Sightlines Explained

This excerpt from the "Foundation in Chairmaking" is about using and making sightlines to drill angled holes in chair seats. The scale shown in the video is available at www.petergalbert.com under the store/sightline rule. This is part of the series available on vimeo on demand, www.vimeo.com/ondemand/galbertfoundations

[@timothyhall1377]

You are a good video instructor.

[@shortliner68]

Thank you for making that sightline rule available in pdf form. I had worked out all my angles by a method used on another video. Using your sightline rule I checked my previous work and found my sightline angle to be off by 1 degree which made my resultant angle off by 1/2 a degree. Now I feel confident I have the correct angles to drill holes for two chair back posts. The chair has a pedestal mount, so no legs are required.

[@shahbazking9628]

Woow❤this really helpfully
God bless you sir

[@d6c10k4]

Your's is a pretty practical method of laying it out. For me it would be simpler to do a little math to figure triangles and come up with the sight line and drill angles. Your scale looks to be developed for a particular seat height and would change for other heights.

[@PeterGalbert]

the scale works regardless of the seat height, it's really just a way of comparing the "angular travel" of the baseline of the three triangles formed by the leg positions, and triangles can be compared for this result regardless of size as long as they all share a common length on one side (which they do, all originating from the "plumb" position.) I hope this is makes sense! I can't imagine math being faster or simpler. My layout is as simple as measuring out a right triangle using my scale, the hypotenuse is the sightline and it's length is the resultant angle. Thanks for watching and the feedback

[@ScottShook]

This is brilliant. I have used trigonometry to calculate this but never this quick or cleanly. I have even built a 3D model is Fusion to figure out my resultant angle abs sight line - NO MORE, I will only use the Galbert method.

[@PeterGalbert]

Great to hear! Let me know if you have questions!

[@bobwhelk2117]

🤪