While shopping in antique stores, I came upon a couple of ancient 78 rpm examples of the novelty style parallel-spiral records. One had two nursery rhymes on each side ("Belda Mysto-Magic, the Wizard Record"), and the other one is a copy of THIS horse racing record:
http://www.youtube.com/watch?v=85q2Vk0Qons
It contains 5 grooves on each side, giving each of the 5 horses an equal chance of placing 1st, 2nd or 3rd. What the maker of that video didn't portray is that the record also has a spinner that the needle pushed against, which gave you your odds at the end of the side (using the label) and allowed you to use the record to GAMBLE.
One of the remarkable things is that the tonearm truly whisks its way through the side, which is about 50 seconds long and has no lead or outro groove.
I'm guessing that each spiral is functioning at roughly 20 lpi. Non-microgroove. 100 lpi total.
Has anyone here cut such records? It seems like it might be fun to get a special feed screw cut to allow for such games. A 24 lpi Presto 6N feedscrew would look like 3 lpi on the actual screw, if I am remembering this correctly. That would allow you to have 8 starting points at 192 total lpi.
Then the question is....How do you align each new groove when cutting? I'd think it might work if you turn the crank exactly 1/8 at the start of a new side, and don't touch it at any other time.
The "mysto magic" record DOES have a lead out groove, and it is nasty looking. It is deeper than the other grooves, and deliberately overlaps with several of them to yank the stylus down and out at the end of the side.
parallel spiral/multigroove/puzzle records
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Steve E.
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parallel spiral/multigroove/puzzle records
Last edited by Steve E. on Fri May 04, 2012 1:54 am, edited 1 time in total.
I recently cut one of these. I did in on my Neumann VMS66. I figured out how to automate it so I can't be of much help. I tried doing it manually but was less than successful. At 20LPI it would be easier. I was at about 200LPI.
I won't elaborate on my technique as it took a long time and a lot of material to figure it out.
I won't elaborate on my technique as it took a long time and a lot of material to figure it out.
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Aussie0zborn
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Re: parallel spiral/multigroove/puzzle records
The lead-out would have been cut after the two grooves were cut.Steve E. wrote: The "mysto magic" record DOES have a lead out groove, and it is nasty looking. It is deeper than the other grooves, and deliberately overlaps with several of them to yank the stylus down and out at the end of the side.
The eccentric locked groove on 78rpm discs was also cut separately after the song was cut, not as a continuous groove.
The Neumann AM32B lathe has a platter offset to cut an eccentric locked groove.
Hi Steve,
This is something I've been wanting to try as well. I have some ideas on how to do it. One advantage that the 6N has over the better pro lathes is that the feed is synced to the plater rotation. So, if you place some numbered markers around the platter to indicate the start of each groove, you can be sure that the head movement will track. Here is what I would do:
1. Mark the platter as stated above. Also mark a reference on the stationary bed of the 6N. You'll use this as a reference for each pass.
2. To cut each groove, move the head to the outside limit to establish a repeatable reference.
3. Align the first platter marker with the fixed reference.
4. Engage the feedscrew (platter is stopped now). Leave the head up for now. You should be outside the start of the lacquer.
5. Start the tuntable and wait unil the head is at the start of the lacquer.
6. Drop the head when marker 1 passes the fixed reference. This will make sure that the lead in starts in the correct place (evenly spaced around the record).
7. Cut the lead in, audio track, and lead out. Then lift the head a bit before you expect to cut a locked groove (see below).
8. Stop the platter, return the head to the far outside and align fixed marker to the second platter marker.
9. Rinse and repeat.
10. When complete, cut a locked groove to capture the playback stylus.
I'd opt to cut at 33RPM or even slower using a VFD and preprocess the audio for playback at 45 or 78 rpm to make it easier to manage.
Someday, I'll make a course feedscrew to experiment with. I really want to make a replacement for a Chatty Cathy doll record and make it say bad things.
Mark
This is something I've been wanting to try as well. I have some ideas on how to do it. One advantage that the 6N has over the better pro lathes is that the feed is synced to the plater rotation. So, if you place some numbered markers around the platter to indicate the start of each groove, you can be sure that the head movement will track. Here is what I would do:
1. Mark the platter as stated above. Also mark a reference on the stationary bed of the 6N. You'll use this as a reference for each pass.
2. To cut each groove, move the head to the outside limit to establish a repeatable reference.
3. Align the first platter marker with the fixed reference.
4. Engage the feedscrew (platter is stopped now). Leave the head up for now. You should be outside the start of the lacquer.
