Elegent Scroll Frame Skeleton Clock

[crueby]

You don't want to use oil on the bearings unless you have the really thin clock/watch oil, so whatever materials you use they should be free from galling when dry. Can you buy oilite bushings the right sizes? Or make them from Teflon?     It seems like if the one side is hardened AND polished, you should be good. Polishing the ends of the pivots is standard clockmaker practice. As you mention, the ends of the pivots are normally turned to a barrel type shape, then burnished/polished.

[Kim]

You don't want to use oil on the bearings unless you have the really thin clock/watch oil, so whatever materials you use they should be free from galling when dry. Can you buy oilite bushings the right sizes? Or make them from Teflon?     It seems like if the one side is hardened AND polished, you should be good. Polishing the ends of the pivots is standard clockmaker practice. As you mention, the ends of the pivots are normally turned to a barrel type shape, then burnished/polished.

Yes, that is my plan, to burnish the pivots and the arbors so that they run smoothly, with minimal friction, in traditional clockmaker fashion. 

We'll see how it goes!
Kim

[Dave Otto]

I tend to agree Kim. With the bushings hardened and polished, and the shaft journals polished and burnished I would think that you should be good. 
I was more worried about soft stainless running on soft stainless, appears that you got that covered. I don't have any experience in the clock lubrication department.

Dave

[bent]

" That’s a lot of work for not much change. But I’m pleased regardless!"

Nonsense, that's a lot of detailed work forming the heart of a complex machine.  And having the assembly shots makes it all make (more) sense. Very cool! 

[Kim]

Thanks Bent! 

Thank you Dave.  I really do appreciate the input from you on this (and everything else).  I have minimal experience working with metal (though it's getting more and more all the time!) and am always learning from you and others on this site.  I can't tell you how much I've learned here.  Thank you for taking the time to provide meaningful, supportive, instructive comments.  I really appreciate it!

Kim

[Kim]

Today I worked out the process for making my lantern pinions.

I started with the Great Wheel Pinion, which meshes with the Great Wheel on the Fusee, but shares a pivot (shaft) with the Center Wheel.

I made the bobbin for the pinion from 1/2" 303 stainless steel.  I did most of the shaping with a flat-ended parting tool.  I was very careful to work my way from the outside in so that there was enough material to support the cutting forces.  Then I drilled the center hole through it after the shape was turned.


Then I moved over to the mill to drill the holes for the pins.  I used a #2-56 machine screw as a mandrel, which fit the hole quite well.  And I drilled and tapped 2-56 in a piece of scrap aluminum and marked that as the origin for the DRO.  Then, after securely attaching the pinion on this center hole, I used the DRO to center mark and drill the six pin holes.  I couldn’t make a center mark on the bottom of the bobbin, so I just touched the drill bit down very carefully (with the bit spinning very fast!) to start the hole, then proceeded to drill through.  This worked quite well!


And I was super pleased with the results!

That was, until I looked back at the drawing.  I’m supposed to have eight pins in this pinion!  Not six!    You'd think I'd have checked this BEFORE drilling the holes, wouldn't you?  Grrr.... 


That was somewhat upsetting.  But, as I said at the beginning, I now have my process figured out.  So, I’ll do it again tomorrow.  But with eight pin holes rather than six!   

Thanks for looking in,
Kim

[Dave Otto]

Bummer, you must have looked at the drawing at least briefly, you got the PDC correct? 

Dave

[crueby]

Look at it another way, you put in 6 of the holes, and kept two as spares...  okay, no. At least the process worked!




Having used similar  fixturing, I  would suggest making a new tapped hole in the aluminum for each part, last thing you want is the hole to develop a  wobble after running the screw in and out a few times.




 

[Dave Otto]

Personally I would not trust the tapped hole for location. I would dial the part in with a DTI after mounting it. I would also sweep the top of the flange to insure that it is not tilted.

Dave

[Kim]

Good points!  I did make sure that the jig was level and that the bottom of the bobbin was flat and held well against the jig. But checking the top of the bobbin is square and centered also.  I'll try to work that into round two.

See, the second one will be MUCH better than the first, thanks to your help, Dave and Chris! 

Kim

[kvom]

Consider drilling three of the holes in the fixture using the DRO.  Then using the after drilling the holes in the top, you can reverse the pinion and use three pieces of stock in the fixture holes to locate the pinion's position to drill the bottom.

[crueby]

Consider drilling three of the holes in the fixture using the DRO.  Then using the after drilling the holes in the top, you can reverse the pinion and use three pieces of stock in the fixture holes to locate the pinion's position to drill the bottom.

That is a neat trick - then would not have to worry about the drill skating on the second surface.

[Kim]

Consider drilling three of the holes in the fixture using the DRO.  Then using the after drilling the holes in the top, you can reverse the pinion and use three pieces of stock in the fixture holes to locate the pinion's position to drill the bottom.

That is a neat trick - then would not have to worry about the drill skating on the second surface.

Very interesting idea!  I may have to give that a try today! 

Kim

[bent]

D'oh!  Hate it when I forget to check the drawing.  Oh well, that was a practice part anyway...

[Kim]

Bummer, you must have looked at the drawing at least briefly, you got the PDC correct? 
Dave

Yes, I did get the PDC correct.  Just not the number of pins required for the pinion.

And yes, Bent, I do hate it when I forget to check the details on the drawings.  It was just so obvious, apparently.  So obvious that I got it wrong! 
Kim