Lightbridge base mods

[Carbon]

I just competed a couple of mods to the base of my 12" Lightbridge.

To improve the altitude motion I modified the base by removing the original felt strips and replacing them with teflon pads, and adding pebbled laminate strips (ebony star substitute) around the stock alloy bearings. The base cradles needed to be widened slightly to accommodate the additional thickness of the teflon and laminate. In the process I chopped off about 3" off the top of the base. The altitude motions are now butter smooth.

I also drew degree circle marks directly on the ground board, made a cutout on the upper board, and installed a movable pointer. A small LED reading light will be installed over the pointer.

Thanks for looking!

[swamp thing]

Nice job.

Did you find the altitude sticky, out of interest before?

[Carbon]

Nice job.

Did you find the altitude sticky, out of interest before?

Thanks. The altitude had some stiction and the bearings had some gouge marks from grit making their way, waxing helped, but I wanted something smoother.

Eventually, when time allows, I plan on constructing a smaller and lighter base out of birch plywood and correctly radiusing the bearing cradles instead of the plain and easy V cuts.

George

[Bart]

Nice job. Like it.

[Carbon]

OK....so I plan on sizing down the base now. I find the ground base boards to be overly large so I will trim them down resulting in a much smaller footprint.....basically down to the size of the rocker box. I will also add metal braces to beef things up a bit as there will be less material under the rocker box. I also ordered a set of 2" wide round rubber feet for the down sized ground board.

The degree circle will have to be modified as well.

I decided to 'butcher' the base after transporting my scope to a local star party last weekend and realized the base took up a lot of space in my vehicle. Why such a large 25" diameter base for a 12" scope? I realize it's press board and all that extra material helps but I think it could be trimmed down without losing structural strength.

I will update as work progresses.

[fwm891]

Its that diameter for stability during viewing. Bringing the diameter down will make transport easier but you viewing will be less steady, certainly if you push the mag with short eyepieces or barlows. Make a better base than that supplied but don't you think the manufacturer would reduce the size to a minimum if possible...

[JamesF]

I have wondered about the possibility of designing a "fold up" base where a transportable version is required. I can't believe it would be that hard. Even it it required half a dozen nuts to be done up hand-tight to give the necessary stability it has to be easier than getting a fully assembled mount into the average car.

James

[fwm891]

Why not bolt the 'box' to the circular base when you get to your observing site, you can transport the discs on their edges. Put a square of material inside the 'box' to keep it rigid and bolt that to the top disc...

[Carbon]

Its that diameter for stability during viewing. Bringing the diameter down will make transport easier but you viewing will be less steady, certainly if you push the mag with short eyepieces or barlows. Make a better base than that supplied but don't you think the manufacturer would reduce the size to a minimum if possible...

True. But if you look at most commercially available high end dobs out there, say 10" and up to whatever, their ground board foot print is no wider than the size of the rocker box. They seem to be plenty stable enough.

I think manufacturers that use press boards have to use more material to take into account potential damage from moisture, for instance, which can weaken joints and so forth.

We'll see what happens.....I already began chopping the base down to size this morning.

[Carbon]

I have wondered about the possibility of designing a "fold up" base where a transportable version is required. I can't believe it would be that hard. Even it it required half a dozen nuts to be done up hand-tight to give the necessary stability it has to be easier than getting a fully assembled mount into the average car.

James

I would imagine a fold-up base wouldn't be too difficult to build, but I wouldn't use press board for that.....with the constant bolting and unbolting of parts. Hardwood plywood would fare much better and last much longer.

[Carbon]

Here's an update:

Ground board diameter was reduced from 25" down to 20" in diameter.

Those large knobs on the rocker box are for the wheelbarrow handles so I can wheel the fully assembled scope in and out of my storage area. The handles attach and de-attach in under a minute.

I also attached a ball knob on the upper tube assembly for maneuvering the scope.

I tested the new base last night and it was rock steady. And with the scope aimed at near zenith the base gave me more toe room without accidentally kicking the base which I did before on several occasions.

I'm sure I'll come up with more mod ideas as I use the scope.

[Carbon]

Here's an update on some additional butchering I did with all the excess material that came off of the stock base.

[JamesF]

That's an awful lot of bits

James

[Carbon]

That's an awful lot of bits

James

I can now move the dob in and out through the obs doorway easily.

[iamjulian]

I would absolutely love to do this, but taking a saw to something I spent £700 on makes me nervous I admire the people who have courage to give things a try. I suppose the mount isn't the expensive bit anyway. Extra tempting as I currently have to tilt my base to fit it through the door frame to get outside. Hmmm.

[Carbon]

I would absolutely love to do this, but taking a saw to something I spent £700 on makes me nervous I admire the people who have courage to give things a try. I suppose the mount isn't the expensive bit anyway. Extra tempting as I currently have to tilt my base to fit it through the door frame to get outside. Hmmm.

Well, I've 'butchered' many things in the past to make them smaller, lighter, and sleeker.

This includes Brooks bicycle saddles too. I've butchered over a dozen of them.