Why use a super accurate cartridge protractor

In discussions about cartridge setup, there are those who say that unless one has a cartridge setup protractor like the Mint, Wally Tractor, Dennesen, etc. one cannot expect to extract maximum performance from your rig. Then there are those that say that even the best alignment tool still only nets you a position that needs further tweaking by ear. In my case, I've used a Dennesen and a number of downloadable free protractors and have been able to get good results with the free downloads if I took my time to make those little .5mm shifts that make sound pop into best focus. Is the superiority of a Mint or a Wally Tractor because one doesn't have to make those final last tiny adjustments? Is it that the mirror surface is easier on the eyes?
I believe that they are for those with younger eyes who wish to spend more time on alignment than most of us do. I have not used then myself as the arms I usually use, VPI and Graham, come with gauges that do a very good job. Would Mint etc do better, possibly but not with 70 year old eyes and nerves. The Graham is especially good as it comes with a gauge that fits over the detached arm wand so you can look DOWN through the gauge at the stylus instead of trying to look at it from the top. Also has device to set arm at correct piviot distance. I wish more arm makers would provide similar devices. I have been aligning cartridges since before most users had a sound system other than a baby rattle and appriciate its importance but it seems to border on an obsession with some.
The advantage of the Mint over a downloadable arc or two point protractor is its precision.

The drawn arc and null points of the Mint are very fine indeed and the flat mirrored surface allows you to adjust accurately to these lines (and of course the mirrored surface and guidelines at the null points assist in avoiding parallax errors).

But it will not save you from making those tiny adjustments - these are what the Mint is all about! You must make these micro adjustments to avail yourself of the Mint's precision. The precision possible with the Mint is much better than 0.5mm - Magnification is a must!
Like the designer, I recommend strong natural light if you can avail yourself of it.
Lots of confusing and conflicting info with regards to alignment-- Lofgren, Stephenson, Baerwald, Rega-- all different alignments, all compromises. I've been trying find a definitive answer, but I think the geometry is not sufficient to address tracking distortion errors, given the different vinyl properties, cutting methods, etc. I did find that on fine-line or shibata type styli, a careful alignment can improve the sound, but I do not think the change in sound was due to the alignment "exactly" matching any one particular recognized alignment scheme-- probably more just trial and error. I use a denneson soundtractor and have spent WAYYY to many hours trying to visually align the stylus-- not so sure its worth the effort though.
I have found that it is worth the effort....after all, you just have to do it once...
The Mint-and Uni tractor are the only kind which include
the spindle as variable. Mint is specific for a given TT(aka spindle diameter) and tonearm combo while Uni is the so called 'universal tractor'.

Cocoabaroque, I started a new thread 'Tonearm geometry and
setup' with the intention to get answers reg. Bearwald,
Stephenson,etc. 'confusion'. The 'compromises' you are refering to are meant as (our) choice where on the record radius we want the least distortion. This means 'depending'
of the records we own (see Dertonarm's post in the thread
mentioned). My own problem is to understand the different tonearm designs, say,the Japanese preference for Stephenson geometry while 'the rest' seems to prefer Bearwald. Ie our 'choice possibility' will also depend from the used tonearm. I hope Dertonarm or somebody else will address this 'point' or, as I called it elswere the tonearm 'on its

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I have a Graham Phantom arm, which comes with the cartridge set-up jig. While I don’t have the jig in front of me, IIRC, there are 2 markings (for 2 different alignment curves) roughly around 1mm apart, which is a big difference considering the precision level members are talking about here.

Now, as John Gordon and Dertonarm pointed out in another thread (if I understand correctly), which alignment curve to choose really depends on the inner and outer radii of the groove area, as well as the music piece and, of course, the users’ preference.

So, I really fail to see the need for an ultra precision alignment protractor, as the “best alignment” is probably different for different LPs and individual users. Taking the Phantom arm, I suppose even if I “misaligned” the cartridge and placed it somewhere in between the 2 markings, I would just get slightly different null points than the 2 standard alignment curves. This might, or might not, be a good thing depends on the LP played.

