Is a centre strip necessary on a ukulele?

[Quinny]

I am on my third uke build and thinking of the finer points of a build. I am wondering if a centrestrip is necessary or a preference? Is it more important on the soundboard than the back? The main reason I am asking is that I know it is best to recess the braces strips over the centrestrip and I am thinking that may be an unnecessary hassle, but maybe something important not to overlook.

Thanks
Andrew

[charangohabsburg]

Hi Andrew,

When joining plates, hardwood (which is commonly used for backs) can almost not at all be compressed, respectively almost does not swell when glue is applied. So every less than absolutely perfect planed edge is likely to be less strong than necessary for a long trouble-free life of the joint. Spruce or western red cedar can deform enough under joining pressure and introduction of humidity (water based glues) that less than perfectly straight glue edges still are good enough to make a seamless hence strong joint. When using a decorative center strip (between the plate halves) the reinforcing center strip needs to be a bit broader, add 3mm to each side and you'll be fine.

I never have seen an instrument with the back braces fitted over the center strip. Of course this can be done and most likely has been done, but the normal case is that the center strip gets chiseled away where the braces cross.

[Quinny]

Thanks for the detailed reply Markus. That makes sense now. Good to know I don't have to recess the braces. I am using hardwood top and bottom, so it sounds like a centrestrip is the best way to go.
Is it important to do both soundboard and back or is one more important than the other??

Thanks

Andrew

[charangohabsburg]

I think the tighter doming a plate gets forced to, the more important a center strip becomes. So, in many cases the center strip may be more important for the back than for the (hardwood-)top.

For reinforcing a hardwood top you could use cleats instead of a center strip. Split wood to make thin and strong cleats, don't just plane down a sawed piece. Here I explain how I make the cleats I use. Good woods for cleats are spruce, western red cedar, "Spanish" cedar, most pines (don't know about those Australian pines), mahogany and most mahogany-like stuff. Stay away from beech which is a b**ch to split, and also from other too dense woods, and from woods with pores greater than Spanish cedar.

BTW, you already have one big cleat outside (the bridge) - in fact I have had an instrument or two in for repair where the top separated almost completely, only held firmly together by the bridge and the rosette! .

[Allen]

It depends on the design of your bracing on the top to some extent, but on many instruments using fan bracing the top is getting a reinforcement strip on most of it's length.

The fret board from neck to sound hole. Some transverse braces. A bridge patch and bridge and a fan brace that goes down the centre seam on a lot of tenors and sometimes concerts.

I've never seen braces being notched to fit over a centre reinforcement, and never would consider doing so. And while I have seen some ukes without that reinforcement down the back, again I'd never build without it.

[Quinny]

Thanks for the benefit of your experience Markus and Allen. I can see how the soundboard is essentially braced with all the extra wood glued to it. Also good not to have to recess the back braces, but will go with the centrestrip on the back.

Thanks again

Andrew