View Full Version : Step 1?

01-04-2004, 10:19 PM
Any ideas or suggestions to the following.

I need to make L & R tail light housings about (8" wide x 4" high x 2" deep) on the back of a street rod I am putting together, unfortunately there is not a flat place back there only compound curves from top to bottom and left to right.

Trust me, I would buy them if I could find them.

The forward portion will need to be machined to the contour the rear portion of the housing will be flat (no problem on the flat side :) )

How does one go about getting this contour into a my CAD system.

Any and all thoughts/ suggestion/ideas/opinions/guesses will be appreciated.


01-05-2004, 07:28 AM
I would try to tape a piece of card stock to the fender in such a way that it would be in the desired plane and orientation, then use a scibe(compass type) to transfer my lines. Then I could scan such an item and use as a background image.
I have to use this method in buiding to scibe panels around mantel pieces, or stone work.
Just a thought.

High Seas
01-05-2004, 07:48 AM
You could take the "hull" (read - rear fender) offsets from a known plane - just as thuffner3 suggested, you could use a laser level (a good excuse to buy one) and follow the example at:
It walks you through a larger project of reverse engineering a hull - but you'd be on a smaller scale and have some tighter points/tollerances to get a good fit. Principle the same tho, wouldn't need to use Prosurf - just your cad program of choice.
:cheers: Jim
Simpler said - set a plane of reference, measure offsets from the object to the plane, transfer the offsets to CAD, press on.

01-05-2004, 08:56 PM
Thanks for the input guys,
Gave me enough to at the least get started, often that can be the hard part.


01-05-2004, 09:49 PM
Ken when you get finished with your street rod would you build mine :D . I am too broke and don't have enough time to build it.

Seriously what kind of rod are you building. I have a 51 GMC pickup I am wanting to turn into a street rod. I have a Cadillac Northstar engine and an wanting to use the new c5 vette transaxle so I don't have to build a special transmission for it.

Keep us posted, well at least me, on your progress.

01-05-2004, 10:11 PM
Take an impression with facsimile putty. Then you could lift the numbers from that, on a surface plate with an indicator on a height gage. Not fancy but it works. Here is the Hi-tech version. http://www.faro.com/Products/Gage.asp Drop the numbers right into your CAD.

Gary :D

01-05-2004, 10:13 PM
LOL Mike, by the time I get done I will be too old to qualify for a drivers license :D

Trucks are a hot project and the Caddi North Star is an awesome engine, wish I had one of those.
Mine is painted Cadillac Diamond White!, does that count for anything :)

1942 Studebaker 4 door, rear suicide doors, Chrysler 440 with 727 tranny (not installed) , ford 9" posi, Mustang II front end, power steering, original interior configuration except new instruments and re-upholstery. Lots of work to be completed.

Attached is a picture of the rear where I need to make the tail light housings. I do not like where the original lights were ( two holes in rear fenders) nor the bulkiness of the original.

01-06-2004, 08:43 AM
another idea might be to use that "great stuff" or similar foam and using control taping or such, make a negative of the openings and then digitize or even cast. Then there is the lens creation?

01-06-2004, 11:03 AM
Ken can you do a close up of the light area or are you going to weld that up and reposition the lights?

I know about the getting old too. I turned 53 on the 3rd and I haven't even started my truck yet. I had a chance to own a Stude President once I think it was about a 38 or 39 but it has been so long ago......the age and everything!:D


01-06-2004, 12:00 PM
I reposted the picture showing where I am considering re-positioning the lights. If they are moved then filling the holes is a must do :( That is my big issue with doing this.

Each light would have 2 4" flat oval lens.

With the ideas posted and some others I do not believe getting the geometry into my cad is going to be all that bad (where have I heard that before):D