[ARC5] Fwd: Spline Adapter

[Phillip Carpenter]

> From: Phillip Carpenter <carpenterpa at tds.net>
> Date: October 29, 2014 at 11:58:06 AM EDT
> To: "kgordon2006 at frontier.com" <kgordon2006 at frontier.com>
> Cc: Mike Everette via ARC5 <arc5 at mailman.qth.net>
> Subject: Re: [ARC5] Spline Adapter
> 
> The easiest way to install the spline adapter listed on eBay is to temporarily remove the front panel from the ARC-5 receiver.
> 
> This requires drilling out eight small aluminum rivets, two on each lower side and four in the front middle section, then remove nine screws from the panel's rim and ten on the front, unscrew the tuning dial disc nut, remove the tuning dial disc, and slide off the front panel. Now you have access to the spline.
> 
> Slide the adapter shaft onto the spline shaft, tighten the two set screws (apply Locktite if you like), slide the front panel back on by slipping the new shaft through the ARC-5 shaft sleeve, snap the front panel back in place, replace all the screws, replace the tuning dial disc and nut, pick the knob of your choice that accepts a standard 1/4" shaft, put it on and tighten its set screw, and your ready to go with no backlash or slipping!
> 
> Takes some work but the benefits of having a nice, solid, permanent shaft are worth it.
> 
> This shaft fix is not for the purest. It's for the homebrewer, experimentalist, and those who don't mind taking some effort or don't mind net having a completely stock military ARC-5 receiver.
> 
> Hope this helps!
> 
> Phillip
> 
> Sent from my iPhone
> 
>>> On Oct 29, 2014, at 11:09 AM, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
>>> 
>>> On 29 Oct 2014 at 7:46, Mike Everette via ARC5 wrote:
>>> 
>>> I don't have a receiver handy at the moment to check this, but thought the
>>> couplings had pins in them to prevent rotation.  Take a careful look at the
>>> front side of the receiver panel, at the flange on the coupling.  Should be what
>>> looks like two pins.  If so, they would have to be driven out.  Maybe then the
>>> coupling could be unscrewed.
>> 
>> Yes. Actually, that coupling can be unscrewed withOUT removing the two 
>> small pins, although doing so wrecks the pins and leaves marks on the front 
>> panel. Although I have never done this, several of my derelict receivers had 
>> had that done to them before I got them. I was not pleased.
>> 
>>> the spline.  The coupling nut from the cable was slipped back over the spline
>>> and a 1-1/4 inch knob attached to the shaft.
>>> 
>>> Yes, I did try out one of the cables before the surgery.  With a right angle
>>> adapter on the receiver, you wouldn't believe how much effort it took to crank
>>> the control head.  So much for precision tuning....
>> 
>> To me, all this is too much work, and the result is "marginal". For one thing, 
>> the original tuning devices, even when used like you have done, result in 
>> considerable back-lash in the tuning. FYI, Fair Radio Sales sold thousands 
>> of such adapters which were made exactly as you have done.
>> 
>> The original tuning keys also exhibit what to me is unacceptable back-lash.
>> 
>> There is a LOT of slop in those fittings where they fit over the spline, yet the 
>> gearing to the capacitor from the spline includes anti-backlash gears.
>> 
>> The far more simple adapter I arrived at is, to my mind, far less trouble, and 
>> far more useful, and furthermore, it preserves the anti-backlash capability of 
>> the original tuning mechanism.
>> 
>> About 1" of hard, brass, 1/4" diameter tubing, with two 1/4" long slots cut into 
>> the spline end, a good knob attached to the other end, then carefully driven 
>> over the spline precludes all the other folderol and preserves the 
>> anti-backlash tuning.
>> 
>> My adapter exhibits zero back-lash, is cheap, and easy to implement.
>> 
>> I'm a very firm believer in and practiser of the KISS principle.
>> 
>> Ken W7EKB
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