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Hello Everyone.
I installed the Losmandy one piece work assembly yesterday (fully assembled with the HP worm from Losmandy). The problem I'm having is I cannot get anything except a loose mesh without getting RA lag messages, or hard motor stalls.
I've worked around the worm gear to find the best overall performance, but no matter what I try I have to leave a fair amount of backlash between the two. The backlash is 3mm+ (estimated) at the end of the counter weight shaft.
The SST worms had less backlash....
My questions, for those who have installed the OPW, are:
1) How much backlash do you have?
2) Is there anything I can try to reduce the backlash?
3) Is this "normal" for the OPWB?
Also, the PemPro results show a signifncant reduction in the "76" error, but the overall P.E got worse. Before the installation the P.E. was 11~12 (+/- 6) arcseconds overall, and after is 20 arcseconds (+/-10). Not good.
Any insight?
Thanks.
Joe
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Check for side to side movement of the worm in the block.
Floyd
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--- In Losmandy_users@..., "kc5dfp" <kc5dfp@...> wrote:
Hello Everyone.
I installed the Losmandy one piece work assembly yesterday (fully assembled with the HP worm from Losmandy). The problem I'm having is I cannot get anything except a loose mesh without getting RA lag messages, or hard motor stalls.
I've worked around the worm gear to find the best overall performance, but no matter what I try I have to leave a fair amount of backlash between the two. The backlash is 3mm+ (estimated) at the end of the counter weight shaft.
The SST worms had less backlash....
My questions, for those who have installed the OPW, are:
1) How much backlash do you have?
2) Is there anything I can try to reduce the backlash?
3) Is this "normal" for the OPWB?
Also, the PemPro results show a signifncant reduction in the "76" error, but the overall P.E got worse. Before the installation the P.E. was 11~12 (+/- 6) arcseconds overall, and after is 20 arcseconds (+/-10). Not good.
Any insight?
Thanks.
Joe
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Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
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Joe,
The problem is probably that you have too much end play in the worm. My experience was that I had to squeeze the two bearing blocks toward each other as hard as I could with my hand and then tighten them down to eliminate the end play. The worm should still turn smoothly by hand once you do this. Then mount the opwb and motor assembly and adjust the mesh. It takes only about a 1/8 turn of the little adjustment thumbscrew to make a difference. At first I got RA motor lags. I slightly loosened the screw holding the opwb on the end away from the motor and screwed in the adjustment thumb screw a 1/8 turn at a time until I got no more RA motor lags. You might have to slightly loosen both screws holding the opwb. I discovered that you can leave the motor and gearbox slightly loose and it will tend to find its own center. I was able to adjust the end play on the end of the counter weight shaft to slightly less than the 2 mm spec. I have never done a pem pro run on my GM-8, but I get nice tight round stars consistently. Before installing the opwb I had to throw out about 6% of subs due to football shaped stars.
Steve
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----- Original Message ----- From: "kc5dfp" <kc5dfp@...> To: <Losmandy_users@...> Sent: Sunday, September 25, 2011 1:01 PM Subject: [Losmandy_users] Losmandy OPW Assembly Hello Everyone.
I installed the Losmandy one piece work assembly yesterday (fully assembled with the HP worm from Losmandy). The problem I'm having is I cannot get anything except a loose mesh without getting RA lag messages, or hard motor stalls.
I've worked around the worm gear to find the best overall performance, but no matter what I try I have to leave a fair amount of backlash between the two. The backlash is 3mm+ (estimated) at the end of the counter weight shaft.
The SST worms had less backlash....
My questions, for those who have installed the OPW, are:
1) How much backlash do you have?
2) Is there anything I can try to reduce the backlash?
3) Is this "normal" for the OPWB?
Also, the PemPro results show a signifncant reduction in the "76" error, but the overall P.E got worse. Before the installation the P.E. was 11~12 (+/- 6) arcseconds overall, and after is 20 arcseconds (+/-10). Not good.
Any insight?
Thanks.
Joe
------------------------------------
Yahoo! Groups Links
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Joe,
The amount of end play needed to mess up the adjustment is so small that its possible to be fooled about that.
Steve
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----- Original Message ----- From: "kc5dfp" <kc5dfp@...> To: <Losmandy_users@...> Sent: Sunday, September 25, 2011 2:30 PM Subject: [Losmandy_users] Re: Losmandy OPW Assembly Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
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Yahoo! Groups Links
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Steve,
Not sure what you mean. Please explain.
Even though I have about 3mm backlash I still get motor stalls. Let me know.