Am I missing anything?
To answer the original question: no reason at all. Unless you can't hear a thing but want to feel like a true purist audiophile.
Thekong, The distortions we are talking about are the
opposite of each other. We are of course interested in the least (aka 'minimal') distortion but what about the maximal 'kind'. The so called 'zero points' mean minimal distortion
at those 'points' on the record radius. But there must be
the corresponding max. distortion at some other 'points'.
Well it seems to me that we should worry about those also.
I have never seen any numerical values for those in this forum. It may be the case that while I feel 'proud' about my own selection of the zero points my records are in a
sade state because of my choice?


Hi Nandric, I agree with you that we should also worry about the max. distortion, actually maybe more so than the min distortion, as it is already quite small.
Thanks to those who've replied so far, it's been interesting to hear the different approaches and perspectives. Like Stanwal,I think the difficulty of setting dead on correct pivot/spindle distance is something that could use more attention in devising set up tools. I still remain unpersuaded as to obtaining superior results with a Mint vs. less precise methods IF one still has to "make the final adjustments by ear." (Assuming one has properly set up spindle/pivot distance.) In the cartridge setup instructions with the Vacuum State Guru protractor, Allen Wright says that after checking many cartridge alignments with final adjustment tunings done by ear, there is a consistent trend of finding settings about 1.27mm behind traditional Cotter points on an alignment arc. After spending part of last Sunday setting up an Ortofon Kontrapunkt H with a super fineline stylus, I ended up very close to those points myself.
Dear Thekong, dear Nandric, we should in specific worry about where on the groove's radius the maxima and minima are located. The groove's walls do change with decreasing radius and thus do the conditions for the stylus' polished areas. Thats why high derivations from the tangential zero are most "lethal" to the sound towards the inner label.
Hi Dertonarm, if I understand correctly, the alignment you chose aimed at minimizing distortion at the last 1/3 of the groove’s radius, which I think make a lot of sense, as the inner tracks are inherently harder to track, and in addition, many of the classical pieces have the climax towards the end.

What I wonder is the need for ultra precision in the alignment. If I am using a 9” arm, and misalign by, say 0.5mm, then how far would the null points shift?

Best regards,
Hi Thekong, the null points will shift and the curve will be a different one. If you go to Vinyl Engine and play a bit with the alignment comparator - you will see, that small alternations have huge impact.
Dear Thekong, the alignment I did choose actually minimizes distortion in the last 2/3 ( not just last 1/3) of the record groove's radius.

Hi Photon46

In the cartridge setup instructions with the Vacuum State Guru protractor, Allen Wright says that after checking many cartridge alignments with final adjustment tunings done by ear, there is a consistent trend of finding settings about 1.27mm behind traditional Cotter points on an alignment arc. After spending part of last Sunday setting up an Ortofon Kontrapunkt H with a super fineline stylus, I ended up very close to those points myself.

Don't get misled by vague statements which offhandedly negate or discard existing knowledge, and appear to have discovered something new in promoting a product. Another way of saying the quote above is:

"If you try a Lofgren B DIN alignment you might find it suits your LPs better than the Lofgren A/Baerwald IEC (which is the usual alignment with nulls at 66 and 121), which is what I (the Guru) am doing, but not telling you."

But that doesn't quite have the same mystique.....

That is in effect what is happening with the new alignment - it is LofgrenB-ish - for a 230mm arm, it now has effective length of 228.73, overhang reduced to 16.78 and offset angle reduced to 22.87degrees.

Hi Nandric,
you said
But there must be
the corresponding max. distortion at some other 'points'.
Well it seems to me that we should worry about those also.
I have never seen any numerical values for those in this forum. It may be the case that while I feel 'proud' about my own selection of the zero points my records are in a
sade state because of my choice?

For most alignments there are three maxima (Stevenson being a special case). Typical distortion values for these are (for a 230 arm) 0.65% for the three equal LogrenA/Baerwald IEC maxima and 0.42% average across the side.

For Lofgren B IEC the average is 0.38% but the maximum is now 1% at the innermost groove.

For DIN alignments, there is more distortion when playing a DIN LP but less at the inner grooves when playing a IEC LP. This is why I chose a DIN alignment 30 years ago.

