School Me on Straightedges

Discussion in 'Luthier's Corner' started by Gilmourisgod, Sep 22, 2016.

  1. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    I own a 36" aluminum "straightedge" I bought a few years ago that's been plenty straight for general woodworking. At the time I bought it, I don't recall any specs claiming straightness in the .000" range, as you often see quoted in the more expensive Stewmac offerings like this one:

    The edge on my rule does not have the kind of milled appearance I associate with precision grinding like you see on a level, jointer, or table saw top. I've read that cast iron jointer or tablesaw surfaces can bend over time if heavy weights are left on them, so I've always been careful about that. They certainly appear to be dead flat and straight compared to my "straightedge", and I've used them to clamp neck glue-ups against on that assumption.

    I'm at the point in my build where I need a fret slotted straightedge to check fingerboard straightness prior to fret leveling, and I've sen a few like this one on ebay:
    The price is cheap, but I have no idea of the quality, I assume it's Chinese made.

    Most good hardware and Big Box stores sell aluminum bar and angle stock like this:

    Comparing the bar stock to off-the-shelf decent quality levels (which I'm assuming, perhaps wrongly, are straight) it's hard to see any daylight, though careful measurement with feeler guages might show some deviation.

    My question then: How straight is straight when it comes to Luthiery? Is a couple .000" of deviation really detrimental in fret work? Is it even worth considering making my own custom notched straightedge for odd scales like a Ric?

    Thanks for looking, and I'm fine with "shut up and buy a good straightedge" if it's really the only option, but given the level of ingenuity here on TB, maybe I'll be surprised.
  2. rudy4444


    Mar 13, 2012
    Central Illinois
    Years ago I took the advice given from one of the only books on guitar construction at the time and purchased a quality cast aluminum 24" level that could be used for sandpaper jointing top and rear plates and other assorted duties. The procedure was given to hold several levels face to face to see how straight they were, and it did reveal if there were any that had a few thousandths of curvature along the entire length.

    The level I picked out served me well for many years. There are tool suppliers like Veritas that supply good precision ground straight edges. It's worth purchasing something that you know is straight within .001" along its length to work with. If you don't start with a good reference it's difficult to ensure the quality of your work.

    I would check surface level before fretting and forget about the need for a notched straight edge. There's lots of suppliers who would like to convince you that it's necessary to part with your hard-earned dollars.
    Gilmourisgod likes this.
  3. Radio


    Jan 8, 2010
    New Haven, CT
    I don't have a picture handy, but I bought a generic 24 inch rule at Home Despot and introduced it to my bench grinder to notch out for the frets. Deburred it and it works like a charm for guitar necks. I need to make another for bass necks.
    Gilmourisgod likes this.
  4. HaMMerHeD


    May 20, 2005
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  5. Means2nEnd

    Means2nEnd Supporting Member

    The slotted straight edge you showed from ebay are very good I have a few from them for guitar and bass. I also have 36" $100 straight edge I use to check the fingerboards on new builds before I do fretting work to make sure everything is perfect. The notched ones I use for set ups and to check fretboards to see of they are true before I go doing any fret yanking on repair work.
    Gilmourisgod likes this.
  6. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    Thanks for posts, all. I guess what I was driving at was what level of precision is required for guitar work? I suspect that many off the shelf rulers and levels are extremely straight given modern manufacturing techniques, but in the absence of a known perfectly straight rule, it's impossible to tell. I'll probably suck it up and get the notched Ric scale straightedge, I'm building two Ric 4001 clones, so it will get some use. The back edge is also ground straight, I can use that to check my other tools and surfaces. I was checking out some Starrett straight edges on line, some up to $600! Too rich for my blood, and probably an unnecessary level of accuracy for wood that's going to move seasonally anyway.
  7. Means2nEnd

    Means2nEnd Supporting Member

    Hey Gilmourisgod here is one I bought about two years ago.. If you need something better than this then you probably work for NASA..

