Cutting a bullnose.

[trialscot]

Hi,
I'd like to cut a full bullnose profile on 40mm solid wood kitchen worktops. Two of them are joined in a corner and can't readily be turned over.
I'm looking at a Carbitool bull nose radius bit to do top and bottom in one pass. Does the bearing need a guide under the worktop to run along?.
For a half bullnose on the top edge only, does the bearing run along the edge of the worktop?.
I've done a bit of straight routing, mitreing etc..

 

[Harbourwoodwork]

With wooden work top's I normaly butt joint the tops then run round the tops with a rounding over cutter with the base on the top and the bearing on the edge, and finish the internals with a file,I have never done a full bullnose in situ and wouldn't advise doing any fancy moves with the router unless you are really experienced, in theory you could round the bottom edge, with the router base on the face with the bearing running on the underside ,but of course the internal corners will have to be completed by hand.

 

[big-all]

you cant router in situ as walls and cabinets will stop the router cutter from getting to areas
you need around 3" clear to get to all bits off the edge

 

[Deleted member 174758]

I'm looking at a Carbitool bull nose radius bit to do top and bottom in one pass. Does the bearing need a guide under the worktop to run along?.

A bullnose cutter is like these whilst what you appear to be referring to sounds like a top and bottom round-over set which have the bearing in the middle between top and bottom cutters. I have yet to see a true bull nose for a router which can work the full depth of a 40mm thickworktop - and if anyone did make one it would be massive (I have the Wealden 16mm radius one for window boards which can bull nose 32mm thick stock and it is about as big a cutter as you could ever manage freehand - used with a deep auxilliary fence because tacking a guide onto the undersides is just too time consuming). Ideally the edges of a worktop should be radiused before installation. If done afterwards square internal corners always seem to look a bit awkward to my mind and you may have issues at the start and end of cut getting the router in and need a wood file, etc to finish the radius off.

For a half bullnose on the top edge only, does the bearing run along the edge of the worktop?

Yes. BTW those cutters are called ovolo or round-over bits

 

[trialscot]

Many thanks to you all, as usual invaluable advice and food for thought which always helps to turn on the rather dim lightbulb in the head!.

Harbourwoodwork - Good idea about running the router on the face of the worktop to do the bottom corner, it's a half inch dewalt with a baseplate extension/auxiliary fence I'd forgotten about. Will need a bit of care of course.

big-all - as usual I was pretty sparse on detail sorry. Son no. 2 did the measuring, cutting out, radiusing ends and joining of the worktops (nice job) before remembering his mum had asked for edge detailing (she now wants a pencil detail top and bottom!). The worktops aren't fixed down yet so I can slide them all around but am wary of taking them off the units and turning them upside down with the joint and the 2 cut outs.

JobAndKnock - "Ideally the edges of a worktop should be radiused before installation." Yeah, tell me about it!. At least I can do the long one on the other wall in the normal way.
Thanks for info on kit, it's a 6mm cutter job now and maybe the old powerfile on slow speed to do the internal corner, thats the only nuisance one as explained to big-all.
Many thanks to you all again.[/i]

 

[Dave54]

Use a hand file as Harbourwoodwork said. Just a sharp, new (preferably) flat file. With a power tool you'll take off more than you need to in a second, adn you won't get the sharp inside corner you want.

 

[trialscot]

Thanks Dave,
I had a look at the powerfile last night and did suspect it might be too quick for comfort even on slow speed. I have a new 2nd cut which I'll try out this morning on an offcut.

 

[Dave54]

That should be ideal. You don't use files much on wood generally, but for that sort of job it's about the easiest. If it hasn't got a "safe edge", that is one plain side with no teeth, watch out for cutting into the other edge in the corner.