Blades...Who Knew

While I still have a chance (before returning to work) I have been continuously cutting out the many bulkheads/frames required. I have also been learning about a multitude of things along the way...

I ended up purchasing a Bora Cutting Guide for $40 at Lowes thinking that this would be the end-all solution for straight cuts with my jigsaw...the idea was perfect. As you can see in the images, the guide has a quick clamp with rubber fittings to secure it in place. The first difficulty I encountered was the setup time required for the level of accuracy required. It took quite some time to setup the guide for each cut and with hundreds of cuts looming...I think that I may save its use for very long straight cuts. Also, the guide is limited to angles less than 22.5 degrees. This also made it somewhat cumbersome to use.

I also spent some time learning about jigsaws and jigsaw blades. Turns out that a Swiss engineer by the name of Albert Kaufmann invented the jigsaw/jigsaw blade. He did this while working at Scantilla AG company by simply replacing the needle on his wife's sewing machine with a blade....interesting. Apparently Scantilla was later taken over by Bosch and there you have it. 

I am also learning that there are many different types of jigsaw blades...wood, metal, etc. I currently have three different types of blades (Bosch) in my possession...T101BR, T101B and T101AO. T101B and T101BR both have the same number of teeth per inch but the tooth orientation is simply reversed. This allows for nice smooth cuts with less splintering either on the top or bottom of the cut (T101B - bottom and T101BR - top). The smaller blade T101AO has a larger tpi, is thinner and is slightly off centerline. This coupled with orbital blade motion apparently allows for smoother cuts around curves. The teeth on the T101AO blade are oriented straight out. 

All of these blades have what is called 'taper ground back teeth' that allow for an almost splinter-free cut. According to what I have read, they cut at a slower speed. This is why I may have seen the splintering in my previous post. I was using full blade speed with a very high feed rate. Interesting stuff...at least to me, the novice.

Patience Is A Virtue

Well, I have yet to finish drafting all of the frames but I could not wait any longer to do some actual cutting. Even though the thought of cutting into this expensive plywood is somewhat unnerving, I decided to go ahead and cut out some of the 9mm frames that I have already drafted and that have simple geometry. A few interesting things happened while doing this....

Now, I will be the first to admit that I am not yet a true woodworker so these findings may seem trivial to those with more experience....

I decided that in order to make the process a little easier, I would cut the large plywood board into a more manageable piece that would allow for easy manipulation to cut the smaller frames. I made the cut very quickly with the jigsaw and found that the outer lamina splintered along the curves (as seen in the image). This is a little concerning. I had read that Meranti plywood is prone to splintering and have thus confirmed it. I will have to pay attention to grain direction and also adjust the jigsaw blade speed and feed rate when I cut curves on the actual frames. I am also wondering if a small coat of epoxy on the outer lamina around the curves would also help prevent this from happening.

It also turns out that my freehand attempt at cutting straight lines with a jigsaw is not as good as I thought it was...overconfident from my sailplane days. It seems a guide is in order. I think the frames I cut will suffice but being somewhat OCD about things like this I will not continue until I get a guide. I am looking at a Bora Cutting Guide to help alleviate the issue. I know that a peice of straight metal and a couple of clamps would work but the thought of a quick release cutting guide is enticing.

All in all...I have my first frames cut...exciting stuff!

Back At Work

I was finally able to return to work on Summa. Albeit daunting work, it was still nice to be out in the garage. I have spent the majority of my time transferring the drawings to the plywood. This is a rather easy process but still very daunting and time consuming. I have to admit that I had to acclimate myself to the coordinate systems that John Welsford uses on his drawings...format is somewhat strange.

I needed to generate some nice smooth curves on the plywood so I ended up getting a relatively cheap piece of molding from Lowes (the long white plastic piece in the image). I was able to pin it in place and generate the larger curves for some of the frames. For smaller curves, I ended up using a french curve.

Mattie was keeping watch for me over the neighborhood. She has turned out to be quite the helper fighting off June bugs that are attracted to the floodlights that I use at night.

I cannot wait until my little first mate can join me in the garage (assuming she is interested). The weather has been tolerable thus far but the Texas summer is fast approaching and the heat will make it somewhat miserable.

A Slight Delay

My apologies about the time gap in posts....I had to take some time off from working on Summa.

My little first mate was born on May 1st. One of the best days of my life...two women now occupy my heart.