edges: what round over bit?

[The Captain]

Hi, anyone know what spec/ size router bit for for std round edges for fender cabs? Ive measured a similar round edge (on my kitchen top) which seems to be a 20mm curve.. but how this equates to the bit in Q is beyond me. Spent hours trying to find this info now!

These go in mm's in UK btw, if any eu folk can help.

thanks, Capt

[tubeswell]

I use 13mm radius on the outside edges and 8mm radius on the cutaway and cutout holes.

[The Captain]

Thanks alot- I've been searching for a 12.5/ 13mm radius.. I cant find any at all. btw Ive seen the round bearing guide thingy that sits on the end, some of varying sizes. (which adds to the frustration): what am I after re these? I can't even see its diameter specs on some, or know what size Im after for a smooth curve, or to what relaton to a 12.5/13mm radius type.. blimey this simple task is proving nigh on impossible!

[tubeswell]

FWIW the Evacut ones I use have the guide-bearing on the end. As far as I am aware the bearing is sized to enable the correct radius to be cut as the bit moves along the edge you are routing.

This link should take you to the catalouge:

http://www.pandn.co.nz/pdfs/Evacut.pdf

The router bits start on page 29

[pila]

The inch spec has been 1/2 inch, like about the 12.5mm you mention. I built a few cabs with 3/8 round-over cutter before using the 1/2 inch type, and it's hard to tell the difference visually.

[defaced]

The bearing size is the difference between a round over bit and a beading bit: http://eagleamerica.com/product.asp?...cd2=1224553220
If you buy a round over bit, the bearing will be sized properly, so it's specific size is not of particular importance.

These are what you're looking for:
http://www.tooled-up.com/Product.asp?PID=29427

http://www.tooled-up.com/Product.asp?PID=133616 (for 9 pounds, I'd forgive the fact that it's 14mm (9/16"))

All I did to find these was go to Google UK and search for "round over bit".

The other think you need to pay attention to is the shank diameter. If the shank diameter is not correct, you'll end up with a bit that won't work with your router.

[The Captain]

thanks alot for that defaced- only just seen your reply. I must need a bearing, logic says, whose width is dead flush to the start of the bit curve.. or Im gonna always have either a groove if bearing wheel to small, or a non-smooth curve if bearing too wide.

Ive established it has to be a 1/2" or 13 ish mm radius bit for edges.. the 10mm one Ive got now is wrong/ too small- the edges are too sharp Imo.

"rounding bit" is another term: this yielded lots of ebay ones wheras "roundover bit" yielded barely any (its taken me weeks to get this piece of info!!).

[krusty]

The bit will come with the appropriate bearing attached. The only thing you need to be concerned about is the depth you set it at. Rout some scrap to test. Too high relative to the router's base and you dig a deep groove, too low and you leave an unrouted corner along one side.

In determining what radius you will need, have you looked at the hardware for your corners to see what radius they require? Some are 1/2" (12 or 13mm), like a lot of metal ones. Others. like the stackable plastic variety, can require 5/16" radius corners.

My Fender Acoustasonic Ultralight cab is a 5/16" radius on all edges.

[WMThompson]

Edge Radius Sizes

I've found that on narrow panel amps that the radius is closer to 3/4"
and 1/2" for blackface.
a little more than 3/4" on some, probably from extra sanding on the big disc
sander at the Fender factory.