Construction Notes for a Steel String Guitar
Preface
CONSTRUCTION NOTES for a
STEEL STRING GUITAR
by
Denny Brown Foreword by Robert Rober t O’Brien O’Brien 1
Construction Notes for a Steel String Guitar
Binder Spine Label Print Print this page, cut out the label and place in a binder spine
Cover: Steel String Rosette Inlay by Denny Denny Brown Photo credit: Denny Brown © Dennistoun Brown 2012 2
Preface
S T E E L S T R I N G G U I T A R
Construction Notes for a Steel String Guitar
Preface
Preface Construction Notes for a Steel String Guitar is a conversion of my notes into detailed building instructions for a 25.4 inch scale length steel string guitar. Like its companion, Construction Notes for a Classical Guitar, it is based on study under Robert O’Brien, while he directed the Red Rocks Community College Lutherie Program in Denver, Colorado. The original audience audience was students in Robert’ Robert’ss classes. However, with the release of his “Online Acoustic Guitar Building Course” in 2012, the first version was rewritten for the benefit of online students, as well. Greatest credit for this handbook goes to Robert O’Brien, who in 2003 founded and, until 2012, directed the Lutherie Program at Red Rocks Community College in Denver, CO. This is primarily a tabulation of his teachings. Other information in Construction Construction Notes for a Steel String Guitar comes from a variety of sources. I am indebted to fellow teaching assistants, Mike Boggess (www.treesongguitars.com ( www.treesongguitars.com),), Jim Mcmurdo and Karen Kemerling (www.k2guitars.com (www.k2guitars.com),), who have guided my guitar building and, remarkably, have kept me out of trouble. Their wisdom is greatly appreciated. Many of their tips are found in this this handbook. handbo ok. The r est, est, which really doesn’t seem to leave much, I learned on my own through a combination of technical technical successes, a few “design opportunities,” i.e. mistakes, and outside reading. Robert O’Brien, to date, has supervised the building of over 500 guitars by students in Colorado, from teenagers to retirees. Several of his students relocated to Colorado specifically to take one or more of his courses. Robert’s commitment to teaching is known internationally. The DVDs that Robert made for his early students students have guided thousands of guitar builders who have purchased guitar kits from LMI, Int’l. Int’l. More recently, Robert’s “Online Classical Guitar Building Course” and “Online Acoustic Guitar Building Course” were released, which display his ability to distill the complexities and mysteries of guitar making into logical steps. Besides his personal and professional commitments, Robert finds the time to host and actively participate in a Google Chat Group on guitar building. Participants hail from the U.S., Canada, Europe, South America, America , Australia Austral ia and Asia. You are invited invit ed to join his group at www.groups.google.com/group/obrien-forum at www.groups.google.com/group/obrien-forum.. 3
Construction Notes for a Steel String Guitar
Preface
None of this is to say that Robert has made guitar making easy. It is not, and it probably never will be. However, he has given many people worldwide worldwide the confidence to take the risk to do what for them had only been a dream. Denny Brown Boulder, CO
4
Construction Notes for a Steel String Guitar
Introduction
Introduction While these notes are based on several sources, they distill down to one of many ways to build a steel string guitar. Indeed, every luthier has his or her own method to make a guitar. With so many steps, variations quickly develop. Nonetheless, what I have recorded recorded closely follows the current cu rrent methods used by Robert O'Brien. Experienced builders can use Construction Notes for a Steel String Guitar alone as a reference reference to refresh his or her memory on the steps of building, or to see another way to do things. For the first-time guitar maker, this handbook alone may be inadequate as a guide to building a building a steel string guitar. Some things just have to be seen once or twice before they make sense. The materials and dimensions used in this handbook are based on the LMI (Luthiers Mercantile, Int’l ) KLSRO kit , used in Robert’s classes and in his online course. However, this does not preclude preclu de the use of materials from numerous other quality luthier sources. Construction Notes for a Steel String Guitar can also be paired with Robert’s DVDs and his free YouTube “Luthier Tips du Jour” series. Several books and videos are are available