My Clock Build Project Thread

[devils4ever]

I'm not sure how much interest there is on this forum, but I'm thinking of posting my clock build project here. I've been looking for a long term project and I think I found it. I think I have enough information on clock mechanisms to be dangerous. So, I'll proceed slowly. I expect this project to last over a year.

I plan on using involute gears for this and maybe use 7075 aluminum instead of brass based on the crazy prices. I plan on using a deadbeat escapement with a weight driven clock.

So, here we go.

I'm starting on the escapement mechanism to make sure I can get this thing to tick. Then, I'll proceed with the gears. Here's some photos of escapement wheel. As with many machining projects, trying to determine how to hold the parts is the main challenge. I had to make a fixture to hold this part on the rotary table.

I'm using my CNC mill to cut each tooth on the rotary table. I think this gives me maximum accuracy minimizing backlash (which I have some especially on the Y axis). I started with a 1/4" end mill leaving 0.010" material for a second pass with a 1/8" end mill. This part has 30 teeth.

Teeth cut:


Close up:


Crossing out (clockmaking term) or making spokes (machinist term):


Almost done:


Last one:


Drill for 2-56 screws:


Final part:

 

[f350ca]

Certainly watching, a clock is on my long list of want to builds.
I understand the cost incentive but will aluminum wear well?

Greg

 

[WobblyHand]

Certainly watching, a clock is on my long list of want to builds.
I understand the cost incentive but will aluminum wear well?

Greg

Not as well as steel, obviously, but compared to brass? Probably similar. Loads better to work it all out on aluminum and see if it works, rather than going through hideously expensive brass.

 

[Eddyde]

Yes, we are very interested in your clock build! Please post your progress.

 

[devils4ever]

From what I can gather on the web:

material	Rockwell Hardness/Brinell
6061-T6511 (common aluminum)	B60/95
7075-T651 (aircraft aluminum)	B87/159
1018 (mild steel)	B71/126
4140 (alloy steel)	B92/197
C360 (common brass)	B78/141
C353 (clock brass)	B65

So, clock brass is harder than 6061, but much less harder than 7075. In fact, 7075 is harder than mild steel.

The escapement wheel shown above is made from 6061 aluminum and was a test case to see how well I can make it. I will probably remake it in 7075 if all goes well. The anchor pallet that engages this part will be made from 4140 steel.

Yes, price 353 brass and you will see what I mean!!!

 

[tq60]

I would like to suggest all ball bearing support.

Fans and hard drives contain tiny high-speed ball bearings, great use for them here.

Sent from my SM-G781V using Tapatalk

 

[devils4ever]

I thought I remember reading that ball bearings in clocks are a no-no. I don't recall why.

 

[Eddyde]

Anodizing the aluminum might give it a good anti-wear quality.

 

[rwdenney]

I thought I remember reading that ball bearings in clocks are a no-no. I don't recall why.

Ball bearings work best with loose bearings that need to turn fast. Clock bearings minimize end shake and turn very slowly. Too slowly for balls to distribute oil effectively.

The tooth shape is a classic clock escape wheel and will work with a bent-steel verge with properly filed tips unless you have something more elaborate in mind. My worry with aluminum for an escape wheel would be the strength and wear resistance of the tips. But if it's like my clock collection, you won't routinely run it anyway.

Rick "too much noise when they all run" Denney

 

[devils4ever]

Okay, some more progress. This time on the anchor pallet made from 4140 steel.

I started with a 1/4" roughing end mill offset again by 0.010" followed with a 1/8" end mill. The part is mounted in my vise holding my mini-pallet with some scrap aluminum under it.

Work piece ready to be milled.


First pass done.


Almost there.


First pass complete.


First pass on the 1/8" end mill.


Completed and ready to have the tabs removed.


Completed part except for fine tuning.