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Old 18-05-2022, 06:28 PM
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Bassnut (Fred)
Narrowfield rules!

Bassnut is offline
 
Join Date: Nov 2006
Location: Torquay
Posts: 5,005
Today, drive for the slot door.
Rack and pinion is easy for a ROR, straight rack cut to length and a gear to match.
Curved rack for a dome is a bit of a problem, Id hate to think what a custom diameter curved rack would cost. I see flexible rack for sale but for huge money, and it seems to me the spec would change the more it was curved.
Anyways, i thought id post this update as its as it solved a problem unique to domes. And I havent seen this solution on the net.
ABS 3d printing is not suited to small engineering mechanical parts, so I made the rack and gear big and chunky. The gear goes onto a 6mm gearbox shaft with a flat. That would last 5 seconds before stripping the ABS and spinning. So I alradited a metal knob with a grub screw in it into the gear, so strong.
Ill use the same rack but a different diameter for the dome drive. The rack was printed in sections (size the printer can take)that can be easily be bolted together. Those segments BTW can be printed by many 3D shops in OZ in 5 days for about $10ea. I will use about $50 in ABS stock on rack and pinions for the whole project. The $20 motor/gearbox from ebay in the pic also has an encoder attached, so if something goes wrong whilst opening /closing the controller will know immediately and alarm.
Attached Thumbnails
Click for full-size image (Rack and pinion A v8.jpg)
138.9 KB45 views
Click for full-size image (Door rack and pinion.jpg)
157.3 KB71 views
Click for full-size image (Slot door gearjpg.jpg)
188.8 KB78 views
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