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Compact Clock 16 Friction Clutch

Having fun tweaking Compact Clock #16.

My first-ever 3D print is coming along nicely as I fix and upgrade the first print -- which admittedly was rough. Eventually, it will be finsihed. Right now the clock is ticking along nicely. However, the hands are running at about half speed.

Data:

In Compact Clock 16 that means the middle arbor is not turning normally.

Middle arbor is driven by Gear 4 (which is driven the Gear 5 and the weight shell.) Gear 4 is friction clutched to the middle arbor. It is escapement controlled to 1 R/Hour.

Gear 4b is set screw attached to the middle arbor so both 4 and 4b turn at 1R/H.

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Steve

52 minutes ago

This diagram shows the gear topology in the clock.

There is a long unbroken chain of gears between the winding drum and the escapement. If the pendulum is swinging properly then gear 4 must be rotating at close to once per hour. The rate is determined by the pendulum length and it cannot run at 2/3 speed. Therefore, the issue must be between the friction clutch and the hour hand.

The friction clutch adds a loose connection between gear 4 and gear 4b to allow changing the time without affecting the pendulum. It does not need to be very strong. It only needs to be strong enough to overcome any downstream friction. Music wire (also known as spring steel or piano wire) creates enough pressure against the M3 arbor. Soft steel or brass wire might not apply enough pressure.

Gear 6 is the primary gear to check for friction. The printed gear 6 arbor must pass through the dial without binding. Also gear 6 must not be pressed against the back of the dial. Push and pull on the hour hand to make sure gear 6 has some end shake. Look for end shake in gear 5 as well.

One more thing to check is the gear 4b set screw. The friction clutch is circled below in green in the exploded diagram below. It loosely presses against the M3 arbor. Gear 4b tightly connects to the M3 arbor using a set screw, also circled below in green. Move the minute hand and make sure gear 4b moves at the same rate. There should be a slight resistance felt by the friction clutch.

Hopefully, this will give you some ideas to check. Please report back if you find the cause.

steve.fensome

6 days ago

Rolling Ball Clock (Balls always jamming)

has anyone else had this problem?

Every morning the clock has stopped due to the chrome balls sticking on the upper ball ramp.

I have checked all the sizes of the metals balls and all are 18.8 to 18.9mm.

I have reprinted the upper ball ramp 1% bigger in X&Y still the same problem.

I have reprinted in metal type filament as that seems to give a very smooth finish, but still the same result.

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Steve

6 days ago

I have noticed it as well. The effect is exaggerated by the ball limiter that allows the balls to creep forward instead of jumping by a full ball width each time a ball drops. This creeping motion gives the balls more chances to find a bump or a flat spot where they can rest.

The upper ball ramp has a 3 degree slope with the balls rolling along the 45 degree surfaces. The lower curves have a larger radius than the upper curves so the slope might be just under 3 degrees.

Possible fixes may include:

1) Sanding the 45 degree slopes anywhere a ball stops.

2) Removing all oil from the balls and any that may now be on the tracks.

3) Adding oil to the balls, although I suspect this might make it worse.

4) Redesigning the upper ball ramp with steeper slopes.

The first two options might solve the problem.

The last option might be the best long term alternative. The clock would either have to be made taller or one spiral loop would need to be removed. Removing one spiral is the least intrusive since only the upper ball ramp would need to change. It might limit the clock to a 30 hour runtime using 100 balls.

Steve

14 days ago

Rolling Ball Clock ball drop fix

A few builders reported that their clock would randomly stop where balls enter the upper ball drop. I could see the risk, but my prototype clock was running flawlessly. My second clock showed the problem. It would stop every day or two, always just after dropping a ball into the upper ball drop. Both clocks should have been identical. One ran great and the other randomly stopped. So, I designed a throttling mechanism to hold back balls in the upper ball ramp. Both clocks run perfectly now.

Here is the fix that will be released as soon as I update the assembly guide.

A paddle wheel is added to the upper ball drop. Gears keep the paddle wheel synchronized to release one ball at a time.

The back profile shows three new gears and a new back plate.

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Joy Loxton

11 hours ago

HI Steve, I haveprinted the new parts and installed them, day 5 keeping perfect time and balls are rolling (no longer getting stuck) Thanks you for the new version. Joy

ksmietanski

27 days ago

SP17 Clutch Slipping

Have SP17 running very well, however, I do seem to have slippage in the wire clutch setup. I seen that a few people have had this problem.

Any hints how to make the clutch "stronger".

I also have another question. When a ball bearing enters the first top chamber, the next ball bearing is pressing on it. Sometimes, the clock stops as there is not enough energy to overcome the force of the next inline ball pressing on the one that has just entered the chamber. This is more prevalent if the top rail is full of ball bearings. Has anyone had this problem???

Cheers

Krys S