available from other reputable reputable authors. However, all of these resources differ to some degree from this handbook. In the case of Robert’ Robert’ss DVDs, certain sections are dated. When there is a disagreement between the DVD and these notes, the methods here are most current. For convenience, hyperlinks are provided within the text to “Luthier Tips du Jour” episodes and to each “Online Classical Guitar Building Course” Course” lesson. The Table Table of Contents also links to respective sections in the handbook. The best learning experience, of course, is to build your guitar with Robert O’Brien in Colorado.. For those who cannot, his "Online Steel String Guitar Building Course” is a Colorado remarkably close second best option. It is every bit as detailed as his classes, perhaps more so. 5
Construction Notes for a Steel String Guitar
Introduction
You may print this manual. manual . Use it to take notes. Lots of notes. The true discovery of great things in your guitar will happen over 250 pages from here when you first put pu t on the strings. No sooner. If your guitar is a home run, wouldn’t wouldn’t you like to have some clues how it happened? On the other hand, if your guitar doesn’ doesn’tt come out the way you wanted, wouldn’t woul dn’t you also want to know why? Take notes. When you are ready to build a classical guitar, be sure to take a look at Robert O’Brien’s O’Brien’s “Online Classical Guitar Building Course”, Course”, and the companion handbook, Construction Notes for a Classical Guitar . Input for for Construction Notes for for a Steel String Guitar is welcome. welcome. Write to me at
[email protected]..
[email protected]
A word of caution Several steps of building a guitar are dangerous, including those using hand tools. It is the reader’s responsibility to learn how to use and maintain equipment safely and correctly.
This is not a safety manual.
6
Construction Notes for a Steel String Guitar
Foreword
Foreword Denny Brown’ Brown’s Construction Notes series for guitar building bui lding is the set of books I had planned to write for my students, but somehow I never got around to actually actual ly doing it. With a young family and a growing lutherie program, this task never managed to move to the top of my “To Do” list. I was thrilled when Denny unexpectedly presented his first book on the classical cla ssical guitar to me in December of 2011. I immediately asked to use it in my classroom and hoped he would write a steel string version, version, too. (Obviously, he did.) Actually, I think that I was not only thrilled, but relieved that this long overdue project project was finally complete. Denny went above and beyond what I had envisioned and created an interactive manual. Students have instant access to my online courses and Luthier Tips du Jour videos just by clicking on the active links throughout the text. Since Denny introduced these texts, my students’ work has improved significantly. Students now have a written study guide that allows them to prepare for class ahead of time. In the shop, they have a detailed checklist to minimize mistakes. And as importantly, they have a place to record notes on their progress. progress. As an instructor, these books have made my life easier and helped my students build better guitars. Denny has meticulously captured how I build guitars. He also offers offers some additional perspective, which is a bonus for the user. These handbooks have become an indispensable part of my teaching and are now required reading for for students in my workshop. Using these books will make your guitar-building experience more more rewarding rewarding and easier than ever, leading to the result you want: a guitar that both looks and sounds beautiful. Robert O’Brien Parker, Colorado www.obrienguitars.com 7
Construction Notes for a Steel String Guitar
Forward
About the Author Denny Brown discovered discovered fine woodworking in 2007 after retiring from a career as a general surgeon. surgeon. He found one of the premier premier woodworking programs programs in the United States just forty-five minutes from home. His passion for fine craftsmanship and detail led him to Robert O’Brien’s guitar-making classes. Denny builds both steel string and classical guitars. He is a teaching assistant for O’Brien’s guitar building classes in Denver, Colorado. He is also the author of Construction of Construction Notes for a Classical String Guitar and Guitar and writes the “My Guitar Notes” blog at www.flatironfrets.com at www.flatironfrets.com.. Denny lives in Boulder, Colorado with his wife and children.
