Ok,
I am going to attempt the Rowan Astronomy EQ6 belt mod on my old mount.
I will also be cleaning and replacing the grease, installing SKF bearings and replacing the shims.
This brings me onto my question..where can I get Delrin shims from in Australasia if mine are (more than likely) disintegrated? I know of one fellow in America who used to supply them but is he still going? Also, any tips from those who have done this mod would be marvellous.
I haven't actually done the belt mod myself (the previous owner of my mount did that) but I found the Astrobaby site a site full of valuable information.
I did the Rowan belt mod on my NEQ6 Pro last year. There were a couple of things I found that might help you. First not all the housing castings are the same. The RA housing where the motors mount may have left over aluminium flashings around the motor mount, gear area, and the opening into the worm drive area. I found I had to grind off some of the casting to make room for belt clearance. You don't want the belt fouling on anything. Secondly, the toothed gear that you need to install on the worm shaft has to be positioned correctly and directly in line with the belt motor sprocket. This may require you to adjust the worm drive belt sprocket on the shaft. The instructions contain some general advice about positioning the worm gear sprocket, but you may need to loosen the lock screws and allow it to find its alignment position through running the motor. Check for rubbing of the belt as it passed through the casing wall. You have some adjustment range with the motor lock screws. Don't make the belts too tight but then again you don't want them slipping or jumping teeth on the sprocket - this will be readily apparent when you start testing. Don't over tighten the worm shaft end cap bearing, you just want it held in place not able to slip back and forth but not restricting. When you tighten up the bearing end caps you want to not make it too tight that it restricts turning. Make sure you use a grease that is not too heavy, silicon grease is ideal. Clean off the old grease if you can and make sure you lube the worm shaft. Don't get sloppy with the grease and don't get it on the belt. Move the bearing through a complete 30 degree circle, spin the housing, RA and DEC and check for slop and binding. Wiggle the counter weight shaft to check for play in the DEC bearing, likewise wiggle the RA housing to check for play in the RA bearing. I hope this helps.
BTW I hope you bought the bearing removal tool when you got the kit from Rowan, it makes removing the worm drive end caps and the bearings really easy.
Thanks for the excellent advice. I have had a browse through the "astro baby" pages for the strip down methods and all seems straight forward.
Did you all measure the parts with a digital micrometer as she did??
Did you need to replace your shims too? As for grease, i'm looking for TF2 lithium grease which seems to be the thing to use.
Having read a few other forums (sorry) with comments from modders, they only seem to suggest replacing the 4 worm gear bearings so that will save a fair penny or two..
Hi Stu,
I have done the belt mod and highly recommend it. I also recommend you replace the bearings while you have the mount opened up. My mod was done in two stages, first I got some bearings from a member here and installed those and did a quick lube, that was almost two years ago.
Recently about 2-3 months back, I got a second hard belt kit. I recommend you get the tool kit which allows you to screw the end caps off and also the long pincers allow you to tease out the belt a lot easier.
I haven't replaced the shims, but it doesn't seem to matter.
Anyway, after some tweaking, I got results like this below. It was only on light tackle (ED80 with dual finder and guide scope setup with DSLR), but I was very impressed with the tracking.
Do it, you won't regret it!
Bo
Just the worm bearings Stu.
I cleaned and greased the main brass gears with white lithium grease and a few dobs automotive bearing grease.
Good luck.
Bo
