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kbrown

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About kbrown

  • Rank
    Star Forming

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    London
  1. This is not going to help at all but I think you have used the wrong kit if you used the one in the link. The M10 bolts are 1.5mm pitch. Not 1.25mm. That would explain why they failed.
  2. Oh dear. The threads on my NEQ6 aren't in a very good shape either. I was going to fix them with helicoils like you have done but now I'm having second thoughts. Following this thread with interest. Maybe a time-sert or a big-sert (oversized time-sert) would work (I've never used them):
  3. kbrown

    DIY Refractor

    Finally got all the parts done and assembled to get this in a working order. Turns out the focal length is more like 500mm. Remains to be confirmed when I get to do some astrometry. I had the objective fully AR coated too (all four surfaces) . I also took the easier route and bought a 2" star diagonal rather than making one myself. That actually extended the optical path a lot more than anticipated. But I managed to find a sweet spot in the tube length so I can easily switch between visual and imaging use. The OTA weighs just under 1400g without the finder and star diagonal. Should be ok with my star adventurer even with a CCD and accessories. Can't wait to get to test this
  4. kbrown

    3D Printers

    I put off getting a 3d printer for years. I just though I don't really need one since I already had a CNC router/engraver that I've successfully used to "mill" rather complex plastic, aluminium and even stainless steel parts. Then little by little the idea of getting a 3D printer overwhelmed my resistance and I finally got a Prusa i3 Mk3 kit. Now on hindsight I'm thinking why didn't I get it sooner. There's been so many things small and large that I've done with it and I get a new idea almost every day
  5. James is right about the insufficient control over the camera. I have an RPi compatible Arducam module which is also Sony IMX219 based. I don't think it can do more than about 6 second exposures. Also controlling exposure, gain and white balance etc is a bit convoluted to say the least.
  6. kbrown

    Dec backlash

    I've had my fair share of problems with my NEQ6 Dec axis. The number one source of play has been the worm meshing adjustment. It can be very fiddly and take several iterations to get right. Some times less than an 8th of a turn on the adjustment grub screws makes the difference. But of course if your worm shaft has axial end play then that should be fixed first. The locking ring might be secured with loctite and might require a bit of local heat to get it moving freely. A small gas torch is good for this but you don't want to over do it. You don't want to burn the rubber seals on the bearings... Might not be a bad idea to replace the bearings with new ones, clean the threads etc. The bearing on the opposite side to the locking ring should be leaning against the black cap thingy and like stated before the locking ring needs to be tight enough to take out any slack but no more than that. Another unexpected source for backlash / play on my DEC axis has been the clutch lock. I guess mine is a little worn and the lever wanted to go further than 90 degrees to engage. This made it harder to lock the clutch properly so I just unscrewed the lever and turned it a couple of notches back to have more leverage.
  7. kbrown

    Broke my NEQ6 Pro

    Yay. Got it back together with helicoils. They're amazing. Used a 1.5D size for the deeper blind hole (screen right on the pic) and 1D sizes for the other three. Was a bit nerve wrecking to manually drill the holes as I don't have a drill press. The 6.3mm HSS drill bit in the kit cuts the aluminium like butter. Was a little easier after I first drilled them to 6mm. Bit of cutting oil helped too. Drill press would have helped to get the tap in straight too but I managed to do that manually too. Not really necessary but I used a drop of loctite to secure the helicoils before putting the mount back together again. Oh, and the backlash is gone now too
  8. kbrown

    Broke my NEQ6 Pro

    The play / backlash came from slightly loose worm adjustment (worm too far away from gear). For some reason the DEC axis has been problematic in my mount. It's really fiddly to get right without binding in a position or another. This is what I was playing with when the bolt thread stripped. The RA axis does not suffer from this and performs perfectly.
  9. kbrown

    Broke my NEQ6 Pro

    Thanks for the links! I bought this mount used and the first time I opened these bolts when I did the belt mod they were super tight. Had a look at the threads and they didn't look very good. Part of the damage was probably already done...
  10. kbrown

    Broke my NEQ6 Pro

    I did think about this and may still get back to it. The problem is the heads of the bolts are in a recess in the housing: Don't know if I can find M8 bolts whose heads would fit in there. There might be enough space if I left the heads outside the DEC axis housing and put big and strong enough washers under them...
  11. kbrown

    Broke my NEQ6 Pro

    Are you perhaps referring to time-serts? Had a look at them but the kits are super expensive...
  12. kbrown

    Broke my NEQ6 Pro

    So it finally happened. The thing that I've been fearing for a while already. In an attempt to minimise the backlash my DEC axis had developed I had to loosen and tighten the four M6 bolts on the housing one too many times. One of the threads stripped completely and the other three don't look very good either. My initial thought to get me out of the trouble is to use helicoil thread repair inserts but having no previous experience with these I'm a little scared of putting them in. Three of the holes are through holes with maybe about 6mm wall thickness. Is this enough for the insert to work? The fourth hole is a blind hole with probably enough depth so I can break off the tab on the helicoil once it's fully inserted. On the same note I noticed the latitude bolt threads on the mount are quite loose and manky too. Thinking of giving them the same treatment before the worst happens. Has anyone here done this sort of thing before?
  13. Thanks a lot. This would be purely for educating myself more in the subject out of interest. I work in completely different field full time (although wouldn't mind a career change... as if :P).
  14. Been looking at this every now and then and thinking I might be able to fit this in my life. Can anyone recommend it or maybe tell me it's not worth the time and financial commitment? https://www.ucl.ac.uk/physics-astronomy/study/certificate-astronomy
  15. kbrown

    The ED 66 Project

    Can I have your workshop, please? :D Great job so far! Wish I had a proper place to do my work in. My flat is becoming increasingly inhabitable with my projects
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