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Using heavy duty planetary gearboxes for a diy mount?


soulvagabond@...
 

Guys, there's plenty of the heavy duty gearboxes for sale, for example on aliexpress, which, by the first look, can be easily adopted for making a telescope mount.
Just an example: https://www.aliexpress.com/item/1005001631354710.html
Backlash precision stated: L1≤3arcmin;L2≤ 5 arcmin
What do you think about it?


tomofreno2000
 

Less than 5 arcmin seems very good to me. Iirc the steppersonline "precision" gearboxes are < 25 arcmin.


Dave Schwartz
 

Unaffordable?

On 2021-01-12 10:38 a.m., soulvagabond@gmail.com wrote:
Guys, there's plenty of the heavy duty gearboxes for sale, for example on aliexpress, which, by the first look, can be easily adopted for making a telescope mount.
Just an example: https://www.aliexpress.com/item/1005001631354710.html
Backlash precision stated: L1≤3arcmin;L2≤ 5 arcmin
What do you think about it?


Khalid Baheyeldin
 

On Tue, Jan 12, 2021 at 12:40 PM, Dave Schwartz wrote:
Unaffordable?
Exactly how I felt when I saw the price.
Even if these are super excellent mechanically, you need two of them.
Then you need to buy motors, mount them and so on.

For a bit more money, you can get a mechanically sound mount that
already has the right gears and such (Losmandy for example).


soulvagabond@...
 

The idea is to have a mount, capable of carrying a 20kg telescope. That's brings us to ~2k usd+ area, for a factory mount.
Found a used Japanese made harmonic gears: aliexpress.com/item/4000296672091.html, the manufacturer states Accuracy <1 arc-min: harmonicdrive.net/products/servo-mount-gearheads/harmonic-drive/csf-gh/14/csf-14-100-gh
Tbh, I don't quite understand the Permissible load data, will that require the used of the additional bearings, for the telescope mount purpose?


Khalid Baheyeldin
 

On Tue, Jan 12, 2021 at 12:57 PM, <soulvagabond@...> wrote:
will that require the used of the additional bearings, for the telescope mount purpose?
Ignoring the cost, complexity of the build, and any other considerations ...

This gearbox is only 100:1.
Realistically, with 400 step motors, you need at least 360 overall.
For example 144:1 wormwheel as in an EQ5, with 2.5:1 pulleys.

So you need a minimum of an additional 4:1 pulley somewhere.

And you are actually better off with 720:1 overall, and mode switching in the controller
to speed up slewing.


soulvagabond@...
 

To make it a bit more clear, I live in Indonesia, for the past few years. Here you can find precisely, ZERO supply of any telescope related products, everything has to be imported. Shipping and Tax will easily double the price.
And then again, isn't diy-ng addiction, is what we are here for?


George Cushing
 

I believe these are what Kevin MA used on his vintage Meade LX3 mount. They can also be found used for a about a hundred on eBay.


Khalid Baheyeldin
 

On Tue, Jan 12, 2021 at 03:50 PM, George Cushing wrote:
I believe these are what Kevin MA used on his vintage Meade LX3 mount. They can also be found used for a about a hundred on eBay.
There are two other harmonic drive mounts in the showcase (scroll down to Custom mounts).

One was by Simingx, and the other by someone in Korea.


soulvagabond@...
 

Thanks, I keep on forgetting about the showcases section, plenty of useful info on there.
The other advantage of the harmonic drives is that the use of the counterweight becomes optional.
Anyways, I posted in simingx thread, hoping to get a bit more info..
Thanks


George Cushing
 

Yes, it's quite a treasure chest and a good reference. It is somewhat searchable with google.