Re: Full ceramic bearings on a G11
Here have replaced the bearings on a G8, two G11s, and a Titan, with
ceramic bearings long ago, all improved, not that they where unusable before.
The biggest? improvement was the G11 smoothed out the most. I get some temp
changes in my rolloff here in Montana, that issue calmed down. I just use them
for years with now, they work great.
?
leroy
?
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From: Keith
Sent: Sunday, May 09, 2021 10:56 AM
Subject: Re: [Losmandy_users_io] Full ceramic bearings on a
G11
?
Hugo: You've
changed many variables, which one(s) is(are) the source of the
improvements?? Note that in disassembling the drive train (worm, gearboxes
etc), the system is highly unlikely to go back together the same way it was as
there are so many degrees of freedom (e.g. the OPW is not one piece at all, its
still 2 bearings blocks that can be misaligned, gear mesh ... and that's not
factoring in spring tension on a SLW, which I don't have).? Unless one does
the experiment of disassembling and reassembling several times (changing nothing
else) and re-evaluating under the same measurement conditions (same part of sky,
similar seeing conditions, etc) to get a baseline uncertainty, its very hard to
make any concrete conclusions whether even a single variable (let alone several)
made a statistically significant improvement.? No one probably wants to put
in the (precious) time.? I've thought about, but have never
done). Believe me I want to implement meaningful mods as much as anyone
(e.g. I think I've seen improvements in tracking in just picking the best pair
of bearing I have in my 'collection', though haven't tried ceramic) and if
you're tracking/guiding has improved, then of course onward and upward!?
But you've posted for the benefit of the group, and to be honest I don't know
what to take away from it to improve my mount.
?
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Re: Full ceramic bearings on a G11
Hugo:
You've changed many variables, which one(s) is(are) the source of the improvements?? Note that in disassembling the drive train (worm, gearboxes etc), the system is highly unlikely to go back together the same way it was as there are so many degrees of freedom (e.g. the OPW is not one piece at all, its still 2 bearings blocks that can be misaligned, gear mesh ... and that's not factoring in spring tension on a SLW, which I don't have).? Unless one does the experiment of disassembling and reassembling several times?(changing nothing else) and re-evaluating under the same measurement conditions (same part of sky, similar seeing conditions, etc) to get a baseline uncertainty, its very hard to make any concrete conclusions whether even a single variable (let alone several) made a statistically significant improvement.? No one probably wants to put in the (precious) time.? I've thought about, but have never done).
Believe me I want to implement meaningful mods as much as anyone (e.g. I think I've seen improvements in tracking in just picking the best pair of bearing I have in my 'collection', though haven't tried ceramic) and if you're tracking/guiding has improved, then of course onward and upward!? But you've posted for the benefit of the group, and to be honest I don't know what to take away from it to improve my mount.
I'm interested to see you guide logs - did you post somewhere?
Keith
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Re: Full ceramic bearings on a G11
Hi,
The version of PHD2 I used is 2.6.9dev4?
I used Multi stars guiding.
I posted screenshots of 2 normal use (imaging) with no messing with the mount and settings and similar conditions.
Things to consider:
Changed the type of grease used
I polished the points on the worm where the bearings sit.
I sanded high points on the east side bearing block where the bearing sits.
My conditions are highly variable. I live up in the mountains. 30 degree changes in temp from day to night. Sudden winds and clouds.
I might test other bearing types like hybrid bearings and abec 11 grade bearings.
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Re: Reducing DEC Backlash with Titan 50
If you have no problem with guiding, then don't worry about what these backlash tests tell you. I've never had any serious problems with backlash with my Titan.
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On Sun, May 9, 2021 at 11:40 AM, <dkfcpalfd@...> wrote:
Several years ago, I was having trouble getting PHD2 calibrated, so I went on the PHD2 help forum.? One of the principle developers on the forum said that the Titan is well known to have a lot of DEC backlash, and if I make several calibration attempts, I should always hit the up arrow key on the HC until I see star movement, to knock out backlash before the test begins.
When I began this thread, one of the things I brought up was basically how important is it if the GA backlash test shows huge backlash, yet my DEC guiding looks pretty good?
