What radius arris?

[el_Pedr0]

I'm going to invest in a router bit to trim my arrises: Arris Rounding

What radius should I go for?

Context: This will typically be for 18mm sheet material (birch ply, mdf, edge-banded veneered mdf) used in projects such as cabinet making, typically with a contemporary/minamalist/slab style.

 

[recipio]

1.5 mm is plenty. You don't want to expose the layers of ply.

 

[el_Pedr0]

They do a 1mm too, so I could go smaller if smaller is better?

In the past I've always taken the arrises off by hand and judged by eye, so don't actually know what a 1mm or 1.5mm radius would look or feel like nor whether there'd be much discernible difference.

 

[ajs]

Do you even need a bit? A true Arris isn't rounded at all. Obviously you need something at the corner to prevent breakout, when I've needed similar in the past I've used an ROS across the corner for a tiny bevel.

Perhaps a balsa plane?

 

[el_Pedr0]

I tend to find that the super sharp corner along the edge can give the piece a bit of an aggressive/hard look and feel - but maybe that's a subjective thing. But on a more practical note, if it's going to be painted, I find a slight round can be a bit more tolerant to use before the paint chips.

Definitely don't 'need' a bit, because I'm just a hobbyist. But have got a couple of bigish projects coming up which will involve quite a lot of sheet materials.

I'm thinking that passing a palm router along the edge will probably gain me some time and uniformity, vs what I've previously done with sandpaper and cork block. Bit worried that with an orbital sander I could whip off a bit too much too quickly, or create more of a chamfer than a round.

Edit: Hmm - maybe a 1mm chamfer would actualy fit the contemporary vibe while still doing something to help the piece be a bit more tactile.

 

[Against_The_Grain]

I tend to just use a 3mm radii, as that’s what’s required for most paint companies to honour their warranty should there be an issue with the paint, which isn’t really worth the paper it’s written on anyway.

I don’t see a point going any less than 2mm, it begins to be a wasted effort as you could do it quicker with a quick swipe with some sandpaper, which you usually need to do after routing anyway.

 

[D_W]

I'd break the edges with sandpaper or a plane. You can do it visibly even with little experience and very safely as far as chipout or errant cuts go.

That'll be enough to deal with the surface tension issue at corners with clear finishes and paints (the issue of them not wanting to build on corners above and beyond the crisp corners being a magnet for chipping and denting.

if you're not much of a hand tool user, a hard rubber block and sandpaper used evenly works well.

 

[Jacob]

You get a nice regular radius with sandpaper. Hold each end of a sheet and pull it too and fro over the arris like you'd dry your back with a towel. Likely to be much more error free and faster than fiddling with a horrid little router.

 

[el_Pedr0]

Thanks all - I'll stick with the sand paper then, but ditch the cork block. That's kept 20 quid in my pocket!

 

[Phil Pascoe]

If you work it out a 3mm radius cutter actually takes off less than two thirds of a millimetre - easily done with abrasives.

 

[Doug71]

I like the ease and consistency of an arris bit in the router, can't remember if mine is 2 or 2.5mm but it makes a tidy job

 

[stuart little]

I'm going to invest in a router bit to trim my arrises: Arris Rounding

What radius should I go for?

Context: This will typically be for 18mm sheet material (birch ply, mdf, edge-banded veneered mdf) used in projects such as cabinet making, typically with a contemporary/minamalist/slab style.

There's nothing like a nicely rounded 'arris'!

 

[Keith 66]

As most of my work is on boats an arris in the usual sense isnt used. Sharp edges anywhere on a boat are a disaster as they will get knocked & paint or varnish chips. Plus when you land on things or bump into them a nice radiused corner doesnt hurt as much!
I usually use an 8mm minimum radius, 10mm if its a big section.

 

[Ollie78]

I thought an arris was a chamfer ( a pass or 2 with a block plane) rather than a rounding over.

Anyway I have a bit from Axminster called the edge breaker bit. It's fundamentally a round over but the straight part is eased a bit.
It works great, I have the 2mm I think, but they do 4 sizes.

Ollie

 

[recipio]

They do a 1mm too, so I could go smaller if smaller is better?

In the past I've always taken the arrises off by hand and judged by eye, so don't actually know what a 1mm or 1.5mm radius would look or feel like nor whether there'd be much discernible difference.

You could certainly. I found 1 mm a bit sharp and prefer the 1.5. Routing is the most consistent method - it's amazing how the eye picks up these small details.