i've herd of people of pie cutting the frame, but how much of a degree of a pie cut will give you what kind of drop in inches??i've tried to search it up on here but couldnt find anything about it. OR is the pie just to drop the frame and i would have to end up maken new mounts for the rear suspension anyway to make my designated height???
A pie cut is just that - taking a pie shaped triangular sliver of metal from the frame. There is no set angle. Just depends on how much you cut.
The angle required is relative to the distance over which you intend to achieve the drop. For me, I pie cut the front of my frame, a 7* cut gave me a 2" drop over the distance from the cowl to the crossmember. Easiest way to calculate this stuff is to do a scale drawing. Much easier, quicker and cheaper than working it out in steel. Pete
You can figure it through the use of Trig, just remember the angle of the pie cut is half of the angle change you are wishing to make. I work with trig most days and it's seems simple to me, however I know Trig is a four letter word to most people. Or as suggested above, do a scale drawing.
Or . . . cut up some cardboard to duplicate the frame sides. 4"? Cut some angles, see what you come up with. You can use the cardboard templates to scale it out on the garage floor. If you have some chalk and an angle finding device, draw the whole frame side out on the garage floor.
Get a sheet of 1/8 luan plywood and make a template of the side of your frame, it cuts with a box cutter. Lot easier to cut plywood than the real deal.
When I'm doing it I go at it different. I start with my Known factors. Chassis length, given spring mount position. Firewall location and Prefered angle for the Look I want. Then I do full scale Chalk lines of the Frame rail on the Shop floor. Where the two angles come together measure the change in degrees and then make the cut. I also do a strait line for Ground referance. I do that for Z'iing frames too. I've learned numbers on paper don't alwayse give you the Look your after. Seeing is beliving. The Wizzard
Don't get crazy... Just trace the shape of the rail on a piece of cardboard. Cut a straight line (from top to bottom) leave like an 8th onf an inch of cardboard on the bottom to act as a hinge. Bend it up to where you want it, trace a new line where the cardboard over laps it's self, cut along the new line so you've got a "pie shape" and use that as your template. P.S. just tack everything in place. Dont do any final welding until you've measured enough times to make yourself sick... Only weld it it up completely once you know everything is squared up...
What works best for me....I use cardboard to mock everything up....The best seems to be old Bud Light cartons. I go to the store and get a 30 pack....then drink the beer....then start mocking up. If it's something as big as a frame, it seems to be more fun! Gary
Depends on where you cut... You didn't specify what type of susp., but if you cut ahead of the mounting points, it will change the height and angle. Personally, I agree with NVRA 84 about the trig (we use it all the time and it WORKS), but however you lay it out, be sure to take 1/2 the cut angle off each side so the pieces line back up correctly.
your gonna have to either A) make a cardboard mockup and guess B) learn some algebra. A is probably easiest
This should turn this thread into a them against us discussion. I can make patterns and use a ruler, just what are you TRIG guys talking about? I can't wire a car either, but I've done National award winning paint & body work.
It less tedious to do the simple calculation. They taught this shit in like 6 or 7th grade if you google it you can learn it again in like 1 hour
NOTHING wrong with ruler and patterns, trig just makes it faster. If you know any two dimensions of a triangle (length and height of a frame "Z" for example), the trig functions allow you to find out all the other dimensions (lengths and/or cut angles). Not going to go into it unless somebody wants it; but if you measure correctly it works every time, even on compound cuts.
When I pie cut my frame in the back, I made this template out of aluminum. The template has holes up through the center line that helped me to align it perfectly. I did the pie cut at an unused body mount hole in the frame on each side which was convenient to make sure the cut was at the same exact place on each rail of the frame. The template worked well, because I could hold it against the frame and scribe it to make a nice sharp cut line. I made the cuts with a sawzall. Remember that your pie cut needs to be this type of triangle with the center-line of the triangle perpendicular to the rail in the area where you're cutting it, so that the two sides will meet together when you "fold it" back up. When you pie cut it, the suspension angle will change, and the axle centerline will pull in towards the pie cut, so you probably should add the crossmembers that support the suspension AFTER you do the pie cut, unless the crossmember is a round tube or something and you have worked it out on paper where the crossmember will wind up after folding up the pie cut so that it winds up where you want it.
I used pie cuts to reshape the front and rear of my 36 frame by cutting 1/4-1/2 inch cuts, you may have to make more than one pie cut so it does not have a sharp line and it takes reverse cuts from the bottom to level your frame out. If you block and level your frame at ride height and you know the compressed height of your suspension you can make small cuts and slowly bring it to the desired height. PM me if you have any question I will try to help.
now using trig you can figure out how much the rear of the chassis will raise up having pie cut that amount out
...and here's a GREAT thread on kickup math... http://www.jalopyjournal.com/forum/showthread.php?t=214782&highlight=frame+match
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