i recently read something on rafter jig for a 12/12 roof .cutting plywood and building this jig and then measureing the 2×10 and clamping a square on the bottom of the plumb cut and so on is it realy worth the time to do it.if so please explaine the best way to build the jig for a 12×24 addition. THANKS
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"i recently read something on rafter jig for a 12/12 roof .cutting plywood and building this jig and then measureing the 2x10 and clamping a square on the bottom of the plumb cut and so on is it realy worth the time to do it.if so please explaine the best way to build the jig for a 12x24 addition."
You don't need to build a jig at all. All you have to do is layout your rafter with the plumbcut, birdsmouth and overhang and nail a block at the top and at the bottom and use the rafter as a pattern for all your rafters.
Freehand all your cuts. That's all you have to do. You should already be able to cut with a circular saw so no need for any clamps.
Here's a drawing of what the rafter pattern should look like. Using that rafter as the pattern will ensure you that all your rafters will be the same. You will never need your tape.
I love you're diagrams dude. Simple but effective. That's how we cut our commons most of the time too, but I've been playing with gang cutting lately as well.View Image
"I love you're diagrams dude. Simple but effective. That's how we cut our commons most of the time too, but I've been playing with gang cutting lately as well."My good old paint program is my friend.If I was like Tim and just did house all year I would definitely start gang cutting. He's got the best set up for that.Brian, do you do many additions throughout the year or is most of your work all new homes?Joe Carola
I do four or five additions a year... that's about it. In enjoy the challenge of marrying the new and the old work together. But to be honest.... it just doesn't pay that well around here.
The GC's want pricing comparable to new work and I just don't see them as comparable work. There's inevitably a little demo, a little head scratching, and a little digging into the bag of tricks that comes along with additions and remodeling. That stuff takes time. And as you know, time=money.
So I take the few that I actually land, but I can usually be more competitive and profitable with the new work. View Image
Brian,If the GC's want to pay you the same price labor wise for a addition as compared to a new house then they can go pound salt. Your better off framing houses. The square foot is way bigger and you can make more money.Joe Carola
That's about the way I see it too.View Image
Joe,
On this house http://pic9.picturetrail.com/VOL293/2163851/8885471/127341520.jpg I used patterns. I make a pattern of the birdsmouth for the 10-12 and the 6-12 and used those on the jacks. We had had so much rain and finally had a decent day and I wanted to keep everyone busy so I only gang cut one section. I'm not good at organizing bastard racks yet and I get confused.
Tim,You can't go wrong with the pattern.Have you let anyone else figure rafters out yet?Joe Carola
Joe,
Jasen did the last roof. Figured the load, the list and then gang cut it. I didn't give him any help. He knows how to do it, it's just a confidence thing. When he left us for about 8 months for a remodeling company, we did a number of smaller >2000sq houses, so I was cutting a roof every 2 weeks and they were the same plans. So I got confident, now it's his turn and everything worked out on the money. It was this house http://pic9.picturetrail.com/VOL293/2163851/9094915/126297529.jpg I'll get some shots today of it with the garage finished and the roofing on. Looks like we are going to side these two starting today and we've got sunshine for the next week :-) I can't wait. This winter has been dark and rainy and even though normally I'm not affected by the weather so much, its gotten to me.
More pics of Jasen
http://pic9.picturetrail.com/VOL293/2163851/9094915/128490699.jpg
http://pic9.picturetrail.com/VOL293/2163851/9094915/128490704.jpg
http://pic9.picturetrail.com/VOL293/2163851/9094915/128490700.jpg with Kyle
Matt splat rat hat cat fat Matt (that's his entire nickname spoken as quickly as possible)
http://pic9.picturetrail.com/VOL293/2163851/9094915/128490702.jpg
Kyle http://pic9.picturetrail.com/VOL293/2163851/9094915/128490701.jpg
How are you gang cuttiing the bidsmouth.
10" wormdrive (Bigfoot) with a swing table. Just getting started at it and to be honest, a little hesitant. Not sure why, we gang cut all our I-joists anyway and those piles of stock are more costly than the rafters I think. But then again... those are just square cuts.View Image
So is that saw fitted with stacked blades,not sure what you mean by swing table.been trying to find a skil with stacked blades
If you have the current FHB you can see Larry Haun doing it (or alternatively his book as well).
No. have not seen that issue.Is he rackin them up and cutting the birdsmouth in one pass?
Yep. And he is using a swing table. He covers this a little more thoroughly in the Very Efficient Carpenter.
