2235 vs 3M Roloc

[1audiohack]

So I am putting the mass rings in two of the 2234's I used during the re-surround job on my 4435's and didn't end up with a glue line I was happy with so I cut the cap back off and re did it.

I was in the process of flattening the old adhesive with a 90 degree die-grinder on the other one and when I let off the throttle, the Roloc wasnt locked and spun off the mandrel. Where did the disk go? Right accross the other 2235. Damn the luck!

There is an obvious lesson here.

I am writing this while I wait for my adrenalin level to go back down so I can sleep.

[ARMED]

Nnnnnnnnnnnnnnnnnnnnnnoooooooooooooooooooooooooooo ooooooooooooooo:(

[Challenger604]

Are you pissed?

[pos]

At least this did not happen on one of your 1501AL-1 :o:

[Ed Zeppeli]

Well that sucks! Luckily, it's just a flesh wound.

[grumpy]

Instant hindsight smack in the face... I really hate when that happens.

[quindecima]

The only think I can think of worse than that is cutting off the end of your little toe with a cigar nipper.

[Challenger604]

The only think I can think of worse than that is cutting off the end of your little toe with a cigar nipper.Ha ha ha! That's funny!!

[wsilva]

CRAAAAAAAAAP!

Those kind of events drive me NUTS.

It almost would have been better if the cone was destroyed, so you wouldn't have to keep looking at it.

Bummer, Barry :(

[ivica]

So I am putting the mass rings in two of the 2234's I used during the re-surround job on my 4435's and didn't end up with a glue line I was happy with so I cut the cap back off and re did it.

I was in the process of flattening the old adhesive with a 90 degree die-grinder on the other one and when I let off the throttle, the Roloc wasnt locked and spun off the mandrel. Where did the disk go? Right accross the other 2235. Damn the luck!

There is an obvious lesson here.

I am writing this while I wait for my adrenalin level to go back down so I can sleep.

HI 1audiohack,

This is really bad luck, but I beleve that You can fix it.Wish You a good luck
Regards
Ivica
Ps. Is it necessary to convert 2234 into 2235 applied to 4435.
May be only one would be enough?

[1audiohack]

I have done dumber things but dang!

I am going to load them in my 4430's, put on the grills and call it a day. They look best with the grilles on anyway.

Side note, the JBL C8R2235 cone kits that I put in these while I re-surrounded the original 2234's have surround half rounds the size of the butyl surrounds I got from Japan. Since the old ones are long gone I cannot measure them to determine what has changed. Possibly the new foam gaskets are slightly narrower now than the old ones giving the impression the new surrounds have a smaller radius.

The good news there is that I am not loosing sleep over the 4435's either.

Thanks all!
Barry.

[M-D-Z]

That unexpected cone-scar must have caused you quite a moment!

There is a short period where you know something has just gone wrong, and you start looking around only to discover irreversible damage.

It could've been much worse though, like it "buzz-sawing" into your naked exposed cornea, in the unlikely event you had not been wearing protective goggles.

I've found that it is safe to use only 3M brand mandrels and abrasives.

Foolishly I fell for the enticingly low price of a Harbor Freight "quantity purchase" of Roloc compatible discs.

My 0.250" diameter collet die grinders spin (with no-load) at between 18,000 & 28,000 RPMs, and with low mass rotating parts, come down to zero RPM in ~/< 0.5 seconds.

The male "thread" of the expendable disc's locking post has a steep helix, dual lead, tapered fit attachment and by itself enough inertia to overcome the air motor's braking effect and the rapidly slowing mandrel, which then launches the coarse abrasive "mini-flywheel" into space.

The 3M brand interference fit is perfect, I have NEVER shot one from these tools.

To salvage some use out of the H/F discs, I put a wrap of rubberized self-blocking tape around the threaded post to keep them secure, but they are not manufactured uniformly to be even remotely well balanced either, so there is a constant vibration, plus they still sometimes jump off from the mandrel, either that or the cheap glue fails and the plastic hub stays in the backing mandrel.

After the aggravation they've caused, I just gave them away, lesson learned.

Do you think a small wipe of sealer would help prevent further fiber disintegration?

[1audiohack]

Hi M-Z-D!

Welcome to Lansing Heritage!

I thought about including the facts that these were genuine 3M mandrels, backers and discs. Yeah $22 seem steep for a backer and +$50 a box for discs but thats what I buy.

I chalk it up to me being dumb. It simply could not have been fully seated.

In our fab area at work there is a cut off wheel fully halfway embedded in the ceiling. The center was pulled out of it and it exploded off the mandrel as sometimes happens and we leave it there a constant reminder.

All the best,
Barry.

[JuniorJBL]

Well I am glad it was minor damage to the woofer and not any of your extremities! ;)