Dertonarm's Uni-DIN alignment is a variation on this which reduces the inner maximum to 0.5% for DIN LPs and lowers the middle max to 0.5% while increasing the outer max to over 1%.


Hi Thekong

Dertonarm said
the alignment I did choose actually minimizes distortion in the last 2/3 ( not just last 1/3) of the record groove's radius

He should have said
...the alignment I did choose reduces distortion....

The alignment reduces it. It doesn't minimize it.

It can easily be reduced further, but at the expense of an increase elsewhere, which is the point being ignored.

Regarding changes in overhang and offset. For a 9" arm, if the overhang is increased by 0.5mm, and offset increased by 0.5 degree, they tend to compensate, as they also do when reduced by similar amounts.

If one is reduced as the other is increased, the errors add and the distortion increases. So you could have made unintended errors in your setup and they could sound ok. Or not.

As an illustration, if the overhang is increased by 0.5mm without the offset changing, you basically get Lofgren B, which may well sound better on your favourite album...

No offense intended, but the notion of "alignment by ear" is idiotic. This is simple geometry. Good alignment protractors trace a line that minimizes distortion across the surface of the record. Different alignments optimize different areas of the record.

Overall - do you want to minimize tracing error and tracking distortion on your analog setup? If so - then you want the most accurate protractor you can get. I use the MINT, and I can align my cartridge with a very high level of precision in 10 minutes with it
Apparently there is no need. Well Tempered tonearms do not allow for overhang adjustments, and the are well regarded by many.

Goatwuss, I agree with proviso that 'idiotic' means something like 'mental aritmetic' versus ' calculator'.

The reason you might do them by ear AFTER you had them aligned by protractor is that sometimes the stylus does not sit perfectly on the candilever.
John Gordon, thanks for your take on it all. Perhaps Vacuum State's unfortunate title for their protractor is a result of "English as a second language." They aren't selling anything, it's a free download they offer on their website. Goatwuss' point regarding "simple geometry" is of course true. Perhaps what is really meant by "ear tuning" is that one finds through fiddling around with their alignment that they prefer the distortion distribution of Lofrgren B points vs. A, as John said.
I use the DB protractor and find it easy to use and very accurate. Plus it is not arm/table specific like the Mint.
Hi photon

Allen Wright of vacuum state was an Australian. His english was just fine :-)
Mauidj, I think that you missed the 'point' by Mint tractor. Ie the spindle diameter as variable is included.This means that the tractor is 'spindle'(aka TT) specific.
BTW 'easy to use' and 'very accurate' seldom coincide. I am alas not familiar with Dertonarm's tractor but I know that the spindle variable is also included. But reg. the 'ease of use' one can check by the thread about this tractor.

Just my tuppence worth...
I have only used the Graham Phantom Setup Jig on my current cartridge but as it may have been mentioned elsewhere this allows a very clear, well illuminated, view of the cart undercarriage during setup.

The most important thing I observed is that tensioning the cart screws is very critical and not the final result that people think - even when they are convinced they've been extraordinarily careful not to upset the "perfect alignment". After the first 60 tries (yes you read that correctly) I was still unhappy with the final cart position which often ended up with an estimated 0.2mm offset from target in any given direction(!!!). I finally got the perfect result (and was only truly happy) after 70 tries...
(Admittedly I was using nylon washers to protect the headshell finish and am unsure that these are a better idea than steel washers for cartridge mounting...)

With this experience under my belt I was sure I could do it in less than 10 tries from then on, but it clearly illustrates the unpredictable nature of the process. Our mindset tends towards the conviction that once we've tweaked the hell out of it, we don't want to move it again for fear of upsetting it. My contention is you probably have upset - almost every time - merely by trying to lock it down.

