Replies

1. 
   coonass | Sep 24, 2007 05:00am | #1

   louey,

   Get shear and a nibbler. Kett makes a set with heads that swap on the drill body. There is a small learning curve to get a straight line with the nibblers.

   KK

2. 
   Dinosaur | Sep 24, 2007 06:52am | #2

   There is no good way to do what you need to do without factory jigs and a hydraulic shearing press...which no one but a dealer/installer would have (and sometimes not even them). That is Reason No. 1 that I hate screw-down ribbed steel roofing and do everything I can to avoid it. Especially for applications like yours.

   Traditional metal roofs are different; each pan is made to fit where it's going to go, and it is cut from flat stock before it is bent and folded. That means you can make straight, neat cuts with a roller-cutter on a brake, or with a pneumatic nibbler/shear and guide.

   But nibblers get stuck trying to follow the contour of pre-ribbed steel, and roller-cutters won't work on it at all...which leaves you (and just about everyone else) with the unsatisfactory methods you're already talked about. So in the end, screw-down steel relies on copious quantities of goo to hide the ragged cuts and 'seal' the hips and valleys and ridge caps. There is damn little craftsmanship involved, and the result shouldn't be looked at from less than 20 metres away, IMO.

   Dinosaur

   How now, Mighty Sauron, that thou art not brought
   low by this? For thine evil pales before that which
   foolish men call Justice....
   

   

3. 
   seeyou | Sep 24, 2007 02:20pm | #3

   Just got one of these:

   http://www.malcoproducts.com/products/shears/ts1.asp

   Won't cut the seams (use a sawzall) but will cut the field like butter. The extra handle helps with control immensly. It's the shizzle.

   http://grantlogan.net/

    

   I was born in a crossfire hurricane..........shooby dooby do

1. 
   Dinosaur | Sep 25, 2007 02:36am | #9

   Need an SDS-plus version of that tool to fit in my Bulldog, LOL.

    

    

   Seriously, what are the advantages of that Malco unit over a pneumatic shear? I generally use a circ and one of those special steel-roofing blades and cut from the back like Piffin. Or I use an air nibbler for curves and cutouts etc. I've thought about getting some powered shears and always figured if I did I'd go with air.

   Dinosaur

   How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....

4. 
   STAINLESS | Sep 24, 2007 06:26pm | #4

   Top of the morning to you LL!

   Abrasive cutoff blade in a circ. saw does work: it is noisy, leaves a rough edge and is tough to keep on a straight line in an angular cut, especially as the material changes its profile as you put weight on it.

   Having said all that I'll share my own experience cutting 66 pieces of steel roofing with just such an animal. The toughest part is to keep the sheets from deflecting under your weight while you cross cut them, this changes the profile and produces a wrong cut.  If you are not familiar with a "shooting board" as used in crosscutting plywood you might like to look that up to get an idea of a working approximation to the jig I cobbled up.

   I used a scrap piece of  roofing material of the same profile as my sheets about 3' long to make my "shooting sheet" (Scrap sheets are often included as the outermost pieces of  the bundle as protection for the actual sheets and may be painted wrong or have some other blemish or profile error, check for that before using the scrap piece)

    I carefully screwed (3) plywood straps (3/4" X 3" ) across the "top" width of my scrap piece to hold its size and profile as pressure from using it tries to distort it. (Be careful to match your profiles so the shooting sheet can "nest" on top of the sheet you wish to cut) I did this by over-hanging the scrap sheet off the material bundle just enough for me to drill holes for the short flat head screws I used to fasten the straps in place. The screws go in from underneath the metal up into the ply in countersunk holes so that when the shooting sheet nests on top of the sheets to be cut, the screw heads won't scratch the sheet. (I actually counter sunk the screw holes in the ply and then counter formed the sheet into the recess with a hammer & punch) By putting some moderate weight on the bundle you force the sheets to "nest" & assume the proper profile while you screw the straps in place. This Shooting Sheet then becomes a rigid form that you then use to force the sheets to be cut into the correct profile when they are placed under the SS (Shooting Sheet) and you run your circ. saw along a guide strap of the SS.

   Screw one of your straps at the exact angle you wish to cut and use that strap as a guide for your circ. saw foot plate to run against. Cut your Shooting Sheet to length at the correct angle using the guide strap and you will then have a rigid SS that registers its cut by its own edge. I carefully filed all sharp edges on the SS to reduce scratching and used tape where appropriate as further protection.

   I found I could cut (2) sheets at a time by clamping my Shooting Sheet to the material to be cut using Vise Grip style C-clamps so its edge registered where I wanted my cuts to be. I then ran my saw along the SS holding it against the guide strap. Since I was actually sliding my saw on the SS and not the material, I didn't scratch the material below. 

   Support the material as you cut or it will bind the saw and damage your cut edge.

   Use a fine file to finish the edges of your material to remove the burrs. (A fine grinding fiber-disc in a 4-1/2' angle grinder with a careful & light touch speed this up on the flat portions of the profile.)

   Never turned out as good as the die cut edges from the fabricator, however I was happy with the result at much less than 1 meter viewing distance! (I did use a bit of touch up paint as the heat from cutting discoloured the paint slightly to about 1/2" from the saw cut.)

   IIRC I used 9 cutoff wheels for the entire job; about 200 lineal feet of cut. Since my profile was quite deep (38 mm), the "spent" cutoff wheels were actually still quite large in dia. & I have since used them on different jobs.

   Don't forget the ear & eye protection!

   Sincerely,

   STAINLESS

1. 
   leaninlouey | Sep 24, 2007 09:16pm | #5

   Thank you all for the tips, I appreciate the answers. I may try to make that jig, Stainless.

1. 
   McDesign | Sep 25, 2007 12:13am | #6

   Hey, thanks for posting this thread.  I've got to cut some 5V roofing this week to hip roof a little building.  I'll use all this good info!

   Forrest - not a roofer

2. 
   Piffin | Sep 25, 2007 12:18am | #7

   I don't understand the part about deflecting under weight. I cut from the back side with the circ saw and do not put any weight on it. The saw has a handle to hold the weight with.I use a chalk line to mark where to cut. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

5. 
   catfish | Sep 25, 2007 01:55am | #8

   If your cutting a stack at a time go ahead and drill for screws.