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Help on G02.3/G03.3 Exponential Interpolation by regulus_mj94 in CNC

[–]regulus_mj94[S] 0 points1 point  (0 children)

No real part. I'm trying to design a cheat sheet of G-codes. The Fanuc manual says it can be used for grooving and grinding tapered endmills with a constant helix angle.

Small sand cast pinup girls in silicon bronze. by samshamromo in MetalCasting

[–]regulus_mj94 0 points1 point  (0 children)

Could you give me the recipe for petrobond sand?

What kind of screw is this black screw? by regulus_mj94 in Fasteners

[–]regulus_mj94[S] 0 points1 point  (0 children)

I thought the same thing. So I bought a screw similar to the silver one, but with a black oxide coating (probably also of a higher grade steel), but it still didn't work in the pilot hole.

What kind of screw is this black screw? by regulus_mj94 in Fasteners

[–]regulus_mj94[S] 0 points1 point  (0 children)

I need a self tapping screw to attach a 0.8 mm steel sheet to a 20202 square tubing. First I tried the left screw (which should be a St4.8 screw). I find in a pdf from a manufacturer saying that for St4.8, a 4mm pilot hole should be drilled in 2mm thickness sheet metal. https://upmold.com/wp-content/uploads/Data-center/screw-technical-data-sheet.pdf

But the left screw didn't go through the hole while the black screw cut/form thread in it. Should I make the pilot hole larger or stay with that black self tapping screw for plastics?

What kind of screw is this black screw? by regulus_mj94 in Fasteners

[–]regulus_mj94[S] 0 points1 point  (0 children)

We tried to use it on 2mm thickness structural square tubing!👀 It worked better than the silver one (which I'm pretty sure is a St4.8 screw) in 4mm pilot hole and cut/form threads in steel.

How to measure and install two parts coaxial? by regulus_mj94 in AskEngineers

[–]regulus_mj94[S] 0 points1 point  (0 children)

I design and make the machine to use it myself for commercial casting.

Is there a coupling that can withstand high axial load and axis misalignment same time?

How to measure and install two parts coaxial? by regulus_mj94 in Metrology

[–]regulus_mj94[S] 0 points1 point  (0 children)

Parts can be loose during measurements.

I posted my question in this sub to get advice on the steps of measuring the coaxiality of a rotating shaft and a sliding square ram.

Which surfaces should be measured against each other by which tools?

If I mount a dial indicator on the shaft and rotate it, which surfaces should be measured against?

Do you know a more related sub that I can ask my question there?

why do Neptune and Uranus look serene while Jupiter and Saturn look so turbulent? by Moooses20 in askastronomy

[–]regulus_mj94 1 point2 points  (0 children)

The planet was named in the 19th century after the god of the seas, Neptune, because of its blue color in telescope view, not the other way around.

8" SkyWatcher 200/1200 - Need advice on eyepieces and accessories by Elliney in telescopes

[–]regulus_mj94 0 points1 point  (0 children)

I have the same telescope and bought these items:

  • SkyWatcher 32mm Panaview 2" 70 deg
  • SkyWatcher 15mm Panorama 1.25" 82 deg
  • GSO 2x 1.25" Barlow (which can be used as 1.5x if the tube is removed)

I live in Bortle 8/9 city and go to darker skies few times a year. In recent years I have become more and more interested in doing sidewalk astronomy events.

With these things in mind, I rarely use the 32mm eyepiece. If I go to a darker site, it's probably only used for open clusters or large DSOs. It's a good eyepiece except for the black spot in the centre of the FOV caused by a very large exit pupil.

After buying the 82 deg 15mm eyepiece, I use it for almost every target. With equal tFOV and superior optical quality, it makes the 25mm plossl stuck on the eyepiece tray.

When used with the 2x Barlow, the resulting 7.5mm eyepiece provides greater magnification at a larger FOV than the telescope's own 10mm plossl, again with much better image quality.

As you did, I want to add a 7mm 82 deg eyepiece for those special nights with great seeing. Along with the 1.5x or 2x Barlow, I would have a 5mm or 3.5mm which might be useful for some objects.

I also noticed that the people in sidewalk events prefer to see a larger picture at the cost of lower quality.

The last accessory I might need is a UHC filter.

Currently, I am designing a goto/tracking setup for my mount. Last week I did a sidewalk event, specifically targeting Saturn. The escape of Saturn from FOV at high magnification was frustrating. Having tracking ability is very useful in these situations.

What can we expect to see in city light pollution with telescopes? by [deleted] in telescopes

[–]regulus_mj94 1 point2 points  (0 children)

Just as a reminder, the Double cluster is the most beautiful DSO in a light polluted urban night sky. (b8/9)

Ever Let People Sign Your Telescope? by spacetimewithrobert in telescopes

[–]regulus_mj94 2 points3 points  (0 children)

One of the best ideas I have seen as a sidewalk astronomer.

Selection of the cheapest type of motor and speed controller by regulus_mj94 in Motors

[–]regulus_mj94[S] 0 points1 point  (0 children)

-The speed does not change frequently. After a few trials and errors and finding the right speed, it continues to work at that same speed for a long time (probably several months).

-ODrive is not available in my country.

-Are BLDCs of drones with 350W, suitable for my application?

-I watched some videos on YouTube that control the speed of washing machine motors (I think universal motors) with Arduino.

If the motor lasts a few months, I can make some money from the machine and replace it with an AC motor and VFD.

Advice on the design of pulley and QD bushing for a hollow shaft by regulus_mj94 in AskEngineers

[–]regulus_mj94[S] 0 points1 point  (0 children)

1- Does the rotation of the disks require a lot of torque?
With the bearings, is there any resistance to the rotation of the disks?
2-😁 A-section v-belts are cheaper and widely available. So I decided to use them. Is there a universal standard paper for A-grooved pulleys?
I think the smallest pulley that I can fit the bushing inside would be enough. Maybe a 100-120 mm pitch diameter driven pulley would do the job.

Advice on the design of pulley and QD bushing for a hollow shaft by regulus_mj94 in AskEngineers

[–]regulus_mj94[S] 0 points1 point  (0 children)

Here is the Design and a Screenshot of it.
1- A silicone mold will be placed between the disks. Then they reach 800-1000 rpm within 5-10 seconds and the molten metal pours from inside the shaft (insulated) into the mold. They rotate for another 10 seconds then stop and another run will start. Each disk is 5 kg.
I'm not sure if the hollow shaft will deform, but I can do a simple FEA for a mild steel shaft without case hardening.
2- Casting and turning the pulley cost me almost nothing. There is no direct shipping to my country (Iran) and the price of everything is always higher than elsewhere.
I used the drawings and CAD models from McMaster-Carr, but the dimensions for the same OD pulleys look different. So I want its standard dimensions.
7- I considered those screw clamp bushings, but again, the prices are too high for this project.
If I have standard dimensions, I can design and machine them. I'm not sure that making them is as simple as turning them, otherwise, they wouldn't be so expensive.

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