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Topics - Callistemon

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Misc / Interior Trusswork
« on: September 02, 2020, 05:37:17 am »
Interior Trusswork
--> View Model

This is a new and different method of reinforcing cubic towers with trusses. Instead of the four sides being filled with trusses, the truss beams cross through the center, and the two perpendicular beams intersect in the very center to form a plus shape (when viewing from above). Unless you have a large supply of orange peg clips, this can only be assembled using blue 3D connectors in the center. If there were white rods running horizontally between the yellow connectors, equilateral triangles would be formed, but that requires many peg clips.

At the top of the truss section, the white rods should be angled outward in all directions, and an X can be added. This requires 6 peg clips if you are alternating in a checkerboard pattern between gray 3D connectors and red connectors along the vertical running corners of the tower. As long as all four connectors on the top and bottom edges are gray 3D connectors, the tower cannot lengthen and shorten from rods sliding through the red connectors.

With exterior truss, even if there are available blue rods between X units, adding a solid connector railing requires a blue rod to clip onto at every green unit, and connectors cannot clip onto a green rod beside a white connector. Interior trusses retain robust structural strength while allowing there to be blue rods on every single horizon. The trusses do connect to the edges by looping yellow connectors through the blue rods, but that does not interfere with adding railing unless there will be less than 1 connector-width (6mm) between the rails.

Instructions will be coming soon (hopefully).

Project Ideas and Help / Orange gear rotation inverter problem
« on: September 01, 2020, 08:30:02 am »
I recently received 4 orange half-crown gears for building mechanical rotation inverters (spin continuously in one direction and outputs reciprocating rotation). Supposedly, half of the time with Design 1 (left), the output gears (blue) are turned by either the orange gear on the left or the right side, and all else being equal, turning a gear on the opposite side reverses the output rotation. The direction adjusts based on the rotation, not by the second (slower rotation induces slower alternation). With Design 2, which functions essentially the same, instead of alternating which side both output gears are spun, it alternates which yellow gear turns the output axle (gold). These mechanical inverters would be the opposite of my upcoming mechanical bridge rectifier, which would use ratchets to sort the movement to one channel or the other based on direction of input rotation, and then reverse the reverse.

There is one huge issue, enough that I demolished these and will not attempt further unless someone prints a custom gear. Whenever switching directions, instead of momentarily disengaging the first and then engaging the second, there is a bitter instant where both are engaged, and it is a tough grind to switch directions. Someone (which should be lazy me) needs to print a custom orange gear with 2 fewer crowned teeth, and with the interlocking slots exactly perpendicular to the crown half. When 2 of the existing orange gears are inserted with opposing crowns on a single rod, and are clipped with tan clips, there is 1 tooth of transition space on one side and 3 teeth of 'neither' space on the other, even though it should be 2-2 or 3-3.

Photo looks bad even after editing due to dingy 80 CRI light. Always choose 95+ CRI.

Misc / Small-size Mass Damper
« on: September 01, 2020, 07:36:32 am »
Small-size Mass Damper
--> View Instruction

First off, I apologize for publishing the second consecutive instruction. Please, someone besides me, publish something. Anyways, this is a small-sized mass damper weight that swings around at the top of a tower. Mass dampers respond to vibration and reduce the movement and swaying of tall structures. It is ideal for towers that are the size of a blue square.

The weight is partially surrounded by a slick 37mm tire. The upper 2 white connectors have 2 Y-clips on each side that hold the tips of 2 white rods, one on each side. The length of the suspending rods can be varied to adjust the frequency, but a single white rod is the shortest length. The mass unit can swing in all directions, similar to a universal joint.

This design can be extremely beneficial, useless, or somewhat harmful depending on the frequency and amplitude of vibration. It is most effective for high frequency vibrations with small amplitudes. Lower frequency and/or larger vibrations may cause the mass unit to collide with the tower frame (because my designs are always poor designs).

When paired with base isolation (which I will be more motivated to publish if someone else publishes something), mass dampers can be used to simulate higher masses (more inertia and resistance to movement) on the base isolation springs without substantially increasing the weight load (less gravitational force to overload the springs).

Pieces Count
Slick 37mm Tires: 1
White Connectors: 5
Red Connectors: 2
Orange Connectors: 2
Purple Connectors: 2
Green Rods: 2
White Rods: 4
Blue Rods: 2
Y-Clips: 4
Metallic Blue Clips: 1
Tan Clips: 1
Black Caps: 2
Silver Spacers: 2
Blue Spacers: 10

Misc / Rod-Gear Interlocking System without Tan Clips
« on: August 06, 2020, 11:46:29 pm »
Rod-Gear Interlocking System without Tan Clips
--> View Instruction

This is a rod to gear interlocking assembly that does not use any tan clips. I was experimenting with using splice clips and an orange connector to try to make an improved gear coupler that does not clamp to the rod and spaced the gears further apart, but I ended up developing this that does clamp the rod. The splice clips protrude into the orange connector, and the orange connector is clipped to white rods that hold purple connectors clipping into the metallic gold yellow rod. The tips of the white rods would not fit until the splice clips were angled to the side.

