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effect of adjusters

Discussion in 'Setup & Repair [DB]' started by B String, Jan 12, 2003.

  1. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    Has anyone found a reasonably big
    difference in sound or feel
    using different types of bridge
    adjusters? (brass, aluminum,
    wood, etc)
    What are the benefits of each?
  2. anonymous0726

    anonymous0726 Guest

    Nov 4, 2001
    b b cummings


    with adjusters and
    is of the opinion
    it is all in the setup



    almost no difference is realized

    them if you tweak


    what you have

  3. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    Thanks e.e..... I mean B.B.
  4. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    If there is one thing we all agree on, it is that sound is subjective. As far as what adjusters sound the best, it's a matter of preference.
    But, function is more or less absolute. Either the adjusters turn and the maple threads hold up, or they don't. It's this reason I don't use 1/4-20 threads anymore. The larger thread adjusters (3/8, 7/16) are also deeper threads. I have yet to see a set of stripped-out maple that was tapped with these larger threads. Jeff Bollbach doesn't like the big threads, though. Sez that the structural integrity of the foot is compromised by them. On some bridges, 7/16 is a bit excessive. A fella in Cincy makes all my adjusters, with a 5/16 post and a 3/8 thread. I don't know if Stenholm or Kolstein manufactures an adjuster between 1/4 and 7/16, though...
  5. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    I'm glad that Shank agrees with me on the lack of tonal diff-he is very good with sound.
    Nick ol' buddy-I've seen many dozens of failures in wood adjusters. When you cut the leg and look at how much of it the diameter of the shaft occupies its amazing they don't all crack. Drilling the hole dead center is not easy and if it is slightly off at all its gonna be real close to the [end grain] left or right side of the leg. Then it's begging to crack. I've also seen plenty of disc failures. Metal adjusters can be made one piece alleviating that problem. As far as metals stripping their threads-I have seen that happen although not as often. I believe that these failures prolly resulted from either poor threading technique or the adjuster being removed and then replaced with some cross threading occuring. Not a one of my adusters has ever failed.

    ps-Actually, re wood adjusters there is quite a bit of diff in the quality of what's out there. The Stenholm ones are machined unbelievably well and I have never seen one fail by stripping or disc loosening. However, the vast majority of wood adjusters out there are third world imports and are quite poorly made.
  6. I agree with Nick on this one. I think the advantages of the bigger threads out weigh the potential loss of structural strength to the bridge. When given a choice, I prefer the Stenholm made Robertson ebony composite adjusters. For some reason, there seem to be far fewer cases of adjusters freezing up with these as opposed to the 1/4 - 20 metal adjusters that I've installed in the past. From an acoustical standpoint, my personal feeling is that the ebony adjusters color the sound less than aluminum or brass adjusters. To my ear, the aluminum adjusters are a little bright, but I have many customers that prefer that sound.
  7. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    Oops, I just reread Nicks comments and realized that he was using a 5/16 shaft. Never saw one of those. I'm curious Nick-what woods are used and how are the discs affixed[and howare they made a true 90 degrees] Are they available or are they just for you.?
  8. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    My repair persons concern is that
    My new bass has brass adjusters
    with brass inserts top and bottom
    in the bridge legs. This (in her opinion)
    is a lot of weight and mass that
    could be blocking or in some way
    affecting the sound. Ya know what
    I mean?
  9. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    B String-
    The extra weight could affect the sound. But, do you like the way the bass sounds? Sorry I can't give you any help on this... I'd really need to play your bass

    Jeff- these adjusters aren't wood. The centers are aluminum, but the outside threads, the disc, and the outside of the post are composite high-density nylon. I forget the trade name of the stuff; it's wicked hard and looks like plastic. Anybody can buy them. Charlie Mallott 513.561.7975 He's a machinist that makes bass parts. (Seems like every luthier has a "machinist-friend".) Charlie does superb work, and he's a bit of a nut. He can make any size you want, with any materials you want.

    He has also making these adjusters utilizing an ACME thread. It is a squarish-type thread that is designed for lifting/downward tension. Honestly, the regular threads on my 5/16-3/8 work like a champ. Charlie is always trying to improve his stuff. He's complained more than once that he can't sleep at night because he's thinking of bass parts. What a geek :p
  10. I think you repair person has very good instincts. I can't say for sure that it is hurting the sound, but I'm positive it isn't helping it any. Any time you add that much weight to a bridge, it has to act as a mute to some degree.
  11. B String

    B String Supporting Member

    Apr 11, 2002
    Los Angeles
    This is a little tough because its
    a new bass that was shipped with
    these adjusters on from Germany.
    Its a carved Wilfer. The sound seems
    a little choked and uneven in some
    areas. But its a really beautiful bass.
    French corners and the older style
    reddish orange varnish.(not glossy)
    I think this can be a sweetheart.
  12. I've been making wooden adjusters with 7/16" threads for years now, probably over 100 sets. The very first set I made were sort of forced, as a set the client ordered from Kolstein failed; the 'ebony' wheel (looked like rosewood to me...) cracked and about 1/3 of the wheel just fell off when I first turned it at pitch in the newly-threaded bridge. Seems the Kolstein fashion of pinning the wheel to the lignum vitae shaft with a tiny brass nail caused a very focused stress riser. Weird to imagine one could affix a wheel to a slippery core like l.v.!