The moral of this story is that had I been using a gimballed arm, I would have been stripping the arm off the T/T for each tightening exercise and would have repeated that process no more than half a dozen times before losing the will to live and capitulating. I suspect many other enthusiasts would settle at this point too, but, given the above story, would their alignment have been as good as believed????
Moreover, by this stage, would they care???
Moonglum, you're so right. Learning to tighten down the cartridge screws with one hand while exerting just the right amount of counteracting torque on the cartridge with the other hand as things snug up can be exasperating to say the least. Understandably, one may become reluctant to change cartridges if using nylon washers.
The reason to get a MINT is for its accuracy. I agree it is very tiresome to do it correctly, however, if accuracy is your goal, that's what needs to be done. Nylon washers will not mount the cartridge solidly to the arm...I use steel to protect the arm head with no deleterious effects. To set up a cartridge is a huge pain...may take a couple of days, but you only do it once.
Nandric...I think you missed my point ;-)
I did say that the Mint was arm/table specific....which it really is...but I guess it is more accurate to describe it as spindle specific.
My point about the db was to balance the posts you mentioned that say it is complicated.
I cannot understand why some people think it is. It just works on a vernier principal. Easy to use and accurate are certainly not mutually exclusive as you suggest. Actually the best instruments and tools are both of the above in my experience. Because they are easy to use one can be more accurate in their use.
As you have not tried a db I would suggest doing so before condemning it as inaccurate or hard to use.
Precision is mandatory. When we multiply a regular Tonearm by Factor 100, the Arm is about 27.34yd (25m) long, the Cartridge System is about 1.09 yd (1m) high with a Length of the cantilever in the area of 0.55 yd (0.5m) and the contact area from the Diamond is only 0.020 in. (0,5mm) ! Similar is the Mass in comparison. (Another chapter for side wall pressure and diamond polishing...)
A simple example to show what analog reproduction really is ... And why sonic performance can be improved with some care and the right tool.
But honestly, buying new cartridges - and writing about it - create more fun...
I only know that with a Mint and a USB microscope and a Fozgometer/Ultimate Analogue set up record and a lot of patience and chill, I am getting incredible sound out of a Benz Glider SLO mounted on a VPI Classic. If you want to enjoy vinyl to the fullest, you have to really sweat the last 2% of the details to the utmost degree.
Are we not taking it on faith that the great masters of cartridge alignment(!)--Lofgren, Baerwald, Stephenson, etc knew what they were doing even though they disagree amongst themselves? Are audiophiles ready to admit that Rega's (mis)alignment scheme is different from them all yet still sounds fantastic on their current generation of tables? Methinks a paradigm shift is in order here. Geometry is a perfect and exact science, but cartridge alignment is not so perfect. Just as the violin luthier's exact measurements does not produce a Stradavarius, but a skilled craftsman can approach the Strad sound using his experience and creativity. There is still a chasm between art and science-- and music is art.
I am not a mathematician but doesn't the geometry change slightly with every moment when stylus is moving along? So, yes, perfect alignment at every moment would be great if it was possible. The trick is to find an acceptable compomise. By ear.
Dear Cocoabaroque, when Loefgren and Baerwald calculated the respective tangential curves (Baerwald/Loefgren A and Loefgren B), they did do it for monophonic records to be tracked with round styli of approx. 60 µm radius.
Stereo microgroove and fine line or similar styli with polished area of 1µm x 5-6µm weren't in sight at all.
A stereo record's groove is not a homogenous track at all and the differences in radii between the groove's two walls do increase with decreasing distance to the spindle.
In other words: the tracking conditions for a stereo stylus do change ever more towards the groove's lead out.
That's why some designers did choose alignments different from the "old masters" and that's a reason why so many modern audiophile records have rather long dead wax - avoiding the ever more problematic situation close to the inner label.
When Loefgren made his calculation's, our grandfathers were young men and our parents were in pampers. This was almost half a century before micro-ridge, vdH 1 or fine line styli first saw the light of day or the walls of a MFSL LP.
A spherical 60µm needle tracking an old wide groove record has a much easier job.
No worries there about soundstage recreation, increasing differences between left and right groove wall contact areas.
Keep enjoying the discussion - off for 2 week holiday in Africa now,

Are we not taking it on faith that the great masters of cartridge alignment(!)--Lofgren, Baerwald, Stephenson, etc knew what they were doing even though they disagree amongst themselves?