    Igaging 36" straight edge beveled precision ruler hardened steel

    I think it's important so much to have the right tool for the job. I would just stay away from homemade stuff you may or may not distort trying to cut notches out yourself that's just my opinion. I have three different notched edge straight edges for guitars and basses for set ups and well checking other people's work as I do repairs and it's a great way to check out the issue and make an accurate assessment on what is needed. I have three different sand filled leveling beams all the way down to a 6" so I can do roll offs or fall aways at the end of the neck for non compound radiused boards. Then I have that exact straight edge from eBay for checking my fingerboards as I build a neck.

    So some guys do the fingerboard and fret it before gluing it to the neck. Some guys do it after it's attached there are several different methods but what I have learned is I personally have to keep checking it throughout the process. I radius my boards and cut slots then glue it to the neck and have to do it again and sand again. I think when I clamp them together there are slightly different amounts of pressure along the neck and it causes some micro humps and valleys I have to get out later. The as I finish sanding the back of the neck there can be some movement as well. You change a piece on one side and change the stress level the other side is affected as well.

    The whole fingerboard and neck thing to me in my shop is where I get ultra critical of every line. I believe it is worth it to have super accurate edges if you are going to be building necks and fingerboards from lumber. Also at 47 I do not trust my eyes 100% I can tell you I have looked down one of my necks several times thinking it was dead spot on and it was not even close. I have my Stew Mac neck jig and another homemade one just for leveling fingerboards and I use my straight edges and a powerful shop light on the other side to look for gaps then I use a white pencil and make criss cross marks along the fingerboard and continue to level throughout the process. For me my best necks are ones I was not in a hurry I was careful and checked and checked again. Also I let time pass between each step of building the neck and getting it to a place that is ready for a finish to allow it to move and settle and if any micro movements or even slight twists I can remedy before finishing.

    I am hyper critical of necks in terms of stability and and playability to me it's 95% of the instrument and it's where I'll spend the time and money needed. I have been to plenty of shows where there are some kind of well known builders and their woodworking is really high level but the bass itself is set up poorly and the action looks almost unplayable so I do everything I can to not be in this I'll call it the cutting board category because that's about all they are good for IMO. Trust me I have made one or two of them... ;-/
    Gilmourisgod likes this.
  8. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    Thanks for the advice. For some reason, probably my innate cheapskatery and stubborn streak, I have to learn and re-learn the lesson that cheap tools are not worth buying. Having cheaped out a little on a 36" straightedge, I now have a tool of unknown actual straightness, so here I am about to shell out more money for another verifiable straight rule instead of getting the right tool the first time. It may turn out that my 36" rule is perfectly straight, but I won't know until I have something to compare it to.

    I've noticed the variety of means to an end as far as when to fret and glue on fingerboards. My original intention was to fret the board separately, but I ended up gluing it on prior to fretting and neck carve. I'm wondering if I should carve the neck first, prior to fretting, in case it moves a little as stress is released, or fret first and carve later. Here's a link to my glacially, painfully slow build if you are up for a laugh:
    The Hossenfeffer Bass Build
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  9. Means2nEnd

    Means2nEnd Supporting Member

    I had gone through that build before did you complete it? Looks like you have a nice big and clean shop and much invested all the more reason to buy the good stuff. I have about 12 builds under my belt and I just never seem to make time to document them as well as you have. Mostly because I figure nobody is really interested but i am always super interested in following everyone else's.

    I have 4 basses going now and I just started a Telecaster type build and I do post YouTube videos but not much in the way of progress here. Mostly I come here to learn and read everything from the senior builders with much more experience and learn as much as I can.

    I'm in sales and I learned a long time ago if you want to be successful do what successful people do so I see the best builders with the right tool and good quality at that. I was even contemplating a CNC purchase but upon further research none of my favorite builders have them like George Furlanetto, Mike Tobias, Joe Zon, Jens Ritter and several others so I'll put that money into better bandsaw and jointer and planer with helical cutting heads etc..

