DAYLIGHT SAVINGS SUNDIAL or Adjustable Dial

Finally...an adjustable sun dial clock. Most sundials are set so 12:00 noon is straight up. With daylight savings time this should be one (1:00 pm). So you must add an hour from a normal dial and if that is too hard better sundials have a graph that shows minutes to add or subtract. (see photo). Not that you can ever get perfect time from a sundial but this will make it easier.

What to expect...an easy 6 piece print, 5 screws (2,3mm), 2mm rod. Tilt base to set the gnomon angle.

This took me seven minutes to assemble including taking photos.

There are many sundials and they most common is the horizontal. This has an angled fin and projects a shadow to a flat surface. This fin or shadow maker is called the GNOMON. Because the shadow lands on a flat plane the hour dial is not evenly spaced so rotating the dial won't work. The only sundial that has evenly spaced hours is the ARMILLARY type. (ph1) This sundial also has the best sculpture shapes. So just by rotating the dial band you can set the hours for daylight saving and once a month to compensate for the minutes.

The PLANER sundial looks best suited for dial rotation. (ph2-5) But if you look closely you see the hour dial is underneath as well as on top. When the equinox is summer the top dial works and in winter the bottom dial works. So you have to bend over to read the underside of the dial in the winter.

A good sundial sculpture has a graph that shows the minutes to add. (ph6)

Here are most basic types of dials. As you can see the armillary looks the best and works for an adjusting dial the best.

The photos are close to the order to build. The slide prints with some bumps and it dosen't fit well at first. Slid from one end then the other about half way a few times and the slide will loosen. Do NOT file or sand these will fit with just a small amount of force. Be patient.

After the slide is ok then fit the shaft into the carriage. This may take some sanding and file the downward face of the carriage print. The shaft needs to move easily but not loose. Again NO gear yet.

Connect the carriage and sled with a 3mm nut and bolt. The nut will slip into the slot in the carriage. Tighten and keep the two even at the ends.

The sled has 2 slots for the nuts. Insert and install the sled into the base. The arrow is on the side with the degrees.

The dial has 2mm holes that match the holes in the sled. Attach with 2mm screws at all 6 holes with 1.00 pm in the center and the numbers face away from the gears. If you want a regular dial set 12.00 pm at the center. The dial could be printed with the slide but you may prefer to adjust the position of the dial. You may want to glue the dial to the slide if the sundial is mounted in a place where it may be bumped often.

Add a 20mm compass. My print uses a 20mm but some compasses are 15mm so you may have to change the print.

Finished photos. I printed 4 color sets then mixed the parts to get a varied dial. The GNOMON angle is your latitude or around 35 degrees. This scale is on the side of the base and each step is 10 degrees. I olny had room for the 3 as in thirty degrees.

The arrow is any wire. A coat hanger is good but #12 gauge copper romex is 2.5 mm the size of the center hole. The gnomon must be long enough to give a shadow in the winter so keep it about five inches (130mm).

The base has screw holes in the legs as well as the center of the base under the sled. Mount on a fancy 4x4 post for a garden location or on a 1x4 cut to size as the plastic weight may blow off a table.

Oh the building inspector constantly watched as I took all these photos!

Thanks for viewing my sundial. As with my projects I spent hours making sure all pieces fit and went through many prototypes before sharing the post.

Please see my other stuff....oldmaninSC

A final sundial that can only be used in the summer. This uses an empty 3d spool. The dial snaps on and the sled base needs a nut and bolt through the spool to make a base support. The sled and sled base are the same as in the other sundial. Because the spool is heavy the base needs to be screwed down. The dial just rotates around the spool...no gears. The S shaped spokes add a spring tension to the dial so it stays in place.