Joe
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--- In Losmandy_users@..., "bullfox" <bullfox@...> wrote:
Joe,
The amount of end play needed to mess up the adjustment is so small that its
possible to be fooled about that.
Steve
----- Original Message -----
From: "kc5dfp" <kc5dfp@...>
To: <Losmandy_users@...>
Sent: Sunday, September 25, 2011 2:30 PM
Subject: [Losmandy_users] Re: Losmandy OPW Assembly
Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
------------------------------------
Yahoo! Groups Links
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If you have lateral play in the worm, it will show as play at the end of the counter weight shaft, just like it would if there were space between the worm and wheel. So, you could seem to have the play at the end of the shaft, yet the worm lash could still be too tight and you would get stalls.
Floyd
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--- In Losmandy_users@..., "kc5dfp" <kc5dfp@...> wrote:
Steve,
Not sure what you mean. Please explain.
Even though I have about 3mm backlash I still get motor stalls. Let me know.
Joe
--- In Losmandy_users@..., "bullfox" <bullfox@> wrote:
Joe,
The amount of end play needed to mess up the adjustment is so small that its
possible to be fooled about that.
Steve
----- Original Message -----
From: "kc5dfp" <kc5dfp@>
To: <Losmandy_users@...>
Sent: Sunday, September 25, 2011 2:30 PM
Subject: [Losmandy_users] Re: Losmandy OPW Assembly
Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
------------------------------------
Yahoo! Groups Links
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Joe,
My experience was similar to yours. I thought I had eliminated all the end play in the worm, and I still could not get the mount down to the 2 mm spec with out motor lags. In fact, I had the worm/worm wheel mesh so tight I could hear the gears chatter. Also, I had occasional screech with the coupler slipping. I went back and checked everything several times. Finally, out of frustration I took the opwm off the mount, and took the motor and gear box off the opwm. I squeezed the two bearing blocks together on the worm as hard as I could by hand and tightened them down. My experience was that I had to get the bearing blocks really tight, much more so than I thought would work. I was afraid after that the worm would not turn in the bearing blocks but it did , smoothly and freely. I put everything back together with the mesh very snug. At first I got motor lags and chattering. I used the adjustment thumb screw to back off the mesh. I had to start over with the mesh several times because I was turning the adjustment thumbscrew too much. About 1/8 turn is enough to make a difference. Finally I got rid of the motor lags and everything ran smoothly and quietly with the 2 mm spec at the end of the counterweigh shaft.
That was a year ago. The mount loosened up a bit over the summer this year. I readjusted it just a week ago and got it down to just a bit less than 2 mm. I gave some though to putting the opwb on the Dec axis but don't find it to be needed. I consistently get nice tight round stars so am well satisfied. I don't run p.e. correction. I just have a good guiding set up. However, I should say that my usual imaging setup is 1.54 arcsec/pixel but only 735 mm.focal length. I never bothered to check the mount's P.E. If I did someone else would just come along with a lower number. I don't play golf any more so the only low number I care about is my PSA.
Steve
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----- Original Message ----- From: "kc5dfp" <kc5dfp@...> To: <Losmandy_users@...> Sent: Sunday, September 25, 2011 5:42 PM Subject: [Losmandy_users] Re: Losmandy OPW Assembly Steve,
Not sure what you mean. Please explain.
Even though I have about 3mm backlash I still get motor stalls. Let me know.
Joe
--- In Losmandy_users@..., "bullfox" <bullfox@...> wrote:
Joe,
The amount of end play needed to mess up the adjustment is so small that its
possible to be fooled about that.
Steve
----- Original Message -----
From: "kc5dfp" <kc5dfp@...>
To: <Losmandy_users@...>
Sent: Sunday, September 25, 2011 2:30 PM
Subject: [Losmandy_users] Re: Losmandy OPW Assembly
Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
------------------------------------
Yahoo! Groups Links
------------------------------------
Yahoo! Groups Links
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if you can't cure the lag or stalled messages, I suggest going to the Maxon motors which solved those issues for me. Then you might want better gearboxes too! they pit more torque and stress
on the chintzy part plastic housings.
Ross
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Joe,
I had the same issue with my OPWB and, like others have mentioned, it was lateral movement of the worm.
Here's what I would suggest.
1 - remove the motor and gearbox from the OPWB assembly.
2 - Install the OPWB on the mount so that the mesh is tight
3 - Remove the "cover" of the OPWB so that you can see the worm.
4 - Grab the counterweight shaft and move it back and forth. I bet you'll see the worm move laterally.
