Open Source Lathes and Cutterheads

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Open Source Lathes and Cutterheads

Unread postby jjwharris » Wed Jul 12, 2017 7:21 am

Hi There,

I've been spending a lot of time reading through these forums, trying to grasp the basics of all of this.

I've tried cutting a few things with results that are less than great - mainly down to poor quality turntables, less than ideal construction and bad needles.

I've been working on a better setup in solidworks and I'm thinking I'd like to release everything I've worked on as an open source kind of deal.

This is where it may get a bit grey - Since I'm using a lot of your guys stuff as reference (could be using reference very loosely there..) material (Mostly Bryan's Osoo-Miso Picante cutter head, the Zez cutter one lathe and Soulbears perfume funnels) I don't know if this reaches into the realms of plagiarism or if it's not cool to go releasing model files of things based off other things.

Anyways, I've attached a screenshot of what I've been working on - I'm new to both 3d printing and cutting records so I imagine a lot of this stuff could use refinement.

Also as a bonus - I recently picked up a Peter King lathe cut, I have a cheap $20 USB Microscope if anyone is interested in some detailed photos of what his tracks look like. If you want to hear the tracks they're here;
https://theopawa45s.bandcamp.com/releases

Let me know what you think and I'll go ahead and release the model files if people aren't upset with that.
Attachments
lathe.png
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Wed Jul 12, 2017 7:22 am

There's a missing piece in that picture. My software crashed and I lost it so it's not happening tonight.
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Re: Open Source Lathes and Cutterheads

Unread postby Soulbear » Wed Jul 12, 2017 4:28 pm

Hi JJW,
jjwharris wrote:and Soulbears perfume funnels) I don't know if this reaches into the realms of plagiarism or if it's not cool

You go for it my friend, sharing and learning should be what the Forum's all about in my book. I hope your endeavours turn out good BIG TIME, just keep us Trolls up to date with your build, and the best of luck with it too!!
Regards :wink: :P :D Soulbear
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Sat Jul 15, 2017 5:24 am

Thanks Soulbear!

I'll wait until it's functional before I release anything as I seem to be changing it a lot - How did your project work out?
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Sat Jul 15, 2017 9:44 pm

It's been a busy weekend/week...

I've been printing and tweaking and reprinting, and I've arrived at this.

Since assembling this I've decided to add thrust bearings either side of the coupler bearing to try and reduce horizontal movement of the head.

The torque tube is currently 3d printed, I'm considering getting this cast in silver, not sure if aluminium will be too difficult (also my jeweller doesnt cast in aluminium..) planning to secure the cutting stylus with a screw in the front of the torque tube, I take it this is less than ideal, as I want to reduce as much moving mass as possible but I'm hoping it will suffice in the short term.

As I said earlier, all my record equipment is on the otherside of the country in Auckland so I'm waiting to pick that up in late August, but I'm already searching for quotes to get it here sooner.

A couple of concerns and questions I have are in regards to the attachement of the drivers to the torque tube, I've attached a cad drawing of how they are attached (epoxied in eventually) but I notice a lot of people will use a thin wire to attach the tube to the drivers, why is that?

Secondly, the 3d printed tubes on the torque tube I've made thinner than the inner diameter as the funnel as when I glue them I want them to be floating, the speaker cones sitting in the more free position. Is this the right way of thinking about it?

Thirdly, I've made the hole for the cutting stylus as near to the point of contact to the drivers as I figure this will give the needle the most direct movement, is this necessary?

I also realise that the coupling of a stepper motor directly to the threaded rod will probably be less than ideal, I'm thinking I can probably move it and turn the rod with a rubber belt if this proves to be a big issue.

The spring suspension is giving me a bit of worry too, is there any particular thing in a spring I should be looking at?

More than anything I would love to know if there is anything I have overlooked while making this.

Excuse the missing screw - the hardware shop has their machine screws all in a mess and I inadvertantly picked up the wrong length for one screw.
Attachments
torqueattachement.png
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Thu Aug 03, 2017 5:38 pm

I'm still waiting on my turntables etc, been looking a lot at stylus and thinking I'm going to end up buying a diamond stylus. What is the difference between synthetic and natural diamond stylus? I'm guessing the synthetic stylus are more pure? Is it likely to make a difference?

