Feickert analogue protractor....Owners impressions

Oh yes ... a quick follow-up to Joe.

Yes indeed, someone could easily order an arc that resulted in a 222.8 mm pivot to spindle distance.

Typically, you work backwards from effective length, but if you use John Ellison's wonderful spreadsheet and set the precision level to 4 decimal places, you can (using binary search techniques) derive any number you need in 5 or 6 tries.

Once you have an effective length, tell Yip (Mintlp) or Wally what you need and in 3 weeks (Yip) or ??? (Wally), it's in your mailbox.

It's all just computers and numbers and one number (222) is as good as another (222.8).

Cheers,
Thom @ Galibier

Smoffatt - the best way to get a cart aligned in an SME V, imo, is with a Wallytractor. I haven't seen the Mint, but if its the same design and quality as a Wally, then it will work as well. For me, the arc style protractor is much easier than a two-pointer, but those can work. (Say what you will, Wally deserves a boatload of credit for bringing his mirrored arc style tractor to us audiophiles - like many others on this forum, he's a generous contributor to our hobby.)

The fine gradient movement of the SME's sled makes small adjustments simple to dial the stylus in the arc across its length - much easier than manually shifting the cartridge in head shell slots and then tightening the cartridge bolts without changing anything. This, imo, is one of the design's real strengths. Once the tone arm is mounted, the sled makes pivot-to-spindle distance somewhat of a moot point.

If your cantilever (and ultimately your stylus) is at right angles to a line drawn through the headshell bolts, then there should be no need for cartridge adjustment to hit the proper offset on the protractor's grid lines. Otherwise the soft head shell metal makes it simple to *very slightly* enlarge the holes in the headshell enough for minor adjustment. (I did this turning a drill by hand - let me know if you need the bit size, I've got it somewhere in my notes at home.)

Tom - thanks for the follow-up!

Tim

Tim,
"The fine gradient movement of the SME's sled makes small adjustments simple to dial the stylus in the arc across its length"
Wouldn’t you be defeating the purpose of a custom protractor by changing the spindle to pivot distance as an adjustment? If you order a protractor for SME isn't the arc based on the 233.15 spindle to pivot distance, the distance you change to adjust? I bring this up because you mention that the Wally is the best method for SME alignment(IMO), I'm not sure it or any arc protractor is unless the cartridge one uses produces the correct effective length for the 233.15 arc. I just mounted a SME IV.Vi so I'm looking for feedback also. Now, if I measure the effective length and back into the spindle to pivot measurement and it's not the SME suggested 233.15, I wonder if it would be better to order a protractor for the SME suggested 233.15 or order one based on the spindle to pivot number derived from the actual effective length? HMMMMMMM.

Mike

Hi Mjglo,

Your question is indeed a valid one. Every effective length has one and only one correct pivot to spindle distance and offset angle.

Tim is adjusting for a change in effective length with the pivot to spindle change (and likely adjusting offset angle slightly with his oversized screw holes).

I suspect he's getting such good results with a Wally because his cartridge's stylus position closely matches SME's design assumptions, and therfore his tonearm's effective length is close to specification.

Cheers,
Thom @ Galibier

So, if one wants a custom-made arc protractor, shouldn't one supply to the maker the ACTUAL spindle to pivot distance, rather than the optimal theoretical one, which may not pertain to the arm for which the protractor is to be used? Forgive me if the question is redundant.