Weston Bye Magnetic Gear Clock

[kvom]

I did finish the bearing carriers.  I also heard back from Weston that my wound bobbins and circuit board had shipped.  That was the good part.  The bad part is that I received the magnets from United Nuclear, and they don't fit in their holes.  I measured the magnets as .125", and then found that both my 1/8" carbide endmills measure .123.  I have a HSS mill that appears to by on size and should work, but trying to set up to enlarger 150+ holes probably isn't going to fly.  So I'll have to scrap all the magnet wheel done so far and remake with the larger edmill.

[Kim]

Hi kvom,
This is probably a Silly question for more experienced folks, but why couldn't you ream the holes to 0.125"?  Seems a lot easier than making new wheels.  For that matter, doesn't seems that much more difficult to just use the end mill. What's the rub there?

Whichever way you go, I'm excited to watch your progress!  This is a fascinating project!

Thanks for sharing it with us!
Kim

[Heffalump]

Hi kvom,
This is probably a Silly question for more experienced folks, but why couldn't you ream the holes to 0.125"?  Seems a lot easier than making new wheels.  For that matter, doesn't seems that much more difficult to just use the end mill. What's the rub there?

Whichever way you go, I'm excited to watch your progress!  This is a fascinating project!

Thanks for sharing it with us!
Kim

Or bore them out? #noobalert

[kvom]

The holes are .07" deep, so a reamer can't widen them deep enough (tried it).  And trying to visually position an EM over each hole on the manual mill would take forever (150 holes).

[RonGinger]

I would try to remount the wheels and make a pass around it just to re-bore the holes. I would use a scrap plate on the mill table large enough for the largest wheel. Drill a hole in the center of the plate for an arbor to fit the wheel. Set the mill to x and y zero when you drill this plate. Place a wheel on the arbor, install your 1/8 mill and move the mill to X=0, Y= radius of the hole circle. Then rotate the wheel until one hole is right under the end mill. Clamp the wheel and run a simple bolt circle for the right number of holes. It should not be hard to get the wheel rotated close enough so the mill will clean up the holes.

The bolt circle code is a simple wizard operation. That has to be better than re making all the wheels.

[kvom]

Since there are 8 wheels with different center holes  (one is 1/8" hex) and different bolt circles I think it is easier to remake them as they were done on a CNC mill.  What might work well on the 4 larger wheels is to make soft jaws to hold them.  If I can get one hole lined up then the others will follow.  I'll try that first.

[kvom]

Started the day by making the 'intermediate hubs'.  These are turned from .75" brass round, and are straightforward.  The only issue was drilling and tapping a 2-56 setscrew hole at a 30-degree angle between two mounting holes.  I used my hex collect block to fixture this.



The finished parts:



Got the wound bobbins and circuit board in the mail:



In the afternoon I decided to save the 4 24-magnet wheels rather than remaking them.  Cut an OD arc in vise soft jaws to hold them, and used the 1/8 endmill to locate one of the magnet holes. before tightening the vise.  However, after using it to enlarge the holes they were still too tight.  So I used a 1/16 EM to interpolate a .127 hole (still a little tight) and finally a .129 hole where the magnets slide in nicely.



Redid and A and B wheels today, and will attack the C and D wheels next time out.  The 5 small wheels I'll just remake.

[kvom]

Spent the day making fiddly little brass parts needing multiple trips between the lathe and mill.  I have worked out that certain dimensions are key:

.313" (5/16) is the OD of the smaller ball bearings, so any hole with that diameter gets reamed with the 5/16 oversize reamer.

.375" is the OD of the larger ball bearings, so holes get reamed oversize.

.188" (3/16) is the diameter of the large shaft and the ID of the large bearing.  Need to check fit on the bearings.  I intend to make these large shafts from separate pieces held together with loctite.  This is because cutting a long thing shaft with precise constant diameter on my lathe is hard to do, and because I have brass rod of the proper diameter in stock.

.125" (1/8 )is the diameter of the small shafts and the ID of the small bearing.  Again check fit.

It's hard for me to determine how critical any of the plan dimensions are from the drawings.  I suspect I'll find out when I get enough parts made to start assembling.  I am going to use loctite anywhere a press fit is specified.

[kvom]

Here's where I am with the brass parts:



I have a few more to go, and then it's on to the steel rotor, the aluminum wheel too big for brass, and the chapter ring.  Then it's time to try to put it together.

I recently acquired a vibratory finisher, and intend to try to polish the brass wheels with it.  Have to buy some walnut shells for that.

[kvom]

Today's output was to mill the rotor rim from some 1/4" steel plate.



The brass center will be attached using 5-40 screws.

The plans call for 3/16" thickness, but I'm going to surface grind off a few thou from each side and try the fit before going much thinner.  The rotor will be gun-blued eventually.

[zeeprogrammer]

I like that family shot. 

Watching.

[kvom]

Made the rotor center section today and attached to the rotor rim with screws:



It seems I could mount it with either side facing the front of the clock:



The 6 pole pieces for the coils are show partially done.  I had them in the vibratory tumbler for 8 hours, but it still didn't remove the mill slag from one side.  I'll just make that the side facing the coils.  The rest will be blued.  Still need to mill and angle in the tops and drill/tap some holes.

[philjoe5]

Looking good and a nice save on the brass wheels.... 150 holes, yikes

Cheers,
Phil

[kvom]

I have enough parts to try some test assembly, so I cobbled together a temporary stand with 2 pieces of steel rod and some plastic.



I finished the poles pieces and screwed two to the frame.  The separation from the rotor looks a bit too much at this point, but without the coil actually mounted I can't be sure.

A friend of mine who is an electronics expert is going to help me get it wired up as soon as I have all the parts on the rotor shaft done.  Seeing the rotor ticking over one blip per second will mean that the rest is just a matter of fitment.

As far as I can tell the only real tolerance requirements are that the magnet wheels are sufficiently close to the one they interact with to impel the proper motion.  The other two main shafts may need some adjustment from the plans to do the adjustment since there is a wheel afixed to the end of each.

[kvom]

Bit of progress today.  Wheeled out the surface grinder and ground the rotor on both sides, so it's ready to be blued.  Also ground the 5 small wheels still lodged in the original workpiece as well as the rotor center. 

Then finished drilling the pole pieces and did a fitup on all 3 sets.  The separation from the rotor is about .06", probably too far(?).  Options for getting them closer are either to remake them, or to make the mounting holes in the frame larger.  An option I rejected is to reverse them and redrill/tap the mounting holes slightly lower down, but that would leave the original holes exposed.

I also discovered a non-obvious fact.  The little spacers in the accessory hubs need to be loctited inside the hubs.  Otherwise the wheel assembly and hubs can slide over the bearings and shaft.  The through hole in the spacer should also be drilled larger than .125 to be sure to clear the shaft, otherwise it will rub.