My OPWB came assembled from Losmandy as well. And I found that there was a "tough" spot when rotating the worm in the bearings and a fair amount of lateral play in the worm between the bearings. I ended up disassembling the OPWB and reassembling such that the lateral play was eliminated (or close to it) and the worm turned smoothly.
If you'd like to drop by some time this week just give me a call and we can see if we can get it all worked out.
Jared
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--- In Losmandy_users@..., Ross Elkins <rosse25@...> wrote:
if you can't cure the lag or stalled messages, I suggest going to the Maxon motors which solved those issues for me. Then you might want better gearboxes too! they pit more torque and stress
on the chintzy part plastic housings.
Ross
|
All,
Thanks for the replies.
I took the OPWB off and disasembled it. I re-preloaded the worm/blocks assuming there was some lateral play, and after I reassembled and installed it, the backlash is about 75% less!
I ran the mount a few times after starting with an "aggressive mesh", and I did get a stall, so I gave the thumg screw about 1/8 turn, the mount ran fine. I plan to run it around the worm just to make sure I tuned it to the "highest point" on the worm, but overall I am glad it's improved. This weekend I'll do another Pempro run and hopefully it's much improved from the last run.
All, again, Thank You for your guidance!
R,
Joe
Jared, Thanks for the offer, maybe you can join me with I do the Pempro run.
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--- In Losmandy_users@..., "rockjockjared" <jwellman@...> wrote:
Joe,
I had the same issue with my OPWB and, like others have mentioned, it was lateral movement of the worm.
Here's what I would suggest.
1 - remove the motor and gearbox from the OPWB assembly.
2 - Install the OPWB on the mount so that the mesh is tight
3 - Remove the "cover" of the OPWB so that you can see the worm.
4 - Grab the counterweight shaft and move it back and forth. I bet you'll see the worm move laterally.
My OPWB came assembled from Losmandy as well. And I found that there was a "tough" spot when rotating the worm in the bearings and a fair amount of lateral play in the worm between the bearings. I ended up disassembling the OPWB and reassembling such that the lateral play was eliminated (or close to it) and the worm turned smoothly.
If you'd like to drop by some time this week just give me a call and we can see if we can get it all worked out.
Jared
--- In Losmandy_users@..., Ross Elkins <rosse25@> wrote:
if you can't cure the lag or stalled messages, I suggest going to the Maxon motors which solved those issues for me. Then you might want better gearboxes too! they pit more torque and stress
on the chintzy part plastic housings.
Ross
|
I plan to run it around the worm just to make sure I tuned it to the "highest point" on the worm Joe, You will probably only need to check for tight spots around 180 degrees, or a fraction more. The worm would not normally need to drive the other half of the gear wheel. Greg From: Losmandy_users@... [mailto:Losmandy_users@...] On Behalf Of kc5dfp Sent: Tuesday, 27 September 2011 11:39 AM To: Losmandy_users@... Subject: [Losmandy_users] Re: Losmandy OPW Assembly All, Thanks for the replies. I took the OPWB off and disasembled it. I re-preloaded the worm/blocks assuming there was some lateral play, and after I reassembled and installed it, the backlash is about 75% less! I ran the mount a few times after starting with an "aggressive mesh", and I did get a stall, so I gave the thumg screw about 1/8 turn, the mount ran fine. I plan to run it around the worm just to make sure I tuned it to the "highest point" on the worm, but overall I am glad it's improved. This weekend I'll do another Pempro run and hopefully it's much improved from the last run. All, again, Thank You for your guidance! R, Joe Jared, Thanks for the offer, maybe you can join me with I do the Pempro run. --- In Losmandy_users@... <mailto:Losmandy_users%40yahoogroups.com> , "rockjockjared" <jwellman@...> wrote:
Joe,
I had the same issue with my OPWB and, like others have mentioned, it was
lateral movement of the worm.
Here's what I would suggest.
1 - remove the motor and gearbox from the OPWB assembly.
2 - Install the OPWB on the mount so that the mesh is tight
3 - Remove the "cover" of the OPWB so that you can see the worm.
4 - Grab the counterweight shaft and move it back and forth. I bet you'll see
the worm move laterally.
My OPWB came assembled from Losmandy as well. And I found that there was a
"tough" spot when rotating the worm in the bearings and a fair amount of lateral play in the worm between the bearings. I ended up disassembling the OPWB and reassembling such that the lateral play was eliminated (or close to it) and the worm turned smoothly.
If you'd like to drop by some time this week just give me a call and we can
see if we can get it all worked out.
Jared
--- In Losmandy_users@...