Fish,
Pairis Enterprises used to make a universal stacked dado for the Skil , but according to their website[ bestmadetools.com, I think?] they no longer offer it.
thanks , Now if i could track one down.I had one for years,but it walked off a job last summer and have not been able to track one down.Great tool for gang cutting seat cuts.... etc.Seems like every job i'm on has 4x tails.
"Pairis tools" is that the Co. that made the layout stick .
Here's the link.....http://www.bestconstructiontools.com/.
You will have a very hard time finding a dado saw and if you do, you will pay dearly for it. The few people that I know of that have them all had them custom made and it's a costly thing to have done from what I understand. Also better hope OSHA doesn't catch you with one.
A swing table is basically a replacement table that lets the saw swing up to 75 degrees so that you can get the level part of the seat cut. Bigfoot tools sells them, but I forget what I paid for it now.View Image
It's a great tool and would happily pay for someone to rig it up.it would pay for itself on one job.
Curious why the reluctance on the gang cutting?
Maybe reluctance is a poor choice of words. I guess I'm still not 100% comfortable with it so I only do smaller portions of the roof and only when I have the time to fiddle a bit.
The headcutter that I have is the stock model from Bigfoot tools. As big as it is, it's still not big enough to totally compensate for the weight of a chainsaw. Therefore your own personal technique has as much to do with getting a true cut as the tools themselves do.
Best way I can describe it is this: Ever try to take a sliver off a 2X with a wormdrive in you right hand? You have to really focus on keeping the blade square with the wood because there's so little of the table resting on the stock and so much saw floating in space, right? Well that's kinda what's going on when you're cutting with a headcutter. You've got a big heavy engine up in the air and if you don't hold it right on, that table lifts off the stock and throws your angle off. Or you stress and flex the bar and throw the angle off.
Nothing worse looking to me than rafters that don't snug up to the ridge just right. So when I finally rip through a big azz pile of 60 or so 24'ers....... they better be right.View Image
i am very familiar with the swing table and table for the chainsaw,never really paid attention to names and model numbers. Never really liked the stihl attachment.the beam saws are the way to on the plumb cuts. "elbows in and locked.
to be honest .i usually just cut'em one at a time and bet the boys lunch they cant catch up.the dado saw i want for custom beam work.
Wouldn't the dado set tend to wear a 13 or 15 amp motor rather quickly?We have the 10" Bosch from Big Foot (standard table) and it does well but I can't imagine plowing out such a wide swath of lumber.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Yeah, I'd sure think so Jon.
I do know that most of the dado saws were built on the larger Skil bodies that aren't available anymore. Skil used to make a few different models of wormdrives that had larger motors. The model numbers are escaping me right now, but I've read about them several times in several different places. Most recently, I believe, in a John Harman article on gangcutting in JLC awhile back.
I've seen a few go on ebay and even in non-working condition they go for big bucks for the parts alone. Guys who have them want to keep them running.
You're right about those "little" 13amp and 15amp motors spinning the big blades. The 14" BigBoy only comes with a 1 month warranty on the motor. You've really got to baby those big saws along and let them do their thing.
Guys like the dado saws because they seem like and easy way to hog out a swath of seatcuts. But from what I recall, you can only get about 2" deep seat cut with them. Maybe even less. I believe that even most of the 'old timers' have switched to swing tables.View Image
John Harman gets his dado saws made up by his shop guy and I can't remember if he runs 220 or not, but I think he only uses that saw on 6-12 or less. I've found that making 2 cuts with 2 saws doesn't really take much time.
http://pic9.picturetrail.com/VOL293/2163851/9094915/127190525.jpg
http://www.picturetrail.com/gallery/view?&members=1&p=3&uid=2163851&gid=9094915&&imgid=126965332#top
How is that 10" bigfoot with the swing table? Do you have the Skil motor or the bosch? Can you cut the a full depth seat cut for a 2x6 wall? How do you cut the head cuts? Just curious 'cause I've been thinking about testing out the gang cut waters. I do alot of remodel and additions, too, and like you say the tie ins are were the head scratching comes in.
I like the swing table a lot. Nothing really fancy about it, just a table that swings up to 75 degrees. I have the Skil motor on it right now, but I have a Bosch saw that got mangled by my forklift that I'll use to replace the Skil when it burns out.
No, I can't cut full bearing for a 2x6 wall with the 10". But it you step up to the Big Boy from Bigfoot tools, you can. It spins a 14" blade and also comes with a swing table. Pricey saw. I can get full bearing for 2x4 walls with the 10". If I really get into the gangcutting, I will get one but right now I'm still very new at it and just experimenting.