I've had an airpot dashpot arrive, however I'm holding off any redesigns until i test this one.

In terms of blanks, I've found a source for pvc in new Zealand and I'm thinking this is probably the most cost efficient way for me to go considering shopping anything to NZ is somewhat prohibitive
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Mon Aug 07, 2017 8:38 pm

I've been experimenting with the turntable I have an sapphire stylus cutting polycarbonate blanks - to be honest I'm trying to get a feel for it more than anything, it's all a bit slapdash at the moment.

I'm fairly certain I've chipped the burnishing edge of the sapphire, the cutting face seems to be okay though. Still counting down the days to get my records and turntable back.

Anyway, from looking at the cuts under a cheap usb microscope, it looks like there is some modulation in there, but the tracks look like the stylus is bumping around the place, I've got the most pressure the turntable can handle at the moment, so I'm thinking, it's either insufficient pressure, swarf buildup, or maybe too much power to the cutting head?

I'm going to pick up some PVC today, moreso because its opaque and I want to be able to see what I'm doing. Any idea for cheap, silent vac pumps?
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Mon Aug 07, 2017 9:00 pm

I'm thinking a tea straw to a plastic tube, to a jar to a shop vac
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Tue Aug 08, 2017 5:07 am

Got home and searched for metal tube, found an 8mm pipe on a broken blow torch, put it in a vice and now i have this.

Printing parts to accommodate it now - my new method of getting real world objects into 3d programs is to scan them with a ruler, it works a treat!

Printer is going now, also picked up some pvc sheet today, the man at the shop also gave me a sample of acrylic over abs (which i don't have high hopes for) and something called hips or high impact polystyrene, that looks a little more interesting to play with.
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Re: Open Source Lathes and Cutterheads

Unread postby Gridlock » Tue Aug 08, 2017 10:38 am

Acrylic sucks. Ask anyone here
<\\\\\\\\\\\\\\\\\\\\\[[[[[[[\/]]]]]]]\\\\\\\\\\\\\\\\\>
Recordette Sr.......Presto K-8
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Fri Aug 18, 2017 12:36 am

Haven't progressed too far lately...Counting down the days to receiving the stanton decks, I've got the vacuum unit together, waiting on some latex tubing to connect that all up.

I did however pick this up the other day for $15NZD. Looking at it, I'm pretty convinced I can gut it and use the amplifier for the lathe and the housing for the housing for the entire assembly.

Cool wee New Zealand made hifi system, hoping to use the VU meter to monitor the left and right channels (it even has pots set up for the left and right channel) and build the control panel into where the tape deck assembly sits.

Also working on a CNC project at the moment, hoping to end up cncing a few parts out of aluminium.
Attachments
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Fri Aug 18, 2017 12:38 am

My next question is going to be how to connect the VU meter to monitor the output...
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Sun Aug 27, 2017 7:04 am

Well, after a plane ride trying to pretend that the 16kg turntable was under the 7kg limit I've finally made it back,.

So far I've got the auction tube working, managed to do 3 test cuts tonight, one at 32g weight and another with the total weight of the head cutting at about 90g...

Glad I'm using sapphire needles as i feel like there is going to be a steep learning curve.

It's working, obviously not great, and my source material wasnt great either but I'm pretty happy with the results so far. Will be setting up a casting setup to cast the head and the torque tube in aluminium in the coming weeks.

I've attached a sound sample - a few gaps here and there, I still haven't got my record player back down and the Stanton has a straight arm which i don't want to use and no head case. So I'm relying on the generosity of a friend.

