Stylus for Grace F9

the thin end of the wedge
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bra10n
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Re: Stylus for Grace F9

Post by bra10n » 22 May 2019 06:45

bra10n wrote:
21 May 2019 03:37
Just PM your address and I'll get these away to you ;)
These are away to you today.

jc3
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Re: Stylus for Grace F9

Post by jc3 » 22 May 2019 16:59

Awesome - thanks! :D

jc3
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Re: Stylus for Grace F9

Post by jc3 » 27 May 2019 03:40

Wow - this is starting to look like it will actually happen!

I've got a sheet of elastomer in the right thickness that I think will make a good starting point to see if I need something softer or firmer, but the compliance should be set by not only the stiffness of the elastomer, but also the tension on the wire. I'll cut the little elastomer doughnuts with a sharpened brass tube with the diameter I need and do the same with the inner diameter.

I've got music wire in the same size (4/0 piano wire) coming, and various different epoxy formulations onhand. I have the formula for resonance frequency: Resonant Frequency = 1000/[6.28*square root (M*C)]; and will order a test record so I can start experimenting with the weight used to set tension on the suspension - I will use an el cheapo conical/aluminum for those experiments.

I've got all of my brass tubing diameters that I could possibly need (and then some), and I just got stylus shape and cantilever materials info from Namiki. Will put in my order as soon as I can measure an intact full stylus when Dennis' research donor gets here. Thanks again, mate!

The one thing that is holding me up right now is finding samarium cobalt ring magnets in the right size. Turns out not a lot of folks make tiny little ring magnets in the size I need. And I want to keep the same material and not go with alnico or neodymium because if you change the magnetic field by increasing or decreasing magnetic strength, that will alter the output, and I am aiming for an exact replica (with other options, of course). I recon I need 1.6mm diameter, with an inner diameter of 0.4 to 0.6mm and a thickness of 0.6mm. I've been sending out emails to folks who make SmCo magnets, and got a rather funny email from one person this morning.

"They would cost $.16 each in lots of a million and $365 for one." I am thinking a hundred would last me a good long time, but whoa! I've sent emails now to folks in China, as it seems US makers are prohibitively costly. I'm even willing to buy some disks in 1.6 or 1.7mm and 0.6mm thickness and drill them myself as long as they are uncoated. We'll see what the Chinese have to say in terms of pricing.

I'm going in a different direction on the thumbgrips now. Casting was too spotty. More on that later. I've even sourced some 0.5mm carbon fiber for an experimental cantilever (I finally found the tip that broke off of a nearly new retip I did a while ago due to my clumsiness - not the repair work. Mangled cantilever, but the tip looks good). Stay tuned...

bra10n
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Re: Stylus for Grace F9

Post by bra10n » 27 May 2019 09:16

I had the easy bit... I didn't even have to search for the bits ;) The post-office... well that's a whole 150m up the street. Heck, you don't even have a long surname Joe!

I wish you every success with this venture. You're on a hiding to nothing with this, but somehow I suspect you might even get very close.

cheers,

D

jc3
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Re: Stylus for Grace F9

Post by jc3 » 28 May 2019 05:22

Thanks man!

Well, I'm getting closer on a couple fronts. My second quote for ring magnets in the right size came in at around a buck a piece with a 500 piece minimum - but the manufacturer is in Canada and those may be Canadian dollars. Still yikes, but not YIKES! My Chinese lead needs a minimum order of 10,000 pieces, but I sent them an email asking if they had any leftover stock from similar jobs in similar sizes.

Tested the magnet from my first dissected stylus today and it is, as I had suspected, axially magnetized and the north pole faces rearward relative to the cartridge body (N toward the generator), which makes sense. My sharpened brass tube cookie cutter punch worked perfectly and I have several small elastomer cookies that are exactly the right dimensions. They are somewhat stiffer than the original, so might have to find a softer elastomer formula. This one has a rating of Duro 40A - I suspect it will behave a bit differently when the center hole is punched, but we'll see. I'm aiming for a but stiffer suspension than the original - a bit less compliance. So will probably figure the compliance with this material first and then go from there. Off to find a super cheap conical to use as a compliance test bed.

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Re: Stylus for Grace F9

Post by jc3 » 28 May 2019 07:26

My Chinese lead that insisted on a minimum order of 10,000 pieces just shot me a good deal on 500 in the 1.6mm OD, 0.6mm ID, and 0.6mm thickness that I need. All of the bits have been sourced!

jc3
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Re: Stylus for Grace F9

Post by jc3 » 30 May 2019 00:49

I've discovered some very interesting things on pricing from Namiki that will probably make a lot of you upset if you've bought expensive exotic cantilevers. The difference in price between aluminum with the most basic stylus and ruby with the most expensive stylus is about 5 trips to starbucks.