I think I'll just have to manage it and live with it..... as Scott says, adjust the wing bolts on the block so you don't feel any physical play when doing the windage test.? That's about it.
Thank you.
Dan
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Re: Reducing DEC Backlash with Titan 50
Several years ago, I was having trouble getting PHD2 calibrated, so I went on the PHD2 help forum.? One of the principle developers on the forum said that the Titan is well known to have a lot of DEC backlash, and if I make several calibration attempts, I should always hit the up arrow key on the HC until I see star movement, to knock out backlash before the test begins.
When I began this thread, one of the things I brought up was basically how important is it if the GA backlash test shows huge backlash, yet my DEC guiding looks pretty good?
I think I'll just have to manage it and live with it..... as Scott says, adjust the wing bolts on the block so you don't feel any physical play when doing the windage test.? That's about it.
Thank you.
Dan
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Re: Counterbalance weight calculation for rig
Hi Glenn
One recommendation, order and arrange your counterweights to be as close to the mount as they can and still not interfere. Weights at the end of the bar are vulnerable to lower frequency resonances that can affect performance in wind or when the mount is bumped.
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Re: Reducing DEC Backlash with Titan 50
Ideally, you don¡¯t need to reverse direction much in DEC. Assuming guiding is working, the corrections will be mostly in one direction for a fairly long period of time. Decades ago I had a physical switch on the guider that would disable guiding in one direction, just for that reason. I think PHD has a similar software setting.
If guiding does work fine for you, but DEC calibration fails, there¡¯s little reason to try to reduce backlash. Sometimes, it¡¯s just more practical to get the calibration done and then start guiding :)
It¡¯s ok to have some backlash in DEC.
On Sun, May 9, 2021 at 10:40 AM, <dkfcpalfd@...> wrote:
Thanks, Paul.? I am going to reduce the torque on the end caps for both blocks.??
When you say this:
"I would leave TVC set close to zero when guiding to avoid overshooting, but you can certainly crank it up high to complete calibration."
Are you speaking of the calibration routine for RA and DEC, or the backlash test in GA?? If I have TVC cranked up high for either of those routines, but crank it down for guiding....? are you sure I'm not just masking a problem when I am running those testing routines?
I'll reduce torque on the DEC end cap and crank TVC way up just to see if I can get a decent looking backlash graph in GA.
Thanks.
Dan?
?
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Re: Reducing DEC Backlash with Titan 50
Thanks, Paul.? I am going to reduce the torque on the end caps for both blocks.?? When you say this:
"I would leave TVC set close to zero when guiding to avoid overshooting, but you can certainly crank it up high to complete calibration."
Are you speaking of the calibration routine for RA and DEC, or the backlash test in GA?? If I have TVC cranked up high for either of those routines, but crank it down for guiding....? are you sure I'm not just masking a problem when I am running those testing routines?
I'll reduce torque on the DEC end cap and crank TVC way up just to see if I can get a decent looking backlash graph in GA.
Thanks.
Dan?
?
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Re: Reducing DEC Backlash with Titan 50
Tr. stands for tracking. You may need to reduce the torque on the end of the worm block ¡ª it may be causing too much friction and making it harder to turn the worm.
TVC can be set to a maximum of 255, I believe. It simply causes the DEC axis to move at a faster speed for a short time when guiding reverses direction. The larger number simply means that the faster (centering) speed will be applied for a longer interval upon guider DEC reversal.
I would leave TVC set close to zero when guiding to avoid overshooting, but you can certainly crank it up high to complete calibration.
Regards,
? ?-Paul
On Sun, May 9, 2021 at 09:07 AM, <dkfcpalfd@...> wrote:
I ran Guiding Assistant last night after having tightened down the end cap on the block..... no improvement in the backlash test results..... actual was heading off the graph to the right.? At least the test completed.? I then set TVC to 5, and saw improvement, but I turned DEC Comp off in PHD2 so the 2 comp methods would not fight with each other.? I saw definite improvement in backlash test results, but still too far away from ideal.? Actual would at least parallel the ideal curve.? I set TVC to 10, and actual got a little closer to ideal, but still away from it too far to suit me.
