# Trying to pre-plan a project and having mental problems

 Forum topic by cassady posted 09-02-2012 03:55 AM 1071 views 0 times favorited 8 replies
 cassady16 posts in 2402 days 09-02-2012 03:55 AM I am trying to plan a project that will eventually be an octagonally-shaped cart for my air compressor. I have the plan in my head but I apparently lack the brainpower necessary to figure out how to join the pieces of wood AND also figure out the angle I will need to cut the wood at to form the octagon. Picture an octogon about 2 feet across. If anyone has a tip for figuring angles and then also knows a good way to clamp angled joints, feel free to school me! Thank you! -- Cassady in Denver, CO

## 8 replies so far

 DIYaholic19618 posts in 2669 days #1 posted 09-02-2012 04:44 AM Doing the math for the angles wood hurt my brain right now…...Clamping could be accomplished with a band clamp. Like this one on sale at Rockler. -- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing? Ryan Haasen385 posts in 2395 days #2 posted 09-02-2012 04:46 AM Matthias Wandel has a video about how to calculate the angles for a polygon (10 sides). While that part may not be such a great help, he also shows how he glues the angles joints together. Here’s the link, hope it helps: http://www.youtube.com/watch?v=_CRJsn_pQ7Q&feature=relmfu -- Ryan casual1carpenter354 posts in 2469 days #3 posted 09-02-2012 05:18 AM cassady, this might help if I have the tolerances set right lol. tomd2155 posts in 3764 days #4 posted 09-02-2012 05:26 AM Just do a Google search for a segmented angle chart. An 8 sided ring will need and angle of 22.5 degrees on the end of every piece. To clamp them, form the ring with all sides in their place, glue then rap a band aroung it making sure its flat an in an even octogon shape, I use a large rubber band or belt clamp. After it dries screws or splines can reinforce the joints. -- Tom D Howie2656 posts in 2917 days #5 posted 09-02-2012 11:29 AM 360 degree circle-divide by 8 = 45-divide by 2 = 22.5 like tomd said. Key is dividing the circle by the number of sides.I would use bisquits for alignment and a good glue along with a strap clamp or some type of rubber band. I buy surgical tubing at Lowes and it works great for rubber banding odd shapes. -- Life is good. helluvawreck31027 posts in 2861 days #6 posted 09-02-2012 12:26 PM A really good program for a woodworker to have is a CAD program. It makes anything like this easy. A really good affordable CAD program is Turbocad. helluvawreck aka Charleshttp://woodworkingexpo.wordpress.com -- helluvawreck aka Charles, http://woodworkingexpo.wordpress.com cassady16 posts in 2402 days #7 posted 09-02-2012 01:43 PM Thanks for the info everyone! Appreciate the sharing -- Cassady in Denver, CO Monte Pittman29216 posts in 2332 days #8 posted 09-03-2012 11:17 AM 8 pieces (obviously). Diameter X π (3.14) divided by 8 that’s the length of the pieces. All angles are 22.5 degrees. I build a lot of octogons. -- Nature created it, I just assemble it.

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