Laying out a Radius

Ron309753 · Post by **Ron309753** » Wed Apr 29, 2009 8:52 am

I have some of the same composite material that Nick used to make the Adirondack chair. I have downloaded the plans and plan to make a couple of the chairs as my first real project, but don’t know how to lay out the radius cuts. How is that typically done?

Thanks,

Ron

JPG · Post by **JPG** » Wed Apr 29, 2009 11:09 am

Ron309753 wrote:I have some of the same composite material that Nick used to make the Adirondack chair. I have downloaded the plans and plan to make a couple of the chairs as my first real project, but don’t know how to lay out the radius cuts. How is that typically done?

Thanks,

Ron

COMPASS??????

efmaron · Post by **efmaron** » Wed Apr 29, 2009 11:35 am

There are several ways to layout a radius . One way is pictured below. Measure in from each edge the size of the radius. In the drawing I used 1" then place the point of a compass on the center point, next move the lead of the compass out to the edge and swing a 1" radius. Do the same for any size radius. You can make a set of radius gages out of poster board or hard board cut them out and trace the radius on to the wood.

charlese · Post by **charlese** » Wed Apr 29, 2009 2:14 pm

Ron309753 wrote:I have some of the same composite material that Nick used to make the Adirondack chair. I have downloaded the plans and plan to make a couple of the chairs as my first real project, but don’t know how to lay out the radius cuts. How is that typically done?

Thanks,

Ron

Hi, Ron! Here's how I would do it -
Cut the back slats to width.
Lay them out side by side with aprox spacing.
Drill two holes 13 3/4" apart through a scrap board. (one hole is to hold a pencil, the other to hold a wood screw)
Placing the tip of a screw in the center board, Strike an arc with the pencil.
Now, depending on what tools you have, cut the boards to length.
If using a table saw finish the curves by sanding or rasping or planing
If using a band saw, just sand

Ron309753 · Post by **Ron309753** » Wed Apr 29, 2009 2:32 pm

Thanks everyone. I was thinking that spacers and a beam compass was the way to go for the back slats, but what about the 24" radius cuts on the upper and lower back supports and the rear seat slat? The supports are only 5-1/2” wide and the rear seat slat is even narrower.

Ron

robinson46176 · Post by **robinson46176** » Wed Apr 29, 2009 4:04 pm

Ron309753 wrote:Thanks everyone. I was thinking that spacers and a beam compass was the way to go for the back slats, but what about the 24" radius cuts on the upper and lower back supports and the rear seat slat? The supports are only 5-1/2” wide and the rear seat slat is even narrower.

Ron

Do you watch Roy Underhill? Rip a thin slat of wood or maybe use a yardstick. Put a thin brad in the piece at each end where the ends of the cut need to be and then spring the slat back in the center to where it needs to be and tack it back with a brad. Now draw a line along the slat. If you are making more than one measure the distances or better yet make a poster board pattern. Never measure when you can superimpose.
A lot of guys spend hours trying to get something exactly like the plan. I'm enough of a maverick that I look at the plan (on the rare case I am using one) and if I like what I see, fine, I use it. If not I use what I like.
When I want to radius off a corner I typically grab something round like a can of paint (or a coin if something small) and mark it off and see if I like it. You just have to be sure to use the same pattern all of the time.

If you make a pattern to mark with always mark it as the pattern and always use the same pattern. I have seen guys use the last board they cut to mark the next one and it is amazing just how far off they can get doing it in just a few cuts. Always cut a pattern and always use the marked pattern, not the last board cut.
-
Try to remember as you work that unless you want an "exact reproduction" of an item that you are allowed to not follow the plan and just make it how you like it. The "woodworking plan police" will not come after you if you "do it your way".

curiousgeorge · Post by **curiousgeorge** » Wed Apr 29, 2009 4:36 pm

Ron,
I use a long string tied to a pencil. For a 24" radius just measure out 24" of string from the pencil and strike an arc. It ain't perfect but in most cases it's close enough. At least it worked great on the chairs I made.

charlese · Post by **charlese** » Wed Apr 29, 2009 5:37 pm

[quote="Ron309753"]Thanks everyone. I was thinking that spacers and a beam compass was the way to go for the back slats, but what about the 24" radius cuts on the upper and lower back supports and the rear seat slat? The supports are only 5-1/2&#8221]
Do it the same way as the other radius'. Since you want a 24" radius, just lay the board down on a table where you have 24" of room. If you don't have a table, use the floor or a sidewalk, or the ground (Earth).

beeg · Post by **beeg** » Wed Apr 29, 2009 6:12 pm

THANK YOU Ron for asking about this. I've wondered about how to do this also.

JPG · Post by **JPG** » Wed Apr 29, 2009 6:37 pm

charlese wrote:Do it the same way as the other radius'. Since you want a 24" radius, just lay the board down on a table where you have 24" of room. If you don't have a table, use the floor or a sidewalk, or the ground (Earth).

Y'all can tell us early post'ers were clueless about WHAT the question was about!:rolleyes:

I think a cardboard pattern is appropriate here! Only have to play "compass" once.