NewMoon
02-02-2016, 03:55 PM
I used the instructions by Merlin66 and I have added a few comments that might be useful if you are a bit doubtful of your ability.
The process is very simple and it would have been obvious if I had done a bit of looking at the scope.
I assumed that the shafts mounted onto the tube with a boss behind the top of the fork. It is much simpler than that, here are the excellent instructions from Merlin66 -
De-forking an OTA from a Lx200 Classic
If you are considering de-forking a Meade OTA give some thought to the final OTA tube weight. The 10” OTA weighs 15Kg and the 12” OTA 17.1Kg. A EQ5 type mount will hold the 8” OTA (I recommend using a Losmandy dovetail if possible – they are more rigid than the Vixen); the 10” OTA really needs at least a HEQ5 type mount, and the NEQ6 is much better if your considering astro-imaging.
The weight of the 12” OTA puts it close to the limits of the NEQ6pro mount; OK for visual but not recommended for astro-imaging – you need a larger mount.
Also, if you’re considering putting the OTA back on the forks at some future time, you should mark the tube and fork arms to allow easy re-assembly and to maintain orthogonal alignment.
The OTA is held onto the Dec stub shafts by three Allen screws; two large and one small. You’ll also see, if you look at the back surface of the Dec stub plate, two small holes…ever wondered what they were for?? Well, they take long #4 -40 screws to push against the heads of the two larger Allen screws and allow the OTA to be “squared up” to the Dec shaft – neat!
The Dec stubs are supported in bearings at the top of each fork support arm. The arms themselves are fixed to the RA drive base with four large, long Allen head screws, just below the bottom of each arm.
The removal of the OTA involves removing these four screws from one fork arm, removing the three screws holding the Dec stub to the OTA and removing the fork arm….turn the Drive base and OTA over and remove the three screws from the other Dec stub to allow the OTA to come free…as simple as that!
You’ll need a selection of Imperial Allen wrenches, a padded work space and a tea towel.
Notes:
If you are considering future re-assembly, use a fine marker pen and steel rule to mark the position of the Dec arm on the RA base. A couple of alignment marks on the top and sides will make it much easier to reassemble. Also mark the rear cell of the OTA along the edge lines of the Dec stub plates – this will allow them to be repositioned accurately.
Work on a padded table (or on the spare bed!), a folded blanket is ideal.
Remove the cables from the mount – power, Dec connectors etc etc.
Position the OTA at right angles to the fork arms ( this gives easier access to the screws on the Dec stub/OTA) and lock the Dec clutch.
Roll the mount and OTA until the non-drive arm is upwards.
Remove the four large Allen head screws from the bottom of the non-drive fork arm.
Place a tea towel over the OTA just in front of the Dec stub, this will prevent any accident damage to the OTA while lifting and removing the fork.
Remove the three smaller Allen screws holding the Dec stub to the OTA – support the fork in one hand and get ready to take its weight and remove it away from the OTA.
Flip the mount and OTA over so the Drive arm is towards the top.
Again place the tea towel over the OTA, hold the fork arm as you remove the three screws from the OTA. Remove the base and fork arm to a safe distance….
Job done!
I usually put some spare screws into the holes in the OTA, just to prevent dust and rubbish getting into the tube.
The re-forking is just the opposite of the above.
Ken Harrison –Oct 2011
Mine was on the tripod which made it easy to go through the process before starting it.
Tilt the tube horizontally, the mounding screws are near the rear end.
They were just nipped up enough to stop them coming undone, I just undid them about 1 turn so they would be easy to remove later.
The fork attachment screws are behind the plastic cover that is along the bottom of the horizontal piece and goes just around the corner.
Here is the bit that I think is important before you start.
Find the allen key size that is a snug fit into the screws, if you don't have a long one or a hex socket&bit that is long enough to go from a rear screw to clear the corner of the fork then you should borrow or buy one.
I struggled for ages and when I had finally done it I thought that I should have bought one, even $100 would have been worth it.
They were very tight, I managed to get one rear one to start to undo after much 'walking' with the standard size key+. It was still very tight.
Then I tried the other rear one and couldn't budge it. No matter what I did. A long key with a T handle or L handle would have been ok.
I then tried the other fork and as it turned out both forks had a bunch of wires in them so it didn't matter which fork I used.
I finally got the 4 screws to start to undo to the point where I was sure they could be unscrewed further.
Using a bed as per Merlin66 would have been ideal, I just doubled over a sleeping bag on the floor because I didn't want to cart the forks+tube upstairs.
With the 6 screws removed from the tube the tube wouldn't slide out so a fork had to be undone. A fork that could be removed completely would have been good. Mine had wires inside so I undid the 4 screws about 5mm and carefully lifted the end of the fork away from the tube.
I rolled the tube away and lowered the fork.
It was then a matter of tightening the fork screws & covers enough so they wouldn't get lost. Here's a gotcha, if you can't get a screw to get started in one of the bottom holes in the plastic cover it's because they are the ones that are slightly longer than the others.
Ken's suggestion to replace the 6 screws back into the tube is of course essential for keeping the weather out.
They can be screwed all the way in because they don't strike anything inside the tube.