When twisting the purple connectors directly, it is extremely tough and unbreakable. However, when twisting the gold rod with orange connectors clipped to it, the assembly breaks apart under slightly more force than a tan clip can tolerate before detaching. This can be solved by using blue rods in place of the white rods and clipping more purple clips to the gold rod, but even with the white rods this assembly would require a wide chamber compared to a tan clip, like a blue unit wide instead of a green unit. Also, the crown gear must be facing towards the assembly, and if a crown gear needs to be facing away then another gear must be coupled adding unacceptable complexity and width (unless you 3D print a gear with the center area extended on both sides). The interlocking assembly has much more slack than a tan clip.

This is part of the structure surrounding a compact camera holder in a travel set. For years, there were 3 vertical blue rods, as shown in the first photo, and that was one of the aspects I admired since I like rods shooting straight through connectors and the build is overdone with shorter rods and 3D connectors. However, I was recently making upgrades, and while most of them were obvious and I will never look back, this was one where both styles were good. Now there is one, long horizontal red rod shooting through 3 connectors, which is refreshing for a structure overdone with short rods. Both styles are nice, and as the king of paralysis, I don't know which configuration to choose.

Since I am looking to sell 9 K'nex Bridge Track Section Connectors and need to know how many stamps to use, I looked up the mass per piece on K'nex User Group like I always do when I want to know weights. However, their page claims each piece is 38 grams, so 9 of them would supposedly be 12 ounces. That was obviously incorrect, so I emailed them but they said it could not be verified since the part was discontinued.

I don't have a scale, and weight scales are not always very accurate at low weights. So, I decided to assemble a small K'nex balance, even though I thought I did not have enough parts. It's not complete, and will eventually be upgraded with more metallic rods and two X supports that will require 4 orange clips, but it still functions. I placed the envelope on one side and placed orange connectors on the other side, hoping their mass rating of the orange connectors was more accurate than of the one-off piece. It took 42 to 43 orange connectors to equal the envelope, which equals a much more reasonable 2.14 ounces. It's important to ensure the center of mass on one side of the balance equals the other, or else it will be as biased as completely different weights.

Balances use gravity, but are not affected by the strength of gravity. Balances measure mass, and weight scales measure weight. Devices that put gravity and centrifugal force to competition at a set speed measure the strength of gravity. If you want, you can assemble a spindle with several diagonal rods where balls can slide up & out or down & in, but I cannot because I think I have an abundance of purple clips compared to other parts when it is just about a pint.

Project Progress / Crank fan neon connector upgrade
« on: August 05, 2020, 03:49:05 am »
I recently unboxed and washed 100 used neon connectors, gears, and random pieces, packaged in paper as requested and sold at an expensive price. 311 pieces isn't enough to get very far, especially since there were 0 white connectors, but one thing I did accomplish was upgrading the red and green connectors in the crank fan to neon connectors. It gives a large boost and makes for a change, and makes it easier to find.

The shaft spinner part was assembled several years ago based on the drill model, and a propeller was added later. There are orange flexible rods for visibility and appearance. The handle axle, which has not crumbled since being upgraded to a stiff tan rod, spins a yellow gear that meshes with a blue gear to change the axis of rotation. If there is only one tan clip, the clip widens, slips, and chafes the axle. Two tan clips cannot line up oriented upright unless they are of the old style, and if they are placed opposite than the second clip pries open the first. If the two clips are offset by 90 degrees then it is usually reliable but a clip is occasionally ejected at high speed.

Any propeller or impeller inserted has it's own set of the red connectors. The red axle of the shaft spinner just pushes through the blade set's white connector and clips to the blue 3D connectors. It detaches quickly when desired. The curved panels are floppy and fall off, which creates sudden imbalances at 600 RPM that cause serious failures. I would like to build more blades with regular panels and add rod locks to this curved panel blade. Instructions will be made for this crank fan eventually, but I do not have enough parts to rebuild it and it has too many issues.

Site Feedback and Questions / Optional Part Index in Profile
« on: August 05, 2020, 02:51:58 am »
There is currently a short Personal Text entry and a Signature in the profile, but there is no entry for text only displayed on the profile page. I would like if there was an optional entry for Part Index, where users can specify some of the types of parts they have (users can choose which part types to even list) and show a status of Insufficient, Sufficient, and Excessive. That way I can easily see if I want to buy or sell parts to another member. I have a medium desire for this, it's not very important but it's not useless.