5. Start the tuntable and wait unil the head is at the start of the lacquer.
6. Drop the head when marker 1 passes the fixed reference. This will make sure that the lead in starts in the correct place (evenly spaced around the record).
7. Cut the lead in, audio track, and lead out. Then lift the head a bit before you expect to cut a locked groove (see below).
8. Stop the platter, return the head to the far outside and align fixed marker to the second platter marker.
9. Rinse and repeat.
10. When complete, cut a locked groove to capture the playback stylus.
I'd opt to cut at 33RPM or even slower using a VFD and preprocess the audio for playback at 45 or 78 rpm to make it easier to manage.
Someday, I'll make a course feedscrew to experiment with. I really want to make a replacement for a Chatty Cathy doll record and make it say bad things.
Mark
Hi Steve,
I could be wrong (and often am), but I think, the offset happens when you return the head back to the fixed reference and rotate the platter to the next marker before engaging the feedscrew. The head will travel the same distance in the same number of platter turns to reach the start of the lacquer, but the platter start position was offset so the last sprial is futher along in its trajectory at the intant the head reaches the lacquer start. There is some possible error becuase you can't be sure the feedscrew will mesh with the knife blade at the exact point you select. It may need a partial turn to drop in. I guess you could elminate that if you turn the crank to make sure it drops into the threads at the reference home position.
Mark
I could be wrong (and often am), but I think, the offset happens when you return the head back to the fixed reference and rotate the platter to the next marker before engaging the feedscrew. The head will travel the same distance in the same number of platter turns to reach the start of the lacquer, but the platter start position was offset so the last sprial is futher along in its trajectory at the intant the head reaches the lacquer start. There is some possible error becuase you can't be sure the feedscrew will mesh with the knife blade at the exact point you select. It may need a partial turn to drop in. I guess you could elminate that if you turn the crank to make sure it drops into the threads at the reference home position.
Mark
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Steve E.
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I could be wrong as well, but....
The feedscrew on a Presto is controlled and driven by the platter, and the feedscrew controls the head's position relative to that platter. So, the feedscrew is always engaged (though the head may not be), and its relationship to the position of the theoretical/future grooves is always the same UNTIL either:
1) the handcrank is turned, or
2) the record is turned without engaging the screw, or
3) the disc that connects the feedscrew to the center of the platter is turned, without also turning the platter holding the record.
So! Actually, a good way to adjust the spiral would be to make a mark between the platter and that center disc that drives the screw. Turning THAT disc clockwise by a fifth of a turn would move the feedscrew the correct amount, so that when the head re-engages the screw, it slides into the correct spot. Your point is well taken that you'd want the head to start at the correct spot on the platter, IF you care about the grooves starting in a nice neat even circle. But unless the feedscrew is deliberately offset in relation to the platter or record, all you are doing is starting the groove 1/5 turn earlier, where it will then end up back in the original spiral a few moments later.
The feedscrew on a Presto is controlled and driven by the platter, and the feedscrew controls the head's position relative to that platter. So, the feedscrew is always engaged (though the head may not be), and its relationship to the position of the theoretical/future grooves is always the same UNTIL either:
1) the handcrank is turned, or
2) the record is turned without engaging the screw, or
3) the disc that connects the feedscrew to the center of the platter is turned, without also turning the platter holding the record.
So! Actually, a good way to adjust the spiral would be to make a mark between the platter and that center disc that drives the screw. Turning THAT disc clockwise by a fifth of a turn would move the feedscrew the correct amount, so that when the head re-engages the screw, it slides into the correct spot. Your point is well taken that you'd want the head to start at the correct spot on the platter, IF you care about the grooves starting in a nice neat even circle. But unless the feedscrew is deliberately offset in relation to the platter or record, all you are doing is starting the groove 1/5 turn earlier, where it will then end up back in the original spiral a few moments later.
Hi Steve,
I'm using the second of your methods. The record is turned to the next starting position before engaging the feed screw (and locking the relationship). This provides the offset. The other key point is that the head must be reset (locked) to a fixed repeatable reference point. In fact, you could set it right at the begining of the disc. I just picked a easy to establish point away from the start to give you time to get ready for the head drop. You are correct that the drop point need not be fixed other than to distribute the starts symetrically arround the disc. I did a crude plot on paper to verify the result. If I get time, I'll try to post a better version.
