Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Sunday, August 26, 2012

First Parts Completed - Post Mortem

As I mentioned in the previous post, I wanted to use the first parts as a learning tool to fine tune my process for creating the frame parts. Unfortunately, one of the smaller parts was cut too close to the line and ended up being unusable.

Lesson Learned #1 - Insure that you have adequate lighting when cutting out the parts.

Although I knew that I had to cut away from the line outlining the frame, I got too close because of difficulty seeing the line. The light in my garage is not too bad, but for this type of work, a brighter light is needed. So I will spend some time to obtain a second light source before cutting out the next parts.

When I laid out the parts I placed carbon paper on the backside of the patterns, laid the patterns over the wood, and then traced the shape of the part onto the wood. I made sure to line up a straight edge on the pattern with a straightedge on the board. Furthermore, at certain points where lines met, I cut small circles in the pattern and drew lines on the wood. This allowed me to line up the pattern lines with the lines on the wood. So I know that I got the patterns accurately laid on the wood. The patterns were taped down so they would not move.

However, the next step was tracing the pattern lines and it's here that the process wasn't as good. I basically carefully free handed the tracing, which left the lines slightly wavy but for the most part accurately defining the shape. At first I felt this was okay and that I could correct this when sanding down to the final shape.

I was able to accurately sand the parts to the final shape through a lot of constant checking against the patterns.But this episode lead me to the next lesson learned.

Lesson Learned #2 - When tracing the parts, trace some points around the perimeter and then connect the points using either a straightedge or long batten (for curves).

This will insure that the lines are straight when they need to be straight and smoothly flowing curves when they need to be curves.So I am going to see what I can find to use as a batten. I am thinking perhaps a 1 inch by 1 inch by 6 foot long piece of wood. This should have enough flex to curve naturally and connect points transferred from the pattern. The straightedge will either be a yardstick or straight piece of metal.

Some other issues taught me a few other lessons. First off, when I cut out the larger piece, I cut quite a bit away from the line, approximately 3/32 of an inch and as much as 1/8 of an inch in some spots. This was a lot of material to sand down and made it more difficult to get the final shape in some spots. With better lighting, I could have cut closer to the line (without going over the line) and saved some sanding effort.

Lesson Learned #3 - Try to be more accurate when cutting near the line of the part, but don't cut too far away.

I also noticed that the remaining scrap lumber from the first board was more, than I had originally anticipated when I first laid out the parts on the scale drawing of the board. I had drawn a center line at the midpoint of the board and lined up the longest piece on that center line. If I had drawn the line more to one end, I could have still fit all three parts on the board and would have had a larger remaining piece of scrap. When it comes to scrap wood, the larger, the better.

Lesson Learned #4 - Be sure to lay out the parts on the board so that remaining scrap is maximized.

Of course, this last lesson must be tempered with the need to maintain accuracy and also must not force parts to be laid out in unfavorable grain directions.

So overall, I am pleased with the first results, although I regret having wasted lumber on one bad part. But I take heart in the fact that I learned these lessons before working on the remaining parts, so the process should go better on the next round.

I've added some pictures to the photo gallery of the first parts and the sander  bought. Until next time.....

Update 6/10/2015: I've decided to add a small tidbit about the patterns. Because of paper shrinkage, they are a bit smaller than the measured dimensions in the plans. I learned this in October of 2012 (see "Bit Of A Setback To Deal With" in sidebar). I resorted to laying out the measured dimensions on a large layout board and then using that to aid in getting the frame parts correct. Rather than repeat all of that here, it is suggested that you read that posting and subsequent posting to see what I did.

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