During the DEC backlash test, I kept getting tons of alert messages saying DEC Heavy Duty Tr.? Later as I did some guiding, that message was coming up.? I tried setting TVC back to 0, and I still occasionally got the Heavy Duty Tr. alert message.? The lowest compensation factor I saw from GA was still over 4000 (ms?).?
I am wondering if too much torque on the 4 hole end cap can cause DEC to strain, causing these messages?? Also, I'm wondering if anyone has played around with TVC settings.... how high can you set it?? How do you know when it is too high?
Regarding positioning of the wing bolts and allen head bolts on the block, I don't have torque on them.... they are barely snugged up.
Maybe..... I should back off on the torque on the block end cap, and go higher with the TVC setting?? ?
I would like to know what "Tr." stands for..... Traverse?? Transit?? or Trouble?
This backlash issue is throwing me a curve ball.??
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Re: Reducing DEC Backlash with Titan 50
I ran Guiding Assistant last night after having tightened down the end cap on the block..... no improvement in the backlash test results..... actual was heading off the graph to the right.? At least the test completed.? I then set TVC to 5, and saw improvement, but I turned DEC Comp off in PHD2 so the 2 comp methods would not fight with each other.? I saw definite improvement in backlash test results, but still too far away from ideal.? Actual would at least parallel the ideal curve.? I set TVC to 10, and actual got a little closer to ideal, but still away from it too far to suit me.
During the DEC backlash test, I kept getting tons of alert messages saying DEC Heavy Duty Tr.? Later as I did some guiding, that message was coming up.? I tried setting TVC back to 0, and I still occasionally got the Heavy Duty Tr. alert message.? The lowest compensation factor I saw from GA was still over 4000 (ms?).?
I am wondering if too much torque on the 4 hole end cap can cause DEC to strain, causing these messages?? Also, I'm wondering if anyone has played around with TVC settings.... how high can you set it?? How do you know when it is too high?
Regarding positioning of the wing bolts and allen head bolts on the block, I don't have torque on them.... they are barely snugged up.
Maybe..... I should back off on the torque on the block end cap, and go higher with the TVC setting?? ?
I would like to know what "Tr." stands for..... Traverse?? Transit?? or Trouble?
This backlash issue is throwing me a curve ball.??
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Re: Full ceramic bearings on a G11
Did you use same version of PHD2 (mono or multi guiding stars), and which one you used?
Pierre
Le dimanche 9 mai 2021 ¨¤ 07:25:42 UTC+2, Hugo_G <hgarnica33@...> a ¨¦crit :
Hello All,
My name is Hugo, and I'm a newish owner of a new G11. I received my G11 in January and had some problems getting the mount to preform for a couple months, long story short I had a bad RA gearbox and it was taken care by Losmandy. With the help of Michael Herman and Andy, I was able to figure out other factors affecting performance (balance and power issues). Now that I had my G11 performing good, I was looking to improve it. I took Michael's idea of using Molly Graphene grease and this got me thinking about all the points on the RA drive train that can be affected by friction/ imperfections and what I can do to improve them. I considered maybe polishing and or lapping the worm and ring gears, but that was out of my skill level lol. So i started looking at the bearings. I remembered that there were Hypertune kits that included ceramic bearings. I looked up the benifits of ceramic bearings and noted their properties of low friction, lower thermal expansion, and rigidity/hardness. I purchased two sealed full ceramic bearings from vxb.com?
I did receive one bearing that was out of spec. in the inner diameter.? I installed the one that fit and did notice smoother guiding corrections. After receiving the replacement I polished both shafts of the worm gear where the bearings sit. I used a Dremel? with a cotton bit with100k diamond paste.?
I removed the stock bearings by heating? the bearing blocks with a heat gun. The bearings spin very smoothly and freely, they can continue to spin up to 15 sec. after giving them a good spin. I did notice the right end bearing block bearing seat was not perfectly round and my cause uneven pressure during thermal changes. I used a diamond burr, that by luck was almost the same size as the bearing seat, and rounded the walls. The burr was from a set I bought at Harbor freight(use the flat sided disk bit).
