Billet RD-0194/8 tweeter plate design.

gp4jesus

Would you consider making RTI A* series bezels?

If so, I’ll send you one for closer examination. I want to follow you w/tweeter upgrades to 7 speakers*.

If you’d rather not, I understand as the RTi A* bezel is a rather an odd shape. Though I believe many an owner* might upgrade if replacement were easier.

Thanks either way. Tony

gp4jesus

xschop

Going to refrain from more projects this year. I will be doing what I can to support the vintage models that we all enjoy, as parts are becoming scarce as Polk is probably not going to continue making the RD0x tweeters.

Do the magnets fall off the back of those too?
And do the bezels resonate every now-and-then?

gp4jesus

xschop wrote: »

Going to refrain from more projects this year. I will be doing what I can to support the vintage models that we all enjoy, as parts are becoming scarce as Polk is probably not going to continue making the RD0x tweeters.

Its all good. I can’t get into that for at least 6 months. I’m up well past my eyeballs in a LARGE backyard improvement project that includes a above ground pool because the teens are very little help.

xschop wrote: »

Do the magnets fall off the back of those too?

Never saw or heard of that... ...anyone else?

xschop wrote: »

And do the [flimsy plastic] bezels resonate every now-and-then?

during HEAVY lower mid passages in mine. I’m certain the same holds true for unmodded ‘A7 cabinets

I’m speaking for myself along w/1 or 2 other RTi/RTi A series speaker owners have vocalized wishing a tweeter swap were easier because of that bezel and the glued-on, less than squeaky clean or, more accurately, squeaky sounding tweeter filtered by squeaky components...

Perhaps this time next year I can do some R & D in this area. Between your efforts & mine... a pipe dream for the next 18-24 months.

1000 thanks, Tony

xschop

Post a picture of the back side. I said that because I have a couple sets of power-grabbed SL5000's because I found that the plastic magnet mounting tabs in the rear have broken very easily on me before. I've seen comments to the same issue as well.
You can look into doing a reverse-mold sand casting technique that can turn out nice with the right prep-work.

I don't like how the factory mold-injection left the bezel-to-enclosure mount holes on these RD0's or the screw head choice either.
I'll be countersinking them so these stainless 8-32 head specs transition exactly with the plane of the billet bezel on ends....

gp4jesus

xschop wrote: »

Post a picture of the back side.

If you’re asking for the same of a ‘690, I can w/ taking part a speaker, but it will take time to find. On the other hand neither of us is in a rush.

If not now, no sweat. You’re doing a good thing. Kinda like making parts available to resto-mod classic cars😊

Tony

xschop

gp4jesus wrote: »

xschop wrote: »

Post a picture of the back side.

If you’re asking for the same of a ‘690, I can w/ taking part a speaker, but it will take time to find. On the other hand neither of us is in a rush.

If not now, no sweat. You’re doing a good thing. Kinda like making parts available to resto-mod classic cars😊

Tony

I'll build another Porvette in the future. It'll be a 968 LS3 next time.
On a side note, the new billet earplugs came in real handy when I visited a friend this weekend. His Klipsch's were almost bearable.

xschop

Tried posting earlier, the forum dumped my last reply. I guess it didn't like my articulated verbage.
Lets try again...

Basically finished with all milling except countersinking magnet mount holes because they set at a different relation to perimeter countersinks. I calculated extra couple thousandths head depth for perimeter screws due to the VERY high possibility the end-user gets larger diameter flat-heads due to various mfrs' specs being all over the place.

Anyways, finishing up the turning jig today, and will then transfer them to the mill again for the magnet countersinks to match the Factory screws that end-user will need to re-use. Comprende?

xschop

xschop

All 4 of my factory plastic plates differed between 0.045 and 0.050" lip thicknesses. Anyone else want to measure theirs and chime in?

Nesmith98

I measured an RD0198-1 and it is the same as you got, .047".

