077/2405 phase plug

[kenp3]

Planning on building a set of L65's, I have a pair of alnico 2405's and would like to get a bit of info for the phase plug. Namely I'm looking for the thread size of the stud inside the phase plug. I have a machinist friend who has access to cnc lathes and cnc milling and he doesn't see a problem machining it.

Thanks

[Doctor_Electron]

Planning on building a set of L65's, I have a pair of alnico 2405's and would like to get a bit of info for the phase plug. Namely I'm looking for the thread size of the stud inside the phase plug. I have a machinist friend who has access to cnc lathes and cnc milling and he doesn't see a problem machining it.

Thanks

Not much help but I think it is 1/4"-20, non-magnetic. Mainly I wanted to mention that when you tighten the screw, be absolutely certain not to allow the plug to move. If not the diaphram will twist and resemble one of those old "Jiffy-Pop" aluminum popcorn contraptions.

Are your 2405's missing their plugs? If you plan to convert 2402s to 2405's there are also two aluuminum "squeezers", for lack of a better word, in each 2405. Different diaphram also I believe. Just curious.

-D_E-

[1audiohack]

Sorry I missed this;

10-32. It is just a philister head machine screw inserted from the rear and they are regular old zinc coated steel.

Barry.

[kenp3]

Thanks for the replies. I have the plugs, just wondering what size it was 10-32 seems small. In one of the 2405 there was 2 small aluminum washers in the other there were none, what's the purpose of those?

[1audiohack]

Washers where?

Can you post a pic?

Unless someone has modified it 10-32 is the size.

Barry.

[ARMED]

i would say 1audiohack is right, he probably reconed/fixed hundreds of drivers already...
unless its modified like he said...

[kenp3]

Just to be clear, There's an aluminum stud with a 10-32 female thread on one end, is it 10-32 on the other end too?

[ARMED]

that stud is screwed in the middle of the back of that phase plug, you have to take the decal off the back of the magnet and you will see that screw.. if you take that off,l the plug will come off..(with the housing disassembled already of course)

I bet if you youtube it youll see exactly what it looks like... im not doing that for you...

[kenp3]

7420674207

Just thought I'd update this post. I had a machinist friend make a pair of acrylic phase plugs. They fit perfect, same size and shape and the sound is identical.

[1audiohack]

Cool!

You will be able to market those!

Barry.

[audiomagnate]

Cool!

You will be able to market those!

Barry.

Yeah, they wear out so quickly, even faster if you turn the treble up. I replace mine every two years. The difference is night and day.

[1audiohack]

Yeah, they wear out so quickly, even faster if you turn the treble up. I replace mine every two years. The difference is night and day.

?!?

You don't think anyone has ever thought about making 077's from 2405's?

I'm not going to be rude, so I will just say wow.

Barry.

[JeffW]

FWIW, 3 of the 5 "Similar Thread" links below are from guys wanting these phase plugs - and I know that's just the tip of the iceberg.

[kenp3]

The only thing I wasn't sure of is the hole size/thread size in the plug, we just went with 5/16". The part was first turned on a cnc out of acrylic rod turned around and the holes were done, then another cnc mill to make the profile, the post was turned out of aluminum with 5/16" male on one end and 10-32? female on the other. All in all they look pretty good.

[toddalin]

Cool!

You will be able to market those!

Barry.


One would think...,

But maybe not so easy. Most people aren't going to want to take their tweeter apart, possibly damaging it, to change the plug if the diaphragm is not being changed at the same time.

And even then, how do you get the word out? ePay is only so effective.

I had also considered doing acrylic phase plugs. But I would just take an existing plug and make a mold from it and use that to cast acrylic. Machining is not really the way to go on something like this. I have access to this equipment and/or people who do this regularly.

But I'm really not seeing the market to warrant the initial investment in time, effort, and money.

[kenp3]

Well I didn't make them to market them, I only wanted them for myself. As for casting them in acrylic, not so easy. I've been in injection molding for 35 years and have worked with every plastic material available, to cast something with no voids is difficult and to top it off you need a threaded hole, so casting then machining?

The way to go for proper part geometry would be to make an injection mold and mold them in acrylic just like the originals. A cheap mold would be a few thousand then you need the material to mold with and a machine. I have access to machines in my work, material and molds and I still wouldn't bother, too much work you'd have to sell quite a few to just break even.

This was for my personal use only, and they came out pretty good

[audiomagnate]

Well I didn't make them to market them, I only wanted them for myself. As for casting them in acrylic, not so easy. I've been in injection molding for 35 years and have worked with every plastic material available, to cast something with no voids is difficult and to top it off you need a threaded hole, so casting then machining?

The way to go for proper part geometry would be to make an injection mold and mold them in acrylic just like the originals. A cheap mold would be a few thousand then you need the material to mold with and a machine. I have access to machines in my work, material and molds and I still wouldn't bother, too much work you'd have to sell quite a few to just break even.

This was for my personal use only, and they came out pretty good

They don't look good, they look great, and Barry, from now on I'll make sure to put a "smiley" in my sarcastic posts to keep from confusing and/or offending you. :) :confused::crying::dont-know:

[Ed Zeppeli]

They look great!

[bldozier]

Any reason you didn't try a wood plug. Wood, or glass. Idk if glass is resonable. But wood for sure.

[kenp3]

Glass needs special grinding and forming plus there's the problem of the thread for the rod, wood would still need some kind of turning equipment to be concentric that's a compound curve on the sides, besides I wanted it to look like the real deal.

[audiomagnate]

Can you tell if the originals were made in a mold or the same way you make them?

[1audiohack]

Molded, for sure.

Barry.

[kenp3]

100% molded. It would be nice to find the original mold for these pieces, probably sitting in a warehouse rusting away.

[audiomagnate]

100% molded. It would be nice to find the original mold for these pieces, probably sitting in a warehouse rusting away.

Probably scrapped or simply tossed years ago. At Mitsubishi we sent a dump truck full of "obsolete" parts and equipment to the landfill every month. Out with the old, in with the new, no matter how crappy the new stuff was. BTW kenp3, how did you end up with 2405's without phase plugs? Or did you convert 077's to 2405's?

[JeffW]

Said he had 'em, just some question on the threads.


Thanks for the replies. I have the plugs, just wondering what size it was 10-32 seems small. In one of the 2405 there was 2 small aluminum washers in the other there were none, what's the purpose of those?

[Tim Rinkerman]

I have heard that there are many,many 2405's with acrylic phasing plugs that were painted black from the factory.....

[1audiohack]

Heard that too, never seen one. :(

Barry.

[script56]

I could use a pair of acrylic phase plugs.