Where to source a mounting plate for concrete pier?

[HAL9000]

Hi all, I'm planning to build a concrete pier based on reading about & looking at the numerous DIY versions on here & elsewhere on the net, but struggling with finding a metal plate to bolt onto the top & attach the mount (HEQ5 PRO). It seems quite a few people have either made their own, or know someone in the trade / good at metalwork. I don't know anyone with these skills, so I'd appreciate any info on where to get this made (struggling to find any "off the shelf" products apart from the adaptors included with expensive commercial piers but they're out of my budget!) Thanks!

[Oddsocks]

Hi HAL9000

For the HEQ5 PRO the mount carrying capacity is not that great so you don't need to invest in a heavy metal plate for the pier top.

Several of the home made concrete piers I have seen have used a simple wooden plinth made from three pieces of 10mm exterior ply glued together to make one piece 30mm thick.

Very cheap to make and quite sturdy enough for the job, it doesn't need to be very sophisticated so just basic hand tools are more than sufficient.

You don't even need to make it round, a square cut plinth works just as well.

You should be able to make a wooden plywood plinth for around £25 all-in.

Even if you leave your pier outside and uncovered, as long as you used exterior grade ply and seal the finished plinth with good exterior grade boat varnish then it will last ten years or more.

The long central bolt needed to fix the HEQ5 mount to the wooden plinth can be obtained at better motorcycle spare part dealers as it is a common size used on Japanese and American motorcycles.

If possible a stainless steel bolt is preferred.

If you are determined to use a metal plate then the cheapest place to look is in your local "yellow pages" etc to find your nearest metal fabricators and have one made but I doubt you will have much change from £150.

If you don't feel your DIY skills are up to it then a good local carpenter or cabinet maker should be able to make a wooden plinth for around £50.

I did see a home made pier in Sussex a couple of years ago where the owner was making a pier for the bigger HEQ6 and had simply unbolted the legs from the standard HEQ6 tripod and mounted the tripod top to the concrete pier using some home made steel brackets cut from a piece of scrapyard angle-iron.

For an equatorial mount absolute precision with levelling the pier top is not vital because adjustment in RA and DEC angle on the HEQ5 mount can compensate for any discrepancy, so the slight variations in surface level caused by using wood instead of steel or aluminium can be accommodated.

As long as you mount the wooden plinth on long threaded studs (10mm diameter is adequate) set into the concrete to leave a gap of at least 30mm between the concrete pier top and the wooden plinth then using nuts and washers below the plate as well as nuts and washers above to bolt it firmly in place you adjust the level and you can then reach the central bolt easily with a spanner to fix the HEQ5 mount to the wood.

Hope this might have given you a few cheaper alternatives to consider that will do just as well.

William.

[Oddsocks]

I forgot to mention, if the plywood surface is rather soft the HEQ5 mount may compress the wood, "dig-in" over time and loosen.

To avoid this you can glue one or two layers of hard "formica" to the top surface of the plywood plinth, this helps to spread the load and prevents the wood compressing.

[HAL9000]

Hi William, thanks for the extensive reply! I had thought about making a wooden mounting plate (something I'm happy to do myself) but had assumed it wouldn't be strong enough after most of the photos I've seen had metal ones. Using the plywood method you've described is something I'm happy to try as it's cheap & should hopefully work. The heaviest scope I'll be using on the HEQ5 Pro is a Skywatcher 180 pro Mak (been using this setup on the standard tripod for ages & it's fine) so presumably the wood option should cope with that, & beyond visual this would mainly be for planetary imaging so can't see a problem with short guided videos. I'd like to try some longer exposure DSO photography (so far had some good results with a Canon SLR + telephoto lens attached to the HEQ5, but something more permanent & accurately aligned is the aim) I'd like to get a refractor at some point for this, which is likely to be lighter than the Mak anyway. I guess it's a case of try it & see, it might just work well!!

[Carbon]

I sandwiched some plywood for my pier plate:

[Oddsocks]

HAL9000,

I was just composing this reply when Carbon's post popped up, this is exactly what I was trying to explain, a picture paints a thousand words....

One of the reasons that metal is used in volume manufacturing is because it is relatively inexpensive to cast or CNC machine a metal object using relatively unskilled labour.