So to wrap this up, I did see an improvement in guiding compared to the stock setup. My typical RA RMS was around .74" to 1.00 plus", My new Range of RMS as good as .45" to .70"ish
I will load some of my phd2 logs? when I get to my laptop.?
Hugo
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Full ceramic bearings on a G11
Hello All,
My name is Hugo, and I'm a newish owner of a new G11. I received my G11 in January and had some problems getting the mount to preform for a couple months, long story short I had a bad RA gearbox and it was taken care by Losmandy. With the help of Michael Herman and Andy, I was able to figure out other factors affecting performance (balance and power issues). Now that I had my G11 performing good, I was looking to improve it. I took Michael's idea of using Molly Graphene grease and this got me thinking about all the points on the RA drive train that can be affected by friction/ imperfections and what I can do to improve them. I considered maybe polishing and or lapping the worm and ring gears, but that was out of my skill level lol. So i started looking at the bearings. I remembered that there were Hypertune kits that included ceramic bearings. I looked up the benifits of ceramic bearings and noted their properties of low friction, lower thermal expansion, and rigidity/hardness. I purchased two sealed full ceramic bearings from vxb.com?
I did receive one bearing that was out of spec. in the inner diameter.? I installed the one that fit and did notice smoother guiding corrections. After receiving the replacement I polished both shafts of the worm gear where the bearings sit. I used a Dremel? with a cotton bit with100k diamond paste.?
I removed the stock bearings by heating? the bearing blocks with a heat gun. The bearings spin very smoothly and freely, they can continue to spin up to 15 sec. after giving them a good spin. I did notice the right end bearing block bearing seat was not perfectly round and my cause uneven pressure during thermal changes. I used a diamond burr, that by luck was almost the same size as the bearing seat, and rounded the walls. The burr was from a set I bought at Harbor freight(use the flat sided disk bit).
So to wrap this up, I did see an improvement in guiding compared to the stock setup. My typical RA RMS was around .74" to 1.00 plus", My new Range of RMS as good as .45" to .70"ish
I will load some of my phd2 logs? when I get to my laptop.?
Hugo
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Re: Reducing DEC Backlash with Titan 50
Aubrey,
To maintain a constant torque on the RA axis, which is what you are seeking, you need to use a weighted cord wrapped around the RA axis.? Using an unbalanced counterweight rod the torque will vary as the RA axis rotates.??
You put that hanging weight on after your counterweights are balanced.? I am using 1 pound weight....I had tried 7 pounds earlier.? I'm not sure what is an optional weight to use.? My scope is a C14EdgeHD.? ?
Here is a way I implemented on my Titan RA.? I hope the photos are clear enough.? The weight hangs to the East and always provides an Eastward torque.??
Best of luck, Michael
? Thanks Michael for the comments. Fortunately at this time I only have one issue. That is when I am starting out in the lower east imaging, I have nice round stars with 10 min subs. But as the Counter weight Shaft and weights begin to pass the 45 degree angle, I begin to have more flattened stars. As it gets closer to the Meriden I get round stars again. I think I might have too much east bias on the weights. I am getting about 1+/- Arcseconds PEC when guiding. But I have to use the onboard PEC function. I have noticed that if you want good results with the G2 PEC you pretty much have to run it on each target as you begin each DSO. If you do it that way it will work on both sides of the Meriden. I use Maxim DL 6. for guiding and an SX Superstar. My Telescope is the AT 10¡± RC with CF Arms and shroud and 60 mm guide scope so I am caring about 50 LBS load with my heavy camera. ? Aubrey ? ? Sent from for Windows 10 ? ? Aubrey, It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.?? You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!?? Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing). Have fun,...get some nice images! ? Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
What is the size of the bellvile washer? ? Aubey ? Sent from for Windows 10 ?