Anyhow - magnets are in production and I've begun cutting and filing some of the bits and pieces.

I've cut some of the suspension doughnuts - they came out really good. They're a bit tedious to produce - made a punch tool with an outer sharpened brass tube that I strike with a little wood block, then a short spacer tube goes inside of that tube, and a sharpened brass tube of the proper OD goes inside of that and gets a second whack with the wood block. I still get the odd uncentered product, but only about 30% of the time. Here is my first run after QA. The original is the lowest one. One correction to mention here - the outer diameter of the original suspension block is 1.6mm - I initially measured it when it was under tension and that flattened it and made it bulge. These are still quite a bit firmer than the original, so I have ordered some neoprene (not foam, but rubber) in shore 30A and 40A, and a silicone formulation in 30A to try. All should have good long lifetimes in this application.

https://www.vinylengine.com/turntable_f ... 598/source

I've also cut the main cantilever capsule to length, and have cut aluminum cantilever stubs to length, and inserted a length of 4/0 piano suspension wire through the stub and bent the opposite end. In the original, it looks like the stub was crimped around the tie wire and driven into the cantilever with a press-fit. I don't have that option, so I will be adding slow set epoxy to the bent-over end, and working the epoxy into the stub tube with a back and forth motion. Then I'll add a bit more epoxy to the bent-over end, and finally add epoxy to the outside of the stub insert, and the whole thing will be slid up into the cantilever tube and allowed to cure for 24 hours. Should be a good, solid connection.

https://www.vinylengine.com/turntable_f ... 599/source

bra10n
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Re: Stylus for Grace F9

Post by bra10n » 02 Jun 2019 10:17

That package can't be too far away now Joe.

cheers

jc3
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Re: Stylus for Grace F9

Post by jc3 » 04 Jun 2019 21:40

Awesome - didn't come today, but I'm keeping an eye out. Once I get a measurement on cantilever length I can get an order in to Namiki for my first batch of 5 aluminum cantilevers and 5 boron, each with line contact styli.

Delta667
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Re: Stylus for Grace F9

Post by Delta667 » 05 Jun 2019 04:33

jc3 wrote:
04 Jun 2019 21:40
Awesome - didn't come today, but I'm keeping an eye out. Once I get a measurement on cantilever length I can get an order in to Namiki for my first batch of 5 aluminum cantilevers and 5 boron, each with line contact styli.
How do you manage to order small batches of styluses?
I, through an intermediary, could hardly agree on 50 units, they set conditions for at least 100 pieces at a time.

bra10n
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Re: Stylus for Grace F9

Post by bra10n » 05 Jun 2019 10:28

Delta667 wrote:
05 Jun 2019 04:33
How do you manage to order small batches of styluses?
I, through an intermediary, could hardly agree on 50 units, they set conditions for at least 100 pieces at a time.
He bugged them that much they just kept taking a 0 off the min-order-required :lol:

jc3
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Re: Stylus for Grace F9

Post by jc3 » 06 Jun 2019 05:27

Grace has new clothes.

https://www.vinylengine.com/turntable_f ... 648/source

https://www.vinylengine.com/turntable_f ... 649/source

I think this is what the aluminum-line contact will wear.

jc3
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Re: Stylus for Grace F9

Post by jc3 » 06 Jun 2019 05:30

Delta667 wrote:
05 Jun 2019 04:33
How do you manage to order small batches of styluses?
I, through an intermediary, could hardly agree on 50 units, they set conditions for at least 100 pieces at a time.
They told me that they have recently lowered their minimum quantity order to 10 unit down from thirty. To split an order (5 of one, five of another) it would be an extra charge. I may just order all 10 aluminum for now.

jc3
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Re: Stylus for Grace F9

Post by jc3 » 06 Jun 2019 05:32

I need a favor - is anyone with an original F-9 stylus with the entire cantilever intact and a pair of calipers willing to very carefully take an overall length measurement for me of the total exposed cantilever length? I'm going to try to estimate the length from photos so I can get an order in for some styli-canti's.

EDIT: Actually don't worry about it - just did a measurement from one of Dmitry's old photos and found it to be approximately 6.5mm - the longest option they offer is 6.0 +/- 0.2; so look like I'll order them in 6mm length.

Delta667
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Re: Stylus for Grace F9

Post by Delta667 » 06 Jun 2019 08:52

Grace F-9 with two inserts was sent to me for repair. The package should be with me in a week, or one and a half.
I will take accurate measurements of the cantilever and inform you.

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