Doc Posted October 22, 2012 Share Posted October 22, 2012 They are made out of a shaft which has a 50mm diameter base and two countersunk holes to attach to the dob, the shaft is 55mm in length and has a 6mm thread in the end so I could attach a knob to hold the counterweights down. The weights are hydraulic couplings and are 76mm in diameter and 35mm in length. I had them turned down to 27.5mm in length so two can fit onto the shaft. I then had a 15mm hole drilled through the middle so they can be fitted onto the shaft. I have ordered a 50mm x 5mm thick rubber gasket which I hope will take up the circumference gap caused by the 14" diameter tube I am fitting this to. Here are some photo's. I will take a photo of it connected to the dob as soon as the rubber gasket has arrived. This is before any machine work. And together with the 6mm knob attached. Link to comment Share on other sites More sharing options...
Craig Posted October 22, 2012 Share Posted October 22, 2012 Very neat. Link to comment Share on other sites More sharing options...
philjay Posted October 22, 2012 Share Posted October 22, 2012 Nice machining there Mick That looks spot on, a bit of paint on the machined ends will stop them rusting Link to comment Share on other sites More sharing options...
catman161 Posted October 22, 2012 Share Posted October 22, 2012 Nicely done there mick as usual. Very tidy indeed Link to comment Share on other sites More sharing options...
Doc Posted October 22, 2012 Author Share Posted October 22, 2012 Yes Phil the machining is rather neat And the paint idea is already noted and on the list to do. Link to comment Share on other sites More sharing options...
Sheila Posted October 22, 2012 Share Posted October 22, 2012 impressive, makes me feel pretty useless LOL Sheila Link to comment Share on other sites More sharing options...
Doc Posted October 22, 2012 Author Share Posted October 22, 2012 impressive, makes me feel pretty useless LOL Sheila I can't make impressive cakes Sheila Link to comment Share on other sites More sharing options...
Brantuk Posted October 22, 2012 Share Posted October 22, 2012 I need some cakes to counter balance my dob lol Link to comment Share on other sites More sharing options...
BAZ Posted October 22, 2012 Share Posted October 22, 2012 Nice job, as always Mick. Would they have to be rock cakes then Kim? Link to comment Share on other sites More sharing options...
Rusty Strings Posted October 23, 2012 Share Posted October 23, 2012 Nice one Mick, I'm interested to see how they're attached to the dob. The cake counterweight idea is one that should be explored Link to comment Share on other sites More sharing options...
Doc Posted October 23, 2012 Author Share Posted October 23, 2012 I'm in the process of making a concave rubber washer to fir the radius of the dob, then it just bolts down. Simples. Link to comment Share on other sites More sharing options...
8472 Posted October 23, 2012 Share Posted October 23, 2012 Nice work. Intrigued to see how they are going to go on your scope, though. Link to comment Share on other sites More sharing options...
Doc Posted October 24, 2012 Author Share Posted October 24, 2012 Part 2 Could I find a concave washer big enough, the answer was NO. So I bought a 10mm thick rubber washer and tried to make it concave and guess what I made it look like a dogs dinner So I came up with a ingenius idea to make one from insulating tape. By cutting strips and working from the inside outwards and making the outer edges thicker I made my concave gasket. Next was to take the tube of the mirror ring and mark out the holes, I then drilled holes to accomodate the screws. I then screwed the shaft down and cut of any access rubber that got squashed out, now there's no rocking and no visible gap. Here's a photo with weights in place. Put it all back together and tested the balance, nearly perfect with my monster UWAN eyepiece. The finished article, all in all a fun mod and very simple. Link to comment Share on other sites More sharing options...
philjay Posted October 24, 2012 Share Posted October 24, 2012 Ya cant beat a bit of insulting tape. Nice job Mick Link to comment Share on other sites More sharing options...
catman161 Posted October 24, 2012 Share Posted October 24, 2012 Awesome work there Mick. Proper DIY Link to comment Share on other sites More sharing options...
Cazz Posted October 24, 2012 Share Posted October 24, 2012 Very clever idea, nice job. Link to comment Share on other sites More sharing options...
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