Will release stl or solid works parts files this week. There are a few things that will need to be tweaked but I'll put them in the open anyway.
Attachments
John record cutting test-4.mp3
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Sun Aug 27, 2017 7:09 am

In terms of analysing what's going on I'm thinking of cutting 20hz to 20khz sweep left then right channel, then in stereo, is this a good way to go about it?
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Re: Open Source Lathes and Cutterheads

Unread postby markrob » Sun Aug 27, 2017 7:49 pm

Hi,

The sweep can work fine. Just be careful not to feed too much power into the head. Monitor the driver voltage with the DVM to be sure. This is especially important if you intend to encode the sweep with RIAA as there will be a +14 db boost at 10 Khz vs. the level at 1 Khz. Did you make your test cuts with RIAA encoding? You can also use white or pink noise (RIAA encoded) as the test signal. Finally, you can just cut any program material and compare the the spectrum of the original to the playback and use EQ to match (within reason). Then use this EQ on your next cut. The sweep is nice because you can hit the head with nearly full power at each frequency. This helps drag the signal out of the noise. Especially at the high frequencies.

Mark
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Thu Aug 31, 2017 8:53 am

Thanks for the advice Mark!

The test cut I posted did have an inverse riaa filter on, I've been gifted a record player, so now have the ability to record my own tests.

I've attached a recording of the sweep. I'm looking for a program to analyse it, at the moment I'm using Reaper with a plugin

Unfortunately (or perhaps fortunately) after this the torque tube split and my 3d printer broke down so progress has sort of slowed down.

This has however led me to trawl this forum a bit more, specifically the blade runner head by opcode66. Out of frustration I've tried to machine a new torque tube with the cutting needle behind the pushrods with hopes of lessening the distortion and resonant frequencies. I attached a photo of this new torque tube setup. I'm holding off printing the head with 100 percent infill as I'm hoping to cast an aluminum head soon.

My vacuum tube also needs a little attention, swarf seems to be balling up occasionally, I'm going to try and fashion some connectors where the tube meets the swarf jar and the plastic pipe attaches to the latex out of some spare 10mm pipe i have lying around.

I was thinking in the shower that I may be able to acoustically isolate the head with butanol sheeting.

More specifically; where the drivers attach to the head, around the where the vacuum tube enters the head and under the bearing which attaches the head to the lathe. Big weekend plans!

I guess the sweep is becoming more and more redundant but I think it is worth while keeping got prosperity.
Attachments
john frequency test 1 29 august 2017-1.mp3
received_10155049031631491.jpeg
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Thu Aug 31, 2017 8:58 am

Sorry Mark, forgot to respond re the voltage going into the head, I hooked a multimeter into the speaker output in parallel and I'm cutting at a peak rms of .5v, i ended up putting a clamp on multimeter on the speaker lead and was cutting at a peak current of .6 amps, I am unsure if this is what you meant.

The drivers are rated at 5w constant and 20w peak, by My calculations .7a should be in the area of 5w, therefore not driving them too hard and I'm thinking that driving outside of that 5w may cause distortion?
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Fri Sep 08, 2017 12:46 am

I've taken it to pieces again... Redesigned the cones, planning to solder brass pushrods to a brass torquetube (by that I mean, brass screws soldered to a brass screw..) Hoping to cast the cutting head in the next week, got some steel needles on order to grind down for embossing...

I've realised my mistake and the importance of trolling these forums - Been trying to cut with a sapphire from St Petersburg, standard groove and not microgroove!
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Fri Sep 15, 2017 5:57 am

Had a little test emboss tonight with a sharpened tunsten needle...amazingly quiet.

But, I can say that the time has come to get rid of the stepper motor, or at least decouple it. I can hear mechanical thumping throughout the recording.

I've attached the sweep(cut with iRIAA, then recorded into audacity and RIAA applied after cutting), still unsure about how to go over this white noise/eq thing. But I've got a friend coming to help me soon, hopefully, I take it there are going to be limitations in the head that cannot be improved, how do I find those?

Also upgrading the input setup to a poweramp and usb interface, I've fused the drivers in preparation.
Attachments
SWEEPiRIAA-RIAA.mp3
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Re: Open Source Lathes and Cutterheads

Unread postby jjwharris » Fri Sep 15, 2017 6:05 am

Couple of photos - rebuild of the torque tube, got it down to 1.2g, dont look at the spring connection to the head, it's dirty as anything. using tungsten as the rods. did the old superglue + baking soda trick for where I couldn't solder.

the angle of the needle is about 15degrees, I was aiming for 30, or as much as I could, but thats the best I could do.
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