Posts for the month of February 2020

Blinds Tilt Mechanism Repair

We have a large faux-wood blind on our dining room window. The window pane itself is 70"x70"; which makes for a great view. However, the tilt mechanism stopped working in fairly short order. The tilt mechanism uses a pull-cord based mechanism which is no longer offered in blinds. I replaced the mechanism the first time it failed, but when it failed the second time in much the same way, I could no longer find a replacement for the parts. The original mechanism failed because the interface between the cord spool and the shaft driving the worm gear which drove the tilting of the blinds had worn, become loose, and allowed the cord spool to rotate without turning the worm gear shaft. The replacement mechanism failed in a different place; it had a bushing to adapt the sqare rod that runs the length of the blinds to a hexagonal through-hole in the driving gear. That bushing was made of plastic and had worn to the point that the drive gear could rotate without rotating the square rod.

The original tilt mechanism was made largely from metal components, while the replacement I had purchased was largely plastic. Examining them both, I determined that it would be more straight-forward to machine a new pully for the original mechanism than to machine a drive gear for the replacement mechanism. The original pully was made of nylon; I chose to machine a replacement pully from aluminum bar stock.

Cutting the main profile of the spool body:

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And the conical recess in the spool:


Cutting the spool off the stock:

4-cutoff-conical.jpg 5-cutoff-flat.jpg

Milled the slot for the worm gear shaft and the holes required for the threading the pull cord through:

6-milled-slot-conical.jpg 7-milled-slot-flat.jpg

Installed in the blinds:

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This has held up well over the past 8 months, and it was gratifying to be able to repair something when replacement parts were no longer available.