Groove depth discussion

[humongous]

I would like to open a discussion about groove depth as relating to master lacquers and reference discs or acetates. Also what are other considerations between the two? Let's talk about groove depth in relation to different rpms while we're at it.

[opcode66]

I cut 2 Mils for stuff that isn't very hot.

Anything that goes 0 to +3 or above I cut at 4 Mils.

Those are unmodulated. I adjust depth and angle to get nice clean unmodulated grooves or those widths. I also have my sweet spots set for my depth potentiometer and gauge.

Once I'm dialed in I cut at an appropriate LPI. No problems with tracking or skipping of playback stylus with heavy volume and bass.

Or I can squeaze a lot in with a 2 Mil groove. Not a club DJ disc, but a great cut nonetheless.

[concretecowboy71]

I set my machine up to cut a 2 mil groove when the depth gauge is at .30mA. Usually this is a good starting point for most of my cuts. I cut mostly album sides for commercial release and not club DJ cuts.

I have found that a groove very slightly above 2 mils results in good cuts for most work. Noise and ambient records with a lot of strange panning seem to result in grooves that narrow a bit here and there. Using my EE and sometimes opening the groove up a tiny bit helps a lot with these cuts.

On 7" 45rpm records, I try to cut (depending on side length) a little wider (3-4 mils). Recently I had some masters that were mono recordings of old Garage rock records and I was at about 4 mils wide. I cut them narrower to start with and had some tracking issues. I did some research by looking at similar records that were cut in the 60s and some of the grooves were 4+ mils.

[concretecowboy71]

I would also add, that part of this conversation might also revolve around the idea of cutting deeper lead-in and lead out grooves. I was taught not to cut deeper on these, especially lead in due to stamper cracking issues.

I have also heard and read conflicting views on this topic. Anybody else want to chime in?

[opcode66]

I've only heard of the stamper getting messed up by a lead-in groove if it started too early. That is, if the groove starts where the edge of the plate is. That can weeken the material at that point and the press will destroy the plate after so many records.

You have a 70 as well. It is made to have deepened grooves in the lead-in and lead-out grooves. That is one of the perks, so to speak. I say use it.

As long as your switches are set appropriately and you so the automatic head drop your master lacquers will plate and press just fine.

[humongous]

this is great input. how much time do you all spend looking at grooves under the microscope to learn what you can from records you like and don't like?

[humongous]

Do you adjust the groove depth between cutting refs and master lacquers? I have heard different points of view on this.

[dietrich10]

Do you adjust the groove depth between cutting refs and master lacquers? I have heard different points of view on this.

My last two batches of dub plates from Apollo were much much softer than usual and soft compared to master lacquers.

I was cutting 3.5mil unmodulated groove +5 techno record master lacquers.
When I needed to get some dub plates going next with same head depth settings was cutting over 5mil unmodulated.

[concretecowboy71]

I do my test cuts and then a short test on the actual master lacquer to make sure my grooves are the same.

I have noticed a difference a few times and had to adjust the groove width on the master lacquer. If you spend all the time getting the grooves right on the test and then they are different on the master it seems you run the risk of grooves being too narrow or slamming into each other.

I do spend some time looking at other records, I just think it is interesting to see how other people cut. We had one test press that was cut at Abbey Road and I was shocked at how narrow the grooves were, but the thing played.

[dietrich10]

clint-When i did some GG work there were some issues where stampers broke near leadin...you have any same issues? it is only plant the issue ever came up for me

[emorritt]

I've only heard of the stamper getting messed up by a lead-in groove if it started too early. That is, if the groove starts where the edge of the plate is. That can weeken the material at that point and the press will destroy the plate after so many record

The 2 - 4 mil range is where I cut as well. Never heard of the cracking stamper problem though. I have always started outside the finished diameter and cut the lead-in crossing where the record will be trimmed. Op, are you saying that the lead-in should only start within the finished record diameter? No one has ever mentioned having to have metalwork replaced because of this problem. But also, my machine (Scully) isn't set up for the added depth on lead-ins. Never found it necessary.

[opcode66]

Yes, that is exactly what I'm saying. I've never had this happen personally. But, I use the automatic head drop feature on my lathe. So, there is no chance of the lead-in groove starting at the wrong place.

This has been discussed on the board before. Mossboss confirmed the information. I trust his experience...

