# 22mm Bullnose Window Board



## Sheepdisease (Sep 12, 2013)

Hello there, I have a project which requires me to round the edge of a window board other than the already pre-rounded face. The flat side which needs to be rounded must match the pre-existing rounded face.

Can anyone please tell me which router bit I need for this? The depth of the rounded edge appears to be approx. 7mm.


----------



## Gaffboat (Mar 11, 2012)

It sounds like a simple round over bit would work but I am not sure what you are asking from your description. Can you tell us more about what you mean by the rounded edge being 7mm?


----------



## Cherryville Chuck (Sep 28, 2010)

7mm is very close to 1/4". However, like Oliver I would like a bit more information and possibly a sketch. Quite often fits like you are suggesting can be achieved most easily with sandpaper, cabinet scrapers, planes, and or sharp chisels.


----------



## Sheepdisease (Sep 12, 2013)

Thank you for your replies.

The 7mm depth refers to the distance from the edge (tip) of the rounded end to the point at which the wood becomes flat. I have created an image to give you a rough idea.










I don't have the time or tools to do this manually, and I know the results I would get would not be good enough, I'm hoping there is a router bit I can use for this.


----------



## Sheepdisease (Sep 12, 2013)

Hello?


----------



## DaninVan (Jan 1, 2012)

Hey, Shaun; Lots of questions (from me  ).
-How much, in feet/meters do you need?
-Is the flat stock already primed or painted?
-Can you make a drawn profile from the end of an existing piece (as a template/sample)?
-Do you have a bit supplier reasonably close by, to take your scrap piece or template to, for matching?

For myself, I'd do that last item first and if that didn't work out I'd get a HSS or Carbide bit custom ground to an exact fit.
Chances are excellent that if it's a piece from the '60s or earlier, that it was done on a shaper not with a router...ie an exact match isn't gonna happen! 
I'm with Charles on the 'let sandpaper be your friend' thing. You really only need to blend the actual miters, not the whole length, if it's really a close match.
_
*Nice illustration by the way!_


----------



## Herb Stoops (Aug 28, 2012)

What kind of router do you have and what is the bit shank size it will take?

Herb


----------



## Cherryville Chuck (Sep 28, 2010)

Along the lines of what I previously said and what Dan said, normally it only has to look perfect, it doesn't actually have to be perfect. There can be a huge gap in time, work, and tooling between those two concepts.


----------



## Sheepdisease (Sep 12, 2013)

Thank you all for your replies. I have a 1/4 inch freehand router and a 1/2 inch table mounted router.

The total size is less than 1 metre. 

26.5cm deep x 10cm wide x 21mm thickness

It needs to be rounded on two sides like in this image (red represents rounding)










The rounding needs to be done in the same way a window board is rounded.

I don't think there is a bit supplier close to me and I cannot take a profile from the existing as it is from the top of a step profile. I expect that it was made in 1958, so you are spot on!


----------



## Cherryville Chuck (Sep 28, 2010)

Shaun I can't make your link work either. You'll have to down load it to your computer first and then if you use the Advanced Reply it will have a button you can click on labelled Manage Attachments below the text box. Click on it then find the (image?) file you need and upload it into that reply. If you need more help with that let me know.


----------



## Sheepdisease (Sep 12, 2013)

Image link corrected



Sheepdisease said:


> Thank you all for your replies. I have a 1/4 inch freehand router and a 1/2 inch table mounted router.
> 
> The total size is less than 1 metre.
> 
> ...


----------



## DaninVan (Jan 1, 2012)

No mitred corner, Shaun? Can you post a picture (I'm a little confused now...) ?

Just confirming, a 1/4" radius corner? A 1/4" rad. roundover bit and sandpaper; done and done.


----------



## Sheepdisease (Sep 12, 2013)

Hello Danin, thanks for your reply. I am not sure what you mean in your first sentence. It's just a rectangular piece of wood that needs to be bullnosed on two edges.

I think I am going to have to go with your suggestion and route it and then sandpaper, time is ticking and this job needs to be finished. Can you please recommend a suitable bit from amazon or ebay or somewhere else which will do the job as you have described?


----------



## DaninVan (Jan 1, 2012)

Shaun; 1/4" roundover bits are a standard over here...metric isn't quite as straightforward. _Likely you have an edge that was done pre-metric era?_ 
Therein lies your problem, I think; that may be why you can't get a really good match(?)...
Can you find a CMT distributor over there?
CMT Router Bits, Router Cutters, Router Cutters, Saw Blades & Tooling on Westcountry Machinery 4 Wood

Contractor router bits-Roundover and beading router bits-CMT tools


----------



## DaninVan (Jan 1, 2012)

*Light goes on!*
Wait...what? This is a stair tread that can't be removed?! How are you going to get a router in there?
If the tread is off, then just _re-rout the existing edge_ to match the new edge...7mm(?)


