The frame for this orrery will not simply be two brass rectangles. The plan is to begin the top and bottom with some included circles and cut designs into the shaped brass parts with a jeweler's saw. Two opposite edges near the middle of the frame need to be left straight to attach the side panels needed to support the three idler gears. Ideally, the side panels will also have pierced designs, that either hide or accentuate the screws holding the idler supports. An initial sketch is shown below to provide some idea of where this is going. A piece from Mike Duber, engraver extraordinaire, is the source of most of the ideas.
The design was finalized a day later. The photo below is a mishmash of the top and bottom frames. The pointer at one end and the fleur de lis at the other in the photo will be part of the bottom frame. The scroll work and side embellishments will be for the top frame. The scroll cut into the large circle will have a mirror image on the other side. Both frames will have the two circles. A flat is left in the middle of the top and bottom frames on one side to attach the shelf support.
The next step is determining whether I am capable of cutting scrollwork into a 3/16" thick slab of brass scrap. China white was painted onto the brass with a bit of spit and a simple design was drawn onto the brass. The design was cut in one one side and out the same. The cutting went well as seen in the two pictures below. To do this correctly the chips will need to be blown away constantly as they obscure the cutting line. The huffing and puffing was no fun and was insufficient to keep me on the line. An aquarium pump will be used assuming I can find some Tygon or other appropriate tubing. I also need to use my magnifiers!
Was unable to find the tubing I know we have, but believe it is too big anyway for the port on the aquarium pump. I spotted an unused orange extension cord and a crazy idea came to mind. A two to three foot length of the cord was removed and slit down the side with a razor. The three wires inside and the insulation were removed. The split was covered and closed with electrician's tape. The tube fits tightly in the pump's port and it was plugged in. Unfortunately the air coming out of the pump is so minimal that the brass dust was unmoved. Even without the tubing the pump did not blow off the brass dust!
Onward we forge. The optivisor with light was was worn and this made a huge difference, especially the light (after installing new batteries). A cut was completed in a scrap of 1/4" brass and the resulting cut is seen below. Add an eye and the plant becomes a dove.
I will start with the bottom frame as it is a little simpler. It requires almost 7" of 2 3/8" wide brass. The top plate will need 2 5/8" X 4 1/2" of 1/4" brass. The brass plate purchased, 2" wide, is not wide enough to handle this frame design, especially the flourishes extending from the circles. I will try soldering a 1/2" strip onto the 2" stock for the bottom plate. Most of this joint will be hidden, so shouldn't matter. If it looks good enough the top will be done similarly.
A scrap of brass was cut to approximately 3/8" X 2 3/8". After wiping both edges down with acetone the strip was clamped to the edge of the 7" length of brass about 2" from one end. Flux was applied to both sides of the joint and short lengths of solder were placed along the joint. The brass was heated with a propane torch, bottom and top, until the solder melted and penetrated the joint. The two photos below, first the top and then the bottom, show the still hot joint. The joint was cleaned up with sandpaper.
The part's circles were sketched onto the brass using a compass after marking the centers using a tracing of the part with allowances for the two end protrusions. The part was roughly cut out with a hacksaw providing at least 1/8" allowance. The holes were drilled and reamed to 1/4". The part was then setup on the rotary table and the sides of the circles were cut to the line, 0.995" and 1.300" offsets for the small and large circle using a 1/4" four flute end mill. The first photo below shows the setup and the second the milled arcs.
The fleur de lis was traced onto the China white covered brass using tracing paper and carbon paper. The carbon paper image was faint and had to be traced over with a pencil. The outside of the design was cut in about 3 hours of interrupted work. I learned while cutting as the later cuts went more smoothly, quickly and with fewer broken blades. The photo below shows the outside of the fleur de lis completed.
One modification to the process that seemed to help me stay on line was stoning the sides of the blade before use. A coarse diamond stone was run along both sides of the blade prior to installing the blade in the jeweler's saw.
The fleur de lis was drilled with a #60 drill using the sensitive drilling jig as shown in the first photo below. This was followed by cutting out the inside of the design seen in the second photo.
The pointer end was covered with China white and the pointer drawn on using the tracing and carbon paper. The outside was cut first followed by drilling, #60 and #50 for the inner openings. Some of the inner cuts were cut with the blade installed with the teeth facing into the jeweler's saw and cut while pushing as the saw is not deep enough to accomodate the full length of the part. After cutting, work with assorted files completed the pointer. This work is documented in the photos below.
