Box Fest

It was about 10 years ago when I spent a month working at an injection molding plant. I had about 6 weeks before my new job started with GEICO and this gave me something to do while I waited. The shift was from 11 pm – 7 am and I rather enjoyed it. Most nights I was on a machine which made screens which were part of a Maytag dryer. There were about 7 steps in the process and if done correctly it took less than a minute to make 1 batch.

The plant posted daily production results and also had top volume for each machine by hour. The machine I was on had a record of 71 batches per hour, though the average was around 58. My love of Theory of Constraints came into play and I beat the record on the second night, putting up 73 batches in one hour. For the shift I averaged around 70, and I knew I could do better. The next night I was on a different machine, which disappointed me greatly, but the following night I was back on my favorite.

It was amazing how quickly the shifts went. I was so completely focused on beating my own record that each hour was like starting a video game. Shaving just one second per batch would get me a whole extra batch in that hour. The machine had a kill switch and if one opened the door too quickly it would stop things in their tracks and I would need to wait for a supervisor to reset it. This would ruin the hour for me. I tuned my mental clock to know exactly how long I had to wait before I could pop the door. That night I had pushed the new record to 75. I averaged 72 per hour.

Over the remainder of my time there I was only able to have one more record breaking hour, when I got it to 76, but I was able to average 74 per hour. The other two shifts during the day and afternoon stayed at 58. I crushed them. I calculated the excess value by producing an additional 16 per hour. If all three shifts did this, over one year, it would generate more than $750,000 in profit, with no additional expenditures. (Note to TOC enthusiasts: I was able to find out the totally variable costs and included that in my calculations)

I was saddened when after 6 weeks, when my time was up, not a single person at the plant was curious as to how I was doing it. They tracked the numbers with microscopic precision and yet my complete domination of the other two shifts didn’t warrant so much as a ‘Hey, I was curious if you could show us how you are so efficient.’

I love efficiency, for efficiencies sake. When I first started making tiny boxes I spent close to a week trying to get my first set of 4 box sides done. I had to create a jig for my router table, as I didn’t have Jeff the bandsaw yet, and screwed up my first two attempts. The third attempt was successful, but far from perfect.

An Efficient Day

When I finished my 5th attempt I had Jeff the bandsaw and a digital level. This made a world of difference. I could get dead on 45 degree angles, now I just needed to come up with a method to better control the feeding of the wood past Jeff’s hungry teeth. The problem with cutting a piece of wood on a table which is tilted at a 45 degree angle is that pesky gravity stuff. Try as I might to hold the piece steady against the miter gauge, I would still let it slip south slightly, and thus create a curved cut. I could then make another pass, but this led to varying lengths of the sides.

To gain the approval of the sharpening monks, which I so dearly covet, I feel I must be able to develop a methodology which is repeatable and accurate. The first problem which had to be solved was the issue with the gravity. Naturally I first started by trying to convert my anti-gravity super ray gun (originally designed for world domination), into an anti-gravity super band saw jig, which could also kill alien predators from a thousand yards. Sadly, removing gravity from the equation turned out to be more challenging than I had hoped.

I decided to let gravity to continue to do its ‘pulling’ thing, and I would simply construct a barrier which would hold the piece as I slid it past Jeff’s razor sharp teeth. I like to build stuff using Rockler products, it makes me happy because they are so shinny. I took a 3 inch multi track and checked to see if it would fit in the miter slot. It did! This would make a perfect rail to support the pieces.

I tried several practice pieces of scrap and it worked beautifully. I could feel a plan forming in my mind, and though it had nothing to do with taking over the world, I was still very excited about it. I had purchased two pieces of 6 x 36 x 3/8 inch wood, one oak and one hard maple, and they would be perfect for trying out my new method. With a desire to be efficient, I decided that I wanted to get 6 boxes out of each piece. This would require precision and an adjustment to the rail. Since each piece could not exceed 3 inches and I needed to factor in the thickness of the blade for each cut, I decided to cut each piece at 2 and 31/32 in length. The angled cut would need to be slightly shorter still, so I added a piece of wood and another track which I had laying around. This raised the rail up so that each piece after the miter cut would be exactly 2 15/16th in length.

The set up was ready. I started my timer on my iphone and begun working. I ripped the two boards into four, then routed out the groove for the bottom piece. The tools in the shop cheered as I moved on to step two, the cutting of 48 box side pieces. To keep everything straight, I carefully labeled each piece, and after all 48 were cut, I set Jeff’s table to 45 degrees. Each cut box set was carefully laid out on my workbench and I took great care in making the miter cuts.

Because the goal is to have the grain wrap around the box, I discovered a pattern to cutting which would yield the best results. It is hard to explain in words, so I want everyone who cares, to get a piece of paper and draw four squares in a horizontal line. Then number them, starting with the first square, in the top left corner, with a one, then put a two in the top right corner. In the next square number it two and three, then three and four, and finally four and one. These are the corners which need to match up when the box is assembled. One could certainly figure it out by looking at the grain, but with the numbering system, it saves time.

Because the corner left side of piece one and the right side of piece four come together, the grain will never match on that corner. This is important to consider. Each piece is slightly larger than it will be after being cut down. The first cut on the piece reduces it to 2 15/16, while the second cut lands perfectly on the wood as to not remove any additional length, but just cuts a 45 degree angle. This may not make much sense, but the point is that I cut each piece the same way, for all of the boxes. The first cut is piece one, side 1, then side 2. Then piece two is done in the opposite order, cutting side 3 then side 2. Piece three is side 4 then side three, and finally, piece 4 is side one, then side 4. This methodology results in the best match up for the grain as it crosses from one side to the next.

There is one additional benefit of having such a specific order, it requires focus. The need for focus, in my opinion, keeps one from making mistakes, and may help prevent injury. It was not mindlessly making cuts, but really watching how I did each one. In the end, I ended up getting 12 boxes cut, in 1 hour and 24 minutes. Compared to the 1 week it took me to get the first successful set cut, this is a marked improvement.

Now that I have a dozen boxes which are exactly the same dimensions, I will be able to focus on creating a process for efficiently cutting the bottoms and lids. I love efficiency and today was a festival of box making, which brought me much joy. And like any good festival, I choose to celebrate my triumph with a cookie!

2010: 08/04
CATEGORY: Projects
TAGS: Tiny Boxes
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Brian Meeks

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