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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
axelwahl OP
788 posts
 
HALLO!!!!!!!
Welcome to the world of sharing :-)

It just shows that it helps to keep things level.
I for one did not know that Frank was alias Berlinta (Berlin TA --- ah, so!).
Well at least I only had nice things to say about you Frank. And having met you, if rather shortly, at the last RMAF made my impression of a most approachable and VERY dedicated Audio professional (it was just great to what you tweaking your arm set-ups :-)
Now you shared some more, thanks to Herr Kurt's little bantering (not to call it indiscretion). So every cloud has a silver-lining, one man loss the other man gain, hm.

I was actually trying to find out, what it was that caused this less then enthusiastic assessment of the Schroeder arm(s). Alas now I guess we will have some difficulty with this, I guess. Or what say you Daniel?

It also shows that sometimes this 'aliasing can be cause of embarrassing moments...
I myself put my foot in, when questioning Dave Slagle (THE trannie man around here) about his postings being 'oddly reminiscent' of some other originator(s). As it turned out most of it was of course his own -- under his non alias!
Well, Daniel, Frank, embarrassing as thing can be at times I still have to THANK YOU both very much for your valuable contributions, even if they do not converge...
This puts some spice and flavour in this 'blogging soup' :-)

Thank you for sharing,
Axel
dan_ed
2,451 posts
 
If one has the means to adjust P2S infinitely, and has an arc-style protractor custom made for the arm in use, then the concept this thread was started on is moot, as well as any worries about effective length.
axelwahl OP
788 posts
 
Hi Dan_ed,

thank you for your thoughtful input.
Though, the key word here might just be --- IF --- or?
:-)
Axel
PS: IF that distance is way out, as some carts seem to be, the stock adjusting templates e.g. SME can become pretty useless. You suggest to buy a new custom template for each new cart ---- IF that distance we talk about is truly KNOWN! A lot of IFS...
dan_ed
2,451 posts
 
The only reason I say "if" is to keep my post in general terms.

I do have a means to infinitely adjust p2s and I do have protractor that was custom made to the effective length of my tonearm. I can change to any cartridge I want and be assured of the correct alignment. The distance from stylus to center of cartridge mounting holes is a "don't care".

But there is a correlation with what you are posting to this thread about. That is the correct effective length of any particular tonearm. I surprised to find out that sometimes there are differences of a few mm in the published specs for some tonearms. So, check your numbers before ordering a custom protractor. :-)
axelwahl OP
788 posts
 
Hi Dan_ed
I'm not all the way with this adjustable p2s (pivot-to-stylus) protractor.
It obviously is not the 'fixed type' that you warn about below.

>>> So, check your numbers before ordering a custom protractor. <<<

The issue with mh2s is that it is part of p2s, and in any fixed mh head-shell arm of some pretty high importance to know, i.e. certainly no mute point --- lest your overhang AND zenith are out = more distortion.

So, your warring is BETTER well headed!
In the meantime I will stick to my stock alignment, since I DO NOT KNOW as yet what my PW's mh2s actually is.

"IF" my p2s comes to 233.15mm (please note the .15! part of it) I should be in the pound-seat.
No need to mention the arm, since that spec is too well known by now, or? :-)

Axel
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