You don't have to take anything on faith, it is not a matter of "faith". The only reason we can all actually talk about alignments and geometry and use the words to describe them is because Loefgren, (and Wilson before him in the 20's) spent many hours (without calculators or computers) to figure out from first principles how to minimise tracking error and then tracking distortion.

Subsequently Baerwald, Bauer, Stephenson et al came up with variations based on those calculations, which have different perpectives, but in no way disagree. Rega doesn't use a "special" alignment. It is just not Loefgren A IEC. Stephenson IEC is simply a Loefgren A with inner radius around 54.8mm which places the inner null at 60.3mm, the IEC inner radius.

Dertonarm is correct in saying that conditions change as the radius decreases, but the calculations for minimising tracking error are the same as they always have been. It is the distortion caused by that error that is the issue...

Which is why he is advocating different alignments. But these alignments are still predicated on the Loefgren equations and merely reflect his preferences as to where the equations should be weighted. This can now be done by anyone and his brother, who (unlike Loefgren) has access to the excellent Vinyl Engine calculators. In the same way that Stephenson came up with his variation, we can enter minimum and maximum radii such that the shape of the distortion curve suits our purpose for the records we have.

However, as far as I know, no one has yet come up with a formula which has been designed to use different weightings (other than those for average distortion (Loefgren B), or for minimising/equalising distortion peaks (LoefgrenA))

Whatever our reasons, in coping with tracing distortions caused by using modern stereo (versus old mono) stylii, Dertonarm and the rest of us are basically still using Lofgren A, with variations in input parameters.

Although all this doesn't address the issue of how significant are errors in set up in relation to the distortions at particular radii.


After the first 60 tries (yes you read that correctly) I was still unhappy with the final cart position which often ended up with an estimated 0.2mm offset from target in any given direction(!!!). I finally got the perfect result (and was only truly happy) after 70 tries...

Interesting to hear your take - I would imagine that +/-0.2mm is pretty good and that 0.5mm is more typical. I have played around trying to estimate how accurately I could set the offset angle, as I think that is the real unknown when it comes to talking about accuracy, and reckon +/-0.25 degree is the variation.

However, no protractor manufacturer, as far as I know, actually says either how accurately their protractor is made, or how accurate, precise and repeatable are the setups typically achieved with their device. In particular, regarding offset angle. So, is a Mint more accurate than a Denessen, a DB, a Wally tractor, a Feickert? How to measure this?
Löfgren just used euclidean geometry - as does did everybody before/after him in the past 2260+ years in the western hemisphere - be it in tonearm geometry or any other geometrical topic related to mechanics and 3-dimensonal space on earth.
He was however unquestioned the first to muse and care about giving phono playback an optimized geometric solid basis.
And every analog audiophile should be grateful for his attempt.
I for one certainly am.
Viewed in the light of fact that there is a wide diversity of stereo records since 1958 with groove cut area varying by a wide margin, his preferences and weightings aren't as universal applicable as they were in 1934/38.
Dear John, When I stated in some thread that I am hardly
able to see 1mm I got an reprimand from Dertonarm. My compliments for your eye and capabilty to handle fractions of an 1 mm. But if the spindle variations are > 1mm (I forget what Yip from Mint tractor told me) then what is the sense of aiming at 0,2 mm elsewere? Ie some tractors must be more precise then other.

Dear Nikola, spindle diameter variations are usually between 7,00 to 7,25 mm - so we are talking derivations between spindle diameters of maximum 0.25 mm.
As long as one tries to be as precise as possible in as many parameters as possible, it is at least a suitable way to get close to a precise alignment.
If the inaccuracy however builds up and adds ever more with the number of parameters "not cared that much about", one may (not need to - by dump luck) get not an alignment, but a "guess" which may be way off.

