MEADE IMPROVEMENTS: SADDLE


Why

This change makes the scope a pleasure to set up. It is no longer needed to fiddle around with the straps. Setup of the scope is now easily achieved with only two hands. The principle is simple, two clamps hold the tube, they can be opened like a book to insert the tube. When closed, they are so tight that the tube cannot move (rotate or slip). By merely loosening them the tube can be rotated for a better focuser position, or it can slide to accommodate a different weight distribution.

The only modification to the mount are the mounting holes for the saddle. The mounting holes are threaded.

 

Tools

Everything was made using a drill, a power saw and assorted hand tools. (Specifically I did not have access to a router) Since the Meade has a paper tube, it was important to have an exact fit. Otherwise the tube would be deformed when closing the clamps.

 

Description

The clamps are made of plywood, with an inner layer of fiber reinforced epoxy. This epoxy layer is lined with velvet to provide a smooth slide or rotation for the tube. It was foreseen to have the rubber inserts in the top clamp to provide enough friction to prevent the tube from accidentally slipping, but this proved to be unnecessary.

The clamps were made to fit (approximately) the tube by using a power saw and a file. About 2-3 mm of space was left between the (still) wooden clamp and the tube. Next the strip of velvet (that would later be put on the inside of the clamp) was attached to the tube with sticky tape. It was covered by a thin plastic foil. The fiber was put on top of this, also kept in place with sticky tape. Then the epoxy was applied. The fiber should just be drenched. After the epoxy was cured, another layer of epoxy was applied, but before it could cure, the wooden clamp was placed on top of it, so it was glued to the fiber. After this second layer of epoxy was cured, the clamp with the fiber was taken of the tube. Since the clamp was made by hand, it was not an exact fit for the fiber half-ring. It was only fixed in a few places with large holes in between. One side of the clamp/fiber was closed with sticky tape. The clamp was put on this side, and epoxy was poured in on the other side. This had to be repeated several times from both sides until there were no air-holes left between the fiber and the wood. The wood was also impregnated with epoxy. After sanding, the whole thing was sprayed black. The velvet was also taken of the tube, and glued into the clamp (it was self adhesive). The resulting fit on the tube is absolutely perfect.

The top and bottom clamp are permanently joined on one side with a hinge. On the other side they don't touch with the tube inserted, but remain separated by about 5 mm (1/5"). The snap lock on the lower clamp grabs a hook mounted on the top clamp. This hook can be adjusted in length. This allows to regulate the force by which the tube is clamped. (See below)

The whole saddle is held together by six threaded rods, which run through the clamps. There is a tube on each threaded rod that separates the clamps. The description of items on the threaded rod starting at one side is: a bolt, washer, clamp, washer, tube, washer, clamp, washer and another bolt.

Another thing to keep in mind when designing something like this for yourself is the latitude at which you will be observing. This determines the shape of the lower clamp. In the ideal case, the clamps should open along a horizontal line. Though this is not a strict requirement.

 

Costs

Even though you don't need much to make this type of saddle, costs do tend to pile up if you don't have the major items laying around. I didn't calculate the complete costs, but I estimate it at about DM 200 for the whole thing (including paint and small stuff) (Note: that makes about $100)

A tip: when you go shopping for wood, remember that you will need two half circles, not a complete circle. This means that you need less wood if you do some careful planning on beforehand. I made full scale drawings, cut them out, and arranged them so that I would waste as little wood as possible.

 

Result

From a handling point of view, the scope is now very easy to set up and use, the investment in both time and money was well worth it.