Wednesday, June 6, 2012

Wooden Propeller: The Build

A few weeks back we gave you the plans for a wooden propeller, constructed the old fashioned way. This week, we'll reveal our progress on the build.

Buying Lumber
The plans call for four 8"x8' planks. If you have to use boards that small, the sections will all fit (see the layout diagram) and you can buy hardwood at Home Depot or Lowes in that size- although I strongly discourage it. I purchased lumber through a local mill. All the mills in my area are set up to deal with contractors and bulk buys- but a few are willing to work with average Joes who are just looking to build something. The place I visited wasn't terribly thrilled about helping me find four pieces of lumber, but they did anyway. I ended up with two pieces of Red Oak measuring 10"x12' and two pieces of Ash measuring 10"x10'. I was able to dig through a few boards until I found ones free of defects with grain patterns I liked. The mill didn't have any boards in stock at the 8"x8' dimensions so I got the closest they had in the next size up. It turns out the larger size was really beneficial during the layout process to be able to pick more visually pleasing grain patterns. The total including tax was $91 for 44 board feet of lumber. Just one 8"x8' piece of Red Oak from Home Depot costs $49. Definitely worth the trip to the mill. Normally they would mill the lumber down to the size you need, but their planer was broken. Go figure.

New Tools
Without planing the wood, the prop would be about 7 inches thick. That's way too thick for a 6' prop. So I had to find a solution to the thickness problem. The lumber spent a few weeks in a somewhat weatherproof section of my carport waiting to be planed to size. With the mill's planer still being down, I got permission from my wife to add a planer to my tool inventory. I took a gamble on Craigslist and broke two of my own rules: 1) don't use Craigslist. 2) Research a product to death prior to buying it. I ended up getting a Ryobi 13" benchtop planer for $100 less than retail. The guy I bought it from used it to plane one pice of Pine and hadn't used it since. I was happy to take it off his hands. So for once I finally had a positive experience with Craigslist and I got a virtually brand new tool for half off. In regards to rule number two, I later found out it won a best value award from Fine Woodworking magazine and the reviews online back that up- it's not a pro piece of equipment but for what I was doing it was the best choice.

Cutting the Sections
A friend of mine let me set up shop in his garage. It felt like the Ritz compared to working under my carport- electric outlets, a fan, shade, and a steady stream of Navy jets overhead... Before sending the wood through the planer I decided to cut the blanks with my jigsaw first. (Highly recommend this jigsaw- it's won awards from Popular Mechanics magazine). As you can see in the photos, I varied from the original layout, but I had room to do so with 8' more board feet than I originally anticipated having. This allowed me to keep the prop sections aligned with the axis of the grain. I have plenty of scrap leftover for a base/wall mount. We traced the cut patterns onto the lumber and cut with a jig saw. There is quite a bit of cutting to be done with the jigsaw- we went through two blades. Also, accuracy here will save time sanding and shaping later, so be as precise as possible.

Figuring out the ideal layout.

The modified layout. You can see the slight color variation between the Red Oak (R) and Ash (L)

I wasn't sure how the planer would handle the strangely shaped pieces, but I figured it was worth a a shot. Turns out it saved a ton of time versus actually planing down the four planks in their entirety. We were able to shave down 1/64" per pass, so it took a while to get each section down to the desired 1/2" thickness. Had we actually put the whole plank through we wouldn't have been able to do as much per pass and it would have taken for-ev-er. The joys of hardwood. We also learned the circuit in my friend's garage wasn't capable of keeping up with the planer running at full tilt, a shop vac hooked up to the dust collection port and a portable fan. So we unhooked the shop vac and just made a mess.

All the cut sections- before planing. Way too thick.

With everything planed down to the proper thickness, assembly can begin. I started by transferring the vertical centerline on the paper templates onto the edges of the hub of each section. This serves as a reference line to ensure all the sections have the correct rotation to match the drawing. Then I started with section 4 (the longest section) and glued sections one at a time to the top and bottom until all the sections were glued on. Only glue one layer at a time. Clamp and allow to cure for several hours before attaching the next layer. This is where having plenty of clamps comes in handy. The more the merrier. I have 7 Irwin quick grip clamps that I used. I wouldn't use any less than this- I had a few gaps in between layers which I'll have to fill later on. It's cool to see this for the first time in 3D. I'm excited to see it take shape and I'm sure i'll be pleased with the results.
Halfway through the gluing process

You can start to see the profile taking shape

Well that does it for this progress report, check back next time as we start the process of blending the layers together. While you're waiting, check out this more modernized process of propeller building:

You may also like:
Wooden Propeller: The Plans
Plans for a Versatile Garage Workbench
Project Inspiriation

1 comment:

  1. Thank you very much indeed for the most excellent layout of the clear procedure to build this propeller. I have many times read the "report" and have visited the site times and times again looking for the next promissed serial of photos and discriptions - final prop. Please do not leave as orphands. Keep up the wonderfull work and please post more photos.