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About Rusted

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    Star Forming

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  • Interests
    ATM, imaging, Solar system, photography, blogging, cycling.
  • Location
    Darkest rural Denmark
  1. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    Just another update: Shutters on:
  2. Rusted

    Obs shutter drive: winch slipping: fix ?

    10 speed bike chains are usually coated with an anti-rust finish. Colours too, if it matters. Sprockets are readily available but with a big hole in the middle, left or right hand threads and/or oddly splined. Simply Bearings [UK] lists various sizes of "pilot hole" sprockets in 1/2" pitch.. Single, double and triple. https://simplybearings.co.uk/shop/Engineering-Parts-Chains,-Links,-Sprockets-&-Platewheels-Sprockets-Pilot-Bore-Sprockets-Simplex-Pilot-Bore-Sprockets/c4713_5487_5510_5511_7747/index.html I once used a left side, bottom bracket cup [same thread as screw-on sprockets and blocks] with a small sprocket to drive a mirror making machine. Or use a whole, threaded bike hub and sprocket if you need bearing support for a layshaft.
  3. Rusted

    Obs shutter drive: winch slipping: fix ?

    The only obvious way to ensure a flat cable lay is a heart shaped cam and actuating arm with double roller cable guide. Like an old fashioned, Singer sewing machine, spool winder. The cam has to be worm geared. It quickly gets rather complicated and may not stand up to heavy cable loads. I should have added that a cable drive ideally needs a V-pinch roller for grip. That probably means one near, full turn of cable but no more. The more wrap the better but the cable cannot cross itself.
  4. Rusted

    Open-Air Pier Mount

    An open bottomed bag or cover will attract nesting birds, wasp nests and spiders. I speak from direct experience of twice removing birds nests from the base fork of my MkIV. Perhaps a net bag with a drawstring or cord around the pier would prevent such invasions? The waterproof cover can go over the top of the net.
  5. Rusted

    The Dobhouse Is Finished!

    A break-in is for life. Not just their early free Christmas. I don't have damned great steel straps across my shed doors advertising my free gift shop. My security is either invisible or subtle and multi-layered. It is based on the lifetime paranoia of constantly fearing another break-in. Insurance will never replace a lifetime's lost peace of mind. The damage is permanent.
  6. Rusted

    50/50 Roll off build

    An adjustable pier should not need much adjusting beyond early set-up. Why not cut some heavy, thick wall, steel pipe to length to go over each stud once their exact lengths are known? Use thin washers for packing if need be and lose the inside nuts altogether. Rely on the pipes being clamped down hard for their much greater area and resistance to cyclic crushing forces and flexure. The obvious alternative is to use much larger studs. Studding cost little enough up to an inch or 25mm diameter even in stainless steel or galvanized. That just leaves you with finding somebody to drill out the existing holes in your flanges to a far more useful size. It needs a sturdy pillar drill, holds downs and a very low drill speed once you get over 1/2". Though it can be done in a large enough lathe in back gear. I did some experiments using heavy 16mm studs and hefty square roofing washers to stiffen up opposing walls of a huge 1.5" thick plywood subwoofer box. A humble 3/4" chipboard shelf absolutely slaughtered the studs on killing box wall resonances. The heavy studs were only really useful for clamping the chipboard shelves in place. Not an ideal basis for avoiding flexure.
  7. Rusted

    The Dobhouse Is Finished!

    It is difficult to examine your security measures from the photograph. Nor do we know how prone your locality is to break-ins. The vulnerability of any enclosed space to the evil, crawling scum is difficult to determine from a distance. Make sure that no padlock or its hasp or loop is reachable with a bolt cutter, lever or crowbar. Nor cold spray. I like mechanical covers for padlocks because they prevent access to the highly vulnerable padlock. Check that no security screws are accessible to any driver. External strap hinges? Wood screws? Really? Use stainless steel coach screws with domed heads, square shanks in square holes in the hinges and Nyloc nuts and oversized washers inside. Check that doors and windows can't be lifted off the hinges with a crowbar. That windows are covered internally in galvanized or stainless steel mesh with externally inaccessible fixings. If you can remove the mesh from the inside of a large enough window you are probably safe from being locked in. I like roller micro-switches on doors and screeching 110dB piezo alarms in addition to all the other measures. Their contacts can be arranged not to draw any current when the door is normally closed. Guess who thought his own rural workshop was secure with a humble padlock and hasp? Guess who lost all his his electric tools and other vital stuff? I was extremely lucky not to have lost customer's irreplaceable property in for repair. My insurance company wasn't interested. Check outbuildings are fully covered and have them confirm what is covered in writing.
  8. Rusted