Why use a super accurate protractor?
Simply because it helps to get the best (read: best sonic performance) out of your cartridge/tonearm.
Would you use an expensive high performance Porsche or Mercedes (Audi, Jaguar - extend at wish ...) with old worn tires suitable for a 1955 beetle?
Not using an as precise as possible alignment ( = super precise protractor ) is simply giving away possible sonic quality and putting the whole performance of one's audio set-up at risk (sonic wise).
It is as easy as that.
If one doesn't really care about sound and possible wear of his/her records - fine, no problem (at least not mine).
But then the question arise why spending hundreds and thousands of dollars for analog playback at all?
CD-players are cheap to get and don't need a protractor (at least not a super precise one ...).
Löfgren just used euclidean geometry.... He was however unquestioned the first to muse and care about giving phono playback an optimized geometric solid basis.

As you say DT, thankfully we can stick to Euclid and don't have to concern ourselves with Riemann. Re primacy, I believe it was Percy Wilson who published the first analysis of offset tonearm geometry and Loefgren accounted for the factor of decreasing radius as a contribution to distortion. As you say, "every analog audiophile should be grateful for his attempt."

I agree when you say

his preferences and weightings aren't as universal applicable as they were in 1934/38.

My point was simply that the weightings for skewing the tracking error equations
haven't changed. What has happened, as you are well aware, is that we can now easily change the input parameters to the same good old equations and find, as you have done, an alignment that is preferable, and then specify appropriate nulls. But these nulls are not related to the actual inner radius of the records, that is, there is no formula that I have seen published, where I can enter an actual inner and outer radius and come up with say, Uni IEC, or any other null based alignment.


John_gordon, no so far there isn't a new formula.
But then - is there really a need for one?
Given the wide variation in records grooved radius, there is no "royal device"/Königsweg.
The user/operator/analog enthusiast ultimately has to choose the alignment he/she (it..?) prefers.
This choice should be based on the majority of the records in one's collection.
Lucky audiophiles out there with multiple tonearms at hand (Halcro?, Nandric?, Downunder?, Thuchan? ..) might go the way of using different alignments and thus serving all the different records - each with the best suitable alignment.
"My" preference is based on the majority of my collection (mostly US and british records pressed in the late 1950ies to early 1970ies - many with very short dead wax/lead out groove) my preferences in sonics (big and detailed soundstage and up-front, dynamic live-like sonic "picture") AND finally my experience that 0.8% distortion in the lead-in groove are far less sonically "obstructive" (in the negative aural sense) as they are close to the inner label.
Add to that my addiction to big symphonic music, opera and 1950/60 Jazz with many big crescendi towards the end of movements and I have yet another good reason for trying to reduce/minimize distortion in the last 2/3 of the groove.
This of course would in no way apply to a collection of 1990ies to 2010s modern audiophile records where the groove quite often doesn't even come close to IEC inner limit.
I am quite happy that we have a selection of different alignments to choose the appropriate for each collection/preference.
In any case - off now for holiday till mid-september.
Kind regards to everyone and a sunny august!

Dear Nikola,

I find it harder to see (and hear) things as time marches on. But I try.

As you say, the protractor is only as good as the widest tolerance. Which is my point. As DT says, spindles vary, by 0.25mm. So there we actually have a number. But he asks
Why use a super accurate protractor?
Simply because it helps to get the best (read: best sonic performance) out of your cartridge/tonearm.
So super accurate means that "best" is sonic performance, as opposed to physical performance.

In other words to continue DT's analogy, if Michael Schumacher could drive his Ferrari with the old beetle tyres faster than Dertonarm using the expensive ones, then are his tyres better than DT's? Would we buy them?

Wouldn't we rather look at the description of the tyre's performance? The reasons we might choose it for a Ferrari, why it might be suitable.

The analogy here is to the protractor's performance. How accurately can it set up the arm. Will it be within 1mm, 0.5mm, 0.1mm in overhang? Will it be within 1degree, or 0.5, or 0.1? Mounting distance? And how repeatable is it?

I'm not saying Dertonearm's protractor isn't precisely made, or can't give good results, just that neither he, nor anyone else, gives a specification for protractors, one of the few areas in hifi where that is the case. If it was an amp, would manufacturers get away with saying how loud it goes depends on how well you set the volume control?

Perhaps if someone said it was precisely made? Or said it looked impressive?
Or maybe I'm getting too old and too cynical.

