Sunday, May 1, 2011

Lofting

                        
23:03:11
Today we started learning about lofting. The first thing we had to learn was how to form the grid which is the platform for you to draw the boat. To draw this grid you need to start with a center Line and a LWL, these are parallel to each other. You then measure out the station points and draw them in 90⁰ to these lines.
You then have to add in your water lines and the buttock lines (B100 & B250). This then gives enough information so that you can start plotting points for each of the different lines. Sheer, deck-line, chine in profile view, chine in ½ breadth view, ghost line, canoe body/stem by reading the table of offsets to give you the information needed to plot these points.
                                                                                                 

29:03:11
Today we started masking in the lines that form the boat. To do this we first measure and mark out the points then tack in the nails on these points so that we can run a timber bottom around these curves to achieve a nice accurate line that can be drawn in.
We found a few problems with the offset tables where because of them the lines wouldn’t fit. The first thing we did was go to Merf and asked him what he thought, (where has this happened and on what line). By the end of the day there was a few of us that were up to drawing the Butt 250 line in the profile view and we all seemed to have a similar problem where, on station 3 and 5 the batton would not meet the line. We got into a small group and worked together on one lofting and found that a couple of measurements on the table of offsets were incorrect. The measurement on station 0 was -18mm which means that you have to measure 18mm below the LWL. When looking at our line drawing we picked up on this problem and came to the conclusion that it should most likely be +8mm instead so we changed this measurement to see how the line fit them. It looked better but the batton was still not touching at station 3 and 5.
We all agreed that station 4 was the station that was incorrect, because the point was too low. We pulled out the nail at station 4, this made the line fit, what looked to be really well.
We then went back to our line drawings and compared the lines by looking along them and this confirmed to us that the change we made to station 4 was correct. We then got Merf to check what we had done and he agreed with us that taking station 4 out was the best option. We then changed the point for the LWL on station 4 on the table of offsets.

Oilstone Box

To make the oilstone box we used Tasmanian Oak which is a hard wood. I used a single piece of wood to make my box. I first dressed it using the thicknesser and buzzer, I then docked it to length. After that I marked out whereabouts I wanted to clear out for the oilstone to fit inside of the box. Once it was marked out I used the drill press to drill out as much of the excess wood as possible, before using the router on the jig to remove the parts around the edges that the drill missed. This then gave a reasonably tidy rectangular shape taken out from the center. I then used a chisel to tidy up the corners and make sure that the oilstone fit in nicely. I did this for both the top and bottom of my box. Once I was happy with the fit of the oilstone I then found the center of my timber and cut it in half so the lid could then be placed on top. As I had excess wood on the end of my box to allow for any mistakes I then had to use the drop saw to tidy up the ends of the oilstone box and cut it to the correct dimensions as shown on the plans. This gave me a tidy finish to my box.
Once this has been done I then marked out where I wanted the beveled edge on the lid. I used a legit Stanley number four plain to plain off the beveled edges. I made sure the blade (iron) was really sharp to make sure that it gave me a nice smooth finish. Even on the end grain.
The final thing I had to do was the scallops on the base of the box. These are added in the design to make it easier to pick up off benches. I used a spoke shave to create the scallops.
My oilstone box is practically finished but I gave it a light sand after everything else to remove any small imperfections or marks on the timber.

Toolbox

The first thing we made on this course was a toolbox. At first I was wondering why we were building a toolbox as I thought I had signed up to a boatbuilding course.
Once Merf explained the process that we were going to use to build a boat I then started to understand how it would link into boatbuilding. An example of this is nailing two pieces of wood together so when I plain them they become mirror image of each other and match perfectly, just as the hull of a boat should be. It was also practical for us to build this first so we would have somewhere to store our tools later in the year.

We started by making a cutting list so that we had an idea of how much timber we would need for each part of the toolbox; (sides, ends, handle and base).
The timber we were given was rough sawn Radiata Pine, 150mm wide and 25mm thick. We had to dress this down to 20mm thick for the ends. We used the thicknesser until we reached the right thickness. This also gave us a nice smooth surface to work with.












Ends
Each end is made out of one piece of timber, 640x150x20mm after being dressed. We then cut them in half on the line shown in the picture (1). They are then put on top of each other and nailed together (2).
By doing this it means that when you look at the end of the box it is a mirror image on either side because the two pieces of wood used are exactly the same. We repeated this process for the other end of the box. We also rebated out along the bottom and up the 150mm side, while we had them nailed together.
Once the ends were all dressed up we pulled them apart and folded them out. We then glued them together to make the ends of the box (3).
Sides
We dressed the timber for the sides down to get them smooth but left them as thick as possible because we planned to use the big band saw to do a process called ‘deep ripping’(4) . This is when you cut the timber in half, right down the center.
We then had to dress this cut edge once again to smooth it off. This meant that we lost even more thickness on either side. On the plan it showed the sides to be 10mm thick. Because of the thickness of the timber we started with, after we had dressed the timber we ended up with about 8.5mm thick sides. This is still plenty strong enough.

Handle
When making the handle we decided to use a shouldered tennon joint to join the handle to the sides of the toolbox. We kept the piece of timber extra long in case we messed up the join. Once you have one end right you then have to cut it to the correct length to do the other side.
Unfortunately, I started with a really nice join but then once I cut the other end I made a slight mistake which made the join not fit cleanly when I fit it onto the box.
The handle had sharp edges so we used the bench router to round the edges and make it more comfortable carry around.

Base
The base was made from plywood we just cut the sheet of ply on the big bench saw. A few of us cut the ply for the whole group. We made them slightly bigger than we needed so that they could be planed down to the correct size for each box. We used a hand planer for this.

Construction
Once we had all the parts of the box cut and dressed, we were able to start assembling the toolbox. For this we used PVA glue and nails. I felt that my toolbox had been coming along quite well, but I did pick up on a few faults when it came to assembling. For example; when I cut the sides down to length I didn’t check that the drop saw was cutting perfectly square. When it came to assembling my toolbox, not all of the sides fit neatly into the ends of the box.

Some of the tools we used were:

·         Buzzer (planer) - used for dressing the edges of timber.
·         Thicknesser - used for dressing the faces of timber.
·         Bandsaw - used to deep rip the timber for sides.
·         Seed sander -used for dressing faces of timber
·         Large Belt Sander - has the same use as a speed sander
·         Router - used to make the rebate (rabbit), on the ends of the toolbox, for the sides and base to fit into.