Continuous radius window stool

[Aaron Telian]

Some builders we work for just replaced a bank of five 28" windows in a semicircle and need us to make a new stool. The stool is mitered together at each window and describes a radius on the room side. We're going to make up 36" pieces in the shop and then piece it together on site.

We can figure the radius both over the total run and from each piece of stool that was removed, my question is more about fabrication. How would you guys make up these pieces so they're consistent and smooth? We have a stool profile bit but it doesn't have a bearing. Would you make an MDF template with a bearing bit and then run the router baseplate against that with the stool bit?

[tjbnwi1]

The segment would have to be longer then trimmed, but could you use an edge guide and have the outside "tips" be the point of contact on the arc segment? Do all your layouts for the cuts prior to making the arc, it makes cutting to size easier.

Tom

[slomoe]

I would think a template and a router table w/ bearing bit would lead be a little more consistent than running it by hand OR a router table with a shop made fence that has the radius of the stool. Maybe you could make the radius of the fence a little tighter and use a feather board at the bit.

[Kent Brobeck]

Here is a link to an article written by Gary that shows the use of a trammel arm. This is how I would put that sill together. Use wider stock than necessary. Mark it with the trammel cut it to 1/16+ off the line, use a flush trim bit to cut to the actual size then put the stool profile on it to finish the edge. You are making a segmented radius sill so you'll need to join with butt joints and either use biscuits or a domino to reinforce just be sure to keep them out of the finished edge location.

For the apron I'd use flex moulding.

http://www.jlconline.com/drywall/a-c...d-ceiling.aspx

[Aaron Telian]

Thanks all. We're thinking of just cutting the arc in place, to minimize error and avoid having to do an extra setup. Still, putting it on a table outside might be easier, not sure yet.

Here's the sequence we're thinking now:

Fit miters in place.
Mark with trammel in room.
Rough cut with jigsaw.
Cut stool profile with router on trammel.
Install.