Alignment tool for SME V + Shelter

Axel, here again is the link:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&Nsgarch&4&5&st0

And in any case *SRA* is wrong also, since it should be then called *SCLRA* Stylus-Contact-Line-Rake-Angle, since the 'stylus' is only doing that picking-up via its 'contact-line' touching the groove, yes?
And as it so happens, the angle of the contact-line maybe just as unrelated to that 'clump' of stylus also!

Technically you have a point, however, the usual fabrication of line-contact styli (except the Shibata) produces a shape that is symmetrical when seen from the front or the side. Thats why it's so relatively easy (as my photographs show) to determine when the "line of contact" is perpendicular to the record surface. Getting from there to a useful rake angle is a fairly simple calculation, and with some tonearms, a fairly simple procedure (NOT the SME unfortunately ;-(

The idea of properly setting the SRA (again, only an important issue with line contact styli) is to have the ridges on each side of the stylus 'lean' forward at the same rake angle as the cutterhead (or did you think cutterheads were positioned straight up and down? Ever try using a chisel that way ;-)

Ah the fingerlift again. Well, I don't care if you amplifiy it a million times, you won't hear it ;-)

Hi Nsgarch,
maybe we have to set out our trades/professions for some helpful insights?
I'm a trained mechanical engineer and actually have even WORKED with chisels on METAL.
Next, I do furniture- and speaker-building, so again I use wood chisels (even Japanese double laminate ones --- and I sharpen them too, ho, ho). 25 deg. main angle and 30 deg. honed angle mostly, and depending on the cutter AND the tool.
Variations of 10 - 15 deg. depending on the application are not uncommon.

Yes, I did read that thread, not that it changes what I understand, but what I actually disagree with is the statement that the cutter-head is/was at ~ 1.5 deg (obviously tilted forward of the 90 deg. makes 88.5 deg. or 91.5 deg. so take your pick). In fact some 2-7 deg. seems closer to what has been the case when cutting lacquers or DMM masters.

This does in no way explain your take, that SRA is supposed to be NOT related to VTA...
VTA, is the angle between the flat record surface and the line the cantilever makes --- and the cantilever is bonded to the stylus at some angle greater than 90 deg. -- but it is then FIXED! So, how can the two then NOT be related, hallo?!

You are an architect you would understand what I try to get at, and I'm not talking just some numbers not being related here.
Depending on the angle between the stylus' contact-line to cantilever you can get either SRA or VTA, AND in fact those cart manufactures 'stupidly', 'stupidly', quote VTA (if they do it at all) and all then wait for us 'clever' audio-dudes to re-express it in SRA angle terms, wow.
If a cart manufacturer quotes 22 or say 25 deg. VTA you actually know squat about SRA -- because you do not know the angle that was used between the cantilever and the line-contact, or do you?
Do you know what angle the lacquer was cut at for the LP? No way, so you go fiddle your SRA or VTA angle until it sounds the best to your ears - and the rest of it is just a case of intellectualizing what we truly don't know, in terms of the actual degrees.
So you see, that's why I got a-plenty of VTA and SRA by now. Eish!
Axel

Typical cutterhead angle is 1.5 deg. +/- depending on the lathe operator. I confirmed this with Stan Ricker, a well-known mastering engineer and lathe operator (Cardas Test Record.)

The precise angle of the cantilever to the record surface is irrelevant for playback. It can vary from zero deg. (for strain gauge cartridges) to 90 deg. (Decca cartridges) and everything in between.

However, ensuring that a line contact stylus' edges line up with the angled groove undulations is essential, no matter how it's attached to the cantilever, or what the VTA winds up being. Don't worry about those things.

It's nice to be able to adjust SRA on the fly to compensate for different record thicknesses and lathe operator preferences, but 1.4 degrees seems to be a good average if 'on the fly' is not possible (e.g. SME arms.)

If you set up your arm geometry carefully and adjust for close to the correct SRA (or exact SRA if your arm provides) that is at least 90% of the job.

It's then easy enough to check for correct azimuth with a test record, and for VTF by ear. Anti-skating force settings for line contact styli is about 25% that necessary for spherical or elliptical styli because of lower friction and groove drag.

If you'll follow this strategy, you can be confident you are getting the most out of your tonearm and cartridge.

Nsgarch
I think we actually do not have a disagreement on the essentials. BUT if you have carts that like arm down (to keep it KISS) so the V's arm is just avoiding touching the record, I.E. down from level by 3-4mm. Yet another that likes it UP from level by a similar amount for the same record --- it is this what I'm talking about. What has changed is the angle between stylus' line-contact and cart mounting surface (at the optimal VTF) via the cantilever where it is mounted on.

Insisting on SRA is fine: IF I CAN ACTUALLY SEE IT!
Using that tool which produced the pic in the other thread OH YEAH, hurray!
So if I can't REALLY ascertain that 1.7 deg or what ever angle from vertical LP surface to the stylus' line contact -- then what is the good in riding on SRA? I have not the smallest issue with the theory, but in the end I need something more practical/useful I can work with, or?

Who wants to disagree with e.g. atomic weights, but I still get my sausage in pounds or ounces (in US I'd guess).
"Horses for courses" I make MORE mistakes setting SRA not really seeing what's going on, then simply listening --- so far at least my experience.
As nice as it might be to set the stylus contact-line to 1.7 deg. after I established that's what is needed for the record in the first place...
There are many such things in life, but for the practical current status a bit utopia I say.
You see already the MAJOR discrepancy in cutter angle statements! Roy Gandy has it at 0 - 7 deg. , your source knows or uses 1.7 deg. on you go.

In fact I think all of it has been used. So now you use this ASSUMPTION of how the record was cut to get completely immersed in setting SRA to the 1/10 of a degree. I'm sure it sound fine too, but because if it was 1 degree out it still sounded as fine.
Greetings,

The implication that certain arms/tools can provide 'tighter' setup tolerances is just baloney as I see it.

Well, I like baloney. Especially fried. So I guess that the rather large population of A'goners who have achieved better results using both the Wally and MintLP are just delusional?