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Old 12-08-2019, 06:44 AM
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Now about stops or "clicks"....
I decided to start with hex spacer with M3 thread.
I have steel balls ๘3.2mm, so all I need to do is to widen the hole to ~๘3.3mm ~6mm deep, then cut M6 thread ~3mm long and cut the spacer to 10~12mm.
The assembly as pictured below (without ball and spring) will be screwed into platic holder at apprppriate position, then it will be used as guide to mark the position of the rotary part with drill so the ball can click into the recession and the eyepiece tubes are properly aligned.
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Last edited by bojan; 12-08-2019 at 07:00 AM.
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  #22  
Old 12-08-2019, 08:32 PM
Wavytone (Nick)
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Ah... Bojan I think these will be OK at first but with use the plastic will rapidly wear an the click stops will go soft and possibly a bit off-centre.

Someone muttered that its possible to print now in an aluminium alloy of some sort (my guess its sintered or something to get it to bond properly). That would produce a better result esp if you could sooth the surface a tad - a careful hand job with grade 600 wet & dry paper (used wet) would probably produce a reasonable finish.
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  #23  
Old 13-08-2019, 06:22 AM
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Quote:
Originally Posted by Wavytone View Post
Ah... Bojan I think these will be OK at first but with use the plastic will rapidly wear an the click stops will go soft and possibly a bit off-centre.

Someone muttered that its possible to print now in an aluminium alloy of some sort (my guess its sintered or something to get it to bond properly). That would produce a better result esp if you could sooth the surface a tad - a careful hand job with grade 600 wet & dry paper (used wet) would probably produce a reasonable finish.

Good point... but printing with aluminium (or any metal) is way beyond the capabilities of my DIY 3D printer....
I saw such printer in CSIRO Clayton, Lab22... amazing experience.



However, now that you put a bug in my ear, I can place metal shim on the ball path to avoid the scenario you descibed.

One thing I do differently (I think..) from other 3D-printers is I always try to combine techologies to mitigate inherent weakneses of printed ABS (printing time, mechanical strength..).

As another example (apart from ball-spring assembly), I am using ๘6mm PVC rod as shaft (in 3x turret), inserted into machined hole and secured (and glued) with M3 rod (cutoff from m3 screw). Initially I wanted to use brass standoff, which is still in consideration as this 3x turet is preliminary model.. turned out too well not to be used for a while.
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Old 11-09-2019, 07:25 PM
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Printer works again (problem was with dodgy temp sensor connector), now experimenting with printed stops.... looks very promising.

And easy to replace if broken.
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Last edited by bojan; 11-09-2019 at 08:04 PM.
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  #25  
Old 18-09-2019, 11:51 AM
Wavytone (Nick)
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Bojan... here’s another DIY effort FYI https://www.skyatnightmagazine.com/h...epiece-turret/
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