It makes sense. If I had a thin piece of metal and scarred it with a knife and then put a bend through the scar (simulating a groove in a plate at the bent edge of the plate) and then put a lot of pressure on the plate repeatedly, that area would become very week and would likely break (snap, separate, whatever).

[concretecowboy71]

Hey Dietrich...I have not had any stampers crack. You were doing jobs when they just got up and running. It might have been an operator issue more than a stamper issue.

I use the auto head drop also to make sure that I don't cross over the stamper trim. That issue, I was informed on by a lot of different people.

I think it was Al who told me about cracking due to deeper lead-in grooves. I have talked to so many people, it is hard to remember who mentioned that to me. I certainly would not want to quote someone out of context. I have not had any problems or complaints by not using it, but I was wondering if anybody did do that.

If anybody does, what groove width do you use?

[JayDC]

how do you measure that, if you don't have a super snazzy system?

[concretecowboy71]

Groove width is measured using a microscope that has a ruler in the ocular (eyepiece).

I don't think you need a zumo-zappo high end system for that. I would imagine that you could buy an eyepiece that has the scale in it somewhere on the internet.

After a quick google search, the scale is called a reticle.

Here is some quick info:http://www.microscope-depot.com/ret_choose.asp

[JayDC]

ok, I think mine has that, how do you measure the groove depth? or is that a calculation based on the groove width and the size of the stylus?

[emorritt]

I have auto-drop as well, just overrode it for masters. Hmmm. Been doing this for years but I guess will change the setup now. Yes, in theory it makes sense that a groove over the edge of the metalwork would weaken it at that point, but on a stamper the groove is sticking out, not cut into the work?? I've never had stampers taken from my masters break, but I do remember Paul at Aardvark a few years ago saying that a couple pressing plants he worked with were "breaking stampers at an alarming rate". Wonder if this is what was the cause?

[mossboss]

Good thread this one
Ok If you drop the head to early so as to cut a spiral all the way to the start of the track you most likely will finish up with a split stamper
Now this is very clearly stated in the Neumann manual
The depth of the groove is not a contributing factor Suffice to say that once a cut on the lacquer which is of course reproduced on the stamper it will be a weak point
One can get a stamper take a cut across to the start of the cut with a pair of scizors than you can just about "unwind" the stamper like thin wire Try it
Ok Now
Assuming that the baths on the galvanics are a bit low on nickel or at the wrong pH or low on sulfamic acid content or low on dissolved Nickel low temperature etc etc etc it is a big factor in split stampers
If the bath is 100% efficient you will pull out all or some of the dissolved nickel which is an ion donnor so baths are run at slightly less than this so as to replenish the dissolved nickel in the sulfamate solution
If this is the case you will finish up with a brittle deposit for sure
Any of the above will give one anywhere from a slightly stressed deposit which tends to be brittle rather than ductile or a really brittle deposit so this is another contributing factor
A simple rule of thumb is to take a strip of the stamper say the trimming when it is cut down to size and bend it 90 degrees to the left than to the right by holding it between the jaws of a pair of pliers
As an absolute minimum you must have 3 x 180 degree bends
If less you can guarranty yourself a split stamper
At around 4-5 bends it is fine 7 or more its magic You are a master plater
Very important point:
If the begining of the cut is very close to the point where the stamper is pushed down so as to take the form of the mold/die it will difinetly split
This is even worst than cutting across
So take a look at the pressed record from any plant start your cut as far away as possible from the edge of the record
Easy breezy Not hard to do and the cutter will never be accused of anything in that regard as it will be obvious to the pressing man that if he does split a stamper he needs to look elswhere
It saves a lot of heart ache for all concerned
Cheers

[opcode66]

A friend of brought me some copies of a few vinyl releases he's done recently. I of course put them under the scope to inspect the work. I won't divulge who cut the discs.... But, the grooves were about 10 Mils and there were overcuts all throughout the disc. I was actually suprised it played without skipping after looking at it up close.

Anyway, the point is that the grooves on that disc were 10 mils and aparently there was no problem generating a stamper for pressing.

[Nickou]

Anyway, the point is that the grooves on that disc were 10 mils and aparently there was no problem generating a stamper for pressing.

Depend of the galvanic process


i worked years ago in the galcanic departement of a french pressing plant ( wich has closed) , and we had problems with a very ( but realy very ) famous cutting room , the gooves were so deep than the stamper was too much thin , ans so not enough strong to be use for pressing.

this problem has never been sold