Top and back run out

**John Bertotti** · Aug-18-2021, 5:45am

I think I know what runout in a top or back is referring to but I’m not positive. Can some one show me what run out it is and tell me why it’s bad? How to avoid it? Thanks! I apologize if it is asking to much.

**Monte Barnett** · Aug-18-2021, 8:23am

There’s a short thread here: https://www.mandolincafe.com/forum/t.../109030-Runout
… and another link: http://www.lutherie.net/frankford.runout.html

**John Bertotti** · Aug-18-2021, 9:03am

Read them links thanks��

**John Bertotti** · Aug-18-2021, 4:10pm

I have no idea why there are weird question marks after my reply!

**Graham McDonald** · Aug-23-2021, 5:25pm

Run-out, or the lack of it, is important in flat-top instruments like guitars where the soundboards are only 1/8" or less thick and you want the longitudinal cell structure running as closely as you can parallel to that surface. On a carved top instrument it is not so important as the act of carving the spruce (or whatever) into an arch is cutting across that longitudinal cell structure in all manner of different ways. At the same time you have the gluing surface on the bottom of the plate, and you will want that to be reasonable close to parallel to the cell structure for best gluing.

**John Bertotti** · Aug-23-2021, 7:21pm

Ah yes that was exactly one thing I was wondering about. I have a top wedge that before I had a bandsaw I hand sawed and it is far from perfect. I can level it and fix most of the runout but if it is that big a deal then I was wondering what that means with carved tops. You answered that thanks!