(AH) Alignment Hole Click Gear

Steve asks Clayton: 

I've noticed on the Swing Time plans the notation "AH", which I hadn't seen on other plans I bought before.

Maybe I missed it, but what does "AH" stand for?

Thanks

Steve 

Aloha Steve, when parts need to be reinforced during gluing, or need to be aligned in a specific orientation, I will add alignment holes (AH) notations to the plans to be sure that the parts are aligned correctly.

In the SwingTime plans that you are working on, the parts of the Daisy Dial Train need to be aligned correctly to get the hour and minute hand assembly to work properly.  

The Daisy itself has an up and a down.  The cleft in the Daisy needs to be positioned UP, and the rounded bulb placed at the bottom.  The exact alignment can be achieved between the Daisy and its Support by inserting a short length of rod into the alignment holes during gluing.  These rods can be left in place, or they can be removed after the glue has dried.  In this case the choice of leaving the alignment rods in place or removing them is up to the builder.

Also in addition to positioning the Daisy on its Support, the Tri needs to be positioned correctly on the Daisy's Hour Hand so that the the Hour Hand is pointing in the proper direction to show the correct time once assembled.

For both of these situations exact alignment is produced using the Alignment Holes (AH) provided in the various parts.

There is another situation in which alignment of other parts, such as gears, is critical.  For example, in the Genesis plans there is a "wheel set" (a pinion and a large gear) that need to be aligned during assembly.  Alignment holes in those parts show the builder how to achieve the correct alignment of the teeth of these gears that will allow the clock to show us the correct time.  

Other times you might see Alignment Holes in the Click Gear and its Support in the rewind system of the clock.  In this case we Do Not want to remove the alignment rods after the glue has dried between the parts.  The alignment rods in this situation allows for a stronger joint between the parts than what is provided by just the glue.  The reason for this additional strengthening of that glue joint is that the Click Gear must support the entire drive weight of the clock.  We certainly don't want the Click Gear breaking loose from its Support.  Leaving the alignment rods in place allows for a bit more insurance against separation of that glue joint, and helping to prevent the drive weight crashing to the floor.  "Drive Weight Crash (DWC) Prevention" is also why I recommend using only the highest quality plywood when creating the Click Gear and Clicks.

BTW...once the Click Gear is glued and pinned to its Support or Pulley, I also add a coating of cyanoacrylate glue (CA or Super Glue) to the tooth surfaces of my Click Gear ~ just for a little more insurance against Drive Weight Crash.  That additional procedure of adding the CA may be overkill, but I'm superstitious.  (I've also learned to stop listening to the voices that come out of the electrical box in the attic storage room)

In over twenty years of creating these wonderful mechanisms I have only had one DWC...and if you've ever had one, you know that one DWC is one to many.  So using high quality ply to make the Click Gear and Clicks, and the addition of the support pins to assist holding the rewind system's glue joints together, will help to avoid the dreaded Midnight Crash Syndrome.  

I hope you are enjoying your build and please send pictures when you get your SwingTime completed.  

Aloha.  Clayton