Saturday, April 18, 2009

Finished Calf Stretchers

Here is a look at the finished calf stretchers.  These are the ones mentioned in an earlier post.  They are made from Lacewood and Curly Lyptus.  It is a hand rubbed finish of wipe-on polyurethane finish.  These are now for sale for $70 each.  I have prospective buyer for each one, and I am always making more.  I believe I have now made 17 of these.  I especially like this combination of woods and think these are the best I have made so far.

Friday, April 17, 2009

Engine #2 is Up and Running!

I accepted the challenge some time back that I would design and build a Stirling Engine that would run from the heat of your hand, and could be built without a machine shop.  The first engine I made did all that, but it didn't have any spinning parts.  The man offering to publish the book wanted an engine with a rotating flywheel, as this is more appealing to our potential audience for a book.  

I sketched out two more designs that were modifications of my first working model.  But then I got side tracked with more back surgery and both new designs (#2 and #3) were partially assembled for over a year.

This week I took two days off work and made a commitment to get them up and running.  At 1:00 PM today my second design (with a rotating flywheel of sorts) started running, and it has been going strong for most of the last 8 hours.  It has not run from the heat of the hand yet, but it has run on sunshine with no ice, and when inside it runs with ice when sitting next to a 60 watt light bulb.  I have a high level of confidence that this engine will run from the heat of the hand after some minor adjustment to the crank shaft and the addition of a little helium.

I believe the last of the three designs will be the most efficient.  It uses the same ultra-low friction design of the first engine with the addition of a rotating flywheel.  It should be also up and running by the end of the weekend.  After that I then have to get back to the text and finish up all the assembly instructions and organize all the pictures and illustrations.  The end of this project is in sight.

I don't know if I still have a publication deal or not.  I would not be surprised to learn that the offer has expired.  If I have to start over finding a publisher I will be looking into self publication with print on demand.

Sunday, April 12, 2009

Calf Stretcher Progress

It was a nice rainy day today, so I spent part of my Easter in the garage making sawdust.  The picture shows my progress on two calf stretchers I am making.  I am long overdue on this order, so it is nice to see them start to come together.

The dark wood is Lace Wood.  The light wood is Curly Lyptus.  Curly Lyptus is a hybrid of the eucalyptus tree and is a product grown by Weyerhaeuser.

The joint is a dovetail, but because those tend to be a little loose I will also add some braces on the back side.  The pieces are currently a little over sized and will be cut down to their final dimensions before they are finished.  

The wood will remain unstained and will be finished with a wipe-on poly finish.

Saturday, April 11, 2009

Fixing Genoa Sheet Binding Problem

Last Sunday was my first trip out in the boat for the 2009 season.  I was alone on this trip, and I didn't have a lot of time, so I only spent a couple of hours on the water.  The trip quickly reminded me of some of the other little issues that I wanted to fix this winter.  One of them was the way that the Genoa sheet gets cleated.  The standard installation of Genoa tracks and blocks on a Potter 15 uses the same cleat that is used for the smaller head sail.  This causes the jib sheet to have to traverse a sharp Z pattern through the blocks and cleats.  This sharp Z pattern causes a great deal of drag on the lines and it is hard to come about.  Wind alone is often not enough to get the Genoa to change sides.  I repeatedly had to pull rope through the windward side pulley because it was binding in the cleat.

I addressed the problem by mounting a second set of cleats aft of the Genoa tracks.  I looked at lots of options in the marine store and finally settled on a simple clam cleat.  It fits well in the confined space, was pretty cheap, and has a proven track record of working well.

The pictures posted here show the patterns the lines followed both before and after my modification.  This should make the lines release freely and simplify tacking when using the Genoa.