Roof Radius ?

[luvrbus]

Does anyone know the radius curve on a DL3 from the sidewall to the roof in inches,I have tried with a couture gauge and cutting one from card board and nothing is working right.I want to purchased a piece black Plexaglass and have it engraved for all my monitors,controls and gauges with LED back lighting and it needs to almost perfect so how do guys get the radius right the 1st time       

[eagle19952]

Does anyone know the radius curve on a DL3 from the sidewall to the roof in inches,I have tried with a couture gauge and cutting one from card board and nothing is working right.I want to purchased a piece black Plexaglass and have it engraved for all my monitors,controls and gauges with LED back lighting and it needs to almost perfect so how do guys get the radius right the 1st time        

using a rafter square and tape measure....
calculator found here ... i think concave radius.

https://www.trimster.com/radcalc.asp

https://www.trimster.com/crowncalc.asp


dormer...and more here too ...

https://www.trimster.com/CrownRadius.asp

[sledhead]

template template template I used 1/4 " and 3/8" ply and start scribing . it gets easy after a short time cuz it changes all the time

dave

[Jeremy]

Yeah, I would definitely go for a template rather than trying to measure radii too - just less opportunity for cock-ups and misunderstandings between the various stages and people involved. And it's probably dangerous to assume that the bus is symmetrical and the curves identical side-to-side too.

For making the template I would set-up a sheet of something (wood, cardboard etc) well below the roof, and then project the shape down onto it using a home-made offset scriber - in other words a stick with a pencil taped to it. The only tricky bit is to make sure that you keep the stick vertical as you draw, but there's various ways you can arrange that

Jeremy

[chessie4905]

You could also bend  10 GA or heavier copper wire to the curve and transfer it to plywood and use a Discsander to make it precise.

[oltrunt]

Each idea above work just fine.  I like to use tag board (cardboard that was once used to make the Package tray between the rear seat and rear window of 50's and 60's cars) as it can easily be cut with "tin" snips and is cheap.  Once I have a template I then like to make a wire form to match it.  I use 1/8" welding rod as it is very stable and not prone to sagging and bending.  I always put a "L" or"V" bend in the rod to assure accurate positioning at a later date.  The technique works very well when you hand a straight piece of bumper to a guy at the chrome shop and say here, make this.  Jack