ICEINSPACE
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Waning Crescent 33.2%
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22-05-2019, 09:13 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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I knew I m not the only one
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22-05-2019, 11:42 AM
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Registered User
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Join Date: Feb 2011
Location: Kilmore, Australia
Posts: 3,343
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The table was antique before my parents got it sometime in the late 1960's, it is just like crashing and repairing a race car. A couple of decades later it is just another bit of it's history.
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23-05-2019, 08:09 AM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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What nice stories you have, once I had a motorcycle engine on the table in the bedroom. I need some thinking of what I could do with it.
http://www.astrofriend.eu/vehicles/m.../minibike.html
But now the problem are of smaller physical size.
Today I have found shims washers of steel, m40 ID 50 OD, 0.1 and 0.2 mm thickness. I don't trust these plastic shims, the old are deformed by the pressure. It will come photos later. I will keep one plastic shim on top to have it act as a spring when length of shafts changes because of temperature.
I wrote to the university where I studied once, thay had a terrific workshop. But they didn't have it anymore, I must look for a lathe somewhere else.
Everything are in progress now and I can't see any problem that I can't fix.
Lars
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23-05-2019, 08:14 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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Quote:
Originally Posted by Astrofriend
...Everthing are in progress now and I can't see any problem that I can't fix.
Lars
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That is good
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24-05-2019, 11:30 AM
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Registered User
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Join Date: Mar 2018
Location: Wollongong
Posts: 1,909
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Sounds familiar.
My dad used to repair the Kombi motor on the kitchen table. In those days there was no garage with a workbench I suppose.
Must run in the family as when I came home from school my brother had his triumph Bonneville in parts on newspaper in the lounge room.
I like the sound of onstep for the EQ6/EQ5 with belt drive. . I should try that next , having tried it on the fork. Just need to get the wireless module to work.
Quote:
Originally Posted by The_bluester
You sound like my dad bojan.
It was before I was born but my mum's Fiat 500 apparently used to do a head gasket with some regularity and he had replacing it down to a fine art, doing it on the dining table. A table which we still have and that half a century later still has marks on it to prove it where oil went in to the oak and marked out the corner of where the head was sitting one time, among other things like a clear imprint of a ball bearing.
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17-06-2019, 05:19 AM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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It's always so much to do, but this weekend I got some time to work on my EQ6 mount.
I have removed the paint on the surfaces of the lids that cover the worm gear.
You can follow the work here:
http://www.astrofriend.eu/astronomy/...ebuilding.html
To my surpise one of the surfaces was not milled, anyone else that have found that too ?
/Lars
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17-06-2019, 05:29 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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Whenever I have situation like this, I use a large enough sheet of sandpaper on flat surface.
This way the final result is close to what it would be if the paint was removed on milling machine.
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17-06-2019, 07:56 AM
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Registered User
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Join Date: May 2009
Location: Para Hills, South Australia
Posts: 3,620
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Quote:
Originally Posted by bojan
Whenever I have situation like this, I use a large enough sheet of sandpaper on flat surface.
This way the final result is close to what it would be if the paint was removed on milling machine.
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Have to agree, I have a marble cutting board that is never used as a cutting board and place a large sheet of emery paper of varying grits to get an excellent finish. Not much use for protrusions but can be manipulated to get in some tight places.
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17-06-2019, 03:27 PM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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Yes I thought about that, but then I need to find a flat surface with a hole to let the RA shaft through. But even better with a lathe, then I get the surface orthogonal to the RA shaft also.
Lars
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20-08-2019, 12:48 AM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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Now it's time for an update of my timing belt project.
From the beginning I was not convinced that I should modify my EQ6 mount and replacing the spur gears with timing belts. But I do now.
I needed some tools and machines.
I looked for a used desktop lathe but couldn't find any and the time goes on. Later a new friend offer to me to use his lathe, perfect, maybe I can be finished in time and some test later when the darkness comes back.
You can read here what I have done, also added a lot of photos to make it easier to follow:
http://www.astrofriend.eu/astronomy/...ebuilding.html
I can not recommend any to do this, better to buy a ready made kit that is just to mount. I feel it's more exiting to do things myself, maybe a sickness.
