ncjunk

How was it with the guiding George? Did it look good?

The clearance is fine but i am putting it on the Dec hopefully it won't be as critical in there. I am thinking it may cause wear as well.

Neil C

One of my large pullies is slightly out so wobbles when turning. Whats the worst that could happen if i stick it on the Dec?

I'll see if there is anything i can do but it looks like i may just have to suck it and see...as they say.

Shims arrived today so everything will be put back together tomorrow.

Looks good then, no pressure but now you have to apply a PE correction George and redo the graph!

I´m in no hurry so I´ll give you until tomorrow to sort it out and post back here

It´s looking good! as soon as my Allen keys turn up I can put mine back together and test it

fwm891 be carefull with the smaller pully as we are boring it out to within 0.5 - 1.0 mm of its life, my machinist wasn´t too impressed as he thought there wouldn´t be anything left but it is just ok.

It'll be interesting to see what Chris says.

I have ordered a set of 30 Allen Keys so one of them should allow me to put it all back together.

I have put the pully on the worm gear but its really jammed on. I understand that the thermal coefficient of expansion for Aluminium is larger than steel so should i be able to get it off after sticking it in the oven for a bit and smacking it with a rubber mallet?

Its on perfectly for trying everything out i am just preparing myself for if i need to put the gears back on.

I couldn't find mine either but I have one of those micro screwdriver sets and found a flat bladed one I could jam in

Aahhh now thats a whole new set of tools i can try....after dinner..

...and if that fails "to the model shops!". If they have them over here.

Well, my machinist has worked his magic and i have everything back and ready. Now where is that extra small allen key...er....that really small easy to lose Allen key....oh darn it.

And none of the shops have one that small..

I hate mechanical thingies...

One of the first things you learn is that a square wave is made up of loads of sine waves. You can make various shaped waves by adding together different frequency waves. I.e. You can make a triangular wave.

All of this is exactly related to this but instead of generating all the sin waves and adding them together our mechanical system is introducing its own repeating error...each of these repeating errors is like my individual sine waves on the electronic version.

These repeating errors all add together to create our PE or repeating total error.

All the maths does is take the error curve you produce from tracking the star movement and basically calculate each of the repeating errors (the frequency of these) and their sizes (magnitudes).

Then someone like Chris who actually knows what he's talking about, unlike me, can tell us which thingy is related to what mechanical wotsit.

This and induction motor theory are two bits of engineering maths that i thought was...elegant.

I am finding all this interesting.

I liked fourier transforms at uni, very interesting.

Have you got one of your old guiding graphs for comparison?

Also looking at the above graph have you tried guiding the dec in only one direction? Made a hell of a difference on my system as eliminates over correction.

Someone mentioned it on SGL and i tried it last week and it worked well.

Fantastic George! Can't wait to get mine back together and give it a go.

I will see today if i have any insert left then. I have a feeling it may get completely bored out.

Lapping? Ha! I'm too lazy for that, i remember doing it at school 20 odd years ago but i don't have the stuff to do it.

When I took apart the RA i noticed i had bent the dust cover on one if the ra worm bearings, i suspect this may have been causing high freq noise. I would recommend anyone doing a strip down to get a replacement set of these bearings just in case ( they are cheap enough)

My Brothers up a creak without a paddle then!

Fair enough....i was just going by some small pictures on the other website and didnt realise that little bit on top was permenent.

I would have bet my brothers life on there being grub screw....looks like the eq5 on astrobabys site should have them.

Have you got a picture?

My eq6 stepper had two gears each with two grub screws. It was just a case of removing the grub screws and wiggling a bit till the gears came off.

George,

The 12 pully that needs boring out to 5mm, when you drill it basically it removes all of the center section leaving just the main pully. My machinist was querying it but i told him just to bore it out any way.

I take it yours is fine like that?

George,

I have a complete set of SKF bearings, very smooth, and the belt mod kit. I will take the pullies to the machinist tomorrow and start stripping the mount.

Did you need to machine out the RA in the end, to provide more belt tension?

Thanks

Neil C

There is a ratio difference between gears and belt but eqmod has a custom setting for the ratio to cover belt mods.

Sorry, just read the answer in the other thread linked in the first post here...

One question though... How do you overcome the fact that with a belt it will end up rotating the other way around? Is it possible to reverse the direction of the motor?

Er...quickly visualising the gears in my knackered brain..there are three gears one on the motor, one on the worm and one connecting the two. Therefore it is the middle one that is going in reverse with respect to the other two i.e. Motor and worm gears rotate in same direction. With the belt there is a pully on the motor and one on the worm and the belt will cause them to move in the same direction i.e. No difference between belt and gears.

Some of the original gears were plastic, I believe. But I am sure the new mount (EQ7/8) out...er...who knows when...I am sure will have a much better mechanical setup than the EQ6 has now. Plus they have improved things the current EQ6 comes with a duel puc that has a Losmondy connector.

He´s an Artist when it comes to lathe work, but I will make sure he understands it is vital that it is centered....it´s just a shame that my Astro stuff is normally bottom of his todo list. Still, he only has to drill and take off 3mm so I think he should be able to do it quickly (he doesn´t have to buy anything in)

All ordered now so hopefully I´ll have them by the end of the week.

Excellent! Ordering the bits now...I hope I can get my Machinest to actually do the mods quickly rather than in six months!

You are a Star George. (Well what else would you be on an Astro Forum )

George,

How did you remove the oldgears from the stepper motor? I have seen a picture of one that has a largeish brassish nut to undo but on mine this nut looks like a button i.e. No where to attach a spanner...unless the nut is underneath.

I am suffering a few high frequency errors on my RA so hoping this will solve it.

Does it sound good/quiet?

Well done by the way!

I will place the order monday, then i'll have to find someone to bore out the pullies. Let me know how the tensioning of the belt goes, thats the bit i am not sure about.