08082011

Our plan today was to get exact size of the ends by using band saw because there were quite enough margins on our planks of the ends. Prior to machining, we drew centre line and lines for each side, 140mm from the centre line. We drew another two lines for bottome of the end and a parallel line 10mm above the bottom line for makin rebate. On top of the end, we drew R20 line on both sides(right side and left side). To make both ends identically, we nailed two spots where the hole and the rebates are going to be made, which is okay to be made a nail hole. Using band saw downstairs, we found the surface of planks burning due to the blunt blade. We also learned how to sharpen the blade of the hand plane(bench plane) and how to use it properly. First use grinder with water, second use oilstone with thin(diluted) oil, make sure adjust the gap of tooth of the blade in about 2mm and so on.
There are differences between the big band saw down staris which has wider and thicker blade than another small one upstairs. Wider blade can keep the way the plank goes whereas narrow one make the surface curve easier.
Tips
- make sure leave lines that have been already drawn for being able to check when doing another job like sanding, planing, etc
- mind the grain direction before using certain machines such as spindle molder, buzzer, etc.
We cut the top to make radius(R20) by sanding disk which is quite dangerous until it stops(it takes long time to stop perfectly), and we take the nails away in order to put the planks into the sanding machine which is really big and can be adjust the thickness electronically as well as mechanically.
Terms
- faying surface(glueing area)
- AS/NZS 2271(can be used in boat buliding but not recommendable) grade 'A' face, 'C' back
- AS/NZS 2272(for boatbuilding) AA
- BS 1088(for boatbuilding) AA
- epoxy
- vinylester resin
- polyester resin

a nice site below to find the information about plywoods
http://www.gunnersens.com.au/products/building-products/plywood.html

Finally, we choose a plywood, which was AS/NZS 2271, for bottoms and cut it longitudinally by table saw and transversely by spider saw. That was all for today.