Dear John, 'Too old'? What a pity. I think you could be a very good teacher. The persons who know what they are tolking about and have clear thoughts are usualy able to
express them clearly. On the other hand I think that skepticism has more to do with the social enviroment then knowledge.
We are glad to have you and Dertonarm as our members.

Kind regards,

I hope you have an enjoyable holiday, and, of course I agree with you that everyone should choose their alignment according to their record collection - would that were always the case. And for your collection you have chosen correctly. We have never disagreed on that.

Now on to other matters, and perhaps I shall manage a holiday at some point, though some would say, though I'd disagree, that I treat all my life as a holiday.
Hi John_Gordon -
Interesting you should mention offset angle. One of the strengths of the Phantom jig is angular alignment of the stylus/generator.
It's an old article I know, but it stuck in my mind because of it's relevance. Scroll down the link to "The Need For Precise Setup":-


The author's results were very thought provoking....
Protractors are great for aligning horizontal azimuth and effective length with any precision for a given SRA/VTA range. Vertical azimuth, SRA/VTA, and VTF are usually adjusted by ear. Although we can set AZ by eye, that doesn't necessarily equate to the best and usually takes final tuning by ear. In other words, the use of a protractor is only part of the alignment process. My 2 cents worth.

A note. MintLP Best Tractor is accurate to the 2nd digit of a millimeter. It is simply a more precisely printed loefgren A, arc protractor with the added benefit of parallax effect for sighting. Assuming one has the optics and eyesight to use it properly, it allows for alignment of the stylus, not just the cartridge body.
A note - as I am not yet off the computer.
A protractor with just a helping line saying "please rotate till this line points toward the pivot" (talking about eyesight and good target....) has certainly potential for increased accuracy.
The laser lines on the UNI-templates/UNI-Protractor are accurate to the 3rd digit of a millimeter.
The lines are the smallest possible in laser-engravement.
All templates are with 3mm deep true parallax.
The UNI-Protractor's templates allow for alignment of the stylus and cantilever - not just the cartridge body.
It does so for ANY effective length and ANY pivot tonearm to ANY tangential curve desired.
Add to this the fact that most owners of the UNI-Protractor - more than 70 by now - did already own one or more MINT and other protractors before purchasing the UNI-Protractor.
Before I did design the UNI-Protractor I did collect samples of all the other protractors on the market - past and present.
Those 70+ fellow Audiogoners who have worked with the UNI-Protractor already know exactly why they bought this comparatively high priced tool.
Because of it's precision, unique universality, build quality and - last not least - outstanding sonic results.
Hi Dan_ed
The Mint Protractor you refer to,
accurate to the 2nd digit of a millimeter
does that mean to 1/100 of a mm? And what did you mean by
...aligning horizontal azimuth and effective length with any precision
This is one of my points that, while there are figures for how precise the protractors are made regarding linear dimensions, there is nothing regarding angular ones. Even in the case of the Graham jigs mentioned by Moonglum, there are no numbers, so we don't know by how much things are improved by using the jig, ie how much angular adjustment is required. Or ultimately, by how much the stylus is out of alignment on the cantilever, how much the cantilever is out of alignment with the generator, and how far that is out re the body. Of course that is a big ask...!

You are totally right regarding the rest of the adjustments - I agree that a protractor is only part of the set up process - and the other parameters can have big effects.
Hi John,

Yes, I understand that to be the precision of the protractor in all regards. Maybe a good question for Yip. I assume that the lines orthogonal to the groove are drawn to the same precision by a computer.

When I align on a Mint I am not concerned at all with the orientation of the cantilever, within common sense. ;-) What I mean is that I align the stylus to the lines and not anything else. The lines, as tiny as they are, are still a bit wider than the stylus so I'm twisting ever so slightly while staying within the bounds of the line. Whether the stylus may need a bit more twist to the right or left is a pretty tough call. Perhaps this is the angle you refer to? I admit I am still at the mercy of how precisely the protractor is drawn as well as printed.

To the thread question. Even though there may not be good tools for setting all of the parameters I do find that using those that are available do indeed give me better results. I think it is possible to get just as good of results with most protractors, but I find that the extra precision does help me get repeatable results as I do switch cartridges and arms fairly often.