Mark
I'm using the second of your methods. The record is turned to the next starting position before engaging the feed screw (and locking the relationship). This provides the offset. The other key point is that the head must be reset (locked) to a fixed repeatable reference point. In fact, you could set it right at the begining of the disc. I just picked a easy to establish point away from the start to give you time to get ready for the head drop. You are correct that the drop point need not be fixed other than to distribute the starts symetrically arround the disc. I did a crude plot on paper to verify the result. If I get time, I'll try to post a better version.
Mark
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Angus McCarthy
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I suppose you would have to go to extreme measures to get this to work on a swing-arm lathe. Since the whole thing is locked together you'd have to drill a second drive hole in the acetate directly across from the first, unless you had a stock of triple-hole'd Audiodiscs lying around. Then you could cut three grooves fairly easily I'd assume.
Well it has been a while since I had a look and a read of the very patent and it took quite longer to find it in my archives The last time we discussed the subject here was over the Mad magazine 6 or 7 track floppy which was way back
This is quite novel in its approach to the issue talked about on this thread however it has all the necessary steps as what one needs to do to get a result It would certainly be a bit "rough" on the entry points but than again it is not meant to be for Audiophiles is it!!
Here it is : http://www.google.com/patents?id=PSg2AAAAEBAJ&pg=PA7&dq=multiple+cutter+head+phonograph+records&hl=en&sa=X&ei=AjWoT-yBD-eoiAedybzKAw&ved=0CEAQ6AEwBDge#v=onepage&q=multiple%20cutter%20head%20phonograph%20records&f=false
It merely, as I understand it, one does accurate cuts on a standard cut lacquer where the material has been mixed pre-recorded cut in a normal lathe as we normally do Than this lacquer is placed on this gizmo where the lead in & out tracks are cut with preheated sapphires mounted on a rotating head so it is really only a very accurate scriber on an already cut lacquer I am sure that is how it seems to work and if this is so than one can certainly use the method described on the patent so as to do it on any lathe with some templates Quite novel
To my surprise even the company mentioned for the CNC mill is still in existence
Not sure it still carries the model mentioned as it was just a quick search so as to establish its existence : http://servoproductsco.com/html/products.html
Still for any one wanting the ins and outs its all there as what one needs to do on the subject in a mechanical way rather than what would be the normal in the absence of this device The "Artisan" way which of course its spirit here Enjoy reading it as it is quite insightful
Cheers
This is quite novel in its approach to the issue talked about on this thread however it has all the necessary steps as what one needs to do to get a result It would certainly be a bit "rough" on the entry points but than again it is not meant to be for Audiophiles is it!!
Here it is : http://www.google.com/patents?id=PSg2AAAAEBAJ&pg=PA7&dq=multiple+cutter+head+phonograph+records&hl=en&sa=X&ei=AjWoT-yBD-eoiAedybzKAw&ved=0CEAQ6AEwBDge#v=onepage&q=multiple%20cutter%20head%20phonograph%20records&f=false
It merely, as I understand it, one does accurate cuts on a standard cut lacquer where the material has been mixed pre-recorded cut in a normal lathe as we normally do Than this lacquer is placed on this gizmo where the lead in & out tracks are cut with preheated sapphires mounted on a rotating head so it is really only a very accurate scriber on an already cut lacquer I am sure that is how it seems to work and if this is so than one can certainly use the method described on the patent so as to do it on any lathe with some templates Quite novel
To my surprise even the company mentioned for the CNC mill is still in existence
Not sure it still carries the model mentioned as it was just a quick search so as to establish its existence : http://servoproductsco.com/html/products.html
Still for any one wanting the ins and outs its all there as what one needs to do on the subject in a mechanical way rather than what would be the normal in the absence of this device The "Artisan" way which of course its spirit here Enjoy reading it as it is quite insightful
Cheers
Chris
Hi Chris,
Thanks for the link! That's quite a setup. I could see why Mattel would develop this gizmo given the number of interleaved tracks they were dealing with in the toys they were producing. Also, the diameter of the disc's are very small, making the lead-in lead-out cutting even harder. I could see extending this invention such that not only are the lead-in/outs cut via CNC, but the actual audio could be done as well. Just need better servo's and software. Might not be Hi-Fi, but that's not the goal here.
Mark
Thanks for the link! That's quite a setup. I could see why Mattel would develop this gizmo given the number of interleaved tracks they were dealing with in the toys they were producing. Also, the diameter of the disc's are very small, making the lead-in lead-out cutting even harder. I could see extending this invention such that not only are the lead-in/outs cut via CNC, but the actual audio could be done as well. Just need better servo's and software. Might not be Hi-Fi, but that's not the goal here.
Mark