8
Construction Notes for a Steel String Guitar
Table of Contents
Table of Contents Chapter Chapter 1: Sides
11
Dimension the Sides .................................................. ........................................................................... .............................. ..... 11 Joint the Sides
11
Cut the Sides to Width
11
Safe-T Safe-T-Planer -Plane r Set S et Up
12
Thickness the Sides
12
Set Up for Bending
13
Make a Side Template
14
Layout and Taper the Sides
15
Cr ack ack Repair .................................................. ............................................................................ ........................................ .............. .16 Bend the Sides ................................................. .......................................................................... ....................................... .............. 17 Super Soft
17
Set up
17
Bending with a Thermocouple
19
Placing the Side in the Guitar Form Form
19
Heel and End Blocks ................................................ .......................................................................... ............................. ... 20 9
Construction Notes for a Steel String Guitar
Table of Contents
Prep Prep the End Block Bl ock
20
Prep Prep the Heel Block
21
Cut Sides to Length
21
Glue the Sides to the End and Heel Blocks
22
Clean Up the Sides ............................................... ......................................................................... ................................. ....... 23 Radiusing Radiusing ................................................... ............................................................................ ............................................ ................... 24 Radius Radiu s the th e Top Top
24
Radius the Back
25
Install the Kerfing ................................................. .......................................................................... .................................. ......... 26 Shape the Kerfing
27
Glue up
27
Str uts uts ............................................... ......................................................................... ................................................... ............................ ... 28 End Wedge .................................................. ............................................................................ ........................................... ................. 29
10
Make the End Wedge
29
Cut a Wedge in the Body
30
Glue Up the End Wedge
31
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Chapter 1: Sides •
See “Online Acoustic Guitar Building Course”: Intro (free) The LMI Kit (free) Kit (free) Relative Humidity (free) o o o
Dimension the Sides •
•
See “Online Acoustic Guitar Building Course”: Cutting Sides to Width See “Luthier Tips du Jour”: Band Saws
Joint the Sides o
Bookmatch the two sides and fold together Bookmatching is placing the two sides beside each other in a mirror image format, left to right Look at the grain figure and consider what edge will be at the top of the guitar and what edge will be at the back Account for the back edge of the upper bout being cut away slightly in a taper See Make a Side Template, Template, below Select the edge that will that will be the top top of the guitar sides to joint Tape the opposite edges together together with two pieces of tape tape Joint the top edge §
o
§
•
o
§
o
Cut the Sides Sides to Width o
Rip the sides to 110 - 115 mm in width with the band saw, cutting off the taped taped side
11
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Safe-T-Planer Set Up •
•
•
See “Online Acoustic Guitar Building Course”: Thicknessing See “Luthier Tips du Jour”: Safe-T-Planer Note: In 2012, production of the Safe-T Safe-T-Planer was discontinued. A similar product is the Drill Press Planer o o
Put Safe-T-Planer in the drill press Tilt the table very slightly downhill so the exit side of cutter is wider than the entry entry A folded piece of sandpaper under the in-feed side of the table is enough Set the depth to 2.7 mm Set the drill press speed to 2000-2500 RPM Make sure the table is clean so the board is not lifted by debris and cut too thin Test cut Feed a piece of scrap under the Safe-T-Planer and measure the thickness of the cut Adjust table as needed and redo test cuts until correct §
o
o o
o
§
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Thickness Thickness the Sides •
See “Online Acoustic Guitar Building Course”: Scraping Sanding Book match the sides and select sel ect paired surfaces to plane Plane the less desired side since it may reveal a surprise Do a test cut at the beginning of each side This is best done with two people, one pushing the side in and the other pulling it out Hold sides down with smooth blocks at entry and exit of planer head This prevents lifting lifting the side and getting it too thin o o
•
o o
•
o
§
12
Construction Notes for a Steel String Guitar
Chapter 1: Sides
