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Astro-Modified Manfrotto 400 Geared Head

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#1 CharlesStG

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Posted 09 November 2020 - 09:53 AM

The Manfrotto 400 is the bigger geared head for those of us who like manual control and these can handle a great deal of weight.  I use mine on a Manfrotto 161MK2B tripod with adjustable column with my  20-pound, APM 120 binocs.  I also love to use it with my little Meade 5" Mak OTA for a lovely evening of grab and go planetary viewing.

 

What do I mean by astro-modified? Well, this is a camera mount, by design and as cameras are generally used to point somewhat up and possibly all the way down to take pics of what's on your table in macro-mode, the gearing in this really nice geared-head is set-up to allow only that.  You can use it for astro by mounting your scope or binocs on it "backwards", but that creates quite the inconvenience of having to reach around to the front in order to adjust altitude.  Anyone who wants to track the heavens with this would certainly prefer the altitude control to be at the rear, not the front, but the mount is so good, astronomers still use it even with that inconvenience.

 

Well, mine was bought used (they go new for $800., but come up at much better, used prices at the -bay place), looks new and is probably at least 20 years old.  Like many such items, the grease inside was drying out and turning to glue, binding the works and making it difficult to turn the knobs. So, I took it apart to clean it, re-grease it and adjust tension to get the lightest control feel while still having no play in the back and forth, up and down movement, since both axes are adjustable, spring-loaded niceness.

 

Darned if I didn't discover upon re-assembly that the big altitude gear can be reversed! Yup.  So, now I have a 400 geared head with the altitude knob on the back where we astronomers want it and it allows movement all the way to from about -30 degrees down to fully 90 degrees at the zenith.

 

This mount head is pretty simple to disassemble with not too many small parts, but I recommend simply taking a pic at each step and just keep the bolts in the metal assemblies as you remove them, to make re-assembly simple.  Now that I've done it, I could reverse the altitude gear in less than an hour, but getting off all the old grease, testing new greases and adjusting and re-testing took up a long evening, finishing at mid-night. 

 

Honestly, if you have basic manual skills and a good set of metric hex wrenches or drivers, this is a pretty basic mod that requires no real modification as it was clearly designed by Manfrotto to allow for this reversal of the altitude gear.

 

I'll post a pic of the mod in action by Wednesday. 


Edited by CharlesStG, 09 November 2020 - 12:12 PM.

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#2 cookjaiii

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Posted 09 November 2020 - 11:35 AM

The control knobs on these geared heads are very stiff.  Did re-greasing make any difference with that?  What grease did your experimentation point to as the best?



#3 CharlesStG

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Posted 09 November 2020 - 12:49 PM

Hi Cookjaii,  Yeah, the chromed worms against the aluminum gears isn't a very smooth combination. The chrome seems to have a tendency to grab against aluminum. A brass worm would have likely worked more smoothly, but not sure as the binding seems to be as much from the over-tension of the assembly bolts, anti-backlash springs and the plastic sleeves covering the gear pivot points. The yellow grease on the gears had pretty much turned into glue over the years. A thin, black grease on the ends of the worm shafts was still fresh, but washed off in the diesel fuel bath used with a brass toothbrush to remove the glue-like, yellow grease.

 

On the alt and az big gears and worms, I found that Maxima Marine Grease works well, after trying very expensive Krytox 240AC (didn't work) and Nyogel 767A. I left the Nyogel on the tilt worm and gear as it was smooth, but quite firm, which is good for that little-used tilt-feature (except with binocs to adjust most comfortable eyepiece height for both eyes).

 

I put the marine grease also underneath all of the plastic bushings in there. I may later replace those five plastic bushings with brass or teflon if I can find the right size. There are four critical plastic bushings used at the gear pivot points and they are all the same.

 

The assembly of the mount requires testing the ease of movement as you go. I put Loctite blue on the bolts for the pivot clamps as I found there is only a very small sweet spot in tension between ease of movement of the worms and too tight or too loose and the Loctite will allow the bolts to stay fixed in position, once adjusted properly, but you can still easily break the bolts free with the Loctite blue.

 

Turning the altitude gear around required no effort at all -- you just put it back in backwards and all is fine.

 

Breaking down this head is pretty easy as there are relatively few parts. Just keep an eye on the four springs and their end-curved, plastic worm tensioner bearings which will likely fall out on you during disassembly. You will mostly need 3 and 4mm hex drivers or keys and a 5mm is used only on the set screw for azimuth tension.

 

Below are pics showing how it looks once done -- altitude knob at the back; azimuth on the left.  The knob cranks work in most positions for astronomy, but the altitude crank will likely hit your tripod at zenith, so just use the knob and not the crank when you point your scope over 70 degrees up above the horizon.

 

I liked this geared head before, but it's really much better now with the altitude knob at the back as you would want for astronomy.  And, yes, the gear knobs turn much easier after replacing the old grease. Altitude feels nice and light. Azimuth a bit less light since you need to put some tension on the spring set-screw if you want no dead-space slop in your adjusting. If you don't mind a little dead space between changing direction in azimuth, it can be made even easier to turn, but I prefer a very positive movement with no dead space between going back and forth.

Attached Thumbnails

  • 400d.jpg
  • 400e.jpg
  • 400c.jpg

Edited by CharlesStG, 09 November 2020 - 01:00 PM.

