Quote:
Originally Posted by JohnH
Hi G11 owners - I am looking for some advice on the pros and cons of these upgrades - my G11 has the standard 2 piece worm bearing blocks - and a PE of about 25" peak to peak. I think this can be tuned out by those more mechanically gifted than me but the new worm blocks seem to offer an improved performance without too much tweaking. Is this upgrade worthwhile and if yes which of these options do you recommend? I am leaning towards the Ovision currently.
|
I can't talk about the ovision which I suspect has an excellent quality worm but I have a Losmandy high precision worm and one block both in RA and DEC. In my experience it greatly helps with alignment Saying that you'll get better PE depends on a lot of other factors.
Gearbox, bearings, worm quality (eccentricity), state of the gears, orthogonality, meshing. Here's what works for me and what to look for before you buy the one block configuration.
The gearboxes, well I'm not sure how they affect PE but bad ones will affect your backlash even with good meshing and that drives me nuts enough to get 'tighter' ones.
Check your bearings. One hard spot is very easy to feel and that will bugger your PE big time. Just get one end block with the bearing in it then slide the end of the worm in there. Just press a little side ways to 'load' the bearing then turn back and forth feeling if it's smooth, then offset and keep doing it over the whole 360. Little steps back and forth. If you feel any 'click' or 'grinding' even insignificant bin the bearing and change it. You'd be surprised how many so called high precision bearings or other are dodgy.
Worm quality. I guess the only one that comes with a 'certificate' is the Ovision. The losmandy high precision worms are not consistent.
Meshing can be achieved with the two single pieces. It takes a little practice but you can achieve better meshing by shimming than with the one block. The reason is that you still can see the worm, mesh it in the gear, then check the gaps under and behind the blocks and shim them. Hard to see anything going on with the one piece block.
Another issue with the one piece block is that you need to couple the gearbox to the worm before meshing it in. So no chance of 'feeling' by hand the hard spots around the circumference of the gear. Although I'm thinking of drilling a small access hole in the cover to be able to sneak in an Allen key to couple the motors after I did the meshing by hand.
Make sure the coupling is tight against the worm but use a 0.4mm gauge so it's spaced out enough. Very important to secure the coupling on the gearbox shaft first then secure the gearbox on the plate, so everything is inline without any stress or you'll stress the coupling and the worm will be harder to rotate.
Finally clean your gear thoroughly before meshing. Turp them up and get rid of all old dry grease with a toothbrush and tooth pick.
Inspect the worms and gears. Keep both the good ones for the RA, the other goes in DEC.