Router cutters - less that 1/4 circle round-over ?

[aesmith]

Hi,

I hope you understand the question, but is anyone aware of a supplier for router round-over bits that cut less than a quarter circle arc?

 

[StevieB]

Try looking at Dremel, Proxxon and similar small hand held mini drills and routers. Probably will not go in a normal 1/4 inch router without a collet adaptor though.

steve.

 

[Argee]

Use a fence to stand the cutter off sufficiently, or raise it to suit.

Ray

 

[Steve Maskery]

I have one which is 1/8". Wealden, IIRC.
S

 

[flounder]

I am sure I must be missing something, but if you want it to cut less than the full 90' arc then you just move the workpiece further away from the cutter on a diagonal line??

 

[Dibs-h]

Use a fence to stand the cutter off sufficiently, or raise it to suit.

Ray

That's what I've done in the past.

 

[Steve Maskery]

Ah, I misunderstood.
I have a cutter that cuts a squashed roundover - quarter-ellipse. I'm pretty sure that came from wealden, too. It's a deep red colour, if that is any help.
S

 

[Tom K]

I think the question was about breaking the arris. You need to look at your cutters and select a section to suit.

 

[9fingers]

Just play with the depth of cut and/or fit a different size bearing to the cutter.

Bob

 

[aesmith]

I think I need to work out how to post a drawing so show what I mean, and example of a profile that couldn't be cut with a normal round-over. (Or maybe I'm wrong and you'll find some blindingly obvious way that I've simply not thought of)

 

[aesmith]

For example ...

 

[Tom K]

You look for a cutter or combination of cutters to suit remembering that it can be presented from different faces. Anything here thats close?

http://www.titman.co.uk/pdfs/2009/P40_49_Panel.pdf

 

[9fingers]

Ok I see what you want but that is not a round over but a modified ogee.

So it is going to need a lucky match to part of a more complex cutter, a custom cutter or two careful passes with a round over and a cove bit.

A custom knife on a spindle would be best if you have any quantity to do.

Bob

 

[L Harding]

so its a round over and a round nose bit of matching diameters all off the same edge against the RT fence

maybe use a straight to get be bulk out first, then the top with the round nose, carefully line up the round over lower and further in

luke

 

[aesmith]

Its tricky to draw it as it is, but on that profile a normal rounding-over cutter would cut into the profile either above or below. If if doesn't look that way then I've not drawn it properly. I think I'll have to try and redraw with quarter-circle cuts superimposed to make it clear.

The funny think is that older joinery typically uses profiles like this, and old hollow/round planes cut only a smaller arc presumably for that reason.

I've come across other examples, but can't remember them at the moment. You know how it is, the tool you have to hand doesn't suit the work so you find another way of doing it.

 

[Steve Maskery]

Bob's right, that is called an ogee ("O.G."). There are lots in the catalogues.
http://www.axminster.co.uk/category-Ogee-and-Classic-Moulding-Cutters-207682.htm
S

 

[aesmith]

I'll have to see if I can show it graphically. There are plenty of situations where if you want to round over say 60 degrees, then a 90 degree round over bit will cut into the work elsewhere.

On the other hand if the requirement isn't readily recognised then maybe that's why the cutters aren't made.

 

[L Harding]

so this... for example wouldnt give the profile your after? looks like it should from your drawing

http://www.axminster.co.uk/product-Axca ... 809900.htm

 

[aesmith]

Maybe this makes it clearer. On the left you can see that a standard round-over cutter can't make the lower convex curve without cutting where it shouldn't.

The right hand shows what you'd have to change to. Superficially it looks like that is the shape that purpose-made ogee cutters will give as well. Am I the only one who thinks the two are different?

I suppose I started off asking whether anyone knew of a source for cutters that make a shorter arc, but I seem to have side tracked into an argument as to whether or not I need them.

 

[9fingers]

I reckon you can do this with two passes and standard cutters.
First run a cove bit to cut the concave section. Then fit a equal radius roundover bit and either tip the router axis or tilt the workpiece to avoid cutting away the part of the profile made by the previous cut.

Any good?

Bob