Seat Frame

This is the assembled seat frame. It is comprised of 3 pieces of 1" aluminum, the 2 sides and the top hoop.

Total cost: $18.47 CAD
Total project parts cost to date: $62.08
Total project cost to date: $69.27
Project budget: $200
Remaining budget: $130.73

Tube bending jig

These are the 2 tube bending jigs I built to bend the seat frame. The tubes are shown after they were trimmed for length. I had to heat the tubing to get it to bend properly because of the "spring back" when bending. 

Success!

I cut a new bending surface, this time with a 5.5 inch radius instead of the previous 3.5. As you can see no kinking and I didn't even use a groove! I may have to adjust the seat design slightly to accomodate the larger radius bends.

Failure!

Sadly, both the plain curve and the grooved curve both kinked the tubing. I suspect it has to do with the tight 3 inch radius I am trying to bend!

Making the bending jig

Here are some quick pics of me making the jigs for bending the seat frame. These will get screwed to the plywood layout I showed in an earlier post. The last photo shows routering a groove, I only did one this way, I will try it both ways to see if the groove is necessary to stop the tube from kinking.

More Rod Ends!

My eBay purchase of 8-1/4" rod ends arrived today. They will be used in the steering linkage for the trike. I love eBay, this project would definitely be done differently otherwise as parts like this bought locally would blow the budget :)

Total cost: $13.48 CAD
Cost if bought locally: $89.99
Total project parts cost to date: $43.61
Total tool cost to date: $7.19
Total project cost to date: $50.80
Project budget: $200

Remaining budget: $149.20

Laying out the seat bending jig

Today, Jack and I drew out the seat profile on a piece of plywood. This will later help align the bending jigs. I was surprized, the seat is smaller than I thought it would be, just like the frame. I have heard before that you can't lay out angles accurately with a protracter, but now I believe it. I would first measure the angle with the protractor, then have to adjust it after I measured it with a ruler. To measure an angle with a ruler I used:

Tools!

I received my router bit I bought on eBay today. "What does that have to do with trike building?" you may ask. To fabricate the seat frame I have to do some somewhat complex bending of 1" aluminum tubing (LINK). I could buy a conduit bender but as Grant points out, I am too cheap ;) A bender (LINK) costs at least $33.00 and I would probably need 2 of them. I can make my own bender like this LINK or an alternate method is to build a bending jig out of wood. Here is a LINK to an example. I am probably going to build a jig but add the curved trough that the bender has to lower the possiblity of kinking the tubing. THAT is where the router bit comes in. I will assemble the jig, then cut a groove for the tube to sit in as it is being bent. Clear as mud??? I will post some pics when I start bending some tube.

Cost = $2.10 for the bit, $5.09 for shipping from the UK for a total of $7.19 CAD ($45 at Lee Valley). Total project cost to date $37.32