Stylus for Grace F9

the thin end of the wedge
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jc3
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Re: Stylus for Grace F9

Post by jc3 » 18 Sep 2017 02:41

Finally took the time to set up the alignment to the shorter cantilever, and also made a small wedge out of walnut to slip between the back of cartridge and the headshell. Approximately 1.5mm tall and 15mm long tapering toward the front. That gives me approximately 5 degrees less rake and brings it down to close to where it should be.

I continue to be impressed with the Pioneer stylus. I think I have around 8 hours on the stylus and it is sounding better than the SS stylus on everything I play with it. Jeff Buckley's Lilac Wine was amazing, and Grace (the song) had an amazing holographic soundstage. Separation of the instruments was amazing throughout Buckley's Grace (album). The amazing CCR 180g. repress of Chronicle was better than ever.

zacster
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Re: Stylus for Grace F9

Post by zacster » 18 Sep 2017 03:43

I have an original Grace stylus, but it was the rake that was off from being bent. I think I posted some pics before.

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Re: Stylus for Grace F9

Post by ripblade » 18 Sep 2017 16:28

jc3 wrote:Does anyone have an original grace stylus that they could supply a well-lit high-res photo for comparison (or know what the rake angle is on, say, and F-9E stylus)? It would have to be taken as close as possible to perpendicular to an imaginary plane dividing the two cartridge in half front to back and also be taken so that the lens is level with the focus somewhere between the stylus tip and the bottom of the cartridge body. Otherwise, the angle won't render accurately. Probably should be taken with a macro lens as well so that distortion be minimized. Not asking much, I know...
This is the best I can do...

Grace C:
Grace C.jpg
(33.81 KiB) Downloaded 286 times
SS Ruby CL:
Grace Ruby CL.jpg
(25.47 KiB) Downloaded 288 times
Kenwood N-49:
Grace N-49.jpg
(37.76 KiB) Downloaded 284 times
The microscope wasn't repositioned for the shots, so the extended overhang of the SS Ruby CL is as shown. Not sure why that image is darker than the others, but I don't have much control over the exposure with the software I have for this m'scope.

I'll post measurements later. Cartridge VTF is 1.5g but the cartridge is not setup for audio. I do have needledrops of the 3 different needles, but none are of the same track, so nothing to make direct comparisons with, unfortunately. Subjectively, the SS is the quietest of the 2, the others being more or less equal.

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Re: Stylus for Grace F9

Post by stevoz » 19 Sep 2017 02:14

That N-49 angle is way out.....looks like it's a 'vinyl tiller' ready to gouge your LP! :o Another good reason to stick to genuine or styli that are genuinely 'made for' Grace carts. :)

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Re: Stylus for Grace F9

Post by zacster » 19 Sep 2017 02:23

It would be interesting to see how the original Pioneer cartridge looks, whether the angle of the bore is set to match the stylus, and how it differs from the Grace. The wedge would compensate in any case.

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Re: Stylus for Grace F9

Post by ripblade » 19 Sep 2017 15:38

stevoz wrote:That N-49 angle is way out.....looks like it's a 'vinyl tiller' ready to gouge your LP! :o Another good reason to stick to genuine or styli that are genuinely 'made for' Grace carts. :)
Yes, the SRA is quite forward, and viewed from this angle it appears the azimuth is out as well. However, this is a conical stylus so is unlikely to do any serious damage. It sounds quite fine; not as warm and full bodied as the Grace conical, but not distorted in any obvious way.

I should add that the recommended VTF for this needle is 1.5-2.5g, so adjusting it upwards will bring about a more favourable SRA.

jc3
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Re: Stylus for Grace F9

Post by jc3 » 12 May 2019 04:13

Time to revive this thread!

This summer, I plan on a series of experiments aimed at building my own F-9 styli. I have a couple molds and have molded finger grips with varying degrees of success. I've been playing with a new low-viscosity resin that seems to have some promise in being able to produce castings with fewer large bubbles and also has a very short pot and demold time, and is a little harder than the higher viscosity stuff I've been using previously.

But, I lack an OEM stylus, and one of my goals is to make something as close to OEM as possible, and want to start ordering some stock. So I need a bit of help - if someone with an original F-9 stylus assembly and who also has a pair of digital calipers is willing to measure the diameter of the brass tube coming out the back of the stylus grip I would be most grateful!

Also, looking for an OEM stylus that has given up the ghost for a tear-down so I can document all lengths and diameters of the parts, including the tie wire and magnet. Will post the photos in this thread if I can find a donor. Please pm me if you've got one.

I'd like to try producing stylus assemblies with some various cantilever materials, but to start will probably just use the new AT95VML as a donor. There is a group buy over on the Hoffman forum that I'm in on for boron cantilever stylus raw assemblies from Namiki, but he's only currently at 35 and needs to be somewhere near 100 for that order to fly. Anyhow, University is just about out and been thinking about doing this for awhile, so stay tuned.

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Re: Stylus for Grace F9

Post by jc3 » 12 May 2019 06:39

After tearing apart my work area, I found my old F-9 stylus rattling around the bottom of a box of parts. I was able to take some measurements and this is the working drawing right now.

gallery/image/45444/source

I think constructing the outer casing will be straightforward enough. The brass tubing seems like standard sizes - I think I may already have most of the sizes. In the original, that back piece is a machined plug with a hole in the back end for the rear tie-wire epoxy tube, and a small square block that fits in to a notch on the brass tube on the finger grip to stop rotation. I think what I will do is add a ring to act as a stop, but not sure about anti-rotation yet - might just use a bit of cyano to cement it in once alignment of the stylus tip is perfect.

