The Malletweight. An extra 400g counterweight for a Star Adventurer Pro.

[savcom]

I have tried and failed to balance my Altair 72mm with camera on my Star Adventurer Pro with the supplied counterweight, so I decided to add another counterweight.  Looking at the cost of additional weights I thought I could do better for less, so to speak, so I set about looking for an additional 4-500g weight and working out how to add it securely to the shaft.

I'd caught sight of someone else who had managed to balance their Skywatcher Evostar 72ED using a mallet head, so decided to use that as my solution.  Here's what I had to do to make one.

First step is ordering the mallet, of course:

Next was to fit it.  Easy!

No.  Seriously, I did make a slightly better attempt at this....

In short, you need

• a 400g mallet (mine was 60mm in diameter)
• a 70mm M6 coachbolt, an M6 metal washer and an M6 nut.

First step is to cut the handle of the mallet off

The counterweight shaft on my Star Adventurer Pro measures 12mm diameter and is threaded with an M6 thread, so the next thing I did was take some measurements, I measured how much of the 70mm coachbolt was left protuding when it was fully screwed into the counterweight shaft on the Star Adventurer.  The answer was 55mm, so the length of the threaded shaft is 15mm.

After this, I drilled a 6mm hole right through the mallet head and widened the wooden handle end to 12mm to a depth of 12mm to allow for a washer and nut to sit on the coachbolt fixing it to the counterweight.  This left me with a 15mm length of thread from the coachbolt which serves nicely to attach the counterweight to the Star Adventurer Pro.  The end of the shaft goes into the counterweight by about 5mm ensuring a good, solid finish.

Then all that's left is to assemble it:

Final picture is of the new weight (the 'malletweight') against the original 6mm bolt and washer.

Now looking to test all this when it's next a clear night.

Total cost?  £5 for the mallet and 45 minutes to think through and assemble.  The coachbolt was left over from a previous project and the nut and washer were from my spares drawer.  A drop of black paint on the exposed handle end will finish it off when I'm next in the workshop.

This picture shows the new Counterweight against the M6 bolt and washer that were originally fitted.

 

Edited November 21, 2021 by savcom
Correcting two typos.

[Peter Drew]

I bet Timmy was impressed if he saw it!    🙂

[bomberbaz]

nice improvisation, I may be pinching that idea soon.