table to machine a banjo neck. On the banjo neck, you can’t round over from the other side because the headstock and heel prevent the back from sitting flat on the table.
Edited 11/30/2008 6:14 pm ET by Quickstep
Replies
Easily done on a shaper but I don't know of a router bit with that configuration.
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Men will never be free until the last king is strangled with the entrails of the last priest.
~ Denis Diderot
Guys that do corian counters use that bit quite often. I don't know what radius you need but I have seen them for sale on ebay and in the eagle america cataloge
I think there is a bit like that in the CMT crown molding set.
Second vote for CMT.. The page in the catalog is available
here
I should have included the radius. I think I would actually need at least a couple of bits ranging from a 5/8" radius to around 1" radius.
As Routerman has stated the bits are not without some inherent danger, of the work being trapped under the bit, especially in the larger radius you are looking for... Whiteside has close to what you are looking for, up to 3/4" radius, under the category of Solid surface, round under bits.. 1" would be quite a beast indeed..
Edited 12/1/2008 10:57 am ET by BOBABEUI
The Eagle America roundunder bits come in 1/4" 1/2" & 3/4" radii.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Tho common in many catalogs (Freud, Amana etc) it is a cutter I would not use.
No escape on this one, the work is trapped under the cutter in your case. Fence out of square, work or fence not straight, then there could be surprises; not for me.
Routers
Eagle has several as "round under" bits. But I don't think the radii available will work for you.
You might have to do it the old fashioned way, and use a spokeshave.
Talk to a luthier (or get a book/browse online, if you havn't already) Seems to me theres a trick out there to do this safely...Jimmy
The professional banjo makers who make the neck by machine use a shaper. I have a hefty router and table, so I was hoping to find a router bit.
Hmmmmm....I think I see an excuse to buy a shaper formulating..........
I also see the safety issues. I think some could be mitigated by using the bearing with a fence behind the bit so the material would never be sandwiched between the bit and the fence. I don't like the idea of the bit being above the work, but that's how they do it on the shaper. I would definetly want to use a guard above the bit to keep hands away. Also, if the bit wasn't red when I bought it, I would paint it.
http://www.eagleamerica.com Thats whats termed as a "Roundunder" bit in the Eagle bit line.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
Hey Quickstep,
I built guitars for several years, so I've had some experience with what your dealing with... If you can't find the bit you're looking for , you should really try cutting it by hand, you'd be surprised how easy it is to do with a rasp...
Plus you can make the curve compound so it flattens out a little when getting closer to the drum... making it easier the fret the strings. You will really get a better product than doing on a machine. Just cut a few profile guides out of cardboard and you'll be good to go.
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