It will be very interesting to see if I get any advanteges of using a wider 6 mm belt for more stiffness and the GT2 profile pulleys that they use in 3D printers to reduce the backlash.
/Lars
Last edited by Astrofriend; 20-08-2019 at 08:14 PM.
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20-08-2019, 08:10 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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You did a very good job, I would say.
Yes, generally kits are easier to install (but as we know, anything can (and will) go wrong), but they are also much more expensive.. and they are (probably) using the same sources for components... so why not try to DIY, it is always fun.
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20-08-2019, 08:17 PM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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Hi Bojan,
Thanks for the coment.
I have a question for you, you looks to be a big DIY. Do you have any experience of 3D-printing, and maybe Carbon fiber filament?
/Lars
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20-08-2019, 09:48 PM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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I have used PLA at the beginning, and ABS ever since. Never tried Carbon filament.
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20-08-2019, 10:12 PM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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Hi Bojan,
I'm on the move to buy a 3D printer, just need to collect more information what's important.
I setup a new page with 3D related links, the last link is an info page about 3D printing and carbon fiber.
http://www.astrofriend.eu/links/link...-printing.html
See also the spectrograph, very interesting.
There must be many parts that I could 3D print and use in my telescope and others.
I start a new thread later when I have something more to tell about 3D printing and what I do. Lots of ideas in my head for the moment.
The 3D printer I'm interesting in is this one:
https://www.anycubic.com/collections/kossel-series
Maybe more safe to buy a traditional XYZ printer.
/Lars
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21-08-2019, 07:22 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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Yes, there are many thngs you can 3D print.. however you always have to keep in your mind the limitations:
- structural strength is always lower compared to injection moulding of the same material
- dimensional tolerances are usually > +/-0.15mm or even more
I usually apply post-printing machining where needed... of course that means the model must be appropriatelly dimensioned (by 0.5mm or so on surfaces to be machined)
The printer you linked is OK (price is certainly attractive)... judging by reports from some of my friends who also use similar concept (my printer is DIY, cartesian type. Firmware is Repetier, which also support Delta geometry, which is potentially capable of moves Cartesian printer cannot do ).
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26-08-2019, 04:03 AM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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I found a lot of interesting information about 3D printers. One link is about parametric CAD model of pulleys.
All links are collected here, this link is the second last:
http://www.astrofriend.eu/links/link...-printing.html
If I can 3D print pulleys with enough accuracy it's fantastic. I can then print odd dimension and teeth numbers. If it not possiblie today it will be soon.
Next time I need a gearbox or timing belt drive I will give it a try.
/Lars
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26-08-2019, 07:26 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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I was printing pulleys and gears, see here, here and here.
Parametric designs (using OpenSCAD) are a good way to go, especially because it is easy to taka care of details like tolerances where needed... And printer settings are also VERY important... Once I even needed to alter the design to get desired outcome on my printer.
Last edited by bojan; 28-08-2019 at 07:47 AM.
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28-08-2019, 07:46 AM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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BTW, this guy published VERY useful parametric designs for all sorts of gears.. I used one of them for my dobson encoder (large helicoidal sector).
Also, I used this design for my timing pulley (for encoder).. However, there was an error (IMO) in the design, the timing belt thickness was not treated in calculations as it should have, resulting in wrong teeth pitch (2.4% smaller.. I notified the author about this, and it is easy to correct the design to the pulley turns out OK).
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29-08-2019, 08:05 PM
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Registered User
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 443
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Hi Bojan,
Thanks for the links, I added them to my link list about 3D printers: http://www.astrofriend.eu/links/link...-printing.html
What filament (material) have you found that works best when printing pulleys and gears?
I have no experience yet but have read that carbon fiber filament are strong but give a rough surface. PETG I have seen recommended for this purpose.
I got the printer delivered yesterday, now I assembling it. Looks to be of very high quality, but not better then I found some small details to improve. I will setup a page about it later when I'm finished.
/Lars
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29-08-2019, 08:46 PM
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amateur
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,962
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I was using ABS for everything.. it is strong enough, but you need to know what and why you are doing.
When you need strength, you should use metal.
Carbon fibre is OK (so I am told) but it is ver abrasive, it wears nozzle (there are nozzles made of ruby for that)
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