Replacement parts etc 90 (cogs/gears)???

[Lordspace]

I have found that inside my etx 90 base that one of my gears/cogs as had a few teeth broken off.

I've looked on Meade's website but don't see spare parts for these.

Does anyone know of a third part vendor that may have them or if I can get them from anywhere??

I fear that my mount will be for the scrap man because of one plastic cog. 

The photos aren't the best but I need one of these tiny gears.

Cheers.

Edited February 26, 2020 by Lordspace

[furrysocks2]

If not, it might be possible to 3D print a replacement. The link below won't necessarily be the right part and there may not be a model already for the cog you need, but it proves the point.

https://www.thingiverse.com/thing:1761570/comments

The hard bit would be 3D modelling what you need, anyone with a printer could then print a few for you.

[Lordspace]

I don't have access to a 3d printer 😕 also I don't know how much I would trust the strength of 3d prints in harder materials.

I know you can buy plastic gears online but it's finding the right measurements and I have no idea how to even start measuring it. All I can see is that it was a 24 tooth gear.

[MarkAR]

Did a quick google for precision gears uk and came up with these possible links.

https://www.accu.co.uk/en/622-precision-gears

https://www.reliance.co.uk/catalogue/precision-gears/

http://www.davall.co.uk

http://www.edgertongears.co.uk

It probably would have to be a custom made job but having it made in brass would be a good upgrade.

 

It looks like you have 2 gears sandwiched on there. Measure the diameter of the spindle, the outside diameters and number of teeth of each section.

Edited February 26, 2020 by MarkAR

[Lordspace]

35 minutes ago, MarkAR said:

Did a quick google for precision gears uk and came up with these possible links.

https://www.accu.co.uk/en/622-precision-gears

https://www.reliance.co.uk/catalogue/precision-gears/

http://www.davall.co.uk

http://www.edgertongears.co.uk

It probably would have to be a custom made job but having it made in brass would be a good upgrade.

 

It looks like you have 2 gears sandwiched on there. Measure the diameter of the spindle, the outside diameters and number of teeth of each section.

This is the single broken gear I need. No idea how to even measure one of these. I can only assume that it has the same amount of teeth as the one it sits flush with which I counted as 24.

[joe aguiar]

Not sure u would do this but I just traded my lxd85 goto mount for a 125 etx with case ep etx

I deforked it as I dont like the small plastic base. I may sell the base arm and autostar to somone who has the ota and wants to convert it.

I then put it on eq4 mount but really a eq3 or 2 would do for a small ota.

joejaguar 

Edited February 26, 2020 by joe aguiar

[Lordspace]

The value of the mount would be next to nothing now it doesn't work.

I wouldn't get any where near enough to fund a new mount 😕 I have no idea how to even calculate the dimensions for a new gear and I doubt I could just get one from eBay.

Looks like I may just have to sell everything as faulty and cut my losses...

[geoflewis]

Where are you located? If in the UK you could try Steve Collingwood at SCTelescopes https://sctelescopes.com/

There is also Buck's Gears from Peterson Engineering in the USA http://store.smartastronomy.com/bucksgears.html. It's been a few years since I used him as I no longer have a Meade scope, but maybe worth calling him.....

Edited February 26, 2020 by geoflewis
added link to Buck's gears

[Davey-T]

Where are you based, have a search for local model engineer clubs no doubt a member there would be happy to make brass replacements for the plastic ones for a small fee.

Dave

[joe aguiar]

3 hours ago, Lordspace said:

The value of the mount would be next to nothing now it doesn't work.

I wouldn't get any where near enough to fund a new mount 😕 I have no idea how to even calculate the dimensions for a new gear and I doubt I could just get one from eBay.

Looks like I may just have to sell everything as faulty and cut my losses...

no its not that bad at all

just the hand controller autostar alone  last time I looked almost $150 with tax u can get $90 to $99

then someone like u that had another part break can or will buy your to use the part he needs maybe $40 to $50 if that part wasn't broken you would get a lot more.

If I sell my etx 125 base fork arms and hand controller I would list it for $199  yes your is broken so it get a lot less

A eq2 can handle the 90mm mak, its not a write off the ota is an excellent little scope.

a eq2 used can be $60 in uk maybe that's $35 not expensive at all

joejaguar

Edited February 26, 2020 by joe aguiar

[Lordspace]

1 minute ago, joe aguiar said:

no its not that bad at all

just the hand controller autostar alone  last time I looked almost $150 with tax u can get $90 to $99

then someone like u that had another part break can or will buy your to use the part he needs maybe $40 to $50 if that part wasn't broken you would get a lot more.

If I sell my etx 125 base fork arms and hand controller I would list it for $199  yes your is broken so it get a lot less

A eq2 can handle the 90mm mak, its not a write off the ota is an excellent little scope.

a eq2 used can be $60 in uk maybe that's $35 not expensive at all

joejaguar

I only use goto mounts tbh or tracking mount as i used the mount/scope for imaging... I'm not really into just viewing so kind of useless to me now. 

I can't see why Meade wouldn't sell spare parts when they still sell the mount/scope.

I was quoted £65 for the whole gear set from a third party vendor which is was too much just to fix this mount.

[Lonestar70]

3 hours ago, Lordspace said:

The value of the mount would be next to nothing now it doesn't work.

I wouldn't get any where near enough to fund a new mount 😕 I have no idea how to even calculate the dimensions for a new gear and I doubt I could just get one from eBay.

Looks like I may just have to sell everything as faulty and cut my losses...