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#4 dcosmar

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Posted 09 November 2020 - 09:17 PM

I took mine apart a couple of months ago to remove the side/side leveling handle and it never even dawned on me I could try reversing the gear. This is great news. I've almost pulled the trigger so many times on the APM 120SD to use on this mount. I'm assuming you are pleased with the Manfrotto 400 with the APM 120SD? I'm curious what magnifications you use since, by your sig, you use them for planetary--does the 400 hold up well with the 120SD at higher mags?



#5 dcosmar

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Posted 09 November 2020 - 09:59 PM

Wow. I just made the reverse modification in like 15 minutes. Thanks so much for passing this information along. 


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#6 CharlesStG

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Posted 10 November 2020 - 09:46 AM

I took mine apart a couple of months ago to remove the side/side leveling handle and it never even dawned on me I could try reversing the gear. This is great news. I've almost pulled the trigger so many times on the APM 120SD to use on this mount. I'm assuming you are pleased with the Manfrotto 400 with the APM 120SD? I'm curious what magnifications you use since, by your sig, you use them for planetary--does the 400 hold up well with the 120SD at higher mags?

I was using the modded 400 head with my 120SD binocs last night on Mars.  The local seeing was messing with the images, but it was fun.  I briefly put the power up to 260x using a 6.5mm Morpheus and a TV 2.5x barlow in one eye just to check the image and shake and such. The 400 head worked effortlessly with the big binocs on top. Be aware that it's the tripod you use which will determine vibration issues. After focusing, which induced mild to medium vibration, it took about 3 full seconds to settle, showing the weight and length of the binocs is putting the 161 tripod to the test. Whereas, when using my Meade 5" mak, vibes settle in less than 1/2 second on the same set-up. Just be aware that you need fairly long arms to reach the azimuth control with the binocs since it puts you a bit behind your tripod.  I take a 34" sleeve, and my left arm reaches the azimuth control without much effort while seated in my astrochair.

 

So, in sum, yes, the 400 head handles the 120SD just fine.  I bought my binocs from a fellow CNer located less than 20 miles from me for a great price, especially for a set which had been praised to the skies here on CN in reviews. Star tests reveal crazy good optics and I have no problem merging high power views as I was using 104x last night.  I didn't bother trying 260x since I wasn't using a finder and would quickly lose Mars at the power without one.  I love a laser pointer-finder and plan to mount one on the binocs soon.  Be aware, that like anything commercially made, these binocs have reviews indicating some are wow and some are less than wow. Mine are wow and I hope you can find the same.


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#7 CharlesStG

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Posted 10 November 2020 - 09:58 AM

I suppose I should add that even in yukky seeing last night, I managed to see the shrinking white polar ice cap on Mars, sitting at 8 o'clock on the face of the planet, at 260x with the binocs and some surface detail, but the image was generally boiling and shaking with local seeing issues.  The 400 mount head allowed very nice control with the 120SD binocs on top, smooth, effortless and steady movement. I think the 400 could handle even more weight.



#8 dcosmar

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Posted 10 November 2020 - 10:09 AM

I was using the modded 400 head with my 120SD binocs last night on Mars.  The local seeing was messing with the images, but it was fun.  I briefly put the power up to 260x using a 6.5mm Morpheus and a TV 2.5x barlow in one eye just to check the image and shake and such. The 400 head worked effortlessly with the big binocs on top. Be aware that it's the tripod you use which will determine vibration issues. After focusing, which induced mild to medium vibration, it took about 3 full seconds to settle, showing the weight and length of the binocs is putting the 161 tripod to the test. Whereas, when using my Meade 5" mak, vibes settle in less than 1/2 second on the same set-up. Just be aware that you need fairly long arms to reach the azimuth control with the binocs since it puts you a bit behind your tripod.  I take a 34" sleeve, and my left arm reaches the azimuth control without much effort while seated in my astrochair.

 

So, in sum, yes, the 400 head handles the 120SD just fine.  I bought my binocs from a fellow CNer located less than 20 miles from me for a great price, especially for a set which had been praised to the skies here on CN in reviews. Star tests reveal crazy good optics and I have no problem merging high power views as I was using 104x last night.  I didn't bother trying 260x since I wasn't using a finder and would quickly lose Mars at the power without one.  I love a laser pointer-finder and plan to mount one on the binocs soon.  Be aware, that like anything commercially made, these binocs have reviews indicating some are wow and some are less than wow. Mine are wow and I hope you can find the same.

Yes, I've previously owned the 70 & 100SD versions and the 100 seemed to be rock solid on the Manfrotto 400, but needed a better tripod to reduce the vibrations. When I paired it with a Berlebach UNI19C it was like an offensive lineman stuck in concrete with the 100. The only reason I didn't spring for the 120 at first was because of the load capacity of the Manfrotto 400 being around 22lbs and with the 120 + a pair of APM 12.5 HiFW would be right at max capacity and I had always had bad experiences when exceeding even 50% capacity on most mounts. If I can get 147x out of a 4.5 Morpheus pair on the 120SD, I'll be happy with it for planetary viewing and others seem to say it can take that (and some have samples that take a 3.5 Delos/189x). Many thanks again for posting this--I've got some Marine grease on order now from your recommendation as well. 


Edited by dcosmar, 10 November 2020 - 10:11 AM.

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