Large cove bit?

[Larry Edgerton]

I have a project that requires a large cove bit for arch top window trim, but with a twist, its made out of Azak. I don't really want to do it with a shaper, I would rather have the material clamped down and use a big router. When Azak catches it is ugly, so I feel safer with a big router. I have the proper cove in a shaper cutter but it is 7 1/2 inches in diameter, I have no bearing setup for it, and frankly the idea of freehanding with a guide bit on that cutter scares the hell out of me.

So.... I did a cursary look about for a big cove and didn't find one. If someone here knows a source please save me some internet/phone time.

Ideally the curve would be a ellipse section 1 1/2" deep and 1 3/4 deep, or aprox. a 1 1/2- 1 3/4 radius,but anything close will be fine. I do not want to go to the expense of having one made custom if at all possible.

Thank you for your support.....:)

[Rob Cunningham]

Would one of these bits be what you are looking for? (upper left corner of the page)
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/cat/Site/0020.html
They are not the highest quality bits on the market, but I've used them and they're pretty good.

[Larry Edgerton]

That is the radius that I am looking for but would not work on arched pieces. That would work if the pieces were straight, but they are arched with wings off of both sides so I need a bottom bearing bit.

I looked a Freud and Ballew Tool catalogs this moring at the shop and the largest radius I have found so far is 1". 1 1/2 is minimum.

Thanks for the effort though, Larry;)

[David DeCristoforo]

Check with a company like Nordic. (nordicsaw.com). They have piloted 1/4 rounds and coves up to 3" radius.

[Josiah Bartlett]

Why don't you fabricate up a curved radius sacrificial fence for your shaper? That should be much safer presuming there isn't a compound curve.
See page 24 (28 in the box) of this PDF for ideas:
http://owwm.com/pubs/1141/1060.pdf

[Larry Edgerton]

Why don't you fabricate up a curved radius sacrificial fence for your shaper? That should be much safer presuming there isn't a compound curve.
See page 24 (28 in the box) of this PDF for ideas:
http://owwm.com/pubs/1141/1060.pdf

Josiah: Can't do that. Most of the windows have a double arch and I want to make them out of one piece.

David: Called them today and they do have one for $372 for the router bit and $521 for the shaper. I'm going to continue looking for a less expensive alternative, but if all else fails...... Thanks!

I have a call into Oella Tool and they are searching for a solution, maybe some custom knives for a Leitz adjustable angle head I have.

Moneys is tight these days and I have to bid lower than I like to get these jobs or I would just buy the bit/cutter, but those days seem to be over. :(