The orrery bottom frame was mostly finished with two processes. Two lines were engraved to denote a "rope" crossing another as shown in the first photo below. (More engraved lines might be appropriate.) The frame was then sanded with 120 to 600 grit sandpaper. This sanded bottom frame is seen in the second photo below.
A slight change in plans, the top frame will be made out of 3/16" brass. A 3" wide piece of this is at hand. This should also be easier to saw and a lot of sawing with the jeweler's saw is in store for this part. A 4 1/4" length of this brass was quickly cut with the hacksaw. The design, chubby baby, was traced onto tracing paper and is seen below. As with the bottom frame the first task will be drilling the circle centers and using the rotary table to mill most of the curves.
New Year's day and I am ready to continue this project, having skipped partying last night. After first repairing the mill, the z-axis dial was loose as near the top of its travel it gets very tight, the outer lines of chubby baby were transfered to the brass rectangle. The hole centers were punched, drilled and reamed to 1/4". Much time was spent trying to use the rotary table plate to hold this large part on the small table. After much gnashing of teeth the plate was switched out for the two extensions. With these in place the part was easy to clamp in two spots for milling the arcs. The large arc was milled first, followed by the smaller arc. The first photo below shows the setup for milling the large arc. The next two photos show the completed large arc and then both completed.
The external decorations were completed this morning. First the design on the side with the flat were cut, requiring one hole drilled. The design on the opposite side was cut next and also required one hole to be drilled. The part was sanded from 220 to 600 grit and the two photos below document these two cuts. (The flat still requires filing so it is actually flat.)
After a few day off for various reasons the first scroll was cut this morning. It took about two hours. My biggest challenge was where to drill the holes for access and avoid cutting where the part does not fit. I should probably purchase a jeweler's saw with deeper access for situations like this. In any event after a bit of filing the scroll looks pretty decent. For some reason I am enjoying this work. Picture below is of the backside ?? of the scroll.
The second scroll was transfered and cut this morning. As can be seen it was meant to be a mirror image of the first. It comes close. It is shown below after some filing and sanding. The cutouts are kind of cool, but I don't know what they would be good for.
Part of the morning was spent determining the size and drilling pattern for the shelf support. Washers also need to be made to support and separate the gears. Eight 1/32" washers will be needed to stand the gears up off of the bases and shelves. An additional four washers; 1 - 1/4" & 3 - 9/32" are needed to separate the gears in the fixed stack.
A quick sketch of the shelf support layout was made. Two holes will be drilled for the 1/4" top and bottom and for each of the shelves. These holes will be centered, in distance from the bottom edge, at 1/8", 7/8", 1 9/32", 1 11/16", and 2 1/8". The shelf itself will be 2 1/4" long.
A slight problem was diskovered upon aligning the completed bottom and top with a 1/4" pin in one hole. The two flats do not align in either direction. The top is 1/16" further from center than the bottom and the centers of the two flats are 5/8" apart. The latter is easily seen in the photo below with the centers of the flats marked.
This challenge presents the opportunity to create a feature that I was hoping to somehow incorporate. The rectangular shelf support would have looked off amongst all of the curves this orrery already possesses. Consequently, this error will become a feature, a curved shelf support system. This should pose no problem in positioning the gears correctly. The photo below shows a rough sketch of the planned shelf support.
A piece of 3/16" X 2" brass was cut from scrap. The ends were squared up and the piece was shortened to 2 1/4" in the mill. The height gauge was used to mark out the lines for the holes. Two lines were scribed at an angle to offset the top from the bottom by 5/8" and to set the width at 7/8". The holes were then marked 7/32" inside these lines. The photo below shows the holes laid out on the brass stock.
The reflection of the fingers holding the camera is a nice touch.
The holes were drilled as through holes for 2-56 screws with a #40 drill in short order as seen in the photo below. Now back to the drawing board. A design was sketched out and transfered to the back side of the brass blank. This is seen in the second photo below.
Cutting proceeded well and the part was completely cut in about two hours. It was sanded to 600 grit and is shown in the photo below sitting on a scrap of purpleheart. I have to admit being pretty impressed with the completed shelf support. Of course, installing the part will require drilling right through the ornamentation on chubby baby's back as the flat is hidden behind the two leaves.
