I get a lot of questions about the rim of the drum, or bearing edge. This is an important part of the drum shell. Done incorrectly it can cause a vibration that could drive you crazy trying to figure out what it is, at least it drove me crazy the first time it happened to me. The vibration noise is due to a flat spot on the rim of the shell. What is happening is that the skin left bearing edge but then retouches again and starts to make the noise or vibration. There really is only on way to fix it, take the head off and fix the flat spot. When I first started out I was told the rim should look like a side view of your thumb. The finger nail side would be the inside of the drum and the skin (or palm side) would be the outside. That analogy really does work.
One more tip on the rim is if you want the plane of the top of the drum to be flat I have found the best way to get it that way is to glue sandpaper to a flat surface and rub the drum over that surface. It takes a little elbow grease but it is worth it in the long run. I actually use a belt sander to shape the rim but the first thing I will do is get the rim a little pointed so when I do flatten the top of the drum It sands easier. The more I flatten it, and wider the flat spot becomes, the harder it is to sand. I will reshape the rim again and make the top where I have been sanding pointed again until I finally get it flat. I use a piece of glass to gauge the flatness. You actually can tell when it is flat by looking at where you have been sanding and if the sandpaper touches all surfaces, then it has to be flat. If you do not have access to a flat surface and sandpaper, there is the old concrete driveway. I have turned a drum upside and rubbed it back and forth on my driveway, it works but you need to make sure the concrete is flat by using a straight edge in the place where you will rubbing the drum.
When finally finished sanding the surface, you have to get that rounded side view of your thumb look again on the rim. If you had to take the head off to fix the rim there is no need to re-soak the head, you can put the head back on dry, tighten the verticals, put your diamonds in and start playing.
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Great explanation! I bought a "disaster" drum quasi-intentionally for the purpose of taking it apart, putting it back together, etc.. It seems to have just about every ailment in the book including the vibration your talking about here. I do have a drum head question for you. The drum head on my drum is not level in that, the head ring is lower on one side that the other to where when the rope is tightened, the ring is tilted. Does this have a significant impact to it's performance, should I get a new skin and start over (my thoughts), or is there a way to compensate for this tilt?
ReplyDeleteThanks,
Jim
Hi Jim
ReplyDeleteIf the diamonds are in the drum, there is not a whole lot you can do to straighten it, if they are not then you could possibly pull the high side down some. Just start pulling on your verticals where it is high. It i is kind of hard to describe where to pull but you have to keep in mind that when you pull really hard ( i use a tool when i need to move the ring) it will go down ahead of where you are pulling and behind where you are pulling so you have to keep that in mind so that you do not over pull. In other words, move down a loop or two from where you want it to go down and pull there. Being out of level is not the end of the world, i have seen some drums that sounded really good that were out pretty bad.
Shorty
Yes, a row of diamonds are installed. However, the rope is frayed and the drumhead is still too loose. I'm going to order some new rope and having never replaced a head before I'm a bit on the fence. The current head has wear around the outer edge as if it's experienced a lot of rough handling or perhaps the drummer still had a couple of rings on to where the dead is pretty well abraided. In any case, the ring the drumhead is dried around is the ring thats off kilter. Perhaps I should send a scan or two?
ReplyDeleteJim
Hi JIm.
ReplyDeleteIt sounds like your drum needs some work. It is really hard to say a lot when I can not see it. What I do is turn the drum upside down and look underneath and behind the flesh ring and see what the condition of the skin is there. That can tell a lot. if you can see holes or splits or even rust showing through the skin from the flesh ring, it might be time for a new head. Feel free to send pictures. I will assist you in any way I can
shorty
Hi Shorty, To flatten and level the rim, I use a piece of formica, with sticky-backed automotive sandpaper strips, works great! After the rim flat-line is established, I work the thumb shape, leaving it flat 1/8" wide and then lightly sand the two rim edges making a buzz free and very responsive bearing surface.
ReplyDeleteHi Mike
ReplyDeleteI pretty much do the same thing, I use a piece of 1/2" steel 12x24 and glue sand paper to it, It doubles as my flattener for rings.
Shorty