With one person, push the board in as far as possible using a hold down block, then pull the board through with a hold down block on the outfeed side Final thicknessing options o
•
o o o o
Thickness Sander (preferred) (preferred) Scraper Hand sander See “Luthier Tips du Jour”: Scrapers Thickness Sanding Sides §
§
•
Thickness sander The target point is 2.2 mm and flexibility suitable for bending (a good indicator is the beginning of flex transversely) transversely) Measure the thickness of sides, tops and backs with a dial caliper Send sides through sander at 30o angle to avoid overheating the sanding belt A single pass without changing the setting may be all that is needed to fine-tune the thickness Measured final thickness of sides = ______ mm o
§
o
o
o
•
Consider thicknessing the back pieces now while the Safe-T Safe-T-Planer is set up, see Chapter 3: Back
Set Up for Bending Bending •
See “Online Acoustic Guitar Building Course”: Molds Intro to Bending o o
13
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Make a Side Template •
•
See “Online Acoustic Guitar Building Course”: Tapering the Sides Considerations The markup measurements can also used directly on the sides without making a template Use anything thin, such as paper, plastic, ¼” MDF or fiberboard Dimensions Cut a piece of material 80 cm long 11 cm (110 mm) tall o
o
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↓
“End Line”
↓
B U T T
110 mm
K C A B
TOP
46 cm
O cm o
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o
14
↓ K C E N
“End Line”
95 mm
74 cm
Mark up Measure 3 cm in from both ends and draw square lines (“end lines”) The distance between these two line should be 74 cm For a mark up directly on the guitar, use this length and position the space over the most desirable part of the sides From From one of the end lines, measure in 46 cm and square a line Label this line “WAIST” “WAIST” Label the end line NEAREST the waist “NECK” Label the end line FARTHEST from the waist “BUTT” Taper cut On the NECK end line, mark 95 mm from one edge Draw a straight line from this mark to the end of the nearest waist line Band saw this line and discard discard the cutoff Label the template §
o
W A I S T
T aper ↓
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Along the side with the tapered side, mark “BACK” Along the uncut straight edge, mark “TOP” “TOP” Do not get these backwards! ba ckwards! Label the template “STEEL STRING”, in case you later make classical guitars Transfer all of the labels l abels and lines to the opposite side Cut ¼” notches at the ends of the each line to aid marking the §
§
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o
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Layout and Taper the Sides •
•
•
•
Bookmatch the sides and lay the two pieces side by side Select the desired outside surfaces Fold the sides together with the desired outside surfaces on the ou outside tside of the sandwich Mark the layout orientation Use white pencil on the outside of both pieces Select and mark the neck and butt ends Remember that the neck end will be tapered ta pered Mark the jointed edges as the top Align the side template on the sides so the top edge is flush against the top (jointed) edge Use the side template to mark locations of the waist, neck end and butt ends Mark the waist on the edge, too Mark the front taper Mark inside the taper line with an “X”, so the mark remains after the taper is cut Band saw the taper o o
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o o
o
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o
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•
15
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Crack Repair •
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•
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See “Online Acoustic Guitar Building Course”: Crack Repair Cracks can and will occur, particularly in the sides Most cracks are 50 mm, or less, but they can also be very dramatic The rescue is frequently CA glue, plus accelerator Dark wood cracks, especially with the grain, tend to hide well Do NOT use CA glue for tops Light colored woods stain with CA glue o
•
•
•
In all cases, the principle is to get the wood on either side of the crack lined up and held in place while glue sets Another pair of hands might be handy, if using CA glue with accelerator Minor Fixes §
§
§
•
Major Fixes - for example, a long split in the side Identify the length of the crack and mark each end Get the two sides lined up precisely, whatever it takes This is critical Let thin CA glue flow generously into the crack along its entire length If the cracks is clamped, sand over the crack with old sandpaper to fill irregularities in the crack If the crack is being held by hand, apply accelerator Repeat on the other side Scrape and sand smooth o o
§
o
§
§
o o
16
Get the wood lined up Let thin CA glue flow into the crack Apply accelerator and hold until set
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Bend the Sides •