The shelf support was held in place against the bottom frame and the holes were marked on the bottom frame with a punch. The holes were drilled 1/4" deep and threaded 2-56. The support needs a spacer between it and the bottom frame so one was quickly fashioned from a scrap of 1/16" brass. A 1/8" X 3/4" piece was cut, punched and drilled with through holes. The corners were filed off to remain hidden behind the support. The first photo below shows the two frame members on carriage bolts to mimic their final separation, 1 27/32". The support installed onto the two frames is seen in the second photo.
Drilling was not the best way to provide access to holes behind the decorative leaves. Grinding was chosen for this task. A diamond burr was installed in the dremel and used to carefully grind away the excess marked on the side of the brass leaves. It was more effective than expected. The first hole was marked in the mockup, drilled and tapped as seen in the photo below.
The second hole required more grinding to provide the necessary access for the drill and tap. The hex head screws could not be used to hold the support to the top frame as there was no access for a wrench, so two SHC screws of the correct size were prepped. When drilling, the second hole was too close to the bottom of the frame and broke through when tapping, shown in the first photo. Luckily the hole still works as planned and the support installed between the two frames is seen below. That was a nice example of working on a wing and a prayer (not my favorite way of working!), but successful to boot.
Four 1.5" X 3/4" pieces of aluminum were hacksawed from 1/8" aluminum stock. They were squared up in the mill as a unit resulting in four 0.697" X 1.390" rectangles as shown below. An end of each was blued with a Sharpie and marked with a centerline using the height gage. The holes in the support are 7/16" apart, so the four ends were marked again with the height gage at 0.130" and 0.567" from one end for the two tapped holes.
The holes were drilled with the parts still clamped in a block using the new DRO. What a treat! The holes were then tapped 2-56 with a regular tap and then a bottoming tap. A bit of deburring and the shelves were completed, though probably need some sanding. The two photos below show the drilled block of parts and three shelves installed. The shelves need some sanding and a way needs to be found to install the shelf screws without scratching the brass support.
Looking at the installed shelves immediately revealed an issue. Anybody see it? Anybody? The shelves are not in the correct positions to support the idler gears!!! Who designed this thing anyway? New shelves are the next task. They need to angle back from their juncture with the support by as much as 3/4" from their current locations.
A second set of shelves were made with a kink. They were rough cut from 1 1/2" wide aluminum stock and then milled to final shape. The ends were drilled as before. These shelves are seen in the photo below.
A wrench was made of aluminum for installing the screws without marring the brass. A quick milling job beginning with a 1/4" square cross section of aluminum. One end was thinned to 0.10" and then a 1/8" slot was milled in the end. The corners were slightly rounded. This wrench is seen in the first photo and the shelves installed using it in the second. The third photo shows how the new shelves sit squarely between the two gear axle hole locations.
Spacers for the gears need to be made to hold them up off of the frame or the shelves. They also need to prop up the gears to the same height as their mates. The distances between the bottom frame and the bottom shelf is 17/32". The gaps between shelves are both 9/32" and the gap between the top shelf and top frame is 1/4". 1/32" washers will be used below all gears that sit directly on shelf or frame, similar thickness washers will be used between the two central gears of the bottom set.
The gears on the left and in the middle will need washers and separators. The driven stack will all be secured to their tube at the correct height. Consequently, seven 1/32" washers, one 1/16" washer, one 17/32" separator, and three 7/32" separators are needed. All of the gears needing these supports currently have 1/4" center holes execpt for the 11 tooth gear with a 1/8" hole. All except for one 1/32" washer will require 1/4" holes. The total is 1.438" of tube needed plus 0.04" X 11 cuts equals 1.88" of tube made from 3/8" rod.
A 2 1/2" length of 3/8" drill rod was put in the three jaw chuck in the lathe. The free end was faced and the rod was drilled up to an F drill, 0.257" for a distance of 1". A series of spacers were parted off. The rod was then drilled an additional inch and the remainder of the spacers were prepared. After completing the lot of them, plus a few extra 1/32" washers, they were deburred. All were measured and all are oversized relative to plan by about 0.01". The photo below shows the spacers.
The 17/32" spacer made above was a misread of the admittedly incomprensible plans and was shortened to 0.25". A test assembly was then done with the spacers and the driving gears. The driven gears were put in as well for the heck of it, though their spacing will be managed when they are affixed to the tubes. The photo below shows this mockup. A nice fit for the driving gears between shelves.
The first photo below documents another issue diskovered. The screw won't fit in the top hole because the 47 tooth gear, third from right, runs into the shelf support. The support was marked, removed from the assembly and the marks extended across the width as seen in the second photo.
