Creating replica usable Vitaphone records

[davidferguson]

Hi record lathe experts,

I've always been a record fan (got my first record player when I was 7, at a jumble sale), and an enthusiast of various old/retro technology, but the world of lathe cutting records is new to me so I apologies for the silly questions - but I am keen to learn!

My main interest is in film - that is the technology of motion picture photochemical film, mostly the 35mm film used in commercial cinemas as the predominant way to project movies from the late 1800s up until 2014, and still occasionally today for specialist films (such as Chris Nolan's films, Tarantino's films, and more). I have a small 35mm film collection and some film projectors, and I love playing with them and experimenting with this now-obsolete technology.

Film and records do have some crossover, which is why I'm here. About 100 years ago, in the 1920s, the first "sound on disc" movies and equipment was made. For the first talkies, or movies with synchronised music/talking, sound was recorded onto shellac records, which were then played back in synchronisation with the projector, to create image and sound together. The most well known and populate system was Vitaphone, which turns 100 years old later this year, having premiered with Don Juan in 1926.

I'm involved with a group that has lots of vintage movie equipment, including some original sound-on-disc projectors. It would be absolutely lovely to be able to take a modern movie (or even the sound and picture elements of an old one) and create the film picture and Vitaphone record sound disc to run on one of these projectors, to celebrate the 100 years of Vitaphone. Recording image onto film is solved and relatively straightforward, but creating the 16" records is not, which is why I'm here looking for help.

Vitaphone records were a bit special in a few ways:

• First, they use 16" records, not the 10" or 12" standard at the time. This is the same size as some "transcription" records.
• They also run at 33 1/3 rpm, in order to get 10 minutes of playtime from a single disc. 10 minutes is the equivalent of 1 reel of movie film (at the time) so this was used as a requirement for the runtime of the record.
• Vitaphone records also play from the inside to the outside - the reverse of what is normal. This was so that the larger diameter outer grooves would be played last, when the needle would be most worn, in order to get the best fidelity possible out of the recordings.

And while not unusual at the time, it is worth stating that in the 20s, shellac was used not vinyl, and it used "standard" grooves rather than the LP "microgrooves" that came in later.

When doing some research I found a couple of places that have the ability to make a "steel needle compatible 78 record": Duncan at Vulcan Records in the UK, and Custom Vinyl Records in the USA. Both of these look to use a moulding process, where a master is first cut in wax (or similar), and then a mould created, where harder steel-needle compatible records are then made. However, both of these places can only do a 10" max disc, not the 16" I need for Vitaphone, and likely can't do the reversed-spiral groove either.

So I think I have a few options available to me:

1. Convert the sound pickup on the Vitaphone projector to a modern lightweight cartridge. This means I no longer need to hunt for steel-needle compatible discs, however means the playback equipment is no longer original, which defeats the point of this. It also doesn't solve the requirement for the 16" or reverse-spiral groove, so not an ideal option.
2. Find someone that can make "steel needle" compatible 16" records. Most ideal for me, but most unrealistic, I think. But I would love to be proven wrong!
3. Find someone who can make a 16" record wax cut master with standard (non-micro) grooves, ideally in a reverse spiral, that can then be given to Vulcan Records or Custom Vinyl Records, for them to make the mould and steel-needle compatible disc from that. More realistic than option 2., but still not something that most people will be setup to do!
4. Make my own lathe that can cut the 16" size of disc, with standard grooves. Make my own wax blanks, and cut it with the reverse spiral, 33 1/3 rpm groove. Give this to Vulcan Records or Custom Vinyl Records, who create the mould and the steel needle compatible disc. Given the implausibility of options 2 and 3 I fear this is the only real option available to me, but also the one that has the biggest learning curve for me! However I have been inspired by excellent builds such as David's/pentlandsound's lathe

So before I go any further, I'd like to say that if anyone has any equipment that is capable of option 2 or 3 (cutting a 16" wax blank with a standard groove, and either passing that to Vulcan Records / Custom Vinyl Records, or making the mould and steel needle compatible disc), please let me know and I will gladly stop my research and pursuit of option 4. Less work for me is better, however, assuming that option 4 is going to be needed, I have done some research and have some questions below that I am seeking help with.

