My Alt/Az Mount build diary

[Doc]

As I now have a workshop with a Myford lathe and a milling machine I have decided to make an ALT/AZ mount capable of taking my 5" triplet refractor. I drew up quite a few plans and decided on a mount similar to the disc mount idea.

It's basically a 6" cube with an opening back panel that will allow access to the azimuth and altitude shafts so they can be tighten to allow the correct friction to be maintained via the 5" discs of PTFE.

The next step will be to bore the holes in the side for the bronze bushes.

Until next time......

 

 

 

 

[Stu]

Looking good! Always thought it possible to make something better than those on the market so I'm looking forward to seeing your progress.

[Doc]

Thanks Stu, it's made out of 1" thick aluminium so pretty strong. I have owned many mounts over my time so have quite a lot of experience in comparing different models.

 

 

 

 

[happy-kat]

Loving the visual aesthetics of the cube. 

[Stu]

25 minutes ago, Doc said:

Thanks Stu, it's made out of 1" thick aluminium so pretty strong. I have owned many mounts over my time so have quite a lot of experience in comparing different models.

 

 

 

 

I think if you can get the smooth functioning right depending upon the side to side balance, and also the ability to fine tune the tension you are most of the way there. 5" PTFE discs should sort the tension part anyway  

[John]

I'm looking forward to following your progress on this - I love alt-az mountings and have considered many options for my 130mm F/9.2 triplet frac. Currently a Skytee II does the job but I'm always interested in other solutions

[Doc]

I was one of the very first owners off the Losmandy AZ8 John, when it first made an appearance and it's a great mount but I've always wanted to build my own so am going to give it a go, hopefully I can get it to work and be a great mount. If it works I'll fit encoders to it as well.

 

 

 

[Doc]

A few more photo's...

The altitude disc was turned on the lathe. The finished size was 5.250" x 1" thick. The plastic disc is made from 6mm UHMWPE which is supposed to be a plastic with a very low coefficient of friction so I gather should work on this mount.

The other disc was turned on the lathe and then with the M10 bar inserted the plastic was sandwiched between the tow and all trimmed to size. A 10mm hole was drilled into the centre of the cube and the disc secured to the cube. At a later date the 10mm diameter threaded bar will be replaced with a 1" stainless steel shaft and bronze bush.

Close up view of discs and friction plates.

Showing the bush that will be fitted once the cube has been bored.

All connected up.

That's it for now......

[Stu]

Looking very nice Doc! I envy your metalwork skills!

[Doc]

Thankyou Stu, this is the first time in 30 years since my apprenticeship as a turner that I have touched a lathe so pretty happy with it so far, it's like riding a bike, you never forget.

[John]

Very interesting

[Doc]

A little bit more work done.

The bush is 1 1/2" x 1" x 1 3/4" in size and the hole was bored out in the milling machine as the parts are to big for the lathe. The bush was then pressed in using the vice. The shafts are only aluminium at the moment but once it's all working I'll remake in Stainless steel.

I then made up some thumbscrews for the back panel. I undercut the threaded shaft so the thumbscrews will not be lost.

That's the Altitude axis done, the next job is the Azimuth axis.

Until next time.

[Doc]

Forgot to take photo's of the process but did manage a few at the end.

Both axis have been done now. Feeling very smoooth and cannot feel any play at all. 

View from the back. All I need to do is remove panel via thumbscrews and adjust with a 19mm spanner. I'm going to make or buy a thin 19mm spanner and stick inside with magnets.

View from the front. Next is the riser, I think I'm going to need at least 10" to make refractor viewing comfortable. There are a few scratches and marks on it that will need rubbing and polishing out. Unsure of what finish to have on it, either polish to shine, paint, powdercoat, anodised, or plastic dip.

Until next time.....

 

[Stu]

Beautifully simple doc. Do you think you will need a counterweight at all?

[Doc]

I don't think so Stu, but I will know more once I've set it all up with the scope. The Esprit 120ED is a heavy scope so we will see.

[Stu]

Just now, Doc said:

I don't think so Stu, but I will know more once I've set it all up with the scope. The Esprit 120ED is a heavy scope so we will see.

Should be good, look forward to seeing the results

[Doc]

A few more photo's....

Made a 10" riser for the mount. I had so many plans in my head but settled on this one. It's really strong and there is no flex in it at all.

I already have a few saddles so will adapt one of them and then mount the scope.

That's it for now.

 

 

 

 

 

[Doc]

Well here it is....

No need for counterweights, lovely and smooth, stays put while swapping from large to small eyepieces, and good to look at.

Takes the weight of the Espirit so easy, I would imagine an 6" triplet would be a breeze.

Just need to sort out encoders and paint job.

Also going to get a Berlebach Planet tripod for it.

 

 

 

 

[John]

Lovely job !!!

Can you make another one ?

[Starlight 1]

Looking at post all week, so time say nice looking mount love the rat cage look.

[Doc]

Thanks guys.

To answer a few questions I would say the mount has taken me about month to make, and has cost me in materials about £300. I have just condensed it into a week of photo's.

[Stu]

Brilliant! A job well done I would say.

How much does it weight, just out of interest?

[Doc]

Not sure Stu I'll weigh it over the weekend.

[happy-kat]

Looks very impressive.

[Doc]

On 13/10/2017 at 20:18, Stu said:

Brilliant! A job well done I would say.

How much does it weight, just out of interest?

Just weighed it and it is 13.9 Kg or 30.6 Ib or 2.2 stone