Don't give up yet, there are several places to purchase gears from.

First thing is to measure the following: -  as accurately as possible (preferably using a vernier caliper or Micrometer).

Take these measurements in both Imperial and Metric.

1. The outside diameter across the tips of 2 diametrical opposed teeth (use relatively undamaged teeth).

2, The OD of the hub section.

3. The bore through the hub.

4. The thickness of the gear section.

5. The thickness of the hub section. or the total thickness of gear and hub.

From this you can determine if the gear is Imperial (DP =Diametral Pitch) or Metric ( MOD = Module pitch).

For DP use : -   Number of teeth +2 / OD in inches = DP.  Answer should be a whole number and from you pictures the gear appears to be 32 or 40DP

For MOD : -     OD in mm / Number of teeth+2 = MOD.  Valid MOD numbers would be 1, 0.9, 0.8, 0.75,0.7, 0.6,0.5, 0.4, 0.3 and 0.25.

Again,from your pictures, I would guess yours is either 0.8, 0.75 or 0.7 MOD

Once you have established if the gear is Imperial or Metric you can look for a suitable one.

A good source in the UK is : -

https://hpcgears.com/

They do Delrin (white nylon/plastic) and metal gears in a whole host of sizes and styles.

If you are unsure of your results then post again here with what you have and we can advise or assist further.

Even if the closest you can buy is a bit thicker or the hub to big/long... 10 minutes in a lathe could rectify those dimensions and I would be happy to do this for you if necessary.

Good luck and I hope you can get your mount back up and running again soon.

 

[MarkAR]

I think thats a pretty standard part, measure across the diameter with a rule and also the hole. The hole will only be either 3, 4 or 5mm.

The teeth look like 0.5 MOD, so I'm guessing that the diameter is 13mm.

The closest spurr gears that Accu comes up with is a 0.5 MOD, 24 tooth, 12mm PCD, 3 and 4mm bore.

 

[Lordspace]

4 minutes ago, MarkAR said:

I think thats a pretty standard part, measure across the diameter with a rule and also the hole. The hole will only be either 3, 4 or 5mm.

The teeth look like 0.5 MOD, so I'm guessing that the diameter is 13mm.

The closest spurr gears that Accu comes up with is a 0.5 MOD, 24 tooth, 12mm PCD, 3 and 4mm bore.

 

My calipers show the diameter as 12.5 but I'm sure the 0.5 wouldn't matter would it. The hole is 3mm and there are indeed 24 teeth. When ever I search on any sites I always find close to the one I need but never exactly.

[MarkAR]

11 minutes ago, Lordspace said:

My calipers show the diameter as 12.5 but I'm sure the 0.5 wouldn't matter would it. The hole is 3mm and there are indeed 24 teeth. When ever I search on any sites I always find close to the one I need but never exactly.

Excellent, so a PCD of 12mm, 24 tooth, 3mm bore in delrin is I believe what you need. Accu.co.uk only do that one in brass or steel. Brass might be ok.

PCD is the diameter measured from half the tooth height.

Edited February 26, 2020 by MarkAR

[Lordspace]

13 minutes ago, MarkAR said:

Excellent, so a PCD of 12mm, 24 tooth, 3mm bore in delrin is I believe what you need. Accu.co.uk only do that one in brass or steel. Brass might be ok.

PCD is the diameter measured from half the tooth height.

AHH ok, I think I saw the brass one. Would brass be ok next to plastic gears? 

[Lordspace]

Well I went for the brass one on that site £12 all together so I hope it works haha

[Lordspace]

1 minute ago, KevS said:

May I interject? 

You will probably find that the external diameter was originally 12.54 mm (Meade being an American company) 1/2 inch in old money, the bore being 3.2 mm 1/8 inch. Try a search for "imperial gears". Might find the exact one that you are after. 

That makes sense, I will have a look see what I can find.

Its amazing how it can be so difficult trying to find a small round piece of plastic with teeth.

[Davey-T]

47 minutes ago, KevS said:

Think this is the one you may be after: Knowing the noise that most Meade drives make I would hazard a guess that its a 20 degree pressure angle other than 14 1/2.

Tried to purchase some O rings from McMaster Carr and they wouldn't export them, had to get my nephew that works in the USA to buy them and fetch them over.

Dave

[MarkAR]

4 hours ago, KevS said:

You will probably find that the external diameter was originally 12.54 mm (Meade being an American company)

You're right, didn't think about Meade being US manufacturer. Mind you, looking at the DP of the gear, 24 +2 / 0.5" makes it a 52 DP gear.

I think Meade have used a metric set up. Take into account the measured diameter is 12.5mm on a worn and broken gear, it is very possible that it was originally 13mm making it a 0.5 MOD, 24 tooth metric gear.

It could be the 48DP imperial gear if the outside diameter was originally13.7mm

Edited February 27, 2020 by MarkAR

[Lordspace]

On 26/02/2020 at 19:46, KevS said:

 

Well I got the gear from accu this morning.

The general size seems fine in diameter but the sticking out part is huge so hopefully it will fit.

If not someone has offered £25 for the mount as spares.

If it doesn't work hopefully they will let me return it.

Edited February 28, 2020 by Lordspace
Adding photo/s

[Lordspace]

After an hour of cutting and sanding the we fits perfectly fine now and the mount works with no issues so far.

Just got to retrain the motors and calibrate and give it a real test.

But thanks for all the help and advice..

I would have just sold the mount if it had not been for all the help on here so I really do appreciate it!!!