<mailto:Losmandy_users%40yahoogroups.com> , Ross Elkins <rosse25@> wrote:
if you can't cure the lag or stalled messages, I suggest going to the Maxon
motors which solved those issues for me. Then you might want better gearboxes too! they pit more torque and stress on the chintzy part plastic housings.
Ross
|
Joe,
That's Great!.
Steve
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----- Original Message ----- From: "kc5dfp" <kc5dfp@...> To: <Losmandy_users@...> Sent: Monday, September 26, 2011 6:38 PM Subject: [Losmandy_users] Re: Losmandy OPW Assembly All,
Thanks for the replies.
I took the OPWB off and disasembled it. I re-preloaded the worm/blocks assuming there was some lateral play, and after I reassembled and installed it, the backlash is about 75% less!
I ran the mount a few times after starting with an "aggressive mesh", and I did get a stall, so I gave the thumg screw about 1/8 turn, the mount ran fine. I plan to run it around the worm just to make sure I tuned it to the "highest point" on the worm, but overall I am glad it's improved. This weekend I'll do another Pempro run and hopefully it's much improved from the last run.
All, again, Thank You for your guidance!
R,
Joe
Jared, Thanks for the offer, maybe you can join me with I do the Pempro run.
--- In Losmandy_users@..., "rockjockjared" <jwellman@...> wrote:
Joe,
I had the same issue with my OPWB and, like others have mentioned, it was lateral movement of the worm.
Here's what I would suggest.
1 - remove the motor and gearbox from the OPWB assembly.
2 - Install the OPWB on the mount so that the mesh is tight
3 - Remove the "cover" of the OPWB so that you can see the worm.
4 - Grab the counterweight shaft and move it back and forth. I bet you'll see the worm move laterally.
My OPWB came assembled from Losmandy as well. And I found that there was a "tough" spot when rotating the worm in the bearings and a fair amount of lateral play in the worm between the bearings. I ended up disassembling the OPWB and reassembling such that the lateral play was eliminated (or close to it) and the worm turned smoothly.
If you'd like to drop by some time this week just give me a call and we can see if we can get it all worked out.
Jared
--- In Losmandy_users@..., Ross Elkins <rosse25@> wrote:
if you can't cure the lag or stalled messages, I suggest going to the Maxon motors which solved those issues for me. Then you might want better gearboxes too! they pit more torque and stress
on the chintzy part plastic housings.
Ross
------------------------------------
Yahoo! Groups Links
|
Hi, folks.
I had/have a similar issue with my G-11, with a OPWB mounted on the declination axis (O-vision on RA). I had horrible backlash on dec until I disassembled the OPWB and reseated/adjusted all the components.
Having done that, my backlash is better, but I'm still experiencing some odd behavior.
Running the backlash utility in PEMPro, I see sharp (in a good way) moves while transitioning from north to south, but soft/rounded transitions from south to north. TVC is 30; any higher and the change in direction from north to south results in a visible jump.
When calibrating the on-camera guider in MaxIm DL, RA calibrates perfectly, but declination does not. Dec will move the whole distance south, but only part of the way (1/3 to 1/2, typically) north. For example, if I use a calibration time of 10 seconds, dec will first move south by about 60 arc-sec, but only move north by 20 arc-sec.
This happens with both guider relays and ASCOM, and the calibration issue has been observed with the scope pointing both north and south, on the same side of the meridian (west, by preference). The scope is fairly well balanced in dec and RA, though probably not perfectly.
Any ideas or suggestions?
Thanks,
Justin
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I don't have an OPW, just an original brass worm on my G-11. But I have observed the worm's lateral play when moving the counterweight shaft. I am concerned because it may be the main reason for erratic guiding I get (that I am pretty sure is not PE related). The play feels 'big' at the end of the shaft, but looking at the worm shaft, the play translates to perhaps a couple mm across the bearing blocks. Is that normal? I don't understand those who talk about squeezing these blocks together. When I squeeze the blocks together and begin tightening, the block returns to its predetermined positioned when tightened...as you would expect with machined fittings. I don't think I have an issue in meshing the worm and the gear. When I watch a slew (cover off), the worm and gear seem to work smoothly without issue. The lateral play is most obvious and my 'visual analysis' suggests that the lateral play and the mesh are not related. Am I wrong about this? Is the lateral play strictly a function of mesh tightness? From the posts in this subject, it is not clear to me what folks are doing to reduce lateral play. Since the one-piece designs do not appear to be immune to lateral play, I want to try fixing what I have before taking the plunge for an OPW.
