Longcase (Grandfather) clock with 3D printed gears etc.

[Gina]

With the weather so bad for anything astro I'm considering getting back to this.

[MarkAR]

In between the Giant printer build and the Horse Show Mount, I surprised you don't end up with a Horse Shoe that tells the time and strikes the quarter hour 😊

[Gina]

I have a design for the clock for striking the hours (1 to 12) which I plan to incorporate.  Chiming the quarters is a tad more difficult!!  Though designing cams in CAD isn't too bad!  And printing.  Much easier than filing them out of brass.

[Gina]

Thinks...  a horseshoe instead of a gong - well, I wonder 🤣

[Gina]

With the Giant printer being done, I do rather wonder about a roundabout type automaton on the top that comes out and goes round on the hour!!  Stopppitt Gina ...  you're getting carried away!!!  🤣 🤣 🤣

[MarkAR]

Keep going Gina, sometimes it's the mad ideas that make a project worthwhile.

[Wraith_54]

I am looking at the idea of laser printing a clock for my office as I was just gifted a grandfather clock for my living room and this thread is amazing. so glad I stumbled across it! Keep up the amazing hard work Gina!

[Gina]

Back on this but just thinking ATM.

[Gina]

Had a look at the hardware as produced so far and the 3D prints are dire.  My DIY 3D printer was dreadful - only way to describe it!!  Now I have the Creality Ender printers things should be so much better.  The Max has a bigger bed than my DIY jobby so no problem there.

[Galileo]

incredible

[Gina]

Before doing more CAD I'll provide an update on where the project is so far.

 

For a start, all the current 3D printed parts will need replacing as they were printed on my old DIY 3D printer which has been replaced with modern commercial machines to improve accuracy.  The old prints are quite unacceptable!!

 

I'll show CAD screenshots of the present situation.  Starting with the front view I have already posted.

 

Top view.

 

Bottom view.

 

This only goes as far as the minutes.  It is also subject to considerable change as things proceed.  Only the moving parts are shown.

 

I propose normal spur gears to go from minutes to hours.  This will take some of the mechanism away for the cluttered centre.  2 gear pairs with ratios of 4:1 and 3:1 giving the required overall ratio of 12:1.  eg. 4:1 out to a layshaft and 3:1 back to the centre.  Or maybe vice versa.  I'll have to see which looks best.

Edited January 1, 2022 by Gina

[Gina]

Colour added to the CAD.

 

 

[Gina]

To see how much space there is to add gears etc. I decided to add the framework to the CAD assembly.  Also included is the pendulum suspension bracket shown in dark blue near the top.  I have not shown the back panel of the cabinet.

 

 

Edited January 1, 2022 by Gina

[Gina]

Adding the gears that drive the hour hand.

 

 

Using gear ratios of 6:1 and 2:1 was found to give the cleanest appearance after several attempts with different ratios and sizes.

[Gina]

Decided the worm drive was too complicated so looking at dreaming up an alternative.

 

[Gina]

Could just go for spur gears but I would prefer something more quirky and I reckon I have it!

 

A snail cam and ratchet system.  A 60t ratchet wheel for the minutes and snail cam on seconds arbour plus lever(s) and pawl.

 

This is the basic idea.

 

With a linearly increasing snail cam the drive to the minutes wheel will be gradual and visibly the same as with gears.  Maybe just a small pause of a second or less between strokes.  I don't think this will be noticeable.

 

Full view.

Edited January 9, 2022 by Gina

[Gina]

With the hour drive gears in situ the pink gear obscures the cam and end of the lever and the whole idea of the clock is to see the works so a change needed.

 

The solution was a bigger cam and modified lever with a longer pawl.

 

At start of snail.

 

And end of snail.

 

Showing the full size with frame.

 

These screenshots show the minutes wheel i transparent yellow to show what's behind.

Edited January 9, 2022 by Gina

[Gina]

Minutes wheel and the pinion for the drive to the hours can be printed as one item.

 

This shows it driving the pink gear.

 

And this shows cam. lever and pawl as well.