Sunday, April 17, 2011

New Mast for Wanderbird

Wanderbird is a 50 tear old wooden ketch  with a pronounced work boat flavor. The owner had built the mainmast for more than 25 years ago from a tree he cut down in his backyard. It is visible behind the trailer which has two utility poles on it. It is literally falling apart.
These poles are not  actually very straight when purchased. The pole was 12" at the butt and 8" at the top and our spar will be 6" at the base, 8" at the partners and only 4" at the top. We used electric planes to straighten the spar and start to work it down to size.
This is the headstock of my lathe. I also have a full set of face plates for this lathe with the largest being 10' in diameter.

This is the tail stock and also a center rest/support that we built for this application. We poured 12" thick concrete pads under the head stock and tail stock and bolted them down in place.

Here we have the spar chucked up in the lathe and are ready to go.

Here is the tool holder for this lathe.It weighs several hundred pounds and takes 3 of us to drag along the work.

 The problem with this whole set-up is that the pole is not round and in column when we start working on it.
This means that the pole flops around on the center support.It seemed as though it would be simple to just plane off the high spots. But when we marked the top when it spins I can't tell if the hump is on the bottom and pushing the pole up or if the hump is on the top and just needs to be planed off. The pole,  at 50' long is also very spindly and flexible.You can see the out of roundness in the photo below. When the wood spins around and hits the cutter the pole flexes away and starts wobbling harmonically.Even with very light cuts and a sharp cutter the flopping would happen.

My center support started off as a pair of pneumatic wheels that were woefully undersized. The flopping blew out one of the tires. 

In this photo we changed the two pneumatic wheels  with 4 steel wheels of 14" diameter. This didn't work out any better because there was no give and the flopping was just more violent. The wood also was compressing where it rode on the wheels. I learned that the folks who really know this stuff have a center rest that is round and opens up and clamps onto the pole and the rest the rolls on rollers and any out of roundness can then be trimmed off.

We ended up finishing the shaping of this spar with the planes and sanders. We ended up using the lathe just to hold and rotate the spar.
We completed the shaping of the spar and painted it and mounted all of the hardware to it.

We have delivered it to Indiantown Marina for installation.

The crane has just set the mast.
The owner is in the foreground and is very happy with his new stick. We have learned a lot about the process involved in turning a long part. next time we will be more up to speed.