    DIY Dome drive & interface

    An impressive range of skills, Hugh!
  9. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    I don't know of any and I don't think they know I exist.
  10. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    Thanks! Here's some more progress: Building clad in 1/2" grooved ply. Doorway to come onto the veranda at top left [West] and on the ground floor facing South.
  11. Rusted

    PST modders - questions

    I was turned on to H-alpha on this forum so might as well stick my oar in. Be prepared to spend a lot more money than you ever imagined. First I spent hundreds of pounds on a secondhand PST just for the vital etalon and rejection filters. There must be a lot of dodgy PSTs knocking round at the moment being unloaded by equally dodgy sellers flogging cloudy filters. Be prepared to struggle really hard to separate the vital PST components without damage. Most bits are sealed with a thread locking compound! I have a lifetime of practical experience including mechanics, restoration and even plumbing. The PST almost found my limits using approved tools. I almost broke the rubber strap wrench using extra leverage. The PST's rejection filter was [typically] clouded over so that had to be replaced too by a Maier from the USA. More money! I used an old 150/8 Celestron refractor and added the PST bits on the end. It converts automatically to a 120mm F10. No extra expense but you just lost 30mm of clear aperture which you thought you'd paid for and still had to mount a great big lump of telescope. So why not choose a smaller F10 in the first place? 100mm f10 is a nice place to be. Now I needed a 90mm Baader DERF half way down the telescope tube for many hundred of pounds more to protect the PST bits and my eyes. Getting the PST components at the precise measurement is VITAL and will cost another arm and a leg. Prepare to lash out on umpteen spacers, T2 conversions and shallow, helical focusers. The high powered views of prominences and surface detail are really quite amazing. Though I was never able to use the bare PST for comparison due to the VERY obvious filter clouding. Then other projects got in the way before I was able to provide binoviewing at even greater expense. The downside IMO is that very high magnifications are unavoidable as F10 optics increase rapidly in focal, length with increasing aperture. Larger instruments @ f/10 and high magnifications need a really sturdy mounting too. My advice is to think VERY carefully about your budget and what this will means in terms of aperture. You can't leave ANYTHING out of the ABSOLUTELY VITAL filter chain unless you really want to be instantly blinded! There's absolutely no shame in being [relatively] poor and proceeding with rather more modest but achievable plans. Unfortunately my own history is one of endless white elephants but I have a lot of fun along the way.
  12. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    I checked the weight of the cladding panels at 35kg. The shutters will probably be around 50kg total. I could load the dome to see how that affects rotation. Though I expect it will just be more difficult to get going. The wheels/rollers are massively overrated for these loads.
  13. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    I hand crank driving a gear set [like a boat winch] or even having a cable wrapped around the dome might work. A counterbalance weight would allow bidirectional rotation simply by reversing the crank rotation. Plenty of room for the weight drop. Now you've got me started on the next building phase and I've not even finished the dome yet.
  14. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    Thanks & a very good question. The covering is 4mm birch ply. I suppose I could easily weigh that up since the panels are all sitting in the shed ready to go back on. Then there are the shutters and supporting rails. Followed by several layers of paint. I deliberately chose large, free turning, hard plastic wheels with bearings for the support/rotation rollers. Fingers crossed it still rotates just as easily once "fully loaded." I could add more wheels if it would help. Several cranked handles, inboard of the ring and much lower down, for easy reach, will help if I need to put my shoulder into it. It rolls noticeably more freely once it gets going. So inertia is the larger factor over rolling resistance. I'd rather avoid a mechanical or electrical drive system at first because it could easily become a project in itself.
  15. Rusted

    DIY rotating Nissen Hut or Pulsar 2.7m?

    My 3m, 10' dome being rotated by hand Scene 1 take 6:

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