See “Online Acoustic Guitar Building Course”: Bending, Part 1 Bending, Part 2 See “Luthier Tips du Jour”: LMI Side Bender Side Bending by Hand Making Forms o o
•
o o o
Super Soft •
•
•
An optional step Spray the sides with Super Soft, as instructed on the bottle Let dry between paper under a weight overnight
Set up •
•
•
•
•
Obtain or make a guitar gui tar form for your plan Set up bending machine with the correct bending profile Lay the guitar form on the bench in line with the bender, i.e. i .e. neck end in the same direction as the bending machine is set up Mark the up side of the guitar form “BACK”, and the other side “TOP” using tape Lay the sides on top of the guitar form on the table with the outsides up, the back edges to the center and the neck /butt oriented in the same direction as the form and bending machine
17
Construction Notes for a Steel String Guitar •
Chapter 1: Sides
Position the wood Put the first sheet of spring steel in the bending machine Line up the spring steel parallel to one side of the bending form Spray wood lightly with water Put one guitar side outside up on the spring steel and line up the top (jointed) edge parallel to the edge of the spring steel Position the waistline of the guitar side in the center of the bending machine Add the heating pad, then the second sheet of spring steel Double check positioning Spring-clip the sandwich together When bending Do not walk away from the bending machine Avoid distractions distractions such as conversations, telephones Heating moves very fast and can quickly lead to a disaster o
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o o
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•
o o o
Bending with a Thermometer Thermometer •
•
•
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There are several bending routines that work well, this is just one Tighten the waist clamp just enough to flex the wood and hold it in place Put handles on springs Place a thermometer between the heating pad and the spring steel sheet Make sure the thermometer is set on FAHRENHEIT FAHRENHEIT Connect the heating blanket to the timer and turn on the timer Heat to 200-250o F Bend the waist fully Slowly bend the large bout then the small bout Watch temperature There are several several ways to finish the heating process 1. Heat to 300o - 325o F and hold there for 5 minutes by turning the power on and off 2. Heat to 325o - 350o F and turn the heating pad of fas soon as up to temperature 3. Heat to 325o - 350o F, cool, then reheat to 325 o - 350o F, o
•
o o o
§
o
§
§
§
then cool
18
Construction Notes for a Steel String Guitar •
•
Chapter 1: Sides
Cool and remove the side Place the side in the guitar form
Bending with a Thermocouple •
•
•
•
•
•
•
•
•
•
See “Luthier Tips du Jour”: Heating Blanket Temperature Controller This uses a specialized piece of equipment Tighten the waist clamp just enough to flex the wood and hold it in place Put handles on springs Place the thermocouple probe between the heating pad and the wood Set thermostat to 300o F Heat to 200-250o F Bend waist Slowly bend the large bout then the small bout Hold at 300o - 325o F for 5 minutes (Optional) leave side in the bender at 260o F for 15 minutes Cool and remove side Place the side in the guitar form o
•
•
Placing the Side in the Guitar Form o o o
•
Place the bent side in the form top side down, flush with the table tabl e top Insert the spreader Apply cam clamps where there are are gaps
Bend the second side Double check side orientation Bend second side, just like first Insert in form Mark orientation Use tape to mark mark L/R, top and back on the sides This can’t be over done o o o o
§
•
19
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Heel and End Blocks •
•
See “Online Acoustic Guitar Building Course”: Heel and End Blocks See “Luthier Tips du Jour”: Heel and End Blocks Hand Planes Sharpening o o o
Prep Prep the End Block •
•
Orient the grain horizontally Band saw the block to these dimensions 76 mm (wide) 21 mm (thick) 108 mm (tall) Sand the rough sides of the block and bring them close to final dimensions Finished dimensions will be 76 x 19 x 102 mm The ends of the block do not need to be sanded The height of the block will be brought to size when the guitar is radiused later in this chapter Plane a bevel on the two vertical corners that will be on the inside of the guitar This is cosmetic, be careful of blow out Mark centerlines on both ends of the block Remove the sides from the form Slide the end of the guitar form off of the bench Place the block beneath the tail end of the empty guitar form, line up the centerline centerline and trace the contour for planing Plane the block to fit flush inside of the form The line is for reference so that the contour can be planed parallel to it Don’t Don’t round corners and be careful of blowout bl owout Check fit, sliding the block up and and down in the form to look l ook for gaps o
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o o o o
