I envy you guys, being around when these things were brand new and the hot ticket. I can only imagine what it was like to go into an audio store and see all the different speakers & amps as well as demo the stuff.
Didn't know rusty had L150A's. Knew about the 380's, but not those. He had not one, but TWO 380's! Unheard of in the day.. The party was definitely at his house.
I suppose this is still on the topic of 128H re-foam.
I laid the other L150A monkey coffin on its back today to remove the drivers and one of the bolts on the 128H was spinning. Well we've all either heard about loose T-nuts, or dealt with them—if not caused them. But this one gave up too easily. I picked it out and straightened its barbs to re-install it prior to reassembling the drivers. I had a rig of washers and a large nut to help pull the T-nut into the wood (which seemed not to be damaged) but I could not get the screw started in the T-nut. I took it out again and tried it from the other end. Still no go. Tried the bolt in one of the other still-in-place nuts and had no problem. I got out a good LED flashlight to help my old eyes, took off my glasses to get a good look, and lo and behold the T-nut had no threads! Not stripped thread, no threads as in never had any! No problem, I said, I'll just tap it. But, as a BMW guy, I have no SAE taps, just Metric. I guess I'm off to search at Lowe's once the storm goes away! Whoever was manning the JBL assembly line if 1983 sure missed this one!
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Wow! That is lame!Originally Posted by BMWCCA
I hate T-nuts and never use them. I prefer threaded inserts.
Widget
You and Ikea! Not sure how ubiquitous those are in SAE size here in the East. Now if I was working on a custom build, sure!
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Nice helicoils for wood!! I don't use t's either.
Rob
"I could be arguing in my spare time"
Neat, looks like a carburetor jet. What stops it's threads from backing out or digging in further? I haven't got much experience, but I don't mind T-nuts so far. I remind myself not to push on the fastener with the bitdriver once I break the fastener loose.
Yeah, if this was a fresh build I'd likely use something more sophisticated. But I'm trying to replicate the build the way JBL should have done it. Essentially back to original but without the bad T-nut installation!
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
After spending some time re-organizing Lowe's hardware bins, I found what I needed. In case someone else has a similar issue in the future, here's the Lowe's part:
Hillman #10 x 32 Zinc-plated Steel 3-prong Nut
The only #10 x 32 bolt I could find long enough (to set the nut without screwing-up the JBL bolt) was 2-inches and worked just fine with a large washer and too-large nyloc nut used as a sleeve to pull the T-nut into place. The new T-nut's base is slightly larger than the JBL part but it doesn't really matter since even the original ones hang over into the driver opening with one prong resting against the cutout like it was intentional to keep it from spinning.
Getting there! Here's what it looks like when you have enough room to mix hobbies in your retirement:
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Mmm! Look at those PR300's all nice and black like they should be. My L150A's had some recone job that looked purple-ish. That white bike, why the rods leading to the front wheel? I'm used to seeing an arrangement much like that other two bikes flanking that one.After spending some time re-organizing Lowe's hardware bins, I found what I needed. In case someone else has a similar issue in the future, here's the Lowe's part:
Hillman #10 x 32 Zinc-plated Steel 3-prong Nut
The only #10 x 32 bolt I could find long enough (to set the nut without screwing-up the JBL bolt) was 2-inches and worked just fine with a large washer and too-large nyloc nut used as a sleeve to pull the T-nut into place. The new T-nut's base is slightly larger than the JBL part but it doesn't really matter since even the original ones hang over into the driver opening with one prong resting against the cutout like it was intentional to keep it from spinning.
Getting there! Here's what it looks like when you have enough room to mix hobbies in your retirement:
[img]
Not much else going on here, so why not go further off-topic? Since you asked:
What you're used to seeing are called telescopic forks, BMW having been the first to use the hydraulically damped version back in the '30s. Actually last year, 2023, was the 100th anniversary for BMW motorcycles. What that white bike (1966 R27) has is called an Earles Fork (named for its British inventor) which is basically a swing-arm with hydraulic shocks. Sort of a rear suspension used on the front. Sometimes referred to as a leading-link, this was the common fork on BMW and Douglas motorcycles. This fork design offers anti-dive characteristics and, as you can see here, also offers the ability to easily lengthen the wheelbase a bit for side-car use. The downside for the Earles is it's a bit heavier, clunkier, and results in slower steering response. For BMW the re-introduction of the telescopic fork as an option occurred on the bike next to the speakers which is a 1968 R69S-US or simply R69US, where the "US" is the designation for the telescopic fork option rather than an indication of the country it was destined for. The "US" models in '68 and '69 were often looked down upon as un-BMW-like but the handling was so improved that it became standard on BMW's next generation called "/5" starting when production of BMW bikes switched from Munich to Berlin (Spandau) in 1969. The second black bike is a '72 R60/5.
Just slightly over 1,000 R69US were built for the world from '67 through '69. It is steadily gaining the respect it deserves but the Earles often still commands more money as it looks ancient compared to the US-fork version. But the buying and collecting public is beginning to understand the importance and benefits of the R69US which was as close to a "Superbike" as BMW had back in the '60s. I've owned this particular R69US for over 30-years.
As for the black cones, all I did after replacing the surrounds was to vacuum the cones with a tiny brush attachment to my shop-vac. I think the color change comes from sun exposure. These were in their originally boxes in the owner's rec-room when I bought them years ago and have been stored in those boxes in my garage up to when I moved them to our new house maybe 4-years ago.
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Also known as Leading Link forks?
You can certainly call it that. I did!
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
Woops, missed that...
Well, it's your thread and those bikes were also pictured.I tend to pick up on the off-topic stuff in photos anyway.
Ah, thank you for the insight. It does look ancient, which is what caught my attention. Probably be a good design to learn on? My time spent learning how to ride a motorcycle was more like time spent picking it back up.
Oh, that's a great idea. Wish I had thought of that when we refoamed our 2215's. Do those cones have AquaPlas on them? I'm pretty sure every driver in my L150A's was doinked with at some point. Back when I bought them, I knew nothing about vintage JBL's, save for a few "ideal" model numbers.As for the black cones, all I did after replacing the surrounds was to vacuum the cones with a tiny brush attachment to my shop-vac. I think the color change comes from sun exposure. These were in their originally boxes in the owner's rec-room when I bought them years ago and have been stored in those boxes in my garage up to when I moved them to our new house maybe 4-years ago.
I believe the white front of the 128H is Aquaplas. The PR300 has nothing on the front, but the back appears to be rough enough to have an Aquaplas coating on it just like the back of the 128H. Both have that "pulp" texture which may not be a coating but no hint of the front ridges appear on the back so hard for me to say.
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
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