Looking good by the way.

pitdogg2

Those look great!
I'm thinking I have one more upgrade to the 2.3tls

xschop

What's funny is none of the factory curvatures ended up the same between them either.

Gardenstater

What are the radii of curvature (approx.)?

xschop

Gardenstater wrote: »

What are the radii of curvature (approx.)?

Glad you chimed in Gstater...You're like F1 with machining knowledge. They're enroute to my friends shop with a CMM. We'll know tomorrow. I figure its too large to waste a lot of time taking a stab at the programming and messing even one plate up.

So on a design/machine note, the only limitation is not having 5 axis machining, so I figure I'll find the radius of the long part of the rectangle and machine down to the 0.045" thick lip. That will leave the top and bottoms about 0.050" which these plastic ones were measured at any given edge area.

Sound like a plan?

Gardenstater

Ha! Thank you. With a lathe instead of a 5-axis milling machine, I think that's all you can do. After that, you could try bluing it up with layout fluid and lightly scribe some reference lines and doing the rest by hand on an oscillating drum sander or a belt sander. I sure wouldn't want to chimp up one of those beauties after all the hard work you've put in so far. Very nice. PS: If one were to try this I'd think attaching it in a vertical orientation to a squared off 2x4 or a machinist's angle plate would be highly helpful for control.

xschop

That's a 2" thick turning jig trued up with zero runout. I went with edge mounting for the stability during the turn. These will all be machined with same patina as the fine-brushed look of the classic Silver-faced equipment.

The jigs will also allow for some future brass units to be made to go with some brass spikes no doubt.

Nesmith98

A 3 axis machine could get you there, provided a good CAM program with a ball endmill with fine cuts. There are several 3 axis milling tool paths in MasterCAM that may work.

xschop

I've done fine ball end milling on flat plate and don't think the patina looks good for what I'm doing (fine brushed look). And the fact that I'll be making multiple units in batches for other members that'd like to get their projects done this year too.

xschop

30.499" radii averaged from 3 different plates. One was too distorted by previous screw-downs to use.

Gardenstater

Wow! Even more than I imqagined. I wonder if you could do one or two with the 2D or 3D CNC milling machine with the ball end mill and then follow up with a wire brush with the lathe attachement to get the desired finish.

xschop

Alright brainiacs.....what will be the difference in thickness (thousandth of an inch) between short length vs. Long length of tweeter plate lip, based on the radius of the long length being 30.5"?

Nesmith98

You may have to use the segment height calculator for that one....

https://planetcalc.com/1421/

xschop

Thanks Nes, when I get time to Calc. that, I'll compare to what I hit on the lathe. Looks around 0.050" difference, not the 0.005" difference I originally thought. I may be looking at plan B and fly-cutting the long edges at slight angle to the dome throat ensuring all edge thicknesses match. This will look like a hybrid SL2000-RD0194/8. The SL2000s I rebuilt had a subtle pyramidal shape to them....

Gardenstater

How long would it take to do the whole thing with a (say) 1" ball end mill? Then maybe you could use the CNC lathe to do a circular wire brush texture on it, or just wirebrush it manually by hand in the lathe?

ptrooper

I have noticed theres a certain amount of oxidation that occurs with aluminium, maybe consider having them anodized ?

xschop

ptrooper wrote: »

I have noticed theres a certain amount of oxidation that occurs with aluminium, maybe consider having them anodized ?

6061-T6 is highly resistant to oxidation. I've been using Mother's brand diatomaceous wax polish with outstanding results for years on multitudes of machined parts.

Gardenstater wrote: »

How long would it take to do the whole thing with a (say) 1" ball end mill? Then maybe you could use the CNC lathe to do a circular wire brush texture on it, or just wirebrush it manually by hand in the lathe?

I would need to program 20,000 lines of code in my G-code Hurco....GLWT

Gardenstater

Does your shop have MasterCAM?

xschop

Negative Gstater

Nesmith98

MasterCAM is a great program. I use it about everyday and it still amazes me with the things it will do.