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From: Michael HermanSent: Saturday, May 8, 2021 2:47 PM To: [email protected]Subject: Re: [Losmandy_users_io] Reducing DEC Backlash with Titan 50 ? Nice conversation! ? We normally don't hear about Titan drives as they are rarer than the G11 or GM8 or GM811. I got a Titan RA drive on my G11T.? I asked Mr Losmandy at his shop how much torque should be on the 4-hole end retainer threaded (~30 mm OD ) plug.? He said "Just touching." That did not work well for me, as over temperature changes, the pressure from the end cap on the worm bearings could get too tight or too loose.? So I added 2 Belleville spring washers for that sized bearing (30 mm OD 10 mm ID) cup to cup so the outer edges of the spring pair touch the worm bearing and at the end of the 30mm plug.? This gives about 1mm of extra plug compression room for temperature expansion.? If there is no compression... just touching...there is zero force on the worm bearings.? But you can get as much force as you like by torquing the threaded plug in with the spanner wrench.? So I compressed it about 1/8 yo 1/4 turn to give a light, and adjustable force.? This force will not change much as the temperature changes because the springs will just expdmd or compress very slightly.?? Paul's note suggests he or maybe the Losmandy originally put in a Belleville spring in at an earlier time.? My G11T had no spring in the Titan drive to start with.?? Here are some photos of the drive and showing the Belleville springs I used.? I have some left so if you need a few contact me.? My "spanner wrench" (USA usage...I think in UK it can mean something else) is an inexpensive tool I got off eBay long ago.? There are many types on the market, and are used extensively for automotive C clips.? I also tried to measure the worm thread center to ring gear center. That is supposed to be as close to the same level as possible for worm drives...a critical adjustment.? It was almost dead center, but my measurements showed also the need for a tiny maybe 0.02 inch shim under the worm block.? I used some thin brass shim stock for that (also off eBay).? Here are some pictures of that.?? The worm to ring gear should be as low friction as possible. Otherwise you can experience "chatter" as the ring gear is vibrated like a violin string by the movement of the worm gear acting like the "bow".? I tried Superlube ("Cincolon" Teflon only) there but it did not suffice...still chattered.? I tried a product called CRC Brake and Caliper Grease (MolyD, Graphite, and Teflon in an anticorrosion grease) and this eliminated the ring gear chatter.? I thought that ring gear chatter issue from worm friction would not be a problem for DEC only RA, but recent discussion of a DEC glitch also causing an RA glitch makes me wonder! That's not all... my G11T drive story is not finished yet.? I'm still comparing the 3 gear tucked motor drive to a belt drive to see what's lowest for PE.? ?I have switched already to a McLennan 25:1 gearbox.? My PE with the belt drive is running 1.77 arcsec RMS and no trouble in autoguiding to round stars in 500 sec exposures.?? ? On Sat, May 8, 2021, 11:57 AM Paul Kanevsky <yh@...> wrote: it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
? Thanks Michael for the comments. Fortunately at this time I only have one issue. That is when I am starting out in the lower east imaging, I have nice round stars with 10 min subs. But as the Counter weight Shaft and weights begin to pass the 45 degree angle, I begin to have more flattened stars. As it gets closer to the Meriden I get round stars again. I think I might have too much east bias on the weights. I am getting about 1+/- Arcseconds PEC when guiding. But I have to use the onboard PEC function. I have noticed that if you want good results with the G2 PEC you pretty much have to run it on each target as you begin each DSO. If you do it that way it will work on both sides of the Meriden. I use Maxim DL 6. for guiding and an SX Superstar. My Telescope is the AT 10¡± RC with CF Arms and shroud and 60 mm guide scope so I am caring about 50 LBS load with my heavy camera. ? Aubrey ? ? Sent from for Windows 10 ?
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From: Michael HermanSent: Saturday, May 8, 2021 4:08 PM To: [email protected]Subject: Re: [Losmandy_users_io] Reducing DEC Backlash with Titan 50 ? Aubrey, It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.?? You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!?? Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing). Have fun,...get some nice images! ? Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
This might help. The vid was made in 2017 by Scott himself. He is adjusting a G11 but the principles are the same for the Titan.
On Sunday, May 9, 2021, 5:08:18 AM GMT+8, Michael Herman <mherman346@...> wrote:
Aubrey,
It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.??
