Cardas binding post for Duetta : question

[WongKN]

Hi everyone,

It's been some time since my last visit here. Since that time, I have been enjoying my system based on a pair of Apogee Duetta Signature.

Recently I purchased a pair of Cardas CCRR-L binding posts to put into the Duetta. I have a pair of aluminium plates made to replace that original back plate as I want to retain the option to go back to the original binding posts just in case I don't like the sound. The midrange/tweeter selection switch has already been bypassed.

I now have a problem finding the correct specification nuts to tighten the spades of the crossover wires to the cardas post. Cardas does not supply additional nuts and its seems expects owners to solder the crossover wires to their posts. But as explained above, I want to retain the option to reverse the mod so I don't want to cut the spades off the crossover wires for soldering and prefer to use nuts to fasten them to the Cardas posts.

The technical drawing of the Cardas CCRR-L post on the Cardas website indicates the posts to be 5/16" thick/diameter. I tried 5/16" standard industrial grade nuts from the hardware store but they are too small. I also tried 3/8" but they are too large.

Anyone can advice me on what size nuts I need to get ?

Many thanks in advance for any answers/suggestions given.
Best Regards,
WongKN

[henk]

WONGKN,

There are at least two different types of nuts in the american system:

I would not be surprised to find that you are using a UNF (Unified thread fine) nut on a UNC (unified thread coarse) bolt or vice versa....

Good luck,

Henk

[Ralph]

There are at least two different types of nuts in the american system:

For a moment there I thought you were referring to the presidential election

Ralph

[WongKN]

Thanks Henk. Your response prompted me to research on nut sizes used in the US. I am used to metric sizes thus I talk in terms of M8 nuts, etc. It looks as if the US system is a bit more complicated than i expected. From the Cardas website drawing for the CCRR-L, the nut spec I need to find is 5/16-32. I think it is UNF. The big problem I found, after getting through this hurdle is this seems to be an unusual size. As Malaysia follows the metric system, nut sizes in inches are already difficult to find. But 5/16-32 seems to be so unique that even ebay does not have a listing. Even internet search has not given results so far. So my search now has become one for this rather rare nut! Hope I don't go nuts searching for these. LOL !!!

[EldRick]

Um - perhaps you could contact Cardas for replacements?

Or http://www.mcmaster.com/#hex-nuts/=k39qsg -pick the 5/16x32 size and order what you need.

[WongKN]

Thanks oldrick. I did email Cardas sales support but they did not respond. I have been thinking of emailing their customer support. I will check out the site you gave. Didn't see them when i searched google. Also found the actual spec for the nuts are 5/16-32 or 5/16" UNEF (ie extra fine). UNF is 24 threads/inch. UNEF is 32. UNF 5/16" is easy to find but UNEF 5/16" is practically non-existent.

[WongKN]

Old/Eld-Rick,

A quick update for you. I placed an order with McMaster and they rejected me. They cited the 'complexity of US export regulations', which incidentally I never had any problems with at all in all my numerous purchases from US companies in the past. Then they cited that they only accept orders from their established customers and even that if I am to get them to ship 'within the US', they STILL won't accept my order. Basically the email says something to the extent of 'we don't want your business, piss off' but in a courteous manner. Not sure if it is because of where I am from or what, but my email address is with an established US business (VTEC.NET, incorporated in the US). So, I won't deal with them anymore in the future.

That leaves the avenue of Cardas. The last time I emailed them, they did not respond at all. Totally nothing. So I will try to email them again, this time to another email (my first was to sales support, this one I am thinking of trying customer support). If they don't respond again, I will be forced to go to the local bolts and nuts distributor and hope to find something there (Malaysia is part of the Commonwealth and we use a mixture of imperial and metric systems here).

I suppose this has taught me a good lesson which might be useful to anyone contemplating modifying their speakers with binding post replacement from the more 'famous' names. Think carefully before considering Cardas because of the unusual specs they use. 5/16" hole size (1/2" nut size) is already unusually large but they use UNEF or 32 threads per inch and 5/16-32 is close to impossible to find. The closest one is likely to find is 5/16 UNF or 5/16-24. 5/16-18 seems to be the typical size used. Thinking hard about it, I should have considered the WBT that a local shop sells. At least then I can go back to them for anything. This Cardas I bought on special order from the local Cardas authorized dealer (and still Cardas won't respond to my emails). Best I think would be to get the Bronoco that Graz occassionally sells.

Biggest lesson is AFTER SALES SUPPORT is MOST CRITICAL.

Thanks for reading and all the help offered.

[Zardoz]

I'm really surprised they didn't come with the nuts. I replaced the speaker terminals on my Xovers with Cardas, and they came with all the hardware I needed. Sounds like either the wrong part was ordered, or they were left out. Surprised Cardas is non-responsive too. Hope you are able to reach someone at Cardas that can help.

Z

[WongKN]

I am sorry, it looks like my original description was not so good, my fault - english is not my first language.

The Cardas CCRR-L posts I got comes complete. It comes in sealed plastic bags, all the parts, the post itself, the rubber washer and the locking nut. My problem, which is also possibly perculiar to me is that the Duetta Signature cross over is physically connected to the original binding post via a spade and nut method. The Cardas CCRR-L on the other hand, seems to be quite clearly designed for the crossover wires to be -soldered- to the posts. So the CCRR-L package comes with only 1 set of nuts - for locking the post to the back plate. Therefore I need another set of 4 nuts to be used for locking the crossover wire spades to the Cardas post. This then is the source of my problem.

Actually as I want this mod to be reversible in the unlikely event I don't like the sound, I had a pair of aluminium plates made to mount the Cardas posts to. So in the event I want to reverse the mod, I simply remove the aluminium plates with the Cardas posts and mount the original plate back on. For this reason, I really do not want to cut the spades away from the crossover wires to solder them to the Cardas post. That will make it difficult to return back to the current stock situation.

Thanks for your post and I really hope Cardas will respond to me this round.

[Zardoz]

Why not just put the spade between the plate and the locking nut? I realize it's not as elegant, but should work fine, and eliminate the need for the extra nuts.
Good listening,
Z

[WongKN]

I had considered that. The locking nut is supposed to lock the binding posts securely in place and makes use of a rubber washer to do that. So putting the spades between the locking nut and the rubber washer is one possibility. I may have to resort to this as Cardas have not responded to my email (I sent to both sales and customer support) and I don't have any confidence they will ever respond. However I will still go over to the bolts and nuts specialist locally to see if I can source some 5/16-32 nuts first. Thanks for your suggestion.

[WongKN]

Just a quick update about the WIP on my problem, in case anyone else might be in a similar situation. I bought a 5/16 UNEF tapping tool (waiting for it to arrive) and am planning to tap the nut I require. What I am planning to do is to get an M7 nut, drill out most of the threads with a 7mm drill, then tap the nut to 5/16-32 internally. This way the nut will fit into the Cardas binding post and I can use an 11mm deep socket. Metric spec tools are the normal standard here. 5/16" is just below 8mm. But I foresee concern with the nut size as an M7 nut with a 5/16" hole won't have a lot of metal left. I will update when i have a chance to try out the 'project'.