Woodworking in the great white north.

Marble Tower – decisions, decisions

I could go on about great planning and thinking ahead and any number of good reasons for why I went ahead and put the bottom mechanism in place long before I was ‘supposed to’…but in reality, it looked like fun, so I jumped ahead and did it completely out of sequence.

Having done this out of sequence turned out to be quite helpful when I was doing the short and winding road in the previous post, since I didn’t have to guess or calculate how high it had to be when it ended, nor did I have to figure out a way to attach it.  Yea me!

This part looked like fun to me, kind of like a small section of a mechanical binary counting machine you’d find in a kid’s science museum.  Ok, I’m probably reaching, but it evoked that kind of feeling in me.  Basically the divider flips back and forth between the two tracks, using the marble’s weight to move the divider as it passes by.

I pretty much followed the plans to a T for this part.  Well, except for the little trough at the end where the marbles rest….you can’t expect me to do a whole section by the book!

No real significant challenges in this part, just a lot of thankfulness that I’ve got a bandsaw, without which I am dead sure I would have done it differently…as in not at all. 

The one area where I spent some time and did a mock-up was on the little cog-wheels.  I wanted them to be the same and had a bit of trouble making the first one look just like the template, and it ended up a little off balance in the end.  From the exercise of building one, I figured out a more straightforward way of cutting them on the bandsaw.

The plans were to have a wheel with four spokes 90 degrees to each other but each with a slight curve to them, with a cylinder stuck on the end of each spoke to catch the marble.  This is a little tedious to do, at least with my tools….(feel free to read that as skills instead of tools).  So, instead I made each spoke a bit more like a teardrop shape, which was both easier and to my eye, a little nicer – less like the old erector sets.  The cogs spin freely on some thin dowel material (bamboo skewer to be exact), which I later trimmed down and capped off.

Instead of the planned for trough, I decided to let the marbles collect in a triangular pen.  I took some 1/8″ strips of ash and glued them from the uprights back towards the center where they intersected with this last mechanism, as well as one strip across the front to keep the marbles in place. 

 I tried dry fitting the triangular pen in place and it looked pretty good to me, so I glued them down.  Yes kids, it’s lesson time!  Dry fit…glue…sounds right.  Oh wait…there’s a mechanical activity happening somewhere in there too…a marble is supposed to be involved.  The plan should have been:  dry fit – TEST – rethink – dry fit – TEST – glue.  Insert sheepish look.

Apparently the marbles are able to bounce just high enough to hop over the ash strips, only to be found several minutes later with a telescopic magnet on a stick – buried in wood shavings under a cabinet.  After several such tests and some R-rated language I cut an additional strip to increase the height enough to bounce the marbles back into their pen.

Yes, this was done out of sequence (as you can see this part without the bell and winding road)…which I will claim was planned out for your viewing pleasure.  🙂

This was the last step in build process, but I am still far from ‘done’.  The tower now actually works, but there are some glitches and there are a few things I have to go back and revisit as well as some trim work.

My next update will include some pictures of the finished product along with a flawless execution of 10 marbles through the dispensing mechanism and all subsequent ramps, toys, bells and xylophones, to end with a pile of marbles nestled in the triangular pen with nothing but the faint pealing of the bell to give away the maelstrom of activity that just took place.  Too dramatic?  No…just you wait…you’ll see!

Still don’t believe me?  Ok…here’s a teaser….and if you watch carefully at the end you’ll see my issue with the inadequate front pen rail.

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3 responses

  1. Randy

    Getting close!

    September 8, 2010 at 9:18 pm

  2. Sweet tower. Sigh, add another project to the ‘list of things to build my daughter’. At least I have a year or so before she would be beyond eating the marbles 😀

    September 9, 2010 at 11:04 am

  3. Thanks guys,

    Mike…ya…that’s what I thought too. 🙂 My daughter’s 10 now…oh well, she’s still excited about it.

    September 9, 2010 at 3:06 pm

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