How do I get a straight line on my body tobe ?

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Well-Known Member
Apr 28, 2004
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Does anybody know how to draw a straight line on a body tube ? I tried to use my t-square hanging off the end but it came out crooked. I need these lines for fin and launch rod guide mounting. Somebody told me to use a square door frame as a guide, however when your home is 125 years old like mine nothing is square !


Get a peice of aluminum angle iron. {not sure what it would be called}
lay it along the tube this way o> where o=tube & >=al angle.
Should work goodly.

An old trick is to use a door jamb. On most door jambs, there a 1/4" strip of wood which is called "stop" molding which is called that because it's the piece that stops the door from swinging too far inward. Lay the body tube in the angle between the stop molding and the main part of the jamb, lining up the edge of the stop molding with the mark for your desired line. Drag a pencil down the edge and you're done!

Use a pencil, not a big marker, otherwise errant marks on the jamb will bring the wrath of the House Boss.
Originally posted by 11Bravo
Get a peice of aluminum angle iron. {not sure what it would be called}
lay it along the tube this way o> where o=tube & >=al angle.
Should work goodly.


Zackly. With the tube sitting inside the angle, it HAS to be a straight line.

I'd say get about a meter of aluminum 90 degree angle stock, cut it in half, and cut half into one third & two thirds, so you have several lengths for different purposes.

This istuff make great straight edges for tracing lines, or fun cutting against. Where rulers tend to slip, this stuff will always have a vertical "ridge" by your fingers, something to lean them against so the line doesn't slide.
Another idea/point... If none of your door jams are suitable (i know the feelilng, many of the *stops* in our door jams have knicks and dents and are not suitable for making a straight line), you can find a similar *corner* in any wide dresser drawer as well as in your kitchen or bathroom cabinet doors.

Get creative and look around, you'd be surprised at how many things around your house can do the trick.

Heck, for small tubes I have even used the drawers in my parts bin (the drawer handel is perfect)

I personally use an aluminum angle extrusion with 1" legs from the local aircraft surplus store for $3. There are two other methods I have employed to draw straight lines. It just depends upon what you have around:

1) A triangular architect's (or draftsmen's) scale is very handy. Choose the proper size for your rocket construction toolbox, and you can just lay it on the tube to draw your line. These have the added advantage fo allow measuring in many ways.

2) There are a number of designs of framing or carpenter's levels which are made from I-beam extrusions. I have a 24" one that works great for drawing lines on almost any size tube. If the tube is small it nests in one of the angles. If the tube is big, I can just lay the level on the tube.

As Jim said, be creative. Think outside the box.

Originally posted by limd21
Drag a pencil down the edge and you're done!

If you leave pencil marks all over the woodwork, you're going to get in trouble with 'She who holds the checkbook.'

I vote for the aluminum angle. You can get them for a couple bucks at your local home improvement store, in the racks with the all-thread and round rod stock.