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Project Onstep on mount EQ-Sky / Astro-3


Sylvain Mennessier
 

Hello,

My project to motorize an unused mount for about 10 years is well advanced, it is time to show you some pictures and give some explanations.

This frame comes from a Bresser set sold in France in Lidl supermarkets.

Here are some original photos of the frame.


Sylvain Mennessier
 

To begin with, assembly of the whole assembly on ball bearings, grinding of the gearwheel, and new aluminum brake.


Sylvain Mennessier
 

Manufacturing and anodizing of stepper motor supports

 


Sylvain Mennessier
 

The assembly assembled, and the Onstep Mega 2560 and Ramps 1.6 test assembly.

 


Sylvain Mennessier
 

This weekend I started to make a wooden tripod, some photos of the start of the work.

The wood is cut from an old bed.



Sylvain Mennessier
 

Here it is for today, the continuation for soon.

Sylvain

 
 


Drew 🔭📷🚴‍♂️
 

Great project and a good example of what can be done with an old mount, machine shop and OnStep.

I could use a little more descriptive text. The picture are BTW, great. It looks like it  had "good bones" to start with. You pressed out the original bushings and re-machined it for the bearings? I assume it had the worm drive to start with. Re-hobbing it was to improve the performance? Or are those new worms you made? I am also having some difficulty understanding the new brake design. I am sure myself and others are interested in how you did it.

Keep posting this is good info.


GuitsBoy
 

Wow!  What an incredible job!   I'm in the process of converting an ES Nano which is essentially a bresser eq3, and I would love to convert it to cartridge bearings instead of plastic bushings.  Looks like a lot of work went into it.   If I had to guess, it looks like you simply chased the existing threads on the worm gears with the tap, is that correct?  Just to clean them up a bit?   I was also considering drilling and tapping the DEC housing like you did.  Did you find you had adequate clearance to the shaft, and enough meat to thread into?  Awesome job though, looks fantastic!

On 11/16/2020 8:16 AM, mennsylv@... wrote:

To begin with, assembly of the whole assembly on ball bearings, grinding of the gearwheel, and new aluminum brake.


Sylvain Mennessier
 

Drew & GuitsBoy,

Thank you for your feedback.

On the RA axis, the brake was a piece of plastic, with a single screw that destroys the plastic.

Now it is aluminum and the screw is drilled to put a piece of brass that does not make a mark on the aluminum.

For grinding of the gearwheel, they were originally not running smoothly, it's just a simple rectification. Now I can adjust the gears with great precision.



Sylvain Mennessier
 

Hello,

Small work of the day on the tripod, laser cutting of the tablet and fixing.

 


George Cushing
 

We have an expression here: "Making a silk purse out of a sow's ear." As you say these were sold through out the EU about a decade ago. IIRC these were from Jinghua (Explorer Scientific/Bressler) and were their model EM-8. they were offered in a 2010 Bosma (iOptron) catalog I have. Love to see what what you could do with a CG-5!

Please follow up with some performance results.


Sylvain Mennessier
 

Hello,

My tripod is soon finished, I will make a box for Onstep and the motor wiring.


Drew 🔭📷🚴‍♂️
 

You are an inspiration! I also have a old tripod I am adding a spreader to. I am not as far along. I am still trying to work out the design. Here are some pics of it.

I still have some questions on your mount refurb. Did it come with those bearings? It looks like you have an actual worm gear hob. Where did you find it?


Sylvain Mennessier
 

Drew,

There was no ball bearing, I added 8 ball bearings.

No, this is not a specific machine, but just a metal lathe with an M12x150 tap.


Howard Dutton
 

On Thu, Nov 26, 2020 at 12:03 PM, Drew 🔭📷🚴‍♂️ wrote:
You are an inspiration!
Yea this is really something else.

Looks like it might just end up being a nice looking and performing small portable goto mount.


Drew 🔭📷🚴‍♂️
 

On Fri, Nov 27, 2020 at 03:31 AM, Sylvain Mennessier wrote:

There was no ball bearing, I added 8 ball bearings.

No, this is not a specific machine, but just a metal lathe with an M12x150 tap.

You have some good design and machining skills. You have created a much better mount than you started with. It will be interesting to see the end result. I hope you do some "PHD" analysis on it.

So the original worms matched an existing tap size? Or is that a completely new worm gear assembly?


Sylvain Mennessier
 

These are the original worms, I just corrected them because they didn't turn well.


Drew 🔭📷🚴‍♂️
 

On Fri, Nov 27, 2020 at 08:02 AM, Sylvain Mennessier wrote:
These are the original worms, I just corrected them because they didn't turn well.
I just find that remarkable that they would use a standard tap thread. I never seem to have that sort of luck.


Sylvain Mennessier
 

Hello,

Well advanced this weekend, for the foot, there are just the adjustable feet to make.


Prasad
 

Beautiful work. Thanks for posting pictures. What is the type of wood used by you? 

Prasad
Eastern PA, near Philly

On Sunday, November 29, 2020, 07:27:50 AM EST, Sylvain Mennessier <mennsylv@...> wrote:


Hello,

Well advanced this weekend, for the foot, there are just the adjustable feet to make.