Saturday, March 06, 2010

GIS assembly starts! :)

All is well now, but I had a couple of setbacks very early.

Only yesterday I was saying to my brother how good my old Bosch sanding machine was. Well, I thought I'd give the frames a sand before installing them as it's easier now than later. As soon as I turned the sander on, there was was only running at 1/2 speed and there was none of the arm wrenching torque that I’m used to. I stripped it down thinking it was just clogged with epoxy dust, but sadly the motor or the bearings were seized. I've had this thing for 20 years, "Made in Switzerland", so I knew that its replacement was going to be made in China. :(

Off I went to Bunnings. The new Bosch and everything else that looked any good were ALL made in China. NOTHING operated at 24000rpm like the old machine, and the best of the them speed wise was the 250w Bosch at 12,000rpm. However, the Makita (11,000rpm and 250w) had better features than the new Bosch, like better paper grip mechanism and side dust extraction ports rather than through the paper. (My old Bosch had side ports so dunno why they've taken a backward step with "through the paper" extraction, which means it needs holes in the paper.)

And so I walked out with a Makita 1/3rd sheet sander. It's OK, and sucks up the dust very well, but I just knew it was going to be slower than the old Bosch, and it is. It is very smooth and quiet and gets the job done, but I miss the shear performance of the old Swiss made Bosch screamer that you had to really hang onto!

That episode set me back all of 3 hours.
My other problem was during the dry fit. The Paulownia bow stem just couldn't hold the middle screw while I was fitting BH1, and it popped open under the load. Luckily it was a dry fit run, so I've elected to glue up the stem and let it cure overnight under screws and clamps without stressing the joint. This will be nice and strong in the morning for a tilt at assembling the sides and frames. I will just proceed with a glue up and won’t do a a dry run first. Then I'll join the bottom halves for installation during the week.

Here are some pics of it as it is at present, with the stem curing... The $10 ceiling prop comes in handy as a spreader.  It will have some mighty work to do tomorrow, as the sheer has to be spread and the chines pulled in. The sacrificial 3ply that protected the Okoume plywood makes a useful temporary floor!

Below is a shot of the stem. Yes it tapers from top to bottom and therefore the angle changes down its length, which imparts "twist" to the sides, hence the usefulness of the spreader bar. The pic above shows the stem taper quite clearly. You can just see the clamp and the offcut wedges that are taking the pressure off the screws. despite the screw pulling through, I'm not worried about the Paulownia stem being strong enough. There is plenty of glued surface area there to take the forces that will be applied tomorrow. The bow will also get a hardwood cap which will provide further integrity to the joint.
Big day tomorrow!

1 comment:

  1. Nice fit on the stem. I had problems too with screws pulling out of my cedar stem. It was definitely soft. The whole thing can become a wrestling match, especially by yourself. Good move on walking away after gluing the stem!