The Hub

Good morning everyone, I was taking some measurement on production necks with scarf-joint (13° headstock angle) to add some machining process with the cnc. I so recreated the standard neck blank feature (100mm wide and 20mm thick), then drawed the 13° angle. Everything correspond the to the real piace but two measurement: the startingcut behind the break angle is ''off'' by 20mm +/- as well as the cut on the bottom, still off by 20mm…

Let me start with this; I'm trying to find the root cause of difficult fret wire installation of two different SM fret wires. I've spent a lot of time gathering dimensions and experimenting with techniques wich could cause the problem. I enlisted the help of a colleague who arrived at a similar poor performance. His solution was to glue the fret ends/ beat the frets in. My "rather" is to find the root cause so I don't have to go thr…

Doug Proper designed a sanding jig that supports variable concave and convex curves, described in the following Loothgroup article: https://loothgroup.com/post-imgcap/the-variable-radius-sander/ I built one and am impressed with how it facilitates preparing bridges, braces and also allows tracing any radius using the chord formula. I made a rough measured drawing and assembly guide to share, with Doug's blessing. First step, ma…

Hi all. Brand new member. I’ve been building a classical guitar via kit from LMI for a couple of years now. I keep putting it off but recently became motivated to get back to it. Unfortunately LMI is out of business so I now have no one to go to to ask questions. I’m at the stage where I’m putting the sides together in the form. I followed the dimensions for the form based on the plans as I measured them, but the sides overlap pretty ba…

I did a pretty big update to my web tools last week. These are updated from the older versions I had up on celestialinstruments.com. There’s an updated FFT tool now, plus mode detection for guitars and plates, wolf note detection, played-note energy transfer, monopole mobility, plate thickness calculation, and 1/2/3/4 DOF modeling that can be prefilled from FFT data. The part I’m most excited about is being able to fit a measured guitar re…

Technically this is a repair, but I thought there would be some crossover with building, so I posted here as well. A 1950s Gretsch Town & Country Rancher 6021 is missing the two braces on either side of the sound hole (see photo). Because this is such a wide instrument (17” lower bout), I’m thinking that installing those missing braces will help with the stability of the top in addition to repairing the cracked/loose ladder braces. The…

For my current mandolin build, I set out to answer 2 questions: 1. Whether to use physical deflection or frequency analysis to measure stiffness, and 2. How well can I measure wood quality in rough sawn form? (T. Gore says it needs to be planed smooth and rectangular for frequency analysis.) I have 4 different topwood species available for my current build: California Sitka, Englemann, Lutz, and Coastal Redwood. The billets range from 37…

I attach my necks using the LMII/O'Brien jig. No matter the method, there is no guarantee that the neck block and edge of the rim at the top is truly perpendicular to the centerline of the guitar. I’ve just flossed when things weren’t quite right. But now I take a long square, place it on the rim at the neck block and measure where the long square aligns on the top seam. I note Bass/Treble deviation at a known point (I use 290 mm).…

I will tag @member for this question. I hope you are ok with that. Is it of any use, to use the deflection measurement from for tonewood before building? To determine the basic deflection/stiffness for the selection of the tonewood.

Friends - My "go-to" truss rod for my basses has been the rod sold by LMII; however, since they are now out of business, I am evaluating what other rods are suitable for bass guitar necks. The attached photos are all showing truss rod lengths from the front edge of the nut slot location on the blank. One photo shows my last LMII rod (23 1/2" in length) vs. 2 other rods, one longer (23 11/16") and one shorter (22 1/4") -- all measured f…

Dear looth community/colleagues around the world, During 2023/24 I have developed a digital gauge to measure so-called longitudinal twist of (bass) guitar necks: the LTwist® gauge. Just to be clear, this is about the "cork screw" type of deviation along the length of a neck, not the bow of a neck. I think there is no need to explain how a too severe neck twist can make it difficult or even impossible to set up a stringed instrument (guita…