Other Discussions / K'nex Bridge Track Connectors (9) for sale or trade
« on: August 03, 2020, 03:32:39 am »
I don't ever use these 9 bridge track section connectors, because the 30 centimeter bridge tracks are just a one-off piece that can easily be made with solid orange connectors instead. They cost $1.31 each new and are rightfully discontinued. These parts are washed for visual cleanliness only (not that they were visibly grungy before), and have trace amounts of maroon and blue crayon that cannot be removed easily (haven't tried a brush). All 9 pieces are packed in a paper envelope, free shipping (message for location, lax negligent United States). One piece was discovered after the photos were taken, but it is completely identical to the other 8 in condition.

Payment: $11.79 of used K'nex (using new prices) or $9.43 cash
Angled Orange Clips ($0.15 each)
Curved Panels ($2.75 each)
Light Green Flexible Rods ($0.48 each)
Rod Locks ($0.62 each)

Most used discontinued parts are more expensive than they were new.

General Knex Discussion / [deleted]
« on: July 14, 2020, 12:16:28 am »
[deleted - please allow full deletion]

Site Feedback and Questions / New Sections
« on: July 11, 2020, 08:00:39 am »
Would you consider adding a new K'nex Part Discussions section? Don't worry that it will remain empty, I have many part ideas but don't want to flood the general section with them. Also, if you're up to it, you may want to consider setting up a K'nex Marketplace as an alternative to eBay. Thanks!

General Knex Discussion / K’nex Motor Quality and Torque
« on: June 30, 2020, 03:47:08 am »
I asked K’nex many months ago if their motors are brushed or brushless, and if they have a sleeve or ball bearing. They said the information was unavailable. More recently, K’nex User Group said they did not know either. Brushless motors with ball bearings are superior, being quieter, more efficient, and longer-lasting.

DC brushless motors with ball bearings usually last about 70,000 hours before reaching 10% chance of failure. That’s 8 years of continuous operation.

For my motorized fan I want the silver or red 190 RPM motor, but I don’t know if the torque will be sufficient as the line if battery motors is just different ratios at the same power. There is also the stronger 2-speed motor. The batteries will need to be recharged (alkaline batteries are horribly wasteful), but the worm gear motor is so slow and overly forceful.

Update: I have been told that the K'nex motors are likely brushed, amd that the red 190 RPM battery motors have very minimal torque. The 66 RPM plug-in motor is far too slow for my use, and the second fastest battery motor is 48 RPM. So, what about the 2-speed motor, how much torque does it provide at 240 RPM? Can it spin four curved panels at a reasonable speed? If anyone has an extra 2-speed motor I would like to buy it.

General Knex Discussion / K’nex ordering options (deleted)
« on: June 27, 2020, 07:41:59 am »

Update: I have received the boxes and will recycle the broken parts anytime now. The list of broken pieces can be found below as it has been for weeks. Take it or leave it, I am charging nothing.

I have a K’nex hand crank fan that uses a modified version of the model drill attached to a propeller with four yellow curved panels. Every 8 to 11 days, the yellow axle (before axis conversion) spontaneously falls apart and the area crumbles up. The yellow rod always breaks as it passes through the hole in the yellow connector. There was also a time where the red rod (after axis conversion, yellow in the original model drill) suddenly broke right where it passes through another connector, allowing the propeller to fall off.

Failure Dates
April 25 - Yellow
June 2 - Red
June 3 - Yellow (8 days)
June 12 - Yellow (9 days)
June 23 - Yellow (11 days)

Part suggestions: An extra-rigid yellow rod would help. Carbon fiber may also be a good resource for strengthening the rods, although it is currently not used.

A few of the curved panels have deformed tips and the connection is so floppy that they easily fall off. At the time of the most recent axle failure, there were only two blades on the fan since the other two were previously ejected and were not reinstalled. In addition, during the time of having two blades, there were two incidents where one blade fell off while spinning, which instantly made the propeller so imbalanced with just one blade that the entire red axle and the blue gear exploded off at 43 MPH.

I have an entire cup full of more than 60 broken parts, weighing more than 6.5 ounces according to quantity and K’nex User Group’s weight for each part. These parts are 2 to 8 years old. I need to know how to recycle these parts, unless someone wants some of the broken connectors. I don’t know what to do with the curved panels, as it seems wasteful to have the entire panel recycled just because of the tips, especially since they are discontinued.

K’nex responded after 13 days and said that the plastic is recyclable but they do not offer recycling services. All recycling centers near me are closed until further notice. Even when they were open, they were remarkably shoddy, lousy, and incompetent. The local recycling centers didn’t accept most things. One in particular charged fees for scrap metal, and there are rumors that even some of the well marked plastics were being sent to the landfill. They probably burned their e-waste.

If K’nex can’t even recycle their own plastic, they must not be using any recycled material. And they don’t accept broken parts for recycling. It’s not landfill-free to not use recycled material or accept broken pieces for recycling. I don’t know what to do. If anyone is interested in broken connectors, I will post an incomplete (as more are always being found) inventory of the quantity and weight of each type of part.

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