Anyone can do I, all you need is the correct size keys and the instructions from Merlin66.
Bill
The process is very simple and it would have been obvious if I had done a bit of looking at the scope.
I assumed that the shafts mounted onto the tube with a boss behind the top of the fork. It is much simpler than that, here are the excellent instructions from Merlin66 -
De-forking an OTA from a Lx200 Classic
If you are considering de-forking a Meade OTA give some thought to the final OTA tube weight. The 10” OTA weighs 15Kg and the 12” OTA 17.1Kg. A EQ5 type mount will hold the 8” OTA (I recommend using a Losmandy dovetail if possible – they are more rigid than the Vixen); the 10” OTA really needs at least a HEQ5 type mount, and the NEQ6 is much better if your considering astro-imaging.
The weight of the 12” OTA puts it close to the limits of the NEQ6pro mount; OK for visual but not recommended for astro-imaging – you need a larger mount.
Also, if you’re considering putting the OTA back on the forks at some future time, you should mark the tube and fork arms to allow easy re-assembly and to maintain orthogonal alignment.
The OTA is held onto the Dec stub shafts by three Allen screws; two large and one small. You’ll also see, if you look at the back surface of the Dec stub plate, two small holes…ever wondered what they were for?? Well, they take long #4 -40 screws to push against the heads of the two larger Allen screws and allow the OTA to be “squared up” to the Dec shaft – neat!
The Dec stubs are supported in bearings at the top of each fork support arm. The arms themselves are fixed to the RA drive base with four large, long Allen head screws, just below the bottom of each arm.
The removal of the OTA involves removing these four screws from one fork arm, removing the three screws holding the Dec stub to the OTA and removing the fork arm….turn the Drive base and OTA over and remove the three screws from the other Dec stub to allow the OTA to come free…as simple as that!
You’ll need a selection of Imperial Allen wrenches, a padded work space and a tea towel.
Notes:
If you are considering future re-assembly, use a fine marker pen and steel rule to mark the position of the Dec arm on the RA base. A couple of alignment marks on the top and sides will make it much easier to reassemble. Also mark the rear cell of the OTA along the edge lines of the Dec stub plates – this will allow them to be repositioned accurately.
Work on a padded table (or on the spare bed!), a folded blanket is ideal.
Remove the cables from the mount – power, Dec connectors etc etc.
Position the OTA at right angles to the fork arms ( this gives easier access to the screws on the Dec stub/OTA) and lock the Dec clutch.
Roll the mount and OTA until the non-drive arm is upwards.
Remove the four large Allen head screws from the bottom of the non-drive fork arm.
Place a tea towel over the OTA just in front of the Dec stub, this will prevent any accident damage to the OTA while lifting and removing the fork.
Remove the three smaller Allen screws holding the Dec stub to the OTA – support the fork in one hand and get ready to take its weight and remove it away from the OTA.
Flip the mount and OTA over so the Drive arm is towards the top.
Again place the tea towel over the OTA, hold the fork arm as you remove the three screws from the OTA. Remove the base and fork arm to a safe distance….
Job done!
I usually put some spare screws into the holes in the OTA, just to prevent dust and rubbish getting into the tube.
The re-forking is just the opposite of the above.
Ken Harrison –Oct 2011
Mine was on the tripod which made it easy to go through the process before starting it.
Tilt the tube horizontally, the mounding screws are near the rear end.
They were just nipped up enough to stop them coming undone, I just undid them about 1 turn so they would be easy to remove later.
The fork attachment screws are behind the plastic cover that is along the bottom of the horizontal piece and goes just around the corner.
Here is the bit that I think is important before you start.
Find the allen key size that is a snug fit into the screws, if you don't have a long one or a hex socket&bit that is long enough to go from a rear screw to clear the corner of the fork then you should borrow or buy one.
I struggled for ages and when I had finally done it I thought that I should have bought one, even $100 would have been worth it.
They were very tight, I managed to get one rear one to start to undo after much 'walking' with the standard size key+. It was still very tight.
Then I tried the other rear one and couldn't budge it. No matter what I did. A long key with a T handle or L handle would have been ok.
I then tried the other fork and as it turned out both forks had a bunch of wires in them so it didn't matter which fork I used.
I finally got the 4 screws to start to undo to the point where I was sure they could be unscrewed further.
Using a bed as per Merlin66 would have been ideal, I just doubled over a sleeping bag on the floor because I didn't want to cart the forks+tube upstairs.
With the 6 screws removed from the tube the tube wouldn't slide out so a fork had to be undone. A fork that could be removed completely would have been good. Mine had wires inside so I undid the 4 screws about 5mm and carefully lifted the end of the fork away from the tube.
I rolled the tube away and lowered the fork.
It was then a matter of tightening the fork screws & covers enough so they wouldn't get lost. Here's a gotcha, if you can't get a screw to get started in one of the bottom holes in the plastic cover it's because they are the ones that are slightly longer than the others.
Ken's suggestion to replace the 6 screws back into the tube is of course essential for keeping the weather out.
They can be screwed all the way in because they don't strike anything inside the tube.
Anyone can do I, all you need is the correct size keys and the instructions from Merlin66.
Bill