Step by step

Step 1

Measure the gap between the bolt holes on the top of your tube rings. Attach masking tape to the new dovetail clamp and transfer this measurement to the clamp, centring it both longitudinally and laterally. Work out the thread size in the tube ring bolt holes.

Step 3

Drill and tap a 6mm hole, 65mm from one end of the dovetail bar. Do a trial fit of the counterweight to the dovetail bar with a 6mm bolt, washer and Nyloc nut. Shorten and tidy up the thread on the bolt to ensure that it doesn’t protrude through the dovetail bar.

Step 5

Align the dovetail clamp with the top of the tube rings and do a trial of bolting the two together, making certain that the bolts are not long enough to pass right through the tube rings. Shorten and tidy up the bolt threads, then refit the bolts and tighten them.

Step 2

Drill and countersink two holes with a diameter of half a millimetre greater than the bolt size, in the marked positions on the dovetail clamp, ensuring that the holes are vertical. Use a vertical drill stand with a wood block placed under the clamp.

Step 4

Set the mount in its ‘Park’ position with the counterweight(s) down and the scope pointing up, and slide the counterweight(s) down the counterweight bar away from the scope to make the weight side heavier. It’s now safe to add weight to the scope side.

Step 6

Slide the dovetail bar with the balance weight attached into the dovetail clamp, placing the weight on the side that needs to be heavier to attain declination (dec.) balance. Adjust the balance bar until the dec. axis is balanced, and then balance the RA axis.