Piers and brake discs

[wella]

I am thinking about building a mobile/semi permanent/"heavy but I might transport" pier to upgrade my Celestron Mak 127 which, as is well known, has got legs that are about as steady as a freshly born lamb.

I have found some nice metal tubing on ebay in a variety of sizes but does anyone have any details on the suitable break discs that are similar in size to the tubing.

So 5" brake disc and 6" brake disc???  I haven't decided which to use yet.  

Thanks in advance.  

Paul

[wella]

So  

• 127 mm
• 152 mm

[lennylovit]

brake disc is made out of "cast" and can crack very easy

Lenny

[twintin]

I use brake discs in my obsy and they work perfectly. They would need a massive whack to crack them. I used ones for a micro to mount my heq5 to. I will be swapping the top one for a vauxhall omega one so I can mount the neq6.

[mhard26339]

I am using brake disks for my pier head, see the thread New observatory in Norfolk UK. They are the largest I could find that are not vented and come from the rear of a Mazda 5; I got them from e-bay £14.99 each. Another favourite is the Skoda Favorit (no pun intended) at £9.99 each. They may be cast iron (some are Stainless steel) but there is no way that they will crack under the uses that we will subject them to. The days of large carbon inclusions that weakened the cast "pig iron" ingots have long gone. My advice is do not worry about "cracking", if its good enough for your car brakes its good enough for your mount .

Regards

Mike

[mhard26339]

Hi agin, by the way,  as can be seen from my thread I use an NEQ6 mount on mine discs interfacing with a commercial adaptor from Altair Astro, my only extravagance for the pier.

Regards

Mike

[wella]

Looking at the picture below for the skoda favorit brake disc it appears to be too wide (236.3 mm).  I was looking for suggestions for a disc that was a maximum of 152 mm 6"  or maybe 127 mm 5"

[mhard26339]

Hi Paul,

I went to Brake Disc World on E-bay and to get the right disc for what you want you have to investigate the data sheets to check the sizes available. You may have to adjust the design to suit but having just set mine up it is really woth the effort. With a permanent pier initial set-up is so much easier that tripod and spirit level (and then you knock it in the datk!!) as I said check by build thread in DIY Observatories - New obsy in Norfolk UK.

Regards

Mike

[twintin]

Hi Paul

if you have a look at my thread on my build i used a pair of them with the bottom one turned upside down so it went into the tube. i then used the 4 stud holes to fix it into the concrete that filled the pier and drilled the disc part for bolts so that i could fix the top to the bottom. Dead easy really.

Mark

[redfox1971]

This is mine made from a mark4 escort xr3i flywheel whitch i mounted the wedge for my cpc800 on.

[wella]

Yes, excellent, thanks gentleman.  I think i have got my head around it now.  

For some strange reason in my head I was thinking that the whole size of the disc would sit flush with the central pillar.  I had forgotten that the outside flange over hangs.  

I will report back if and when I get any further with my thoughts.

Paul

[kingboya]

Here's mine. <br />

Skoda octavia disk seems to fit my NEQ6, and works a charm! <br />

[astrovirus]

Skoda octavia disk seems to fit my NEQ6, and works a charm!

 Can you provide the details or a link on which type of Octavia barke disk you used. I'm looking for an NEQ6 adapter in The Netherlands and this looks really good.

Thanks in advance.

[kingboya]

Can you provide the details or a link on which type of Octavia barke disk you used. I'm looking for an NEQ6 adapter in The Netherlands and this looks really good.

Thanks in advance.

It was a long time ago that I bought them, but I believe that they were rear discs for a mk2 octavia. Lots of availability on ebay, but just measure the size of the EQ6 circle on the bottom (where the bolt goes through) and get as close a matching disc as possible. 55mm seems to be the diameter of the circular bit at the bottom of the mount?

HTH

Tony:D

[astrovirus]

Thanks Tony

[JohnC64]

If you are looking for something of an exact size, then take a look at laser master  ( http://www.lasermaster.co.uk/metal-laser-cutting )

If you select washer in the cutting type, and specify a inner and outer diameter, it will give you an instant price.

I have used them for small custom aluminium washers in the past. They take a while to come - guess it depends on what material and thickness they are cutting on the day to make a batch job up.

They custom cut mild steel up to 15mm thick and stainless 304 up to 10mm.

It will cost a little more than a disk brake - but you can get exactly the size you want.

Hope this helps 

John

[twintin]

I would just check the bottom dimension of the neq6 its 65mm I believe. I ordered a rear disc for a vauxhall carlton which has a 66mm central hole and it fits perfectly. Just need to make a bracket or something to go underneath so I can put a bolt through and hold it all in place and drill it to fit my existing bottom plate and put an az stud in.

[Winter]

On 22/04/2014 at 21:49, twintin said:

Hi Paul

if you have a look at my thread on my build i used a pair of them with the bottom one turned upside down so it went into the tube. i then used the 4 stud holes to fix it into the concrete that filled the pier and drilled the disc part for bolts so that i could fix the top to the bottom. Dead easy really.

Mark

Does anyone know type of those brake discs or similar ? Looks like Mark will not answer because he was here last time in February.

Edited June 2, 2020 by Winter

[Alan White]

It depends on the tube you plan to use.
Some are Corsa Discs, some are Escort Discs.

I had plans for a 200mm tube and bought Escort discs, still have them in the garage if they are of interest.

[jiberjaber]

I'm currently looking at a disc for a HEQ5 and have found this with all the dimensions in for car models.  Now to find that elusive free delivery sub £10 disc of the right size! LOL 

 

http://www.national-auto.co.uk/assets/content/documents/brake_disc_cat_-_nov_2014.pdf

 

[Adam J]

The issue I always have with these is that you dont need to level a pier top to polar align and so you introduce a vibration source in making the leveling device using threaded rods.

Edited June 3, 2020 by Adam J

[Winter]

13 hours ago, Alan White said:

It depends on the tube you plan to use.
Some are Corsa Discs, some are Escort Discs.

I had plans for a 200mm tube and bought Escort discs, still have them in the garage if they are of interest.

I found similar :

https://www.amazon.co.uk/Brembo-08-2631-34-Rear-Brake-Disc/dp/B005O97IH0

[SamAndrew]

6 hours ago, Adam J said:

The issue I always have with these is that you dont need to level a pier top to polar align and so you introduce a vibration source in making the leveling device using threaded rods.

The separation between the discs is to allow you to get access to the bottom of the mount to attach it to the disc. Once attached there's no reason you couldn't reduce the space between the discs until they touch. In reality the vibrations that can resonate in the bolts are high frequency and damp out quickly. I've never noticed any negative impact.

Edited June 3, 2020 by SamAndrew

[Adam J]

3 hours ago, SamAndrew said:

The separation between the discs is to allow you to get access to the bottom of the mount to attach it to the disc. Once attached there's no reason you couldn't reduce the space between the discs until they touch. In reality the vibrations that can resonate in the bolts are high frequency and damp out quickly. I've never noticed any negative impact.

It would depend on your focal length. 

[stash_old]

6 hours ago, SamAndrew said:

The separation between the discs is to allow you to get access to the bottom of the mount to attach it to the disc. Once attached there's no reason you couldn't reduce the space between the discs until they touch. In reality the vibrations that can resonate in the bolts are high frequency and damp out quickly. I've never noticed any negative impact.

Exactly its not a major problem - 3yrs and still going with no cracks or any other major problem.  Its a tried and tested route 🙂

But if you are OCD about such problems there is plenty of info (been trying to find the orig I read which I think was from Cloudynights) on "Dry Sand filling tubes" etc !