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20
Sand to 180 grit
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Prep the Heel Block •
•
Orient grain horizontally Band saw the block to these dimensions 70 mm (wide) 34 mm (thick) 88 mm (tall) Sand the rough sides of the block and bring them close to final dimensions Finished dimensions are 70 x 32 x 82 mm The finished thickness MUST BE 32 mm for the neck bolts to fit A little less is okay, more is not The ends of the block do not need to be sanded The height of the block will be brought to size when the guitar is radiused later in this chapter Plane a bevel on the two vertical corners that will be on the inside of the of the guitar This is cosmetic, be careful of blow out Mark centerlines on both ends of the block o
o
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o
Cut Sides to Length •
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See “Online Acoustic Guitar Building Course”: Cutting the Sides to Length Place one of the sides, top side down in the form Insert the spreader Cam clamp the side to the form to eliminate gaps around the bouts Push sides down flush against the table Mark the centerline On the side, mark the centerline with white pencil at each end using the form centerline Remove the side from the guitar form With a square, transfer these lines to the inside of the guitar side, making sure to square square off of the top (flat) edge Repeat with the other side Cut o
o o
o
•
21
Construction Notes for a Steel String Guitar o
Chapter 1: Sides
Band saw the sides just short of the lines Save cutoffs for cauls Finish to the line with a sander Replace sides in the guitar form in the correct orientation Reinsert the spreader Clamp sides to the guitar guita r form to eliminate gaps around the lower bout §
o o o o
Glue the Sides to the End and Heel Blocks •
•
See “Online Acoustic Guitar Building Course”: Gluing Sides to Blocks See “Luthier Tips du Jour”: Glues Part 1 Glues Part 2 o o
•
•
Sand the inside of the sides to 180 grit where the end block will be glued, plus 5 cm to either side Tools o o o o o
o
•
Set up o o
8 - C-clamps 4 - Cam clamps Spring clamp Wax paper Rosewood cutoffs for for cauls (from the last step) If there aren’t aren’t enough clamps, or a more relaxed two-step pace is preferred, preferred, only half as many clamps are needed Be sure the guitar form is top side down on the bench Mark the centerline on both ends of the blocks and on the glue faces Put the blocks at the correct ends of the guitar form Make sure the sides of the blocks are square to the bench §
o
22
Construction Notes for a Steel String Guitar •
Chapter 1: Sides
Glue up Set up the clamps with a dry run, this has to move quickly if both ends are being done simultaneously o
o o o o o
Place wax paper on the bench under where the blocks will be Apply glue to the correct face (marked midline) of either block Position the block flush with the bench Align the centerline with the form using the marked lines Clamp sequence Use wax paper beneath the outer cauls, if needed Clamp one corner with a spring clamp to hold the cauls Watch for skating of the end block Clamp both back corners firmly, removing the spring the clamp after the first C-clamp is applied Position clamps towards the outside outsi de of the block bl ock for a flush fit Check the block for square to the bench §
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Repeat this sequence with the other block bl ock Remove the sides from the form Use a spring clamp to hole the cauls in place Add clamps to the top corners of both blocks Clean glue squeeze out Add two cam clamps to the center of each block
20-30 minutes clamp time
Clean Up the Sides •
Scrape and sand the inner surfaces of the sides to 180 grit
23
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Radiusing •
•
•
See “Online Acoustic Guitar Building Course”: Radiusing See “Luthier Tips du Jour”: Closing the Box Radiusing is putting a curvature on the top and back of the guitar to create slight domes in the top and back when are glued to the body It is very easy to become disoriented disori ented and make mistakes in this process Pay attention to having the dish with the proper radius (15’ or 30’) and working on the correct side (top or back) of the guitar. o
o
•
Authors Note: I radius the top first first and the back second, the reverse reverse of Robert’s method. I find it keeps me out of trouble. The end and heel block heights will need to be finalized while radiusing. radiusing. This should be done from from the back side. I find that if I radius the back first, I am tempted to make any final height adjustments from the top, since the back is already finished. Making adjustments from the front risks taking the top edge out of parallel with the grain figure on the sides. There is a significant taper on the back upper bout of the back, so parallel grain is not expected there. This is purely cosmetic, so it is of no functional importance.