You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!??
Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing).
Have fun,...get some nice images!
Michael
Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
![]()
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
Aubrey,
It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.??
You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!??
Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing).
Have fun,...get some nice images!
Michael
Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
![]()
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ?
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From: Paul KanevskySent: Saturday, May 8, 2021 12:57 PM To: [email protected]Subject: Re: [Losmandy_users_io] Reducing DEC Backlash with Titan 50 ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
WOW.... I need to consult with you guys when I'm ready to try tackling lubricating inside the worm blocks.
I said previously that I cranked the TVC (DEC Backlash Comp) from 0 up to 5 on the Gemini 2 HC.? However, it dawned on me the reason why it was set to 0.? I now remember having read some PHD2 documentation stating that if you want to use PHD2 for DEC Backlash Compensation, you need to turn that feature off on your mount, because the two can conflict and work against each other.? So, for now, I cranked it back to 0, and will try running GA again tonight with only having torqued the block end plug.? If I still have poor test results with the GA test, I'll try cranking TVC back to 5.
We will see.
Dan
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Re: Reducing DEC Backlash with Titan 50
Nice conversation! We normally don't hear about Titan drives as they are rarer than the G11 or GM8 or GM811.
I got a Titan RA drive on my G11T.? I asked Mr Losmandy at his shop how much torque should be on the 4-hole end retainer threaded (~30 mm OD ) plug.? He said "Just touching."
That did not work well for me, as over temperature changes, the pressure from the end cap on the worm bearings could get too tight or too loose.? So I added 2 Belleville spring washers for that sized bearing (30 mm OD 10 mm ID) cup to cup so the outer edges of the spring pair touch the worm bearing and at the end of the 30mm plug.? This gives about 1mm of extra plug compression room for temperature expansion.? If there is no compression... just touching...there is zero force on the worm bearings.? But you can get as much force as you like by torquing the threaded plug in with the spanner wrench.? So I compressed it about 1/8 yo 1/4 turn to give a light, and adjustable force.? This force will not change much as the temperature changes because the springs will just expdmd or compress very slightly.??
Paul's note suggests he or maybe the Losmandy originally put in a Belleville spring in at an earlier time.? My G11T had no spring in the Titan drive to start with.??
Here are some photos of the drive and showing the Belleville springs I used.? I have some left so if you need a few contact me.? My "spanner wrench" (USA usage...I think in UK it can mean something else) is an inexpensive tool I got off eBay long ago.? There are many types on the market, and are used extensively for automotive C clips.?
I also tried to measure the worm thread center to ring gear center. That is supposed to be as close to the same level as possible for worm drives...a critical adjustment.? It was almost dead center, but my measurements showed also the need for a tiny maybe 0.02 inch shim under the worm block.? I used some thin brass shim stock for that (also off eBay).? Here are some pictures of that.??
The worm to ring gear should be as low friction as possible. Otherwise you can experience "chatter" as the ring gear is vibrated like a violin string by the movement of the worm gear acting like the "bow".? I tried Superlube ("Cincolon" Teflon only) there but it did not suffice...still chattered.? I tried a product called CRC Brake and Caliper Grease (MolyD, Graphite, and Teflon in an anticorrosion grease) and this eliminated the ring gear chatter.? I thought that ring gear chatter issue from worm friction would not be a problem for DEC only RA, but recent discussion of a DEC glitch also causing an RA glitch makes me wonder!
That's not all... my G11T drive story is not finished yet.? I'm still comparing the 3 gear tucked motor drive to a belt drive to see what's lowest for PE.? ?I have switched already to a McLennan 25:1 gearbox.? My PE with the belt drive is running 1.77 arcsec RMS and no trouble in autoguiding to round stars in 500 sec exposures.??
Have fun, Michael ??
On Sat, May 8, 2021, 11:57 AM Paul Kanevsky < yh@...> wrote: it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not.
?
Thanks
?
Aubrey Brickhouse
?
Sent from for Windows 10
?
?
Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
![]()
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote:
Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Hugo_G
Paul Kanevsky
Michael Herman