Endpin fit

Discussion in 'Setup & Repair [DB]' started by Eric Jackson, Apr 9, 2003.

  1. I have a good quality endpin- rosewood plug, stiff tubular pin, brass collar, substantial thumbscrew, etc. Problem is, the taper is somewhat smaller than the hole in my tailblock. Presently I have a couple layers of mahogany veneer wrapped around it, but the endpin is not square in the hole. Is there a better way of shimming it?

    (Ooops, this shoulda been under setup and repair, I guess. Sorry, I'm new here...)
  2. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    No problem. Fasten your seat belt, and extinguish all smoking materials.
  3. If you really want the endpin to fit properly, shimming is not the answer. You've got two ways to do it. (1) get another endpin with a socket larger than the hole in the end block and ream the hole to fit the new endpin, or (2) Make a plug to fit the hole in the end block with a wood lathe, glue it in, then drill and ream the hole in the plug to fit the endpin you have. Since you probably don't have a doublebass endpin reamer, a trip to your local bass luthier is your best bet. (The cost of buying a bass reamer is far more than what a luthier will charge you to fit your endpin)
  4. Chris:
    Okay, like, I try to be a smokin' bass player, eh...

    Thanks, your response was pretty much what I expected. Being the frugal, do-it-myself kinda guy that I am, I'd like to try and use what I have, if possible. Should the shoulder on the plug contact the ribs when the plug is installed? Will the wedging action of the taper eventually split the tailblock otherwise?

    I have access to a lathe and the knowledge to use it. I'm considering boring a piece of wood (maple?) to fit the plug's taper, gluing that to the plug, then turning the outside taper to fit the bass. Sound workable?
    What is the taper angle on commercially available endpins and reamers? Could save me a buncha trig/ trial & error.
  5. The problem is that there is a very high probabilty that the tapered hole in the end block is not straight to begin with. Most are not, especially if you've already had shims in the hole. If that is the case, your endpin will still not fit right even if you manage to get both the inside and outside tapers of your maple sleave correct (which is not an easy job in itself). If you insist on doing the work yourself, get a bass endpin reamer before you start.
  6. Johnny L

    Johnny L

    Feb 14, 2002
    Victoria, TX
    Being one of those make-the-darn-thing-work-while-unloading-as-little-cash-as-possible kinda guys, I was going to throw in the masking tape trick again...but you've made an excellent point that the hole for the endpin probably needs a ream job now anyway.

