Symmetry Techniques

[HerrDeacon]

Something I always struggle with when making a part (mostly in fiberglass) is getting the part symmetrical. I've made a half-dozen or so parts (tails, fender eliminator, chin spoiler, fly-screen) that all required them to be symmetrical and I've achieved it somewhat. To the naked eye they don't look to bad, but I know they are not perfect. Just wondering if there are any techniques I'm not aware of for helping with symmetry? For smaller parts I've used a contour gauge a bit and find it pretty good, but I now want to make some much larger parts that have to be pretty much spot on, would be nice if there was something that could make this easier.

 

[johnu]

Mk. 1 eyeball, gauges/templates, cnc.

 

[o1marc]

Without CGI and CNC making the molds or bucks it is difficult to make small parts symmetrical. You keep changing one side till you've gone too far and it doesn't match the other then the other to match it and it ends up being a vicious circle doesn't it?

 

[HerrDeacon]

Thanks guys. CGI and CNC are not in my future so it seems like my eye will have to do for now. With the piece I'm making now, I roughed in the shape on both sides first, now I'm attempting to finish one side to the way I like it. Then I'll try and make some templates of it and flip them over for the other side. Not sure how successful that will be but will give it a try.

 

[stroker crazy]

Have you tried one of these?

Some types can be joined together to make longer units.

Crazy

 

[HerrDeacon]

Yes, I have one and used it on smaller parts to some success. I'm using on this piece now for some of the smaller curves.

 

[rockcitycafe]

I like to use cardboard templates, I make them from cad drawings, but you could easily sketch them and just fold in half to get a symmetrical template. for areas away from templates, use a sliding square and a smaller ruler, if your top view profile of the part is symmetrical, then you can use that tool to gauge points on opposite sides of the part... kinda hard to explain without pictures though

 

[HerrDeacon]

I can visualize what your getting at. That technique should work good with the piece I'm making now, thank you.