Sunday 29 October 2017

Rain forest part 4 - all cylinders

Today on the bidoowee channel: we are making cylinders!

I was holding back from tackling the handles for the steam and h.w. in the hopes that I could find something off the shelf. I've been looking for months and I have a number of candidates, but there are problems or complexities with them all so I am admitting defeat and making them out of tree. I wasn't particularly happy about having both wood and plastic in the design in any case, so there is an upside.

All that to say, we are not out of the woods yet ;-)

I cut another section out of leftover lumber and ripped it into two squares profiles.



Then I knocked the corners off to get closer to the final shape. 



Then I put the dreaded four jaw chuck on the lathe. I hate these things - what a pita: use a dial gauge to measure one side of the stock. Rotate the workpiece 180 degrees without upsetting the gauge, measure again. Move the stock by adjusting the jaws by half of the offset between the opposite sides. Repeat until it is correct or you get bored. Then do it again for the other two opposing sides. Tighten everything down, then readjust because the stock is soft. Requires the patience of saints.



I did some fairly careful planning for cutting these parts because they are reasonably complicated. I figured that I can get all the pieces out of two 29 1/4" lengths. The octagons just fit between the chuck and the tailstock of the lathe and, with about 1/8" to spare between the thread chasing dial (which I thankfully no longer have to use 'cause CNC is the just the bees' knees for threading thank you very much) and the pillow block, there is enough travel to machine the entire length. 



The setup for the machining requires good dust extraction to keep all the crap from getting onto the ways and into the screws. A metal lathe is really not the correct tool for this job, but I don't have an alternative. So, I found a high tech solution: elastic bands and bailing wire to hold the vacuum nozzle in place and scrap of plexi held with a magnet.



A number of passes were required, but the carbide bit is fairly sharp and leaves a reasonable finish on the wood. 



I also made a blank out of foam so that I have an expendable test piece that wont break any tooling during the next phase of machining.




Result? Two wooden dowels and a foam blank. Total excitement.



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