    Good luck!
    Gilmourisgod likes this.
  10. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    Thanks, build still in progress, seemingly never- ending, as it's very difficult to get free time to work on it. Expensive, time demanding hobby, but I love it.
    Means2nEnd and RBS_Johnson like this.
  11. Manton Customs

    Manton Customs UK Luthier

    Jan 31, 2014
    Shropshire, UK
    Luthier, Manton Customs
    mapleglo likes this.
  12. Jonny5bass


    May 3, 2011
    Seattle, WA
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  13. mapleglo

    mapleglo Gold Supporting Member

    Sep 7, 2013
    phoenix, az
    I agree - I see no reason to use a notched straight edge.

    I use one of these:

    Bench Dog® Dual Track, 36" - Rockler Woodworking Tools

    $32.00, and straight as an arrow. It can also be used for fret leveling by sticking on a piece of sandpaper to any of the edges.
  14. MarkoYYZ

    MarkoYYZ Commercial User

    Jan 31, 2012
    Hammersmith Music
    We made a bunch here from aluminum extrusions that I had on hand for some slim LED light fixtures. Notched on one side, flat on the other, use whichever your leveling style dictates. We used to fuss a lot over how level the board was before working the frets, but now we find the "average" level of the frets and do our work from there, since everything is more or less new when we do our work. A fret rocker, in combination with a good straight edge, is what you need IMO.

    Also, I've found Philadelphia Luthier Tools to be a good domestic source for tools, rather than StewMac. Other stuff I have ordered from Japan, China, Europe, etc... directly and had pretty good luck with pricing and things getting here fairly quickly.
    mapleglo likes this.
  15. Gaebrial


    Mar 8, 2016
    I like to use a notched straightedge to make sure the neck is flat before I do any fretwork, whenever I get around to it. But I don't see why it is necessary, and have done it without one most of the time just eyeballing the neck.

    Before I say anything else, it is good to get as accurate as possible when measuring and such. I am not going to say that being more accurate is a bad thing. BUT, I think after a certain amount of accuracy you don't really gain much.

    Not to mention that a notched straightedge measures a fretboard, and leveling the frets alleviates any crookedness with the neck. That, and the neck is (supposedly) supposed to have a bit of a bow in it. Not to mention, also, that every stupid thing about music in general and stringed instruments specifically is a "close enough" type of thing (From our tuning system to fret spacing and intonation, not even accounting for room acoustics, power supply quality, gear quality, and temperature/humidity in any given situation); nothing is ever scientifically/mathematically exact. Maybe some professional who is too good for his own good would notice a difference that minute when playing, but I know I wouldn't.

    Basically, having something that precise is good, but I don't think it is a big or small deal whether the straightedge is practically very straight or scientifically very straight. Not for stringed instruments, at least.
    SurferJoe46 likes this.
  16. NealBass

    NealBass Supporting Member

    Jun 19, 2014
    I got this coming in a day or 2. I figure yeah it's notched, but the other side is a straight edge, too (hopefully!).

  17. HaMMerHeD


    May 20, 2005
    Also, if you have a jointer that is set up properly, you can make a straight-edge of virtually any length and thickness any time you need one.
    tfernandez and SurferJoe46 like this.
  18. Hell - bass building isn't rocket surgery either. If we actually need things straight within half a helium light wave, then we is in the wrong industry.

    Wood moves if even just a tiny bit, but I'm sure it's over any differential that one can test for sure with a straightedge - at least until it gets ridiculously bent or warps.

    Here's a better idea - although I am not eschewing straight edges at any time - and in all seriousness - the we keep our tools sharp - sharper than we normally do - and make that the most important touchstone.
  19. PDX Rich

    PDX Rich

    Dec 19, 2014
    Portland, OR
    No idea, aside from results. I didn't have anything fancy for my first build and it turned out pretty damn good. I am sure more level tools would help moving forward, but I figure within a certain degree, you are being pretty damn precise as long as you are paying attention to workflow.
  20. Gilmourisgod


    Jun 23, 2014
    Cape Cod MA
    I do have a well set up Jet 6" jointer, so I can make wood straight edges, but I wouldn't trust them for long, they'd warp over time, wouldn't they? I doubt they'd be any straighter than even a cheap hardware store ruler, which doesn't seem straight enough for fret leveling.