JeromeW

Thank you very much for sharing your teflon upgrade. It has turned my EQM-35 mount from a piece of junk, to a well functioning precision piece of equipment. Last night I was able to maintain an RMS between .68 and .98

I believe one thing that also has helped with this upgrade was the use of the HELIMAX-XP Optical & Instr Helicold Grease.

https://www.ebay.com/itm/123651606955

I'm uploading a revised DEC Motor Bracket. This modification allows me to have interior space for the mini-circuit board and the wiring. It allows a cleaner look.

DEC Motor Bracket V2.stl DEC Motor Bracket V2.AD_PRT

Previously, with my EQM-35 mount in stock configuration I was never able to get it to guide in DEC with Askar V telescope. The DEC axis was too stiff for the stepper motor to overcome the friction. The belt conversion did help.

I tested my mount outside tonight. The sky's were about 70% overcast.

Tonight I was able to reliably guide. However, my results were not as good as yours. I was able to maintain a total RMS between .95 and 1.4. But it was able to guide, the teflon washers make a diffinate difference.

Last night with my 3D Printed DEC axis I was able to maintain .34 to about .7.

Thank you very much for sharing your teflon upgrade.

Paul,

Wow!! Your teflon washers was a great idea!!

The friction in my DEC axis is now less than half!!

I'll let you know how it turns out tonight if we have clear skies.

My teflon washers were 2mm thick, but I was able to make them work by creating a shim.

In the first picture my wife took the measurement about 1 year ago, it didn't take me long to notice something was wrong.

Jerome

I'm very impressed with your results, I'm lucky to get +/-2 with my rig. Now that I finally got my guiding to work properly I have to start fine-tuning with the settings.

I'm expecting my teflon washers to arrive tomorrow.

Although I'm very happy with the performance of my 3D printed DEC Axis, I would prefer to have it stock. I'm concerned that a few hours in a hot car may warp the PLA plastic parts. Temperatures in the high deserts of California in a car can easily hit 160°F. My wife and I often take my telescope to Twentynine Palms for viewing.

Thank you. I'm very pleased with how well my new axis works.

I am expecting my teflon washers in the next few days. I'm very interested about working your DEC mod. I'll let you know how it works out.

I added Index Markers for my RA and DEC. I also added a weight to counterbalance the focuser motor. Finally, I added a knob to my motor shaft to adjust my DEC Axis.

Paul,

I found these PTFE washers on eBay.

Jerome

https://www.ebay.com/itm/404688923477?itmmeta=01HQGSCBW62EXYVHQB2ER46C92&hash=item5e3956eb55%3Ag%3AFYoAAOSwtfJlf6ON&itmprp=enc%3AAQAIAAAAwFNHxkuKA%2FwsA0yGZ9U8A7ArJRJO16ydOtF4ySmWwbYJe1U%2FqjR1XfXgR85mEtceZ1vvlV7HB2f4ZxU5nOz5ptY9YS7air67o9WgIz2UgA8cTPyw9foy9WBa7FUomTGxYtGOvXYD%2Bf9L%2BQGnTRSVlzlA368F31ZgpYt4MGN4jD8d7tmdFNVPmwfeSwlbboBQGStF4rkJt5Lq8Z0DUND1ajWTR7X%2Fn6jd52pqC4eGVRH%2FJJyDRxspjNxzbXEe7PLY%2Bw%3D%3D|tkp%3ABk9SR5i-sZm8Yw&LH_BIN=1

https://www.ebay.com/itm/404688923477?var=674687056860

Here is the list of hardware for my 3D Printed DEC Axis

AWSOME!! The PTFE sounds like a great idea. I have already tried the bearing upgrade and didn't find it beneficial. 

Also, I am very pleased with my 3D printed DEC Axis. I am now able to properly balance my telescope, and the plastic is proving to be strong enough.

To All,

I wanted to report my success tonight. I finally got my DEC to guide properly tonight. My primary problem was that I had my DEC Mode set to North instead of Auto.

Jerome

Paul,

I certainly look forward to seeing your link!!

Were you able to get a good knob?