To make a wooden equivalent takes much more time, many more processing steps and demands certain craft skills that demand high wages.

For many structural engineering challenges timber will always remain the preferred option.

You need have no fear, a timber plinth at least 30mm thick will easily support the heaviest tube that an HEQ5 can accept.

Im retired now but spent forty odd years as a medical equipment engineer suspending 1,000Kg + machinery from hospital ceilings and walls via engineered timber (plywood).

In all that time nothing ever fell down, moved or even worked loose!

Good luck with the build.

William.

[Gina]

I agree, I often use wood where other people use metal. For one thing I have a bench electric 10" mitre saw whereas with metal it's a hand hacksaw. Wood is easier to machine by the DIY enthusiast than metal. It's cleaner too - no oil and no sharp metal shards or chippings. And I much prefer to work with timber than metal. Others may have more metal working equipment.

[RogerTheDodger]

I had a pair of 10mm Aluminium discs as shown waterjet cut by a chap in Scotland, cost less than £30 including postage.

[HAL9000]

Thanks everyone for all the info, I've decided to make a plywood mount as described above. If it all goes well I'll upload some photos of the finished pier, may be a few weeks before I can get it all done but hopefully in time for the darker evenings!

[Macavity]

Another advantage of wood are the many possibilities re. the hole saw.

Thanks to "down-lighting" etc., now available in useful "astro" sizes!

[bigbox]

Hi Hal9000, another alterative is to do what I did and make the mounting plate out of a car break disc...

[Daddystu]

Hal9000 is erecting a monolith and we're offering advice. Architects of our own demise?

[twintin]

Hi Hal9000, another alterative is to do what I did and make the mounting plate out of a car break disc...

Sorry to thread jack but im planning on doing the same for mine any tips or piccies?

[HAL9000]

Daddystu, it appears you are on to me! But don't worry, I'm not building the monolith on the moon or anywhere near Jupiter.

twintin - that's fine I'd be interested to see the disc brake idea too.

[Red-Dwarf82]

You should find that many mounts come with a standard or very similar base, almost unified. Altair Astro produce a pier adapter (costly option) that will fit may skywatcher mounts and some other suc as Ioptron, Celestron etc. I have a CGEM and know that the adapter for this is the same and the EQ6, HEQ5 etc. I have recently made temporary mount pier adapters out of solid Cedar, these were simply cut out using a jigsaw and holesaws and bolt holes drilled and countersunk into them, really easy. If you have access to a lathe or know someone with a lathe, the dimension can be found on the internet for making your own adapter which I will be doing shortly. http://www.nightskyimages.co.uk/eq6_dimensions.pdf

[Penguin]

This is hugely interesting. The guys at the local steam railway have said they may be able to fabricate a steel version as described in thread 145251, so long as the 'boss' allows them, but if they can't I will certainly look into this since I could do it myself. One question though, the steel plates need to have a 60mm diameter, 20mm deep recess cut into them. If I do that with 30mm thick plywood, that means the central bolt is only going through 10mm. Will that be enough or do I need a solid 30mm of plywood and then some 20mm spacers to support the mount? I'm not sure how best to explain it but hopefully my question is clear!

--- Alistair

 

 

[Penguin]

Here's my attempt then.

Hopefully father-in-law can weld something to the bottom of each coach bolt to ensure it can't twist in the concrete. A 1.5 meter length of 200mm diameter PVC tubing is on its way from http://www.amazon.co.uk/dp/B00MM31PMK/ref=pe_385721_126801671_TE_item.

Excited! 

 

[Penguin]

Thought I'd update with a link to my flickr album of the build now that it is done.

[pete_l]

Instead of using plywood (even exterior grade) you could consider making the top piece from oak. It's as hard as nails (not literally - well, not quite) and very durable. If you get a decent piece, even an offcut, it should be good for a  few hundred years.

So far as the bolts that are sunk into the concrete go, if you want to bend them for better purchase (i.e. so they can't get loose), apply a blowlamp to the place you want to bend them and heat them to red. It make it easier to bend the bars and if you bend them slowly, there's less chance they'll snap afterwards.

[Orionstar]

Does anyone have the plans for this mount  ?