More later.

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Re: Stylus for Grace F9

Post by ripblade » 12 May 2019 16:36

Yours is slightly different from mine, a blue conical I believe is OEM. The entire brass shaft behind the plastic bit is between 2.16 and 2.2mm measured with a vernier. This shaft overall is 6.9 from behind the plastic knob, not including the little nub at the end, which looks to be a crimped sleeve roughly 1.3mm to the glue blob and 0.7 x 1.6 across.
F9 conical.jpg
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jc3
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Re: Stylus for Grace F9

Post by jc3 » 12 May 2019 17:35

Awesome, thanks! Yep, that is the other version with the crimped tie wire tailpiece. Thanks for the measurements! Wow - I always thought the U had blue finger grip, not the P. Learn something new every day! The ruby is even stranger still - the ruby shank is bonded in to some sort of steel (permalloy?) tube, and the magnet just attaches to the back of that by magnetic force only. There is no tie wire on that one - the only attachment point is an elastomer block inside the brass tube with a tiny hole that the cantilever goes through - could find no way in which the alignment of the stylus is maintained other than friction with that elastomer block. Interesting system and could explain the different compliance in the ruby maybe. Thanks for the measurements! Wow - I always thought the U had blue finger grip, not the P. Learn something new every day!

Your outer tube measures exactly what my outer tube does. Measured several times and averaged out at 2.2 mm and right around 0.1mm wall thickness. That whole back end with the tailpiece will come out of the brass holder 'sleeve' - please don't try though! I couldn't post photos last night when I was experimenting - phone was in the bedroom and the wife was already asleep. Will post photos of the entire disassembled assembly a bit later to illustrate.

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Re: Stylus for Grace F9

Post by ripblade » 12 May 2019 18:09

jc3 wrote:
12 May 2019 17:35
Will post photos of the entire disassembled assembly a bit later to illustrate.
Yes, please do!

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Re: Stylus for Grace F9

Post by bra10n » 12 May 2019 23:12

Cart Grip

F-9D = Red
F-9E = Yellow-Green
F-9E Ruby = Red
F-9F = Blue
F-9L = Clear
F-9P = Green
F-9U = Smoke

jc3
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Re: Stylus for Grace F9

Post by jc3 » 13 May 2019 06:06

So here is the first step in the disassembly. The entire magnet-cantilever-stylus assembly will slide out the back of the brass tube. First photo is the cantilever assy inserted into a ruby grip to illustrate. The second photo shows the cantilever assembly. I need to fire up the soldering iron and melt the epoxy out of the back tube there to free up the tie wire and get the cantilever out so I can see what gauge the tie wire is and how it's bonded to the cantilever. Later this week when I have time.

I suspect there won't be much of a surprise inside. I think the main brass tube will be fairly thick walled to allow a base for the suspension doughnut - my main curiosity is how the cantilever is bonded to the tie wire.

gallery/image/45456/source

gallery/image/45457/source

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Re: Stylus for Grace F9

Post by jc3 » 15 May 2019 07:02

Interesting internals on the stylus-cantilever capsule.

I started by melting the epoxy cap off the back end to see if that would relax the cantilever. No dice, melted off the epoxy cap and exposed a tiny tie wire, but still held on firmly. The back end of the brass tailpiece actually has a square-ish cross section with a somewaht textured surface - I think it was crimped. Could not get my calipers on that tiny bit of tie wire sticking out.

gallery/image/45473/source

So I tried to loosen the crimp by applying a bit of pressure with some fine pliars all around the tailpiece. No dice. So I cut it off. That allowed the cantilever to move a bit, and then I slid it out, but wait - it looked like another brass tube...

gallery/image/45475/source

So I gently moved the suspension up the brass tube to expose the tie wire. The tie wire is exposed outside of this inner brass tube for only the thickness of the elastomer suspension block - maybe a bit less even. I suppose if you don't want a lot of 'slop' in terms of the cantilever angle there needs to be something limiting the movement of the tie wire. That inner tube with the tie wire inside has an OD of 0.66mm, and the ID is very, very small, just a tiny bit larger than the wire itself. The wire is far too small to use calipers on. I imported the photo above into illustrator and used the OD of the brass tube to calculate the diameter of the tie wire, which is approximately 0.14mm. The smallest piano wire size, 4/0, is 0.15mm, so that will have to be what I end up using, unless I can find high carbon spring wire in 0.14mm.

The main tube is quite thick, as I had suspected - it's 2mm OD and 0.7mm ID. Looks like it might be two separate tubes bonded together. Or, might be a small lip machined in to act as a retainer for the suspension block.

gallery/image/45474/source

Interesting dissection so far. Still need to check the polarity of the magnet, and see how the tie wire is bonded to the cantilever. I suspect an epoxy of some sort.

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Re: Stylus for Grace F9

Post by ripblade » 16 May 2019 00:08

So many little bits and pieces. It's no wonder only one maker is still offering replacements....and not cheap ones, either.

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