Radius the Top •
Take out a 30‘radius dish with sandpaper Clamp the dish to the th e bench with cam clamps, leaving room for sanding o
•
Turn the form TOP SIDE DOWN and put pieces of blue tape around the back ba ck edges Anything that keeps things oriented is good When radiusing, the blue tape should be up o o
•
•
Put the guitar TOP SIDE DOWN in the radius dish and assess for gaps Turn the form over and plane down the proud points on the top side Plane towards the heel heel block to avoid splitting Recheck for gaps Repeat planing until the sides are close to the desired radius of the dish o
•
o
24
Construction Notes for a Steel String Guitar •
Chapter 1: Sides
Sand in the 30’ radius dish with a twisting motion Use chalk on the side edges and the produced sawdust in the dish for a guide in sanding, until there is no gap Additional planing can be used gingerly to speed the process o
o
•
If desired, kerfing can be added to the top, top , now, and the back radiused after the glue has dried
Radius the Back •
•
•
•
Put away the 30’ radius dish Take out a 15’ radius dish with sandpaper Clamp the dish to the bench with cam clamps, leaving room for sanding Put the form TOP TOP SIDE DOWN on the bench and be sure the top of the guitar guita r lies flat With a white pencil, mark in three places on the sides si des where they meet the form, for reference reference if the guitar slips in the form and needs repositioning Turn the form BACK SIDE DOWN and put p ut pieces of blue tape around the top edges Anything that keeps things oriented is good When radiusing, the blue tape should be up o
•
o o
•
•
Turn the form BACK SIDE UP Plane the block height down to near the target heights Target heights: Heel block 80 mm End block 100-105 mm Tilt the plane angled up towards the center of the guitar a little to accommodate for the 30’ radius o
§
§
o
•
Put the guitar onto the radius dish BACK SIDE DOWN 25
Construction Notes for a Steel String Guitar o
o
Chapter 1: Sides
Make sure there is enough of the sides protruding from the form in back to radius without inadvertently sanding the form Wrap fingers around the form If they touch the sandpaper, adjust the form higher If an adjustment has been made, flip the body top side down and be sure the edges are flush with the table top §
§
•
•
Put the guitar BACK SIDE DOWN in the radius dish and assess assess for gaps Turn the form over and plane down the proud points Plane towards the heel block to avoid splitting spl itting Recheck for gaps Repeat planing until the sides are close to the desired radius of the dish Sand in the 15’ radius dish with a twisting twisting motion Use chalk on the side edges edges and the produced sawdust for a guide in sanding, sanding, until there is no gap Additional planing can be used gingerly to speed the process o
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o
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o
o
Install the Kerfing •
See “Online Acoustic Guitar Building Course”: Kerfing More radiusing and Kerfing See “Luthier Tips du Jour”: Kerfing o o
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•
•
•
The kerfing will be the glue surface for the top and the back Be sure the inside is sanded to 180 grit gri t Do top side first Actually, this doesn’t doesn’t matter, but the top can be seen as practice run, since mistakes will be hidden Check that the sides are square to the bench in the form Kerfing clamps are glorified clothes pins with rubber bands around their arms to add more closure force Commercial kerfing clamps are available from LMI o
•
•
o
26
Construction Notes for a Steel String Guitar
Chapter 1: Sides
Shape the Kerfing •
•
Wet kerfing and let outer surface dry Clamp kerfing to the outside outsi de of the body with a few kerfing clamps and let dry Make sure the kerfing is oriented correctly With reverse kerfing, the flat side of the kerfing will be against agai nst the outside surface of the side o o
Glue up •
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Break off the kerfing to about the amount that is needed Lay the kerfing on a flat surface and apply glue to entire strip, blot, bl ot, don’t don’t spread Position the kerfing 1-2mm proud of the side edge Begin at the heel block (front) and get as flush to the block as possible Bunch kerfing together if it breaks Apply kerfing clips flush next to each other as you go Lean clips forward into the body interior After the left lef t and right strips are applied, apply 4 cam clamps to the corners of the form with arms up, then flip the th e form onto the arms Alternatively, clamp the form upright in a bench vise Remove the spreader and inspect the kerfing for gaps Adjust clips or add small spring clamps where the kerfing is not flush with the sides Let glue set up a bit bi t and scrape gross glue squeeze out Clean kerfing gaps with a razor blade o
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Clamp time: 30-45 minutes If desired, kerfing for the other side can be shaped while the glue dries on the first side Turn the cam clamps facing the other way and turn the other side up Reinsert the spreader Shape the kerfing as was done on the first side Continue with the glue up u p after kerfing clamps cl amps have been removed from the first side o o o o