I make the head cuts with.... drum roll please.... a headcutter. It's a table that bolts onto the bar of my 20" Stihl chainsaw to allow clean square cuts with the chainsaw. It bevels up to 45 degrees.View Image
10" w/swing http://pic9.picturetrail.com/VOL293/2163851/9094915/127782309.jpg
http://pic9.picturetrail.com/VOL293/2163851/9094915/127782308.jpg I was cutting octy hips for this ceiling http://pic9.picturetrail.com/VOL293/2163851/9094915/127782311.jpg
The 14" is expensive and I believe in using 2 1/2 - 3 3/4" seatcuts and not bigger. But that's just me.
Tim,What is the benefit of a full bearing seat cut, either on 2x4 or 2x6 walls?Are there any code requirements for full bearing or is it preference?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
I don't worry about the full bearing. For some guys that is their preference. I like to stick to a 2 1/2 - 3 3/4" seatcut. Usually go for about 3" and then round off the heelstand to an even number so it's easy to remember. 3 3/4" is the max you can get out of the 10 1/4" Big Foot saw.
if i'm using 2x12s does the depth cut of the birdsmouth require lowering the ridge to make up the difference from the bdsmouth.
"if i'm using 2x12s does the depth cut of the birdsmouth require lowering the ridge to make up the difference from the bdsmouth."If your wall is a 2x4 and you always use a 3-1/2" seatcut then the bigger rafter will will raise the ridge because the HAP cut(Height Above Plate) will be taller.Besides no matter what size rafter you use you don't have to lower or higher a ridge because you set up the two end rafters on each side of the house for example a gable roof so that means you'll have four rafters set up and then you just slide your ridge in between the rafters and they set your ridge height.Joe Carola
sorry framer what i forgot to add is this will be a addition to the house and i want to keep thhe same roof plane.i think i have to go about the rafters a little different, am i correct.or should i tie new ridge to existing rafter.which way is most easy for me .THANKS.
Edited 2/4/2006 8:32 pm ET by T3
t3.....<<<sorry framer what i forgot to add is this will be a addition to the house and i want to keep thhe same roof plane.i think i have to go about the rafters a little different, am i correct.or should i tie new ridge to existing rafter.which way is most easy for me .THANKS. >>>>
strip the gable end and measure the existing rafter... use the same length from the plumb line of the birdsmouth to the long point of the rafter at the ridge
use the same H.A.P. as the existing... take your first trial and sister it to the existing on both sides.....if it fits , you're good to goMike Smith Rhode Island : Design / Build / Repair / Restore
"sorry framer what i forgot to add is this will be a addition to the house and i want to keep the same roof plane.i think i have to go about the rafters a little different, am i correct.or should i tie new ridge to existing rafter.which way is most easy for me"You have to explain this roof a little more in detail because you said that this roof has to plane in with the existing roof.Does this mean that the addition top plate is the same as the existing top plate and the top of the new rafters have to plane in with the top of the existing rafters and the new roof will be continuous threw the old roof?If so you also said that you would probably be using 2x12's for the addition rafters. If that's the case i hope your existing rafters are 2x12's which I doubt they are. They're probably 2x6's or 2x8's and if so you can't have the same plate height because you can't make the same HAP cut as the existing rafter HAP cut because you will cut to much out of the rafter and weaken it. So you have to lower the wall down for this.This happens all the time when they design things like this. A lot of times the existing house has a hip roof and you have to frame over the existing hip roof keeping the top of the new rafters the same height as the existing rafters. Therefore you extend rafters from the existing hip up to a new ridge to do so and everything has to line up perfect.Adjusting wall height is one of them when you go from an existing 2x6 rafter to a 2x12 addition rafter.Joe Carola
T3, I think your thread got hijacked so Ill try and bring it back around. What you should be most concerned about is what i call the heel height. The heel height is the distance between the top of your birdsmouth and the top of your board on your plumb cut line(the back of the birdsmouth). Before you cut your new rafters, figure out the pitch of the existing roof and what the heel height is and what your overhang is, match those and everything else takes care of itself.
Make 1, put your blocks on(I usually use small rips of scrap 1/2" plywood), trace a second, cut it and test them on the framing before you cut the rest.
Enjoy
Matt
Look at framers drawing take the center out, make from plywood attach block (guide) to the top and theres your jig. Makes plum cut and keeps seat and end cut consistant. On hand cut hip roofs just measure the various length jacks and apply the jig to eather end.
Gary,When I have roofs that are cut up with gables, hips and valleys. I make up a small jig for the common rafter and the hip/valley rafters with the plumbcut, birdsmouth and overhang on it out of a scrap piece of rafter stock.For a false valley I do the same thing with just a plumbcut and level cut. This one I drew in on the second drawing.Joe Carola