    Anyway, my first set was made to get the player back in action without having to make him a new bridge. I happened to have a large-ish block of lignum vitae on hand (about 1 1/2" x 6" x 22", without a serious crack in the whole lovely thing), so I cut a piece off and turned two adjusters on my little Taig lathe. Then I got an 'adjustable' 7/16" die at a local machine shop and hand-turned the threads. This forst attempt was not exactly brilliant, and in three years the G-side thread failed. It was just not a well-formed thread on the adjuster. I made a new set for the guy, as by that time I'd learned a lot, having made a few dozen sets. I also switched to cocobolo, though it is less well lubricated naturally. It's hard, and a good block can support a very fine thread. One other early set I made (#3 I think) had a similar failure. That fellow was in Texas, and had a local luthier rebuild the thread in the lower leg. Those are the only failures my adjusters have seen in the past 6 years.

    Now, given, 6 years is not a hugely long time to prove anything where basses are concerned. But then again, I've see a lot of basses with micky-mouse aluminum wheels installed, with 1/4" - 20 threads, often at silly angles (quite often at two distinctly different angles!), which usually jam up so badly as to require lowering string tension to half and then applying pliers to turn them at all. I've also seen many scrolls sawn off to make way for what prove to be temporary C-extensions. We all know, there is a lot of hooliganism out there.

    But in that context it seems to me a safe enough bet to use the more stable and easily turned wooden adjusters, made each of one piece of very dense hardwood. Properly drilled and threaded, a thicker adjuster shaft seems to stiffen a bridge leg sufficiently to make the sort of flexion leading to cracked feet unlikely. I've repaired a few legs, replaced a few, and always these endgrain cracks have been in bridges with aluminum 1/4" - 20 adjusters. Anecdotal, sure, and perhaps somewhat defensive for a first post here. ;) But I still believe in this kind of adjuster, though I do discourage people from having me make them. Hate the dust. Lathework is not why I became a luthier.

    Oh yeah, one critical point in fitting adjusters. A drilling jig is essential to ensure utterly parallel installation. I made a heavy plexiglas jig for the Taig, and just feed the bridge one leg at a time into the rotating bit, then swap for the 7/16" tap and turn the chuck and feed the bridge by hand, unpowered. Makes for zero mistakes with hand drills and wobbly jigs. I just use the transparency of the jig to line up a scribed line in the plexi with a pencil line on the leg of the bridge.

    Here's an email I got from a Toronto player just an hour ago, after getting his bridge back and installed. It's fairly typical, if again anecdotal:
    "The bridge came in on friday and installed today. The wheels look great and the bass sounds better."
    No one gets extremely excited about the sound, but if there is an apparent difference, it is always for the better, with comments often tending towards a more 'open' or 'relaxed' output. When I used to install a German 3-peice brass adjuster, with a plain shim tube above and a threaded insert below, machined adjuster in the middle, comments tended to indicate that 'at least it's no worse than it was'. Nicer to hear the stuff people say about wooden ones, even allowing for some placebo effect.

    If I do see failures in the future I will of course reassess my choice.
  13. It's been a while since we've had a new luthier in the group. There are at least six other luthiers who regularly post opinions here, but I think you are the first from Canada.

    Thanks for the explanation of making your wood adjusters. It wasn't clear to me if you are still using the adjustable 7/16" die or if you have another method now to cut the threads. I've never had very good luck cutting threads in wood with a die, but mine was not adjustable. I have experimented cutting the threads with my small metal lathe, but that turned out to be more work than it was worth. I would love to know how Bob Stenholm makes his. They are about as perfect as I can imagine in wood.

    I look forward to hearing from you in the future.
  14. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    Hey Gerard-
    Greetings from Cincinnati. Welcome to TalkBass!
    let the hazing begin....
  15. If you really feel a hazing is necessary... ;) I'm new here, sure, but I am one of the most heavy contributors to a number of Pocket PC discussion forums. Got one almost 3 years ago when my forgetfulness started getting in the way of work (missing appointments, forgetting names, that sort of nonsense), and due to the infuriating nature of any Windows platform (I was a total computing newbie, so this was a while in the learning too) I soon became expert in hacking and repairing that device. Now one of my titles is 'Gerard, the registry god'. Feels good, but I've worked for it. Another title, slightly more official, is 'contributing editor' with pocketnow.com - so if anyone is into tiny PC computing, I'll be glad to help out.
    As for the die, yes, I am still using that adjustable one. I crank it to fully expanded for my first run, lubricate with beeswax, then cut very gingerly, watching for true. Then I back off, loosen the screw, and make another ppass or two, each lubricated. Lastly I coat again in beeswax and hit it with just enough heat to melt it into the wood. Simulates the lubricity of lignum vitae fairly well, without the propensity for micro-checking.
    That set of broken Kolsteins I had to go on are rather beautiful in the thread department too! I wish I could get them that clean, but think one needs to have a great machinist's lathe with a clockwork drive of some kind, and to keep the wheel separate - something I won't do. I've considered making a jig with a Dremel and a very smal ruby bit to re-cut a rough thread to perfection, but still can't quite get how to perfect it's design.
    Right now a VSO and Opera guy wants me to make a 4-capo C-extension 'as good as or better than' the one I made for Dave Brown... Got me a bit stressed out with inventor's anxiety. I actually discovered this site this morning in hunting down others' designs. Turns out there are not a lot of people making very interesting extensions. Closer to none, really. Anyone got a pointer or two? Links?
  16. http://www.robertsonviolins.com/extension.htm
  17. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    "Hazing"? What "hazing"? I've never heard of anything like that around here....what IS this anyway, a FRATERNITY???

    At any rate, welcome to TB!
  18. anonymous0726

    anonymous0726 Guest

    Nov 4, 2001
    You didn't hear about the 'Tailpiece' scandal?
  19. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    Yes, welcome to Luthier Central, Gerard! You seem very opinionated-we like that around here.
    If you think the Holsteins have nice threads you should see the Stenholms.

    Are you turning One-piece wood adjusters?

    ps-you could finish that bass if you spent less time on the net! Believe me, I know.
  20. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny