The RV Forum Community

RVing message boards => Remodeling your RV => Topic started by: Heli_av8tor on December 09, 2017, 06:37:58 PM

Title: Ceiling Vent Knob Extension
Post by: Heli_av8tor on December 09, 2017, 06:37:58 PM
The vent fans in my coach have recessed knobs. With 7 foot ceilings it was all I could do to reach them. Forget it if I was barefooted.

I've seen a number of people have used PVC pipe to make a tool to reach and turn the knob. I didn't want to have to deal with another tool to stow some place.

Here's my solution.

I ordered four of these extensions from Amazon: https://www.amazon.com/gp/product/B000CSN4LC

A single screw has to go through the knob, the extensions, and into the fan mechanism.
The thread is 8-32 which is common enough, but long screws are not. I decided to fabricate the screws. (cost $1.04 for the 12" all-thread rod.)

The original setup used about an 1-1/2" extension to get into the housing. I wanted to add two of the 2" extensions to lower the knob 4".

These pictures detail my process.

Picture 1: the original fan and knob

Picture 2: I used a cutoff tool in the lathe to liberate a phillips head from a screw from my junkbox. I left a 0.075" diameter nib, 1/8" long on the head to provide centering and more surface contact area for the silver brazing.

Picture 3: Drilling a 0.077" hole in the threaded rod for the head.

Picture 4: Silver brazing the head to the threaded rod.

Picture 5: The finished extension stack. The bolt was trimmed flush with the end of the extension (about 5-1/2" after trimming).

Picture 6: The knob mounted on the fan.
Title: Re: Ceiling Vent Knob Extension
Post by: Rene T on December 09, 2017, 08:22:16 PM
Nice job Tom. Another thing you could have possibly done was double nut the end of the threaded rod and even used locktite.

You may want to reply to this post also. Members may be following it:

http://www.rvforum.net/SMF_forum/index.php/topic,110521.msg996621.html#msg996621

Title: Re: Ceiling Vent Knob Extension
Post by: Heli_av8tor on December 09, 2017, 08:41:59 PM
I thought about adding to that thread but decided to start anew.
I just put a link in the other thread to this one.
Thanks Rene,
Tom
Title: Re: Ceiling Vent Knob Extension
Post by: NY_Dutch on December 09, 2017, 08:48:15 PM
Another option for folks with limited tools would be to use a cap nut with a screwdriver slot cut into it. A drop of Loctite would serve to keep it in place on the all-thread.
Title: Re: Ceiling Vent Knob Extension
Post by: Heli_av8tor on December 09, 2017, 08:57:13 PM
That would be simpler solution. But then how would I justify my shop?  ;)
Title: Re: Ceiling Vent Knob Extension
Post by: NY_Dutch on December 09, 2017, 09:10:40 PM
That would be simpler solution. But then how would I justify my shop?  ;)


 :)) ;D
Title: Re: Ceiling Vent Knob Extension
Post by: Arch Hoagland on December 09, 2017, 10:08:25 PM
I've seen those very high vents and always wondered how you were supposed to operate them. Figured you'd have to keep a stool handy.
Title: Re: Ceiling Vent Knob Extension
Post by: Heli_av8tor on December 09, 2017, 10:46:58 PM
We have a handy dandy stool. I just hate to get it out.
Title: Re: Ceiling Vent Knob Extension
Post by: Rene T on December 10, 2017, 07:57:18 AM
Another option for folks with limited tools would be to use a cap nut with a screwdriver slot cut into it.

Is that also called a acorn nut?
Title: Re: Ceiling Vent Knob Extension
Post by: NY_Dutch on December 10, 2017, 12:13:49 PM
Is that also called a acorn nut?

Yes it is...
Title: Re: Ceiling Vent Knob Extension
Post by: grashley on December 10, 2017, 05:09:32 PM
Tom, I agree with justifying all of the toys in the shop!!!

To make sure I understand:  You started with 12" of 8-32 all thread, added a cap or head for the handle end and sleeves over the all thread to set the length.  I assume your extensions are "keyed" to the handle and the fan?

I love your idea!
Title: Re: Ceiling Vent Knob Extension
Post by: NY_Dutch on December 10, 2017, 07:15:03 PM
Gordon, the extensions Tom used are a commercial product made for the purpose:

https://www.amazon.com/gp/product/B000CSN4LC
Title: Re: Ceiling Vent Knob Extension
Post by: Heli_av8tor on December 10, 2017, 09:31:57 PM
Thanks.
You are both correct.
Tom