Research

• It is quite common here to emboss polycarbonite with a sapphire stylus. This creates a very shallow/small groove, that sometimes has issues playing on a modern record player. Almost certainly no good for a steel-needle compatible master. A more advanced option is to cut polycarbonate with a diamond stylus - this may need to be heated to do the proper cut. This seems better than embossing, but is still really focused on microgrooves only. Heated cutting was never done on 78s [source].
• For 78s, a standard groove is needed, which is a 5mil groove, cut with a cutting stylus with a 1.5mil tip [source]. Playback is done with a 3mil stylus. On regular 78s, there would be between 88 and 112 grooves per inch, resulting in 3-4 mins on a 10" record [source]. On transcription 78s, there could be up to 120-136 grooves per inch, resulting in a longer playback time, but reduced fidelity. Some rough measuring and napkin maths have showed me that Vitaphone discs used the same 88-112 grooves per inch as regular 78s. They got the extended playback time from the 16" diameter, and the 33 1/3 rpm speed.
• A few years ago lacquer blanks were sometimes used, but with the demise of Apollo Masters in 2020, this is no longer available to anyone but the big labels. These were historically used for standard groove as well as microgroove, so would have been suitable here if I could obtain or make a 16" one.
• Making your own lacquer blanks is something that has been discussed here before, but I don't think I've ever read anyone doing it successfully or a proper guide on how one should do it. There are also some dangers associated with the materials used for the lacquer.
• For 78s (and the Vitaphone discs), originally beeswax was used, which is still readily available today, and seems easier to work with, but has a poorer audio reproduction quality. However I am yet to see anyone discuss much about this, or report results. Obviously a form of this is possible, as it was done back in the day, and Vulcan Records state that their process is to "cut a wax master disc which is used to produce a mould", but they don't say what wax they use, or the process of creating the blanks is.

Questions

1. Can anyone create a 16" wax/lacquer master with standard grooves today? I would love it to be true, but am not too hopeful.
2. The use of beeswax or other similar wax seems my only option today, and has a (slightly dubious) bonus of being historically accurate. Has anyone done created blanks with this? Any advice? Anything from thickness to viscosity and more!
3. Does anyone have a 78" standard groove cutter head that they may be willing to sell? Or advice on making my own? I have looked at countless DIY cutting heads for microgrooves and vinyl recently, but am not sure how it is different to standard grooves cutting in lacquer and wax.
4. Where can I get standard groove cutting stylii? There seems to be some old threads that discuss their availability, and have people offering to sell them, but nothing I can find today. I'm not even sure what was originally used for 78s/standard groove - was it sapphire?
5. If was able to obtain a standard groove cutting stylii, does anyone have any advice on driving it? How do the groove vibrations differ from a microgroove? Would I need to increase the amplification of the driver? Or is that left the same and it's just the groove itself that increases, not the vibrations? What sort of tracking force is needed for these? Does it depend on the material of the wax/lacquer blank?

And lastly, any other advice, wisdom, and comments are most welcome. I'm aware this is ambitious, but I'm keen to learn more, even if I just learn all the reasons I can't/shouldn't do it! Looking forward to any comments and advice!

David

[markrob]

Hi David,

Interesting project. I don't think you need to be too concerned with the cutting stylus geometry. A modern microgroove stylus should be able to cut a standard size wide groove that will play properly with a 3mil playback tip. You just need to cut a bit deeper than normal. The playback stylus will not care about the 1mil or smaller bottom of the groove as it will not contact the bottom of the groove. There are plenty of lathes out here that can cut 16" masters and lots of unused 112 LPI inside out feed screws available, so that is not an issue. I saw on the Wikipedia Vitaphone page that 10" and 12" were used for short subjects, so as a proof of concept, I wouldn't limit yourself to 16". You really just want a deep groove inside out cut that can stand playback using an old style steel needle. I would think that as a first test a diamond cut polycarb 12" would work fine. However, I'm not sure how may plays you would get out of polycarb as there is no abrasive to wear down the steel stylus. Perhaps one of the sources you mentioned could take a poly cut and make a molded gramophone style record with the proper physical properties for repeated playback. I think this portion of the project is the easiest to deal with and you should be able to produce a disc that plays on the Vitaphone projector.

The big question in my mind is how you intend to achieve sync with picture if the recording lathe is not directly geared to the film as was done back in the day. That aspect of the process seems to be key. While today's digital technology is typically locked to a crystal time base, I think it would be difficult to maintain sync of several minutes without significant drift. For example, if you were able to maintain 0.1% speed tolerance over 10 minutes, you would have a error of 600ms. That seems too excessive. 0.01% will be difficult to achieve between two clock sources using off the shelf crystal clocks that are not synced unless you go to great lengths to trim them. What source material do you plan to use? Do you plan take a film with an optical sound track and extract the audio to a digital file to be cut? If so, I could envision a setup where you create a file with mono audio on one channel and timecode on the other (e.g. SMPTE time code). This would then need to be decoded and cut to the target disc with the platter motor locked to the time code. I could see that being possible, but it would require some specialized hardware at the lathe end that would need to be developed.