The support was clamped onto the top of the vise as it is a bit too big to be held by the vise. Two strap clamps held it with the slot square to the mill. Squaring was accomplished by moving the end mill above the lines and ensuring it stayed between the two lines marking the slot. A 3/16" end mill was used to cut the slot to 1/16" depth. The slot was then widened on either side by 0.025". The photo shows the slot cut in the shelf support. The gear spins freely through the slot when aligned with its partner driving gear.
Determining how to mark the shelves for the idler gear centers is a challenge. The middle gears in the bottom should be easier as there is easy access. The shelves need to be marked for position, and then carefully measured from the two axles. A jig will need to be prepared to hold the shelf with two axle centers for marking.
The position of the middle gears for the moon were approached first as it seemed simplest. Since it is difficult to measure the distance from the center of a hole, a plug was made. A length of 1/4" brass rod was faced and sanded to fit in the holes in the base. A tiny divot was made in the center of the end with the 30° engraving tool made for the pantograph. Two mating gears, 11 & 63, were placed on the depthing tool and an easy fit was located. An arc was scribed on the blued base. The other pair of gears, 18 & 42, for this same gear train was then put on the depthing tool. Again an arc was scribed, though I already recognized yet another design error. The gears on the depthing tool are seen in the first photo and the non-intersecting arcs in the second.
A niggling issue has been driving me crazy with these gears. They do not want to fit on the standard 1/4" shafts I have used for every other gear made. The holes all seem just a little undersized. Maybe it is time for a new 1/4" reamer. And while I am at it, I should also purchase oversized and undersized reamers for a complete set.
A piece of brass scrap, perhaps the one cut out of the base was found that fit well. Checking the extensions of the arcs on this scrap showed it was sufficiently large to serve the purpose of supporting an axle, though an axle that is only 1/8" diameter. Soldering the scrap in place will have to wait until the garage warms to at least freezing.
Not quite freezing, but the soldering is fast. I preferred a better fit than that seen above so a scrap of brass was marked with the curve to be filled and cut with the jeweler's saw. A bit of filing and it fit quite well. After figuring out how to clamp the parts in the basement vise, they were moved to the garage vise and are seen clamped in the first photo below. The parts were fluxed and then soldered. After cooling the piece was washed and the joint is seen in the second photo.
The top face of the bottom frame was sanded up to 400 grit, shown below, and then painted with blue layout fluid. Using the insert for the holes the part was again marked for the axle of the central two gears of the bottom four with the depthing tool. In setting the tool up for the 11 & 63 tooth gears it was diskovered that the previous measurement was not done with the 11 tooth gear! It has a 1/8" center hole and the depthing tool has a 1/4" axle! An additional axle was made for the depthing tool by turning a length of 1/4" drill rod to a point and reducing the opposite end to 0.1245" for a length of 1/4", using a collet to insure concentricity. The two intersecting arcs are shown in the photo below. Notice the intersection is intersecting the new joint!
The excess soldered addition was cut off with the jeweler's saw and the hole, now plugged with solder, was opened and retapped. The plan for this gear axle is to drill a 1/4" hole, insert the 1/4" axle and solder or set screw it in place. After diskovering yet another error and bad decision making, the project will be shelved for a while.
After a thirteen day break to recharge and make the jeweler's file handle this project was reinitialized. A scrap of 1/4" brass was painted blue and the shape of the correct side was scratched onto its surface with a scribe. The jeweler's saw was used to cut the curve. A bit of filing was needed to perfect the fit. With the piece installed the angle between its flat edge and the flat edge on the opposite side of the part was measured to be 10°. A scrap of aluminum was milled to 10° using the angle table. The aluminum, the brass insert and the bottom frame were all held in the vise in the cold garage. Flux was applied followed by a string of solder bits. The part was heated from the bottom until the solder melted and penetrated the joint. The entire part, including edges both inside and outside, was sanded to 400 grit. This process is documented in the series of photos below.
It is interesting how the copper in the brass rises to the surface when the brass is heated. It is a very thin layer as judged by how easily it is sanded off.
