The Secret Society of Lathe Trolls

It was NOT a CNC Lathe, it was an old school manual toolroom machine (And frankly rather knackered). Look up Hardinge HLV for a picture of the kind of thing. I cut a small disk (hence the limitation due to centre height), could have done a cylinder I suppose, but I have nothing to plat those back. T...

For shits and giggles I cut a record on a Hardinge HLV, turned up a mandrill to take the blank with a stub to fit in a collet, and mounted the cutting head in a tool holder, then use the power facing mode to cut the groove. Speed was a bit 'iffy' and the headstock belt on that machine is showing its...

There is a bit of a trap with bronze self lubricating bearings, they only really work if the surface speed is high enough, which is possibly not the case here, you might do better to organise lubrication of the bearings rather running them dry. I got stuffed good and proper trying to use a sintered ...

The old school approach when setting up playback decks on rather 'mobile' surfaces in raves might work well here. What you do is use 3 or 4 sorbothane hemispheres (Squash balls cut in half) under a paving slab with the deck placed on the slab. Your basic mass/spring/damper sort of thing really. The ...

Take a look at the actual number of people who invented powered flight within a very small window sometime, there were at least two or three with a reasonable claim. Or the telephone (Two were in a process of being patented at the same time). Or radio, Marconi won the marketing (And Patent) war but ...

Wax for the cutting blank, then shellac disks were traditional for acoustic gramophones in the pre electric machines era, and yea purely mechanical recording and replay was a thing. It **MIGHT** be possible to do a old school standard groove cut on a clay tablet, but I expect controlling the moistur...

You could probably sputter onto a wax target, and IIRC some of the early work at bell labs did just that. I wonder about some of the UV crosslinked photopolymers. Cook it under a UV source until it acquires the required surface properties, cut, then cook it a load more to make it hard. Rather nasty ...

Might be worth investigating something like Floyd–Steinberg dithering to compress to effectively a 1 bit grey scale image.
It **MIGHT** be possible to do colour when viewed in direct sunlight from a specific angle by utilising diffraction effects in what is effectively a grating?

A fun one would be to cut with the picture signal signal as L-R (So depth) and a mono audio track (lateral), that way you could maybe get a picture disk that was also actually playable on a mono system?

Just a silly thought.

Regards, Dan.

Apply IRIAA filter then just integrate the result, you get a displacement waveform, simples.
It is what you do with that waveform that is where the magic happens.

Regards, Dan.

Basically the output of the IRIAA is a velocity signal, and displacement is the integral of velocity. So in effect to make a 'displacement' filter for a lathe you take the IRIAA curve and replace all the horizontal bits with a slope down at -6dB per octave, and all the sloping bits with horizontal l...

That has almost got to be something in the analogue doings (which are fairly extensive according to my copy of the diagrams), could be deeply annoying to find, even with a can of freezer spray. Binary search might be your friend, find a likely lad signal somewhere half way thru the doings, attach mu...

Mine isn't here yet, but the first thing I would be doing is a quick bode plot of both the feedback compensator (gain and phase from feedback input to power amp drive output with no modulation), and a plot of modulation input to firstly the input of the drive pot (which should look basically IRIAA l...

Would hard anodising the torque tube help?
It is a small part, that should not be hard to set up.

Regards, Dan.

That's about the truth of it. 'Sort of works' is easy, for shits I tried cutting with a disk held in a mandrill in my Hardinge HLV-H and a cutting head mounted on the cross slide... It sort of worked. Reliably making a commercial sounding record is MUCH harder. Realise that the noise floor implies c...

Yea pitch (And depth, actually more important!) are way easier when you can just throw RAM and CPU at it. Something like a STM32F7 feels like a good spot for this (But you try getting one!). I would think that on a low end the preview->displacement filter would probably be hardware (At most basic, I...

Now Mark, play nice... Mr Inventor, sit down and do the maths, it is revealing as to just how hard some of this stuff is. Also, grab the AES Disk cutting anthologies, a few hours in a library can save you weeks in the lab. While it is true that we have some better materials today (Magnetics being a ...

The reason for the reversed polarity to one of the drive coils is that it causes the mechanical summation to work correctly to give lateral movement for mono input and vertical movement for the side input. Sure you can do the same thing electrically, but the SAL74 is two sets of identical electronic...

My initial question would be 'reference in what sense?' If this is for checking that a cut will play back successfully on a wide range of reproducers, then you probably want an old school conical stylus as this is worst case for osculating circle size, but that is a very different sort of thing from...

Always a fun one this, going on the rather useful UK site (I think the codes are internationally standardised, but check the US likes to be a pain for import/export). If I was shipping a DMM machine with computer I might be tempted by 8458918000 Lathes (For the removal of metal), other lathes, numer...