Hope you find this helpful.

Mark

[davidferguson]

Hi Mark,

Thanks for your reply. I am glad that what I consider to be the hard part of the project you consider easier, and vice versa!

The big question in my mind is how you intend to achieve sync with picture if the recording lathe is not directly geared to the film as was done back in the day. That aspect of the process seems to be key.

You are correct that synchronisation is critical, and an offset of 0.6s at the end would be very noticeable with lip-sync issues and more. And it would indeed be necessary to synchronise the audio playback with the lathe platter to ensure that proper playback can be achieved with picture. To solve this, I was intending on slaving the audio player to the lathe platter. I have two such player devices that can do this - and it would be something like adding a rotary encoder or similar on to the lathe platter, which is connected to the audio player. Then if/when the platter speeds up or slows down, the audio player will compensate for this and adjust the audio playback accordingly. I do a similar thing for recording onto magnetic tape and it works very well - perfect results.

However, all this custom sync likely means I'd need to build my own - although I should say that having perfect sync isn't just an improvement for Vitaphone discs, it'll also lead to more accurate playback of all records! So maybe I can collaborate with someone who has some existing equipment - anyone interested? Otherwise I will continue down the path of making my own.

I don't think you need to be too concerned with the cutting stylus geometry. A modern microgroove stylus should be able to cut a standard size wide groove that will play properly with a 3mil playback tip. You just need to cut a bit deeper than normal. The playback stylus will not care about the 1mil or smaller bottom of the groove as it will not contact the bottom of the groove.

This would be fantastic if it turns out to be true. Anyone know how deep a standard groove is compared to a microgroove, so how much deeper I'd need to cut? Or rather than depth, should it be force/weight/mass that one is measuring and increasing? What are the risks with this - could it damage the cutting stylus? Is this something that someone else could be willing to try, or should I still be perusing building my own? Any special type of stylus I should use for this?

There are plenty of lathes out here that can cut 16" masters and lots of unused 112 LPI inside out feed screws available, so that is not an issue.

That is good to know - while I doubt I'll just stumble across one, maybe someone who has one may be willing to help. I'll keep my fingers crossed!

I would think that as a first test a diamond cut polycarb 12" would work fine. However, I'm not sure how may plays you would get out of polycarb as there is no abrasive to wear down the steel stylus.

First can I check that you do mean polycarbonate - from what I have read previously, I thought that PETG was recommended for cutting with diamonds, and polycarb was only for embossing? For example, the listing for the RecordLatheParts T560 says that it is "ONLY for cutting PETG plastic. Using on any other material risks destroying the tip."

If I am able to cut polycarbonate, then from my understanding, research on here, and experience with heavy steel needles, I think you're right that it would wear out the groove of the polycarbonate pretty quickly. However if I can do it, it would be fine as a test to check I have the groove setup correctly.


I think my remaining questions are:

1. First, does anyone have a 16" lathe that would be willing to help with this?
2. Assuming the answer to 1. is no, what cutting stylii should I be using, what material should I be cutting in, and what force/other configuration should I be using to get the larger standard grooves?

[markrob]

Hi David,

My bad, you are correct PETG with a diamond for cutting. Since the stylus has ~90 degree included angle groove width is 2X depth. That assumes no tip radius. So you would just need to go a bit deeper. But as long as the playback stylus tracks, you are fine. Something around 5 mils should work. I'm familiar with SMPTE sync to tape recorders. Its been done for quite some time. AFAIK, this is not done at the lathe level. It certainly could be, but I don't think you will find anyone that will do this without some development effort. As I said before, you would have no issues if you wan to cut a disc that will play. It just will not sync very well. If you roll your own lathe and have the technical chops, then you should be good to go. Its either that or find someone local to partner with. You are facing a long and expensive road ahead if you go the DIY rout, but it will be a great project. It may be the only way. Keep us posted if you go down that route.

Mark

[davidferguson]

Thanks for the reply, this is really super helpful!

So you would just need to go a bit deeper. But as long as the playback stylus tracks, you are fine. Something around 5 mils should work.

I actually found a great image which illustrates the different groove depths of various standard-groove 78" manufacturers [source], showing that they varied between 0.0021" and 0.0036". So your guess of 5mils (0.005") is probably a bit much, but larger here is probably not an issue.

78-groove-depth.jpg

And this page on microgroove sizes and geometries helpfully specifies the microgroove depth to be 0.0011". So it seems that I need to cut 2-3x as deep as a regular pressed microgroove record.