----------



## Sheepdisease (Sep 12, 2013)

Thanks for the link. There is a stockist near me so I have sent them a message.

Basically I am making a new piece from a fresh piece of timber and cannot remove the treads to get a profile from it but did use callipers to take accurate dimensions.

I have not removed any of the existing treads and am creating a new piece which is required to compliment the existing due to some modifications. Hard to explain but basically it does need to match.


----------



## DaninVan (Jan 1, 2012)

Hey, Shaun; (I'm in 'work avoidance' mode...) There isn't really an exact equivalent that's readily available, at least not over here. I'd personally go with the 3/8" roundover if I had to pick an Imperial size, or a 1/4" and sand it rounder. Are your collets Imperial sizes or metric...I realize you called them 1/4" and 1/2" but I wasn't really sure if you meant that literally.


----------



## Sheepdisease (Sep 12, 2013)

Thanks for your reply. The shank is 1/4 on the portable router and 1/2 on table mounted. The other sizes I mentioned are in mm.

So actually it should be a 3/8 roundover?


----------



## DaninVan (Jan 1, 2012)

Well 8/32" reduces to 1/4" and 12/32" is 3/8" when reduced ...
7mm is apparently 1/32 larger than a 1/4" (7mm=9/32")
As I said I'd go for the 3/8" roundover because it's a stronger more durable tread edge. If anybody ever runs a hand truck or equivalent up and down those stairs, it's a consideration.
I use 1/8" or 1/4" roundovers on shelves for the same reason; less likely to get damaged from heavy objects hitting the top edge, especially in the shop.

I just happen to be sitting beside one of my bookcases so I took a picture; it's a 1/4" radius.


----------



## DaninVan (Jan 1, 2012)

For the Imperially challenged, here's what 1/4" and 3/8" radii look like...that's 1/4' squared graph paper in the background


----------



## DaninVan (Jan 1, 2012)

Amazingly enough, those squares are only a tich larger than 1/4" on my monitor screen. How'd they do that??? 
I should have added that 7MM radius is somewhere between those two Imp. radii.


----------



## Job and Knock (Dec 18, 2016)

From a British carpenter (i.e. me):

The cutter often used for this is a round-over bit with a bottom bearing, or an ovolo bit with a zero quirk bearing. Examples of these can be found on the Wealden Tools website (not associated with the firm, but 95% of items delivered next day and good quality - been a customer for best part of 2 decades now).

Afgaik here never was a 7mm radius available inthe UK as a standard, but I'd hazard a guess thet the actual radius is really 1/4in (6.35mm) and that it has been possibly been built-up with layers of finish over the last 60 years. TBH that's a bit on the small side and most wiindow boards I make are 5/16in (8mm), 3/8in (9.5mm) or even (on thicker stock) 1/2in (12.7mm) radius


----------



## DaninVan (Jan 1, 2012)

Hey, Eric; good info!
Always helpful to other Brits, I'm guessing, when you knowledgeable guys fill in the blanks. Eg. tool sources over there with recommendations.


----------



## Job and Knock (Dec 18, 2016)

Thanks, Dan. Much appreciated


----------



## Sheepdisease (Sep 12, 2013)

Job and Knock said:


> From a British carpenter (i.e. me):
> 
> The cutter often used for this is a round-over bit with a bottom bearing, or an ovolo bit with a zero quirk bearing. Examples of these can be found on the Wealden Tools website (not associated with the firm, but 95% of items delivered next day and good quality - been a customer for best part of 2 decades now).
> 
> Afgaik here never was a 7mm radius available inthe UK as a standard, but I'd hazard a guess thet the actual radius is really 1/4in (6.35mm) and that it has been possibly been built-up with layers of finish over the last 60 years. TBH that's a bit on the small side and most wiindow boards I make are 5/16in (8mm), 3/8in (9.5mm) or even (on thicker stock) 1/2in (12.7mm) radius


This seems to be the right answer. So which one of the bits from that website would you go for given the dimensions you have mentioned?


----------



## Job and Knock (Dec 18, 2016)

If you have a 1/4in router I'd go for the T1332 (1/4in radius) with the TB216 bearing to get a zero quirk (i.e. a round-over)


----------