    I got to make a pen using a wood lathe a couple of weeks ago and had lots of fun with it. I didn't get the idea to make an endpin plug at the time. What a cool idea.
  7. Good point, Bob. If I tackle this I'll first get the hole reamed to make sure it's round and straight-sided. Hopefully it's not too bad now. The shims that are in it are not 'sticks', they're two thin pieces of mahogany veneer that were steamed and rolled to form sleeves.
    Agreed, trying to turn tapers on a wood lathe with hand-held chisels would be a frustrating sport. However, an engine lathe with a compound rest produces consistent tapers with fraction-of-a-degree accuracy. (John- Think machine shop, not wood shop.)
    Thanks, all.
  8. You need to make sure the hole is straight in relation to the scroll and side to side in addition to being round and straight-sided.
  9. If you are fairly handy in wood and metal, consider making a limited-use endpin reamer. Just turn a tapered piece of something really tough, like rock maple or harder. Then slot it once along one side, and fit a 1/8" or bigger piece of tool steel with a sharpened leading edge in there. It needs to be a very snug fit, but not so tight it splits your new reamer. A more complicated way is to use a deeper slot and a couple of machine screws through a wider piece of metal, sort of how a planer blade is fitted.
    Just use this gradually, taking care to pull it out frequently and checking for tearing of the often weak endgrain of the block. Lubrication with wax is a good bet, as long as you back off with the wax well before you get to final dimensions (wouldn't want the new endpin popping out too easily!).
    Fitting the endpin, try to keep the thing about 1° back of perpendicular, as the tailpiece wire will inevitably pull it forward a little over the next few years. That's because the newly cut wood in the hole compresses a little. Don't quite jam the shoulder up against the rib, partially for the same reason. It'll find its way in. Another reason is that the shoulders are often weak, and that ring can easily snap off, in part, leaving you with a 'used' endpin and a nasty little gluing job.
    I fitted my first few 'cello endpins with one like this, until I got myself a large reamer made for everything from small 'cello to very large bass endpins.
  10. Thanks Gerard, great idea. A piece of a second cut mill file with the edge ground might make a good blade, installed in the wooden arbor in such a way as to give a negative rake to the cutting edge so it scrapes rather than gouges.
    Bob, I understand your reluctance to encourage people to work on their instruments themselves. As a professional luthier I'm sure you've seen some hideous work done by do-it-yourselfers. Over the years I also have seen (and owned) basses that were subjected to gross indignities by unknowing carpenters. (Carpentry is not luthiery.) I've always treated my instruments with respect in the hope that they will continue to exist and make music long after I do. I promise I won't degrade an instrument by attempting to do work that is beyond my knowledge and ability.
  11. Eric - Unfortunately, many do-it- yourselfers do consider bass repair carpentry. Don't get me wrong, I have no objection to good carpentry. The problem is that most would be bass repairers don't know enough to see the pitfalls down the road before they start (then it is too late). For Example - You have now figured out how to make a reamer (thanks to Gerard), but have you thought ahead to figure out how you are going to make sure the endpin hole is straight and true in relation to the bass itself? If you don't have that one figured out, the best lathe work in the world is not going to cover the fact that the endpin is not in straight.
  12. I have given some thought to the reamer angle. I think what I would do is put the reamer on a tubular handle about 1-2 feet long, put the bass on the bench on its side, supported so the centreline is horizontal, then put a level on the reamer handle. I believe that would get the side to side alignment correct. As for front to rear, should the hole be angled slightly towards the back to counter the pull of the tailwire?
  13. That would probably get you pretty close. However, remember that a single cutter reamer will not cut a perfectly round hole (which is why the pros buy the very expensive German bass reamers). Assuming that the existing hole is basically centered on the line where the two lower bouts meet, an easier way would be to make a jig on a wood lathe that would look like a straight rod 2 feet or longer with a taper on one end that matches your reamer. Insert the jig into hole. Mark two points with a grease marker on the center of the lower bouts the same distance from the center line where the bouts meet. With a tape measure or string, measure the distance from the grease mark to the end of the rod. The distance should be the same on both sides when it's straight. Then measure the distance on the centerline where the top and back touch the belly and back of the bass. The distance from the belly to the end of the jig should be a little bit longer than the distance from the back to the jig. You may need to do this several times as you adjust your reaming for drift error. The longer the jig, the more accurate you will be.
  14. erik II

    erik II

    Jul 11, 2000
    Oslo, Norway
    Eric, is there anywhere you could borrow a professional reamer? When I bought my new endpin, the shop let me borrow their reamer for a couple of hours, just had to leave a modest deposit. If everything is well prepared, the reaming job itself shouldn't take so long...
  15. tsolo


    Aug 24, 2002
    Ft. Worth
    Not to rain on anyone's parade but, it cost me 25 bucks for - sixty after i bought an endpin - a luthier to install a new endpin. If you're just after the challenge, carry on. If you want the endpin installed, take it to lex luthier... probably won't be much more than that to plug and ream. I don't know how luthiers get so rich.
  16. Luthiers get rich??? Wow, cool, I wonder when that'll happen to me....
  17. Begins to look more and more like do-it-myself would be foolish in this case. It would require:
    -making a reamer
    -making a straightness checking fixture
    -reaming the hole
    -making a tapered sleeve
    -spending mucho time acquiring materials, machining, measuring, etc., rather than playing.
    All this versus walking in to a luthier's shop and saying "New endpin, please." Maybe I'm too cheap for my own good sometimes...
    However, the whole exercise enables us all to learn something, to better appreciate the luthier's craft, and become more educated consumers of same. Thanks to all who posted, especially Bob B. for sharing his many years of experience. (And I can't see how anyone could get rich working on instruments of this size. Old famous-maker violins maybe, not basses.)
    Now all I need to do is find a luthier I'm really satisfied with- the guy I've been dealing with is youngish, I think he has reasonable skills but lacks in the attention to detail department. Anyone in the greater Toronto Ontario area have a reccommendation? (Perhaps this should be a new thread?)
  18. ronveron


    Apr 13, 2010
    Hi, Eric Jackson,
    this is how to calculate angles using trigonometry
    E.g. go to this page
    if the ratio is 1:17 you write tan(x)=17 and click Enter
    so you get 86.63354°