So as always, I leave with more questions!

1. How deep is a lathe cut groove in PETG using a diamond cutting stylus normally? Is it similar to a pressed microgroove record? Or smaller, larger?
2. On the assumption that a diamond lathe cut groove in PETG is similar to a pressed record depth of 0.0011", how do I get a 2-3x depth? Is it a case of increasing the weight/force of the cutting head? Or do I lower it further into the PETG blank? I'm assuming this could get problematic, and so I then wondered if I could cut an empty groove first and then cut the audio later - but this probably requires more alignment than I'll be able to achieve. I then thought that additional heating/warming of the PETG disc may help - perhaps a heated bed, plus heat lamp in addition to the heated stylus?

Of course, if I can even get a regular lathe working, and then get it cutting 2-3x as deep, the next challenge is whether I can turn that into a steel-needle compatible disc. I'm hoping that one of the previously mentioned manufacturers (Duncan from Vulcan Records, or Custom Vinyl Records) can help with this. But in case not, has anyone else experimented with moulds and harder (resin?) casting?

[spinnertownblanks]

Usually with PETG and a diamond a groove width of 50 microns (2 mil) to 70 microns (2.75 mil) is recommended, but you can definitely cut 100 microns (4 mil)

The depth is set by you by adding more head weight, however if cutting 78rpm theres more chance of stylus damage due to the blank spinning much faster, so make sure the blanks are nice and flat.

All of our blanks are PETG and styli are synthetic CVD diamonds.

[davidferguson]

The depth is set by you by adding more head weight

Thanks for this - I had actually been looking at your store for stylii and blanks.

Does your diamond stylii have a recommended weight to cut the 2 to 2.75mil width groove? Or does that depend on setup? I have heard of people using stylii weight of 14g to 16g - does that seem about right for normal use? I presume this is probably not linear so I will have to experiment with what weight is needed for the 2-3x groove (and I'll need to work out how I'm going to measure this!).

if cutting 78rpm theres more chance of stylus damage due to the blank spinning much faster

While I keep referring to what I'm wanting as "78s", Vitaphone actually runs at 33 1/3 rpm, so that's what I will be cutting at. The larger 16" disc will result in a faster linear speed at the outer edge, but at least it's not as fast as 78rpm at 16" would be!

so make sure the blanks are nice and flat.

All of our blanks are PETG

I will need to be sourcing my own 16" blanks as (understandably) no one has them. Do you have any tips on what I should look for other than "sheet of PETG, 2mm thick"? Or do you have the ability to produce blanks larger than the 14" listed on your site?

[spinnertownblanks]

We have made 16" in the past, it's a custom job but we have done it a few times. Head weight is just a rough guide, all that is important is groove depth. So feel free to set it by weight, but measure the groove depth (by measuring the width) and adjust as needed. You can set whatever depth you like.

Here is a guide to measuring grooves on a budget!

https://spinnertownblanks.com/blogs/spinner-town-blog/measuring-groove-depth-on-a-budget

[mrd]

interesting project. Just a thought, but could the steel needle issue be mitigated by experimenting with a cactus thorn?

[davidferguson]

We have made 16" in the past, it's a custom job but we have done it a few times.

This is great to know - I may be back in touch assuming everything else progresses well!

Head weight is just a rough guide, all that is important is groove depth. So feel free to set it by weight, but measure the groove depth (by measuring the width) and adjust as needed. You can set whatever depth you like.

Here is a guide to measuring grooves on a budget!

https://spinnertownblanks.com/blogs/spinner-town-blog/measuring-groove-depth-on-a-budget

Thanks for this, very enlightening - and your blog is also excellent, I can see lots of useful guides and tips there that I will be using. What a great community this is!

Just a thought, but could the steel needle issue be mitigated by experimenting with a cactus thorn?

It can indeed, and when I talked to some projectionists that had experience with Vitaphone, this was apparently done at the time to avoid wear or change the sound quality. I would still rather create the steel-needle compatible discs if I can, so it can be played on authentic equipment (especially as the playback heads are quite heavy so would likely damage the reasonably soft PETG after a while), but there is hope even if I can't do that.

So it looks like my plan is to:

1. Construct a lathe, with platter that can take the large 16" discs
2. Cut some regular 12" or 7" records with microgroove to prove it works, and adjust as needed for best performance
3. Get the reverse spiral and the 90 grooves-per-inch spiral working
4. Get the deeper groove working

Simple, right?

I'm also still waiting to hear back from a couple of places that may have original Vitaphone material that I can copy - either on original discs or digitised. The early stuff is now public domain, but getting your hands on it is tricky.