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Construction Notes for a Steel String Guitar •
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Chapter 1: Sides
Otherwise, shape the kerfing and do the glue up exactly as was done on the first side Sand kerfing to 180 grit Touch up any sanding on the inside
Struts •
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See “Online Acoustic Guitar Building Course”: Side Struts Struts are strips of wood that are glued to the sides vertically between the kerfing They are decorative, structural and, perhaps, tonal They will help limit the length of a split in the side, should one occur The struts further stiffen the sides and may help project tone Struts can be made from scrap wood, such as cut offs of back and brace wood Some builders make immaculate laminated strips of various woods to add to the decorative value Use three to four struts One on the upper bout, one behind the waist and one or two in the lower bout Make the struts 2.5 - 6 mm thick Thicker strips can be scalloped or tapered on the ends to transition down to the kerfing Position the struts symmetrically from left to right To be precise, count kerfing spaces along the side Mark the locations Cut each piece a little long Fit each piece between the kerfing using a sander sand er to adjust the adjust the angles of the ends Mark each piece with its location on a piece of tape Square the end that will be at the top Put the strut in place on the guitar side and estimate the angle needed to be cut off Sand the angle and adjust it until it fits Glue up Apply glue to the struts, less is more o
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Construction Notes for a Steel String Guitar o
Chapter 1: Sides
Position them straight up and down Use a square from the top, if desired Clamp in place with spring clamps Watch for skating Clean the squeeze out §
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Clamp time 30 minutes
End Wedge •
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See “Online Acoustic Guitar Building Course”: End Wedge See “Luthier Tips du Jour”: End Grafts
Make the End Wedge •
Select a piece of wood long and a nd wide enough for the end wedge with plenty of extra length A piece of curly maple is often used Even a scrap piece of the rosewood back works very well Select a bevel angle that looks good and set it on a sliding bevel Mark a centerline on the back side of the end wedge, extending full length Optionally cover the wood with tape and put the markings on the tape Decide how wide the graft is going to be Mark symmetrical lines on the wood piece on both sides of the centerline, using the sliding bevel Make sure the end graft piece is longer than needed Band saw out the end graft wedg e with a small extra margin outside the line True the edge with a plane on a shooting board shooting board Plane from the wide to the narrow end o
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Construction Notes for a Steel String Guitar
Chapter 1: Sides
Cut a Wedge in the Body •
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Remove the guitar body from the form Mark the centerline on both ends of the end block Apply masking tape over the end block to facilitate marking Orient end wedge up or down, it doesn’t matter Place the end wedge with the centerline face down to line up with the centerline marks on the end block Hold the end wedge tightly in place or with spring clamps, or use an extra pair of hands Mark the outline of the wedge on the guitar body o
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Hang the guitar body on a board suspended from a bench Use a block of wood with a square edge as a saw fence Position the block on a triple-folded-over piece of sandpaper just outside of one of the marked lines and clamp it in place Saw on the marked line only through the side wood The sawdust will change color as soon as the side wood is fully cut Repeat on the other side Chisel out the side wood, checking the graft fit Flatten rough spots on the exposed end block o
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An alternative method for cutting, which is particularly useful for curved end pieces: Hold the end wedge tightly in place or with spring clamps, or use an extra pair of hands Scribe around the outline of the wedge on the guitar body Use a Dremel tool and a downcut spiral bit Rout close to the line Finish with a chisel o
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Construction Notes for a Steel String Guitar
Chapter 1: Sides
Glue Up the End Wedge Wedge o
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Place glue on the back and sides of the graft and on any veneer accents being used Slide the end graft and veneers snuggly into place Spring clamp both ends 20-30 minute clamp time After the clamps are off, band saw or hand saw the excess off Plane/scrape the end wedge flush with the body Return the body to the form making sure the top is flat to a bench
Notes:
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Construction Notes for a Steel String Guitar
32
Chapter 1: Sides
