Radius Jig For cutting 2x Rafters - Contractor Talk - Professional Construction and Remodeling Forum

WNYcarpenter · 10-13-2009, 05:41 PM

I finally found out which project I'm on this season....There's sure to be a lot of progress pics to come!...But I'm going to start out with a question!!

It's going to be a great learning experience and a very cool project.

The pics Here are the rafter drawings and one of the elevations. (best I could do, sorry)

We'll have (don't quote me) some 150 odd rafters to cut with a radius....The Architect and foreman have the patterns figured out, but I'd like to know if any of you have a good jig or advice on how we can bang these out....so far the ideas are jig saw, portable band saw, or router.

FYI, There will be facia and soffit....

Warren · 10-13-2009, 05:45 PM

Circ saw.
Seriously, we do a lot of curves, domes, arches etc, and if the curve is less than 5 ft radius, it cuts nice and is much faster than the jig saw.

**framerman** · 10-13-2009, 05:45 PM

I could be wrong, but those arcs seem shallow enough to do with a skilsaw and get a clean curve. What's the radius on those?

Doh! Warren beat me!

Warren · 10-13-2009, 05:47 PM

Thats why they call it a "circular" saw!

**loneframer** · 10-13-2009, 05:52 PM

Yup, Warren and Framerman nailed it. Circular saw should do the trick. You could look into an Arcus blade too. They are made specifically for cutting arcs.

+ YouTube Video

http://www.youtube.com/watch?v=NMI1PCNN3c0

WNYcarpenter · 10-13-2009, 05:53 PM

Well, I just got filled in to the scope of the project today... I know it's a 56' radius, in I think 8'... It may be shallow enough, but this will be my first experience....

So, with a skill saw do you just slowly work the blade around the curve, or can you actually cut a radius fairly smoothly?

**loneframer** · 10-13-2009, 05:56 PM

Quote:

Originally Posted by WNYcarpenter

Well, I just got filled in to the scope of the project today... I know it's a 56' radius, in I think 8'... It may be shallow enough, but this will be my first experience....

So, with a skill saw do you just slowly work the blade around the curve, or can you actually cut a radius fairly smoothly?

After the first couple of cuts, the blade will warp so to speak and the cuts will actually get smoother.

**loneframer** · 10-13-2009, 06:00 PM

These were done with a Skilsaw.

WNYcarpenter · 10-13-2009, 06:00 PM

[quote=loneframer;786363]Yup, Warren and Framerman nailed it. Circular saw should do the tick. You could look into an Arcus blade too. They are made specifically for cutting arcs.

Arcus blade... Thanks. There's talk about buying a portable band saw...I think everyone will be happy trying a new blade first. Are they hard to get your hands on?

Edit: months later....we sent all the rafters and patterns to the mill to be cut with a bandsaw....We tried the arcus blade, which worked, but the blade wanted to cut too tight of a radius. Once we started cutting tails, it became obvious that any everyday blade was capable of cutting all the radiuses you'll see in the pics. Even the LVLs!...Just to impress this point, I was able to grab any saw within reach and cut what I needed without any trouble.

Warren · 10-13-2009, 06:01 PM

I have a portable bandsaw and cant imagine using it for that purpose.

**loneframer** · 10-13-2009, 06:03 PM

[quote=WNYcarpenter;786373]

Quote:

Originally Posted by loneframer

Yup, Warren and Framerman nailed it. Circular saw should do the tick. You could look into an Arcus blade too. They are made specifically for cutting arcs.

Arcus blade... Thanks. There's talk about buying a portable band saw...I think everyone will be happy trying a new blade first. Are they hard to get your hands on?

I've never actually used one. A 24 tooth framing blade has worked well in my experience. A decent quality blade is a must. I think I used a Marathon blade in the pictured roof.

**framerman** · 10-13-2009, 06:04 PM

A 56' radius is a piece of cake to do. My limit on what I feel comfortable bending the blade around a radius is 12'. You can do a 2' radius if you want but you usually have to do multiple passes or the blade warps to ****.

Timuhler · 10-13-2009, 06:05 PM

Get the Arcus blade for your saw. They make one for blade left and blade right. I have consistently cut a radius as small as 42" or so. I can't recall exactly now, but I cut them in one slowish pass through 2x12.

Make a pattern with a nice curve, then just freehand the cut.

Here are some pics I took while my old framing partner Matt did the work

Regular blade

Warren · 10-13-2009, 06:06 PM

Dont use a blade that is too thin. I tried using a Diablo 24 tooth and it warped way too much. The Dewalt 24 tooth blades are flexible enough, yet thick enough to last for a while.

WNYcarpenter · 10-13-2009, 06:19 PM

Thanks everyone...

Is it recommended to use a high torque saw like a worm drive, or will my PC 15 amp be ok?....also, is it hard enough on the saw to figure on burning one up?

again great advice!

edit: is it possible to cut a bevel and radius?

Warren · 10-13-2009, 06:22 PM

I have never burned up a saw doing that. I usually use my milwaukee 15 amp non worm.
Why would you need to cut a bevel and a radius for that? I have never tried that. I imagine somewhere a trim guy has done it though.

**loneframer** · 10-13-2009, 06:28 PM

Quote:

Originally Posted by WNYcarpenter

Thanks everyone...

Is it recommended to use a high torque saw like a worm drive, or will my PC 15 amp be ok?....also, is it hard enough on the saw to figure on burning one up?

again great advice!

edit: is it possible to cut a bevel and radius?

With that gradual of a radius, you should be fine. However, if you're going for a wormdrive,
I have 4 Skil 77HD wormdrives in all levels of decay. All of them have been thoroughly abused and misused. All of them have had new switches installed and an occasional oil check. They will not die. The oldest one is at least 15 years old.
As a note though, they are rumored to be made in China now.

jhark123 · 10-13-2009, 06:49 PM

Quote:

Originally Posted by loneframer

With that gradual of a radius, you should be fine. However, if you're going for a wormdrive,
I have 4 Skil 77HD wormdrives in all levels of decay. All of them have been thoroughly abused and misused. All of them have had new switches installed and an occasional oil check. They will not die. The oldest one is at least 15 years old.
As a note though, they are rumored to be made in China now.

Not just a rumor, all the new 15amp ones with the rafter hook are. Get the 13amp models while you can!

On a side note, I'll sell my 13amp Skil for only $350 plus shipping

kpatrix · 10-13-2009, 09:41 PM

That 56 foot radius on an eight foot rafter isn't going to match the drawing. That is only an inch and eleven sixteenths rise. You could probably downcrown some 2x6 to get that.

Looks like a really fun roof to frame. I agree with everyone here about using a circular saw with the arcus blade. I have some pics on their website http://www.arcusblade.com/photosandtestimonials.html check out gallery five and six.

I have a similar roof coming up, been waiting for over a year and they just broke ground on the slab last week. Should be cutting my radius rafters right around Christmas time.

Post pics as you go along for all of us to enjoy.

**loneframer** · 10-13-2009, 09:51 PM

So, what's the deal? I don't see a blade with a diamond arbor on that site.
Are they available or not?