Dome bearing ring

[Kaptain Klevtsov]

I was chatting to my neighbour yesterday evening about his new toy. It will roll angle iron into curves or even rings. (You know, like you put on the bottom of a dome?) A couple of sketches (and bottles) later, he reckons that he could do a pair of rings, which fit inside each other and have wheels to control the side to side movement and take the weight, for in the region of £400 for a 3M diameter.

Best guess so far is (design wise) two rings with the flat side out, top ring is slightly bigger so overhangs the bottom one to help stop the rain getting in, top ring has half a dozen wheels at 45 degrees which run on the bottom ring. If they get near the outside, they ride on the vertical bit, but mostly just take the weight.

Any interest out there?

Kaptain Klevtsov

[James]

Could he do smaller stuff like rotating rings for a Newtonian?

James

[Jeff RV]

Sounds ideal KK being in steel it should be very robust, then you'll have to have some sort of anchor brackets to stop it lifting off in high wind, if I've read you right?

Jeff.

[Kaptain Klevtsov]

Will have a word this evening James. I assume we're talking industrial quality embroidery hoops here?

Jeff, it'd probably just need some bits on the bottom ring which go over the top ring. A bit like if you put a G clamp to hold it down, welded it on the bottom, then unscrewed it a bit. In fact, that would be perfect as you would have a locking system to stop it spinning round in high winds. Loosen it for use, then tighten it/them for peace of mind.

Kaptain Klevtsov

[barkis]

Aluminium angle on the menu too perhaps KK?

I might give some thought to a Dave (Centroid) type turret to do away with the roll off.

I will need to run it past the bank manager though, assuming your answer will be a yes.

Ron.

[Jeff RV]

This is how Polydome (ExploraDome) do it, only its made from plastic i think.

http://www.exploradome.us/Docs/06-2007_Wheel_Channel_Guide_Wheel_Retainer_Ring_Assembly.pdf

Jeff.

[Astro_Baby]

I'd be interested in rotating rings for a newt as well

[RobH]

I'd Certainly be interested at that sort of price KK....I'd be looking at 8 ft diameter.

Any chance of posting a sketch.

Cheers

Rob

[centroid]

Sounds like a useful 'source' KK.

I had my angle iron base ring 'rolled' and welded, by a small engineering company in Lowestoft. 1.8m dia, 5mm steel, and 'toe' in, at a cost of £100.

Steel angle iron is quite an expensive commodity now, and there aren't too many people around, who can 'cold roll' angle iron.

Dave

[HandyAndy]

Hi,

My friend had steel angle rolled but it was distorted and unuseable.

I was lucky to get a ring from an old member in my astro club. It was just a flat piece of steel in four pieces with connectors. It had five (less likely to jam) wheels running on top of the steel with five vertical rollers inside to keep it in place. It did take a while to get it to stay on but it works well.

My friend copied a design from America using rubber wheels on a wooden ring for quietness but it has always been hard to push round.

Cheers. Andrew.

[Macmarch]

There is a company down in London that would roll you a ring. they would even be able to roll one using "U" section Ali. It was an offshoot of a company I worked for. (a long time ago) I had them roll me ali angle for rotating rings for newts. Unfortunately the person who I made them for has not been in touch to let me know how they worked.

If anyone is interested, I had them rolled so one fitted inside the other then I machined them to produce right angled faces and used PTFE pads as thrust bearings/runners/. Although it isn't cheap I could be persuaded to make another set. MAX dia 17" OD meaning about 12/13" OTA. Each ring split into 2 halves and were rigidly screwed to clamp on the OTA. Further details pm me

If you want a steel ring then in order to reduce the distortion use unequal angle. Something like 1" x 3/8" x 1/8" thk hockey stick section.