Tenor Dimensions

I'm building a Stew-Mac tenor and will finish the body this weekend. Hopefully get it all completed (except finishing) in a few days.

Most of my lutherie experience is related to classical guitars and the string family. So I have few uke specific questions.

Stew-Mac recommends 3/32" compensation at the bridge/saddle. Sounds reasonable but I would like some opinions. Is it good for both low G and re-entrant tuning? I know compensation can change with string brand and tension and is a compromise at best.

String height at the 12th fret. What's considered good action?

Thanks, Larry

You'll get different responses, so here's a start. I use a straight 1/8th" saddle (with a 7 degree back angle in the bridge) and compensate it across for low g tuning. It's not unusual for the 1st string to be at the neck side of the saddle and the 4th to be towards the okole (end).

Height depends on tension of strings- usually I'll go to about .100" with D'Addario T2's, and a little higher with Savarez Alliance.

Again, you'll get some builders that go lower, wider, etc. Have fun.

Aaron

Do you put the base of the saddle (point of intersection of saddle and bridge) right on the scale length Aaron, and then the tilt back of the saddle adds that little bit extra?

It's worth noting that the steeper the break angle behind the saddle, the more compensation you'll need...by a little bit. The reason is that the bend over the saddle puts a stress on the string right at the "witness point" and so the smooth hinge effect of the saddle is bumped "north" just a tad.

The one tricky issue with tilt-back saddles (which I've been doing on all acoustic-type bridges since about 1992) is that the taller the saddle, the further "south" the witness point. You just have to know that and deal with it. The advantages to making bridges this way more than compensate for that one issue. Pun intended...

Allen said:

Do you put the base of the saddle (point of intersection of saddle and bridge) right on the scale length Aaron, and then the tilt back of the saddle adds that little bit extra?

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Actuall, I put the top of the saddle slot of the bridge at the scale length, which for me is 17". From there the back angle adds the extra, and yes, the base of the saddle inside the saddle slot is actually less than 17", probably less than a few thou, bit I haven't measured it. This works for me, and I have a jig to set the bridge location (of course).

BTW, the back angle idea came from Rick, years ago. I did it initially for pickup installations, but soon after I did it to all. Really helps when setting the action and compensating the saddle, which is 1/8" btw, so a bit of extra on the low g.

Rick Turner said:

. . .The advantages to making bridges this way more than compensate for that one issue. Pun intended...

Click to expand...

The way I take advantage is I set the intonation first, close, then I take down the action from the top, reshaping and fine tuning as needed. Most times, I stick with the same strings, so the saddle shape is the same, and I usually get the compensated shape right away. As Rick alluded to, I bring down the action, but don't change the compensation from there.

Another note when doing this: the ramp after the witness point is fairly shallow while the ramp in front is fairly steep. The StewMac nut vise is REALLY worth it for me. Yes, could've made my own, but it was convenient?
http://www.stewmac.com/shop/Tools/Vises/Nut_and_Saddle_Vise.html

-Aaron

I've been doing the 7 degree tilt back saddle as well after Rick mentioned it to me a few years back over on the ANZLF, but have added just a bit of compensation to the whole unit. Works fine for the couple of string brands I normally use, but have tried some others and found that the intonation was a bit flat. I'm going to switch to your method now. Thanks.

The tilted saddle seems like a great idea. Of course, using the stock Stew-Mac bridge doesn't allow for that, so maybe when I scratch build I'll give it a try.

As furnished, the Stew-Mac saddle is almost 1/8 inch. If I position the center at 17-3/32" (as they recommend), then I can adjust the witness point to create an actual string length of approx. 17-1/32" to 17-5/32". This should give an adequate range for compensation.

Thanks for everyone's replies. I can see you have given the subject a lot of thought.
Larry

One other point: There is absolutely no reason to obsessively dial in the intonation on an instrument until you know the exact string style your client wants and you have the action and neck relief perfect for them. Intonation is pretty much the very last thing to tweak as it depends on the previous adjustments and the exact strings to be used. With our production instruments that are sold through dealers to customers I don't know, I do NOT consider intonation to be my responsibility. That's between the end customer and his or her own local luthier. My job is to make it so the saddle is in the ball park and can be tweaked one way or the other depending on strings and action. A 1/8" wide saddle in the right place allows for this.

Very good approach Rick. I'll make it my own.