I am returning to this project after working on the wooden rings. The next step is marking each of the levels for the gears. The bottom gear set, was marked first using a 1/4" pin in the hole to support the depthing tool tip. Each of the labelled shelves was installed and marked with two intersecting arcs using the depthing tool with the appropriate gears affixed. This was started with the top shelf using a long pin cut to be at the same height as the top of the shelf. The pin had a small divot in its center. The pin was shortened for each of the next two shelves. The holes were then punched with the "drop" punch. The five photos below document this process. The fourth photo shows the modification needed for the pin to fit next to the bottom shelf, indicating some changes needed in this shelf.
The shelves and base need to be drilled in the marked locations. The plan is to glue the gear axles in place in the base and in the shelves with care taken to ensure they are orthogonal. The shelves need to be modified so they fit not just around the axles, but also around the spacers supporting the gears. The latter was tackled first. A design was sketched on one shelf, cut with the jeweler's saw, transfered to the next, and ecetera. The photo below shows the three modified shelves.
The shelves were drilled, first, with a center drill and then with an "A" drill. The holes were reamed to 1/4". The photo below shows the completed, except for sanding, shelves installed on the as yet undrilled base.
The gear axles can be determined now that the shelves are installed. the long axle supporting all of the driving gears: 67, 47, 39, and 39 teeth, will be fixed to each of the gears and will extend below the bottom frame, where it will be fixed to the orrery base. This produces gear movement when the entire frame is rotated above the base. A decision needs to be made on how best to affix the gears to this shaft, but that will wait as it doesn't affect the shaft length. This shaft will be made 3 1/4" long. It can be reduced if it doesn't need to extend into the base by 1/2". A length of 1/4" drill rod was cut off and both ends faced to length to complete this part.
The bottom shaft supporting the two intermediate gears, 42 and 11, needs to have two different diameters, 1/4" and 1/8", to fit the holes in the two gears. Both of these gears will need to be fixed to one another or to this shaft so they turn as one. The former is preferred as expecting this shaft to rotate smoothly supported only by the frame bottom is challenging at best. The bottom 63 tooth driven gear is held 1/4" above the lower frame, so the 1/4" diameter part of this axle needs to be 1/2" long as it extends into the base. The 1/8" diameter part needs to be 3/16" plus 1/32" or 7/32" long.
The axles attached to the shelves are all the same and need to be 3/16" plus 1/8" plus 1/32" or 11/32". The photo below shows the completed axles.
The bottom frame was drilled for the central gear pair and the gears fit nicely. Two of the shelves, top and middle, when installed do not allow the gears to align properly. The through holes in the vertical shelf support were enlarged with a 1/8" end mill, but this was not sufficient to allow all three gears to mesh. Another 0.02" is probably needed. After some initial struggles a solution came to mind. Shims will be installed between the support and the shelves. Favoring one side or the other of the shelf will fine tune the mesh of the center gear supported on the shelf with its flanking gears.
The aluminum wrench made above is starting to "waller out", so a new wrench was made from a homemade 3/8-16 screw found in the scrap box. It is made from drill rod so could be hardened if needed.
The shimming commenced this morning with the middle shelf. A feeler gauge was used to get a first approximation of how much the shelf needed to be moved outside of each screw, giving 0.017" and 0.041" for the two screws with the latter on the 39 tooth gear side of the shelf. After some consideration the simplest path to shimming appeared to be washers of the appropriate thickness. Two more washers were made with dimensions of 0.025" and 0.051"! My parting skills are very innacurate. The washers were used to offset the shelf, but a previously made washer was used in place of the too large washer. This gave nice movement between the three gears.
I noticed some movement of the two shafts supporting the two larger gears and put the top frame in place to get rid of this wobble. The 39 tooth gear no longer meshed. The 0.04" washer was replaced with the oversized one made above and all gears now move smoothly. The process was repeated with the top shelf and gears. When assembling the entire set of gears the bottom shelf was also found to need some adjustment. After shimming all three gear pairs with idlers the orrery was ready for first assembly. This was done and though a few gears are tight they all turn. The two photos below show the assembled orrery at this stage, a major milestone!
The gears on the right in the photos above are not attached to the tubes which will eventually hold them at the correct height. Their edges are resting on the shelves. Assembly is a non-trivial process as a precise order needs to be followed.
Only a week to go in February and progress has been made. Today was spent designing the display side of the orrery. Each of the items represented on the topside will revolve around the earth supported by brass disks. These disks will be separated from one another and the top frame by 1/32" washers. The disks will be 3/16" thick and with the washers will span almost an inch.
