Installing DL-110 on RP3. Weird issues with tracking force.

The Stevenson should require about 2mm less overhang than the Baerwald, is this the arc protractor you are using below?

 

That's the one.

 

The overhang on that protractor measures 17 mm. If you have a metric ruler, you can confirm the pivot to spindle distance is 222 mm. Add 17 mm and you have 239 mm. Then measure out 239 mm from the pivot along the tonearm. On my Rega tonearm, that's very nearly the edge of the tonearm.

 

Sorry to say, but a protractor like this is virtually useless IMO and the chance of achieving a decent alignment with it is low.

Why use a single point protractor when any alignment methodology involves aligning to two null points? There is absolutely no way to confirm proper offset angle, which is critical. With both Rega and Stevenson alignment on that tonearm, the offset angle will be about 22 degrees; with Lofgren or Baerwald about 23 degrees, meaning, as I stated above, that the cartridge will have to be slightly angled in the headshell.

If you want to use a paper protractor and know your mounting or pivot to spindle distance, which should be 222 mm, print off one (or more using different alignment geometries and experiment) using Conrad Hoffman's software. Once you can trace the arc accurately AND align on BOTH grids/null points, you will have a decent alignment.

 

I don't quite follow your reasoning, the offset will be the same at both null points, so if you align the cartridge at the inside null point (like in the protractor above), it will still be aligned at the outside null point unless you haven't set the overhang correctly (in which case, you aren't using the protractor correctly, the stylus first needs to correctly follow the arc over the full range before setting offset at one of the grids). Showing two grids may help people better understand what they are trying to accomplish, and I agree that is worthwhile, but it isn't really necessary to show both grids or to align at both grids on the arc protractor to achieve correct alignment.

 

In theory you are correct. In practice, however, and as evidenced by the number of threads involving problems with cartridge alignment on forums, I would not recommend the use of a 1 point protractor, even a 1 point arc protractor, for alignment unless you are going to confirm the results with a two point protractor. Which begs the question: why not just use the 2 point in the first place.

For example I have Mint Protractors for both my arms. The Mint is probably the most precise protractor out there (I did not say the best-although I think it is if you are comfortable with one alignment geometry and you're not a table or arm flipper) and I'm pretty experienced and knowledgeable with alignment at this stage.

It's quite possible for me to align with the Mint and get pretty accurate tracing of the arc and accurate alignment on one of the grids while still being off on the other grid/null point. Which is why the instructions for the Mint (or any decent arc protractor) have the final stage-or two stages-of alignment as confirming the alignment at the second null point, adjusting if necessary, going back to confirm on the first null point and then ensuring you are accurately tracing the arc. So having that second grid/null point is key for me, and I would suggest it is probably even more important for those less experienced or less knowledgeable about alignment.

The problem is usually exacerbated when a user is switching to an alignment other than that suggested by the manufacturer which will change the offset and result in the cartridge needing to be angled. I have no problem with this and use a modified Lofgren alignment on one of my arms which results in the cartridge needing to be angled but many do not seem to understand this; the fact that the offset will change if you are not using the original alignment geometry and the cartridge will not sit square in the headshell is perhaps one of the biggest problems that those new to alignment struggle with.

Ironically, the OP here seems to be able to achieve a Baerwald alignment (with the cartridge sitting square in the headshell apparently) on an arm which has original alignment geometry very close to Stevenson, and is apparently unable to achieve a Stevenson alignment at all.

So something is not quite right. Heading to a two point protractor (preferably an arc protractor as long as mounting distance is correct and verifiable) and using it properly should take the guesswork out of things and result in a much more accurate alignment IMO.

 

FWIW, kinda intuative, but If you remove platter and tonearm, and measure outside middle of the holes and inside middle of the holes and divide by two you'll get a pretty accurate pivot to spindle. Use an accurate metal ruler.