Mike
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--- In Losmandy_users@..., "bakersfieldbiker" <fblue@...> wrote:
If you have lateral play in the worm, it will show as play at the end of the counter weight shaft, just like it would if there were space between the worm and wheel. So, you could seem to have the play at the end of the shaft, yet the worm lash could still be too tight and you would get stalls.
Floyd
--- In Losmandy_users@..., "kc5dfp" <kc5dfp@> wrote:
Steve,
Not sure what you mean. Please explain.
Even though I have about 3mm backlash I still get motor stalls. Let me know.
Joe
--- In Losmandy_users@..., "bullfox" <bullfox@> wrote:
Joe,
The amount of end play needed to mess up the adjustment is so small that its
possible to be fooled about that.
Steve
----- Original Message -----
From: "kc5dfp" <kc5dfp@>
To: <Losmandy_users@...>
Sent: Sunday, September 25, 2011 2:30 PM
Subject: [Losmandy_users] Re: Losmandy OPW Assembly
Hello Floyd.
I did , and it looks fine, with no side to side movement.
R,
Joe
------------------------------------
Yahoo! Groups Links
|
Some amount of lateral (along the worm gear axis) play is normal, as is
a little play (lash) between the worm and the worm wheel.
Both are reasons you should always bias the mount to be slightly
'east heavy'. Doing so insures that the play and lash are taken up.
Mark Christensen
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--- In Losmandy_users@..., "Mark Christensen" <mjcw500@...> wrote:
Some amount of lateral (along the worm gear axis) play is normal, as is
a little play (lash) between the worm and the worm wheel.
Both are reasons you should always bias the mount to be slightly
'east heavy'. Doing so insures that the play and lash are taken up.
Mark Christensen
I'm not a Losmandy mount expert, but I've built and repaired a number of worm gear driven equatorial mounts over the years. A minimal amount of lash between the worm and the worm wheel is acceptable. Depending on the mount, about 1/8th of a worm rotation is the most there should be. However, I respectfully disagree with the statement regarding lateral movement of the worm/worm shaft between the bearing blocks. For a mount to track properly, there should be zero lateral movement of the worm shaft between the bearing blocks.
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So how does one remove the lateral play in the worm? Is this where a OPW helps?
Mike
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--- In Losmandy_users@..., "thechuckster27" <cburton@...> wrote:
--- In Losmandy_users@..., "Mark Christensen" <mjcw500@> wrote:
Some amount of lateral (along the worm gear axis) play is normal, as is
a little play (lash) between the worm and the worm wheel.
Both are reasons you should always bias the mount to be slightly
'east heavy'. Doing so insures that the play and lash are taken up.
Mark Christensen
[Non-text portions of this message have been removed]
I'm not a Losmandy mount expert, but I've built and repaired a number of worm gear driven equatorial mounts over the years. A minimal amount of lash between the worm and the worm wheel is acceptable. Depending on the mount, about 1/8th of a worm rotation is the most there should be. However, I respectfully disagree with the statement regarding lateral movement of the worm/worm shaft between the bearing blocks. For a mount to track properly, there should be zero lateral movement of the worm shaft between the bearing blocks.
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Lateral play is removed by holding the two blocks together, pressing with thumb and finger, while tightening the blocks down. This is done after setting the lash. Then there is a slight preload on the worm and no lateral play.
Floyd
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--- In Losmandy_users@..., "lamyridge" <lamyridge@...> wrote:
So how does one remove the lateral play in the worm? Is this where a OPW helps?
Mike
--- In Losmandy_users@..., "thechuckster27" <cburton@> wrote:
--- In Losmandy_users@..., "Mark Christensen" <mjcw500@> wrote:
Some amount of lateral (along the worm gear axis) play is normal, as is
a little play (lash) between the worm and the worm wheel.
Both are reasons you should always bias the mount to be slightly
'east heavy'. Doing so insures that the play and lash are taken up.
Mark Christensen
I'm not a Losmandy mount expert, but I've built and repaired a number of worm gear driven equatorial mounts over the years. A minimal amount of lash between the worm and the worm wheel is acceptable. Depending on the mount, about 1/8th of a worm rotation is the most there should be. However, I respectfully disagree with the statement regarding lateral movement of the worm/worm shaft between the bearing blocks. For a mount to track properly, there should be zero lateral movement of the worm shaft between the bearing blocks.
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The bolts that tighten up the worm block have this washer which should keep the worm block from moving when you tighten it. Check and make sure that you have these washers. In the pictures section under\adjustment on the first page are some pictures which I think show this washer. It's not that hard to adjust the worm so that it runs smoothly and doesn't have a lot of backlash although it helps to have a second pair of hands!
Good luck
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Floyd