Ever had a stylus explode on you? Well, I have!

[chenry57]

Was cutting a 7" side today. Right at
The tail end of the fade out my stylus made a loud pop and bits of it flew out over the lacquer. Through the scope on the grooves (attached) it looks like a concussion grenade went off! Under the inspection microscope the stylus looked like it blew up from the inside, not a clean break. Maybe a small pocket of air or water expanded due to heat and finally burst. Anyone had this happen before?!?

[opcode66]

What is your lathe? Pro or semi pro or suitcase? Curious about the head suspension...

How much pressure were you exerting? Sounds excessive. I've never had this happen.

[chenry57]

VMS-70. Has never happened to me before. Cutting on an Apollo lacquer. No explanation for it other than the theory they maybe some water or air got trapped in the formation of the stylus. Not sure if this is even possible, however it wasn't just a break in the stylus from a small crack or anything. It literally blew apart.

[chenry57]

I can't get the picture to upload. I'll try again later when I'm on a for real computer.

[chenry57]

The picture is attached.

[jjgolden]

Another possibility is that the shank came loose in the torque tube, then began oscillating until it just shattered..
If you look at the grooves leading up to the explosion that might reveal something?

JJG

[chenry57]

I looked at them & didn't see anything that looked suspicious. The groove previous to the break has a strange wall on one side that juts out quite a bit, but I can't tell if that was the actual cut or if it is something caused by the point where it blasted apart. On a positive note, the image is kinda cool to look at!

[jjgolden]

Yea Cool Pic for sure!
We've had times where the stylus hit some impurity in the laquer and chipped but never and explosion like that... if your gonna go, go big I guess. :>P
JJG

[dietrich10]

Much head shaking right after this happened eh?

Nice pic. I do not want to experience this one.
any fragments get into the head?

[chenry57]

Yesterday was a comedy of errors. Right after this happened I spilled my giant can of MEK so the whole downstairs of the studio smelled *ahem* Very very sanitized.

[chenry57]

It happened again... With a stylus with a subsequent serial number...on the first cut with it. I was worried I had a problem, so I threw an old stylus on (I keep all of the old ones) and just let it cut through some burner lacquers. Didn't have another issue after an afternoon of cutting. I put an Adamant on & have cut a handful of sides without an issue. Very confused (and weary of putting one of the other 320's with subsequent serial numbers on my cutterhead).

[Phinster]

Looks like you hit a 'rock' ie. undissolved lump of nitrate. Have lost the tip in the past, but never had one explode!

[dietrich10]

2nd time?!?

what would happen if the stylus heater had intermittent issues and sent surge to the stylus?

[jjgolden]

Any chance the jewel facet was in sideways?
I just put in a 320k and the facet was about 30-40 degrees off from the flat square of the shank.
Do you guys use a scope for the stylus alignment or do you go by naked eye?

JJG

[opcode66]

I don't think this has anything to do with stylus heat.

[dietrich10]

I don't think this has anything to do with stylus heat.

What would the effect be of a current surge like that?

[opcode66]

I've read a number of patents regarding diamond cutting tips for more than just DMM. Early digital discs were cut using diamond tips instead of burnt with a laser. The diamonds used to create such discs were "treated". This involved a lot of heat and a regulated atmosphere. This process actually makes the diamonds more durable.

However, the heater wire isn't going to get to thousands of degrees...

[concretecowboy71]

I think a heater surge would just burn the heater wire off. I did that once on my own. On my second lathe I was getting surges through the heater element and it was blowing a fuse also.

[chenry57]

Any chance the jewel facet was in sideways?
I just put in a 320k and the facet was about 30-40 degrees off from the flat square of the shank.
Do you guys use a scope for the stylus alignment or do you go by naked eye?

JJG

I do use a scope for the stylus alignment. The square base WAS slightly askew on both of these styli. I put a new stylus on & cut with different lacquers. After a few weeks I decided to put one of the Apollo lacquers on, from the batch that caused the issue, and halfway thru the first side it happened again. I'm thinking there's something wrong with this box of apollos. I'll stick to MDC for now

[concretecowboy71]

I have been using Adamant stylii recently and been having good luck. The grooves were much cleaner looking. The last one I had on was a beast...kept cutting and cutting. I would check it under the scope and it looked perfect and we could detect no loss in fidelity. I finally changed it because I felt guilty...the new Transco stylus looks very streaky compared.