The top disk corresponds with the bottom set of gears, requires a 1/8" center hole, will show the moon revolving around the earth, and is surmounted by a pole with the moon on top. The second disk corresponding to the apogee gears, will have a 3/6" center hole, and support a pointer showing the current location of the apogee. (A second pointer could be added to indicate the location of perigee, or closest approach.)
The third disk down shows the nodes or a tilted ring supported by two posts. The ring's tilt is 5.1°, most easily provided by differences in post length. This disk is connected to the nodes gear train, 39, 18, 37, or third gear set from the bottom. It will be mounted on a 1/4" tube.
The bottom disk will attach to the top gear set with a 5/16" tube. This disk will support the earth, suspended at an angle from a rod that goes up and over everything emanating from the other disks. The earth is suspended at a 66.5° angle. This disk may also support a ring representing the ecliptic plane. Alternatively, this could be supported from the base.
The disks are currently planned to start with 3/16" thick brass plate. With four disks they begin to overwhelm the top plate, chubby baby. If there is a 1/4" diference in radius the disks will range from 1 1/2" to 3" in diameter. Dropping that difference to 3/16" drops the disk sizes to 1 1/2" to 2 1/2". I would like the ball representing earth to be about 3/4" in diameter and the moon to be about 3/16" as the latter is similar to the real 1/4 ratio of moon to earth. Thus a 1 1/2" moon disk leaves a gap of about 1/4" between the two spheres.
The earth at 3/4" diameter will be heavy and will need to be supported by 1/8" brass rod. The rods supporting other markers could be thinner, either 3/32" or 1/16" diameter. The circle marking the nodes will be made from 1/6" brass sheet and no wider than 1/4". There is more flexibility with the possible ecliptic plane as it will sit outside of everything else. The only other feature of the orreries, which have served as models, is the day/night indicator mounted on the top frame. A sketch of these ideas is seen below.
The materials were first located. The 3/16" rod, and the three tubes with the following IDs, 3/16", 1/4", and 5/16" were pulled from stock and scrap piles. 3/16" brass was also located for the four disks. An abandoned gear with a 1/4" center hole was used to make the 1 7/8" disk. The partially completed gear was mounted on a mandrel and turned to 1.876". The edges were chamfered and the disk sanded to 600 grit. The edge and the first 1/2" inch of the two faces were polished with red rouge. The other four disks were treated similarly, though started with square blanks cut from stock. One blank, third from top, could not be sourced from stock and was eventually cut from a material that was composed of two scraps soldered together.
A two day break was taken on this project to focus on a home repair job. Once again a drawer bracket in the pantry broke. One was made from aluminum as had been done previously, interestingly almost exactly six years ago. The only difference in the project this time was using chain drilling to remove most of the material from the slot that holds the drawer guide rail. Twenty-seven 1/4" holes spaced 0.012-0.015" apart were drilled prior to milling the slot, which went quickly. The milling was done with only vertical movements of the end mill, as if it were a drill. This eliminated the chatter that had dogged most of the milling work on this project. The two photos below show this process.
March has sprung and it is back to the orrery. The disks as currently fashioned need a hole for a set screw and need the central hole appropriately sized. The 2 1/2" disk was tackled first. It was set on edge in the milling vise and its center located with an edge finder. The hole for the set screw was started with a #0 center drill and then drilled through with #36 drill, tap drill for a 6-32 screw. The hole was opened to 0.144", large enough to clear the tap, for a depth of 3/4". The bottom 1/2" was threaded 6-32. The center hole was opened from 1/4" to 0.375" first with a T drill and then with a 3/8" reamer.
A length of 3/8" OD brass tube was held in the chuck on the lathe. Its actual diameter was 0.3755". The first 3/4" was sanded with 220 grit sandpaper until the disk was a sliding fit in the disk. The height of the disk top to gear bottom was measured on the assembled orrery at 0.751". The tube was parted off at this length. After some deburring the tube and disk were assembled and can be seen below.
The remaining three disks were drilled and tapped for set screws. The hole of one was opened from 1/4" to 5/16" and the smallest had an insert installed with Loctite, shrinking its center hole from 1/4" to 3/16". The insert had been drilled with the through drill to minimize interference with the set screw. Tubes were made for two of these disks and the smallest disk was fitted with a 3/16" shaft. All are a sliding fit in their mates. The four disks with tubes/rod attached are seen in the photo below.
