Mounting hole-to-stylus variation / tolerance


Hi all,
I know this particular point has been touched on, raised, in some of the threads dealing with tone-arm-alignment in particular.
I truly think it deservers a dedicated thread since it has a more or less profound influence on various arm designs and their alignment.
It also has a profound influence in how accurate and beneficial any after market alignment tool will work for you!

We have had this far, feed back from Jonathan Carr, i.e. the variations and tolerances with regard to his product (Lyra).
We also had some rather powerful insights by Frank ..., who designs and makes arms i.e. the variations of various products he took note of.

Jonathan quoted, that his current products have a +/- 0.3mm tolerance from the 'standard' IEC...? of 3/8" or 9.52mm.

The findings of some contributors are different, possibly due to simple variations much greater than 0.3mm (Lyra's tolerance) or possibly due to subsequent movement of the 'motor' relative to the body, caused by rough handling, re-tipping, etc.

It is of most importance to get more feedback on this, due to the dependence of a close match to 9.52mm, on arms such as ALL of SME, to name but one. These rely on this to be fairly accurately aligned. If not, some pretty unacceptable misalignment follows as a result, if the stock alignment method is used.

Lastly, HOW can a 'normal' end-user measure this distance with some degree of accuracy?
I have no problem using a vernier (calliper) and measure a +/- 0.05mm variation.
I can not see that this tool will be of use in this case. Optical measurement (like tool-shops use) will be best I should think --- but who, I ask, has this at hand?

Greetings,
Axel
axelwahl
Dear Berlinta, rest assured - I got from the 3 samples what was possible. I just wasn't impressed. That was not a problem of the respective set-up nor of my abilities. As for the sientific dispute and my non-reaction to your mathematical and physical "facts" - I reacted and answered.
It just wasn't posted.
The dispute about the TT drive mechanism between the "gang" and me some weeks back gave a good example of my phrase about Galileo. If your and the comments of your gang-members regarding drirect drive vs. belt drive were indeed serious - than I am definitely Galileos legal successor.

But thanks for your extensive viae vitae anyway.
I've got to agree with Dan-ed. I've been trying to follow Axel's threads hoping to learn something new, but they seem to dissolve into nothing more than idle navel gazing. My god, the math for cart alignment has been available for decades-just choose your poison, and set up your arm and cart however it needs to be done! When you *do* arrive at a new, never-before-used alignment procedure, that you've used extensively and decided you prefer, please open another thread with your info. Otherwise, these pseudo-intellectual meanderings are just a waste of time-it's little wonder they attract few of the regulars.

saying that, I wish you luck, and vaya con dios
Hi Johnbrown,

I truly do not intend this to be some 'navel gazing' :-)

I initiated this thread after there was quite some discrepant information coming about in some of the other related threads on set-up and arm geometry.

It was Frank that made me start (of sorts) when he mentioned some pretty widely spread measurements of a variety of carts. I have no problem with the notion that with a 'variable' head-shell type of arm this to be a mute issue. Not EVERY one might agree, but I certainly do.

If an inquiry into that subject comes to "pseudo-intellectual meanderings" I not so sure.

Look, if carts vary from ~ 7mm - >10mm s2mh it may be good to know. Particularly if as a result the off-set ability of ones arm is past it's limit. Let me hasten to tell you, it just so happens to my case...

I don't know if that makes it more acceptable for you understanding the underlying motivation? Having just spend $5000 on an otherwise good tonearm doesn't make me go out and by yet another one just because I'm a bit lost with these cart variations, that happen do result in increased IGD.

So let see if this will make it a bit easier for to accept our 'meandering navel gazing' :-)

Axel
Good evening Dertonarm,

It has been my experience that even "seasoned" vinylphiles do benefit from a few words of advice when it comes to setting up one of my arms. If you feel that you don't need to take advantage of my offer, - no problem.
I would be most thankful though, if you could reply to me in private with the posts that were appearently banned by the moderator.
I was never referring to or greeting "my" gang, as there in no such thing. I was merely using a tongue in cheek expression to address everyone active in this forum.
And it looks as if you still don't think that an apology is in order for your remark about my "real life"..

Trotzdem schöne Grüsse nach Utting,

Frank Schröder