10 votes
Accepted

How do you make a 3D print with an accurately aligned bore hole?

3D printing bores/holes is inherently and wildly inaccurate. You can continuously tweak the model, material, and print configurations to get better results, but for best results, in my experience, ...
  • 1,578
5 votes

Converting rotary motion to linear motion (door for sliding trash can)

This is actually two different questions. Mechanisms to convert linear motion to rotational: There are different mechanisms around, the most common of all crankshafts. what is the best mechanism for ...
  • 219
5 votes

How can I attach a rotary encoder to a retractable dog lead?

Instead of a shaft driven rotary encoder, you might be able to build an optical encoder that uses optical sensors to read a pattern printed on a disk. A simple encoder uses white/black alternating ...
  • 151
3 votes

What's the name for a kind of gear that slips tightly over the top of another gear and can drive the gear it's surrounding?

I would call it a splined crank (i.e. a crank/handle that has a splined socket on one end -- like on some higher-end bicycle cranks). In your case, it seems that you want to place the splined end of ...
  • 141
3 votes

What is the process called for up-sizing a proof-of-concept prototype to full-scale?

In my experience (your mileage may vary) these are the sorts of processes and terms used in product development: The breadboard is your proof-of-concept work; can be messy, often by taking something ...
3 votes

Converting rotary motion to linear motion (door for sliding trash can)

You have already arrived at half of the simplest solution. You need a dual tension system. When you open the door, the string pulls the slide out. When you close the door, you simply need something to ...
  • 241
3 votes
Accepted

How does the Nest Learning Thermostat bezel rotate without bearings?

Just prior to this point in the video you can see that the display has been inserted from the front and this portion will be added from the back and screwed in. All that is required is to ensure that ...
  • 8,774
2 votes

Converting rotary motion to linear motion (door for sliding trash can)

A small plastic rack and pinion will work well and eliminate the need for strings. The rack will be on the drawer slider while the pinion at the hinge of the door.
2 votes
Accepted

Prototyping tubular components

EDIT - I've solved this issue after a bit of searching for similar application requirements, so I'll post my solution: Applying a bit of heat using a heat gun to sand-filled PVC pipe allowed me to ...
  • 141
2 votes

What is the process called for up-sizing a proof-of-concept prototype to full-scale?

It's still a prototype, but its a prototype for a different purpose. People use different languages to refer to this. Personally, I call it "iterative prototyping". Others might call it moving from ...
2 votes

How to retrofit seed starting trays to prevent root circling

Coffee (stirring) sticks might work. After potting is complete these could be inserted vertically with the narrow edge against the side of the pot in multiple positions around the edge. Seeing as ...
  • 8,774
2 votes

Which software to get started with 3d Modeling

This probably belongs in Software Recommendations and perhaps an agreeable moderator will make the migration. Fusion 360 is a good choice. It uses sketch modeling and also sculpting to create both ...
  • 6,417
2 votes

Switching a Circuit on-and-off In-step with the Rotation of a Drive-shaft (Mechanically)

Without a sketch your setup is difficult to visualise. A typical industrial solution would be to use an inductive proximity switch. These are non-contact, fast switching, water-proof, etc. Figure 1. ...
  • 8,774
2 votes

Prototype for Injection Molding

There are 3D printers that are meant for quick prototyping of injection molds. They print the molding parts, and remove most of the cost of machining the mold. They arent suitable for mass ...
  • 3,435
2 votes

Engineering Best Practice: Rev control for trial parts after release?

When I worked at an (in theory) ISO shop, we did the same thing as the OP, and in-development designs were uncontrolled and informally and inconsistently versioned. A recent question here (talking ...
  • 1,367
1 vote

Fasten adjustable perpendicular cylinders rotating on axis

If you search on the internet on swivel joint for the rotating joint and under screwdriver joints for the fixed joint you will find manny examples.
1 vote

Which software to get started with 3d Modeling

For 3d modelling there a few out there. For entry level professional 3d design and modelling, the software I am mostly familiar with are: Solidworks: Its my preferred one due to User Interface (mind ...
  • 22.8k
1 vote

How to prevent an object doing a full rotation on a shaft

Ok, so completely not the best image, but if you have the shaft with a hardened pin fitted - the angular width of the slot can be adjusted to control the angle of rotation and it only needs to match ...
  • 14.2k
1 vote
Accepted

Designing A Freely Spinning Object

Option 1: A plain old ordinary motor with a clutch of some sort that is completely non-contact when it is disengaged. If losses when you're spinning the thing up don't matter too much, then a rubber ...
  • 2,263
1 vote

oscillation motion from DC motor (computer fan)

Yes and no, maybe. Computer fans are specialized, cheap brushless motors, with their own built-in controllers. The ones that I took apart 30 years ago had 4-pole coil assemblies and an unknown ...
  • 2,263
1 vote

Ball and Socket Wheel Concept

You looking for an element in a ball table. Search for ball table conveyor A castor is almost the same, but cheaper.
  • 401
1 vote

Spring Industry Naming Convention

Usually spring's geometry is denoted as : OD* ID* Length. Outside diameter* Inside diameter* Length.
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1 vote

Buckingham-Pi Dimensional Analysis when there is a non-dimensional parameter: How is it accounted for?

Let's assume that you will work out the right combinations of dimensionless terms on your own. Let's consider only the question of what to plot once you have those terms. By example, in heat transfer, ...
1 vote
Accepted

Mechanical tolerances on a CNC machine

It's going to be an uphill battle from that point on. While you can get every part of the machine and the process to tighter tolerances, their errors may compound to the sort of tolerance of 0.025; ...
  • 6,133
1 vote
Accepted

How to retrofit seed starting trays to prevent root circling

Attach some L-shaped metal sheets or plastic parts in between holes? Attaching can be accomplished by, gluing, nailing, silicone, screwing, etc. depending on the size of the plates and your pots. Or ...
1 vote

Understanding metalwork manufacture -- How are Purchase Quotations prepared?

As Mahendra Gunawardena said, there's not one universally used method of pricing manufacturing projects, but there are some pretty common facts that result from the economics of the situation. ...
  • 4,501
1 vote

How to cut Silicone and leave smooth edges?

A laser would be the best method followed by repetitive razor slicing in ever deeper cuts to avoid frictional deformation. Another method would be cold cuts by freezing the silicone and using a ...
  • 854
1 vote

I am looking for some basic mechanical parts to build structures(prototypes)?

In addition to 80/20 you could use "unistrut" or "channel strut" framing which may be more readily available at a big box store.
  • 1,578
1 vote
Accepted

I am looking for some basic mechanical parts to build structures(prototypes)?

What you're looking for is described as "Perforated", So a quick google for "Perforated Square Tubing Steel" produced: https://www.discountsteel.com/items/Galvanized_Steel_Perforated_Square_Tube.cfm "...
1 vote

I am looking for some basic mechanical parts to build structures(prototypes)?

Try 80-20 structural tubing. It is available is various sectional sizes, often used for robotics and machine framing.

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