best tool to cut galley wall ribs?

[Poorlytiedfly]

I am approaching the point in my build where I will be cutting the completed exterior walls to make the templates for the galley hatch ribs. I have found that my scroll saw does not cut perfectly up/down sometimes when I am cutting thicker stock - the blade drifts just a bit and I get an angled cut. I am obviously wanting my cuts on this very important step to be as near perfect as I can make them.

[halfdome, Danny]

Make a master rib, band saw or scroll saw each blank a little heavy, mount a router in a router table with a bottom bearing flush trim bit or trim them by hand with a router and the same bit.
The other option is find someone with a CNC router to do it for you.
Danny

[Poorlytiedfly]

My question is what tool to used to make the master rib - that will ensure the best cut.

[aggie79]

My question is what tool to used to make the master rib - that will ensure the best cut.

I used 1/4" MDF to make a template. The template was cut by a jig saw just "shy" of the line. Then I sanded down to the line for the final profile.

[KCStudly]

I made my router template out of 1/4 inch luan; easy to cut and shape but only just thick enough for a guide roller to follow.

I made the rough cuts on a small vertical band saw, but a hand held jig saw would have worked, too. Even just scoring several times thru with a utility knife would have worked (if that were my only option). Then I sanded to the line on a small bench top combo disc/belt sander, at least for the outside curve and ends. A hand held belt sander would also work if you clamped the piece up in a vise. On the inside radius, what I couldn't get with the bench sander, I hand worked with a small wood block and sandpaper.

If your ribs will be exposed the trick is to make sure you don't have any nicks or rough spots in the template. Go over every surface with your finger tips and sight along all of the curves to be sure you have nice smooth transitions and no flaws. Any flaws will be found by the router bearing and will be telegraphed thru each part.

[halfdome, Danny]

From my experience I've found using a 1/4" template that it can deflect some, while routing, as all material in that thickness is weak.
I use to use 1/2" Baltic Birch for the master rib and it too deflected some.
You want to get all your ribs exactly the same so it all seals up the same.
I now use 3/4" plywood for my template and screw it in several places to each of my 1/2" ribs.
Danny