[Heathkit] What is a Harmonic Drive Part # 467-1?

[jeremy-ca]

Thanks for all the answers. This one is all plastic including ths skirt and 
it was sold about 10 years ago from the former Heath guy who had a big 
stash.

Carl
KM1H



----- Original Message ----- 
From: "Chris Codella, W2PA" <w2pa at arrl.net>
To: "Heathkit Reflector" <heathkit at mailman.qth.net>
Sent: Monday, September 03, 2007 9:11 AM
Subject: Re: [Heathkit] What is a Harmonic Drive Part # 467-1?


> Bob is right.  The whole thing is platic.  The knob itself snaps onto the 
> knob housing.  The knob skirt is simply decoration that covers the dark 
> green plastic skirt.  The skirt doesn't actually rotate when fixed 
> properly.  No amount of fiddling with it would eliminate the backlash for 
> me.  It's not really backlash (which usually means the dial snaps back in 
> the opposite direction from the way you've been turning) - it's more like 
> "play" or "slippage", where, after tuning in one direction, tuning in the 
> opposite direction produces no effect for a little ways.
>
> It goes together like this (working outward from the front panel): dark 
> green housing, then decorative metal skirt, then flexible inner spline 
> gear with the "cup" pointed toward the front panel is slipped over the 
> shaft and the inner, toothed part of the housing, then the knob is snapped 
> onto the housing by just pushing it in.
>
> Quite a few people (including me) replaced this drive with the one that 
> Swan used on their transceivers.  It's basically the same kind of drive as 
> is used on the HW-101, but has an extra outer knob-ring that you can grab 
> and rotate for a 1:1 tuning rate.
> 73,
> Chris, W2PA
>
> Bwana Bob wrote:
>> The Harmonic Drive was the original vernier tuning drive used on the 
>> HW-100. It was only used on this radio. It was a very simple mechanism 
>> with a plastic flexible spline gear that attached to the VFO capacitor 
>> shaft. The internal teeth on the spline gear meshed with teeth on the 
>> outer knob housing, which was fixed to the front panel. Cams on the 
>> tuning knob pushed against the spline causing it and the VFO shaft to 
>> rotate. It was reliable, but tended to have a lot of backlash unless one 
>> tinkered with it. When Heath replaced the HW-100 with the HW-101, the 
>> dial drive was replaced by a more conventional set of series-connected 
>> planetary ball drive ("Jackson Drives"). Heath published instructions for 
>> converting an HW-100 to an HW-101. This involved some pretty extensive 
>> rework.
>>
>>                     73,
>>                     Bob WB2VUF
>>
>> jeremy-ca wrote:
>>> Its a knob with a seperately rotating skirt but I'm missing the intended 
>>> application nor do I understand how it works!?!
>>>
>>> Carl
>>> KM1H
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