The gears are still bothering me as they don't run well even with the adjustments made so far. This morning I spent some time determining what adjustments were needed to help them run more smoothly. With the help of feeler gauges and washers of various thickness the following changes were determined. The bottom shelf's right side spacer should be changed to 0.045". The middle shelf needs a 0.042" spacer on the left and a 0.075" spacer on the right. The top shelf requires a 0.036" spacer on the left and an additional 0.010" added to its current washer on the right. It is also clear that some gear teeth still need work to improve their fit.
The washer thicknesses identified above were prepped and with some difficulty inserted between shelf and shelf support. The bottom and middle gear's trains turn freely, while the top still has some difficulties, which are mitigated somewhat by shifting the shelf a bit to the left. Maybe good enough when the gear teeth are all fine tuned.
The budgie job above has been bugging me for a week, so decided to do something about it. The shelves will be remade and a better way of marking them for the axle holes will be devised. The trick is to find a way to mark them with the top plate in place. This rules out marking with the depthing gauge as it is too large to fit. A similar tool will be constructed that is significantly smaller as shown in the sketch below. The hole on the right will fit the axles of the gears. The slot will hold a sharp point to scratch the new shelves. The point will be held in place by installing a countersunk screw that can expand the point as it has a slot cut through most of its length.
The slotted brass part was made first. A 2" length of 3/16" brass was cut from stock. After cleaning up the ends a 1/4" hole was drilled and reamed on center and 1/4" from the end. Two holes were drilled 3/16" at 1/4" and 1" from the opposite end. A 3/16" slot was cut through the brass and between the holes that are 3/16" ID. A 1/4" end mill was then used to widen this slot to a depth of 1/8", leaving a 1/16" shelf.
A 1" scrap of 1/4" drill rod was held in the chuck and drilled for a #6 screw about 1/4" deep". It was then tapped and deeply countersunk. The part was turned around and held in a collet. The opposite end was reduced to 0.188" and the headstock rotated to 30°. The 60° included angle was cut. The part was moved to the vise and the hacksaw was used to cut down through the threaded hole. A screw was shortened to fit. It was impossible to hold the scribe in position in the slot while tightening the screw. Back to the drawing board.
A simpler scribe was planned and produced. Another short length of drill rod was found and held in a 1/4" collet. The end was faced and then 3/8" were reduced to 0.188". The end was cut as above to a 60° included angle and sanded to a point. The nice point produced is seen in the first photo below. The reduced end beyond the angle was threaded with a 10-32 die to the shoulder. Parting off at 1/2" produced the scribing point shown below next to the failed slotted version.
No 10-32 nuts could be located in my stash, so one was quickly made. A short length of 3/8" hex was held in the chuck and faced. The corners and six edges were chamfered. The hex was drilled about 1/4" deep and then threaded with a tap in the vise. The nut was parted off at about 1/8" and part way through parting the corners of the new side were chamfered with a file. The hole was also chamfered. The three completed parts of this scribing tool are seen below separate and assembled.
I do not plan on hardening the scribe. It will only be used on these aluminum shelves, so the current hardness is more than sufficient to mark the aluminum, especially when the aluminum is painted with Dykem.
Three more shelves were made. This round of shelf making was simplified. The three shelves were cut from aluminum with the hacksaw and filed to shape. No decorative edges were made as they can't be seen when assembled. The shelves were held as a unit in the mill vise and the DRO was used to drill, and tap all six 2-56 about 1/4" deep. The photo below shows the latest iteration of the three shelves.
The shelves were individually placed on the shelf support. The appropriate gears were depthed and the measurement (outside of the 1/4" axles) transferred to the new scribing tool. The transfer and tightening of the scribe were a little finicky, but all were within a few thou of the depthing tool measurement. The scribe was placed on the appropriate axle followed by the top frame, chubby baby. The scribe was rotated leaving its mark. This process was repeated for the second gear pair at that level, marking the idler gear center. The photo below shows the middle shelf with the scribing tool in place ready for marking.
Transferring to two shelves, middle and top, required a bit of extra care. Both shelves were attached to the shelf support using the holes that had been opened and need to always be installed the same as when marked. The middle shelf was tightened in place and marked when pushed down and right (when looking from the front) better hiding the shelf. The top shelf was pushed the other way, left and down, as its idler gear center is much farther left than the others.
After punching the marked idler gear centers the shelves were held in the vise on parallels, drilled and reamed to 1/4" completing the frame and its many parts. This installment of the Not Quite a Ferguson Orrery will end with three photos of the assembled and gear turning mockup.