Jerome

Paul,

Did you use the needle thrust bearings as per the Super-Tune YouTube video on your Sky-Watcher mount? If so, how did they work out, any improvement?

Jerome

I also need to add some index marks on my 162 tooth timing pulley to line up my rig.

I am gradually making progress with my DEC Axis, and am now starting to get guiding on it. I put my planetary gearbox in an ultrasonic cleaner and flushed out all the old grease and replaced it with a light machine oil. I also removed the shaft seals, I can now back-drive the gearbox easily. 

I have had my rig outside several times now and have seen a few shortcomings with it:

• The primary one is that since it does not have a clutch, I need a stepper motor with a shaft at both ends so I can manually rotate the axis into position. 
• Also, I believe my timing belt should be wider. I feel the 6mm wide timing belt allows too much flex.

I use the ASIAIR system with the EQMOD cable. I have absolutely no experience with planetary gearboxes at all. But I can feel no backlash whatsoever, the gearbox feels very tight. I have noticed the DEC axis now rotates noticeably slower. It feels tighter than it should be. It is Chinese made, and maybe some quality issues got through. The first thing I noticed was that the output shaft was out of spec, I had to grind the hole of the timing pulley to get it to fit. I had read a review where someone took one of these gearboxes apart and found that metal filings were jamming it. I plan on taking this gearbox apart, it will at least be a learning experience. 

I have noticed over the years that a lot of people build their own equatorial mounts. I'm now beginning to understand why, as I read deeper into the forums, the quality of equatorial mounts is an issue.

I uploaded my improved 'DEC Body ver 2.stl' that adds gussets to stiffen the tab for the motor/gearbox/bracket assembly. We had a clear night so I took my rig outside and tested it. I was very pleased that my new DEC Axis worked perfectly and accurately. However, the guiding is not improved, and maybe worse. I strongly suspect the planetary gearbox has too much friction, because it turns noticeably slower.  I'm going to see if I can break it in, or in some way loosen it.

DEC Body ver 2.stl DEC Body ver 2.AD_PRT

DEC Axis Assembly.pdf

I decided to use up some M4 square nuts that I had. They make it easier to locate and fasten the motor/gearbox/bracket assembly.

Jim,

I tested it again, it worked correctly!! I believe the problem was that I did not hit 'sync to mount'.

Many thanks, it would not have been possible without all your help.

I plan on testing my rig outside on Monday night, hopefully we'll have clear sky's.

I will be making a major upgrade to the 'DEC Body ver 2.stl', there is way too much flex in the tab that holds the DEC motor.

You would be jealous to see the freedom of movement in my DEC Axis. I can now easily balance my telescope in the DEC Axis.

Quick question; if I wanted to use a 1.8° stepper motor, I would use a 50:1 gearbox. Is that correct?

Jerome

jif001, I switched the wires, and the DEC motor seems to be rotating the correct direction. But the DEC motor seems to be falling short of its target by about 60°. When I hit 'Home' it then over-shoots by about 60°. I'm wondering if my gear ratio is wrong.

I'm using a 100:1 planetary gearbox, a 45 tooth pulley on the motor, and a 162 tooth pulley on the DEC Axis. Also, the axis seems to be rotating slower than the RA axis. I'm wondering if maybe the planetary gearbox has too much internal friction, because I can't rotate it by hand.

I'm wondering if you have any ideas?

jif001, thank you very much for sharing the articles with me. I'll let you know how it turns out.

I am posting the STLs of my DEC axis. I will notify you if I update any models.Vixen Saddle Adapter.stlVixen Saddle Adapter.stlVixen Saddle Adapter.stlNut Barrle.stl

Bearing Bushing.stl Counterweight Rod Adapter.stl DEC Body ver 2.stl Motor-Gear Spacer.stl Nut Barrle.stl Shaft collar.stl 162 tooth pulley v2.stl

In the above image of the Great Orion Nebula is not cropped. The white band to the left is caused by the DEC not tracking. In other images where the DEC does track, I don't get the white band.

I am posting an image of the M2, where the DEC was guiding. Also using the reducer.