Acrolite Black Galaxy bearing edge bumps

Mr Farkle

Well-known member
I just bought a used Acrolite Black Galaxy. The drum is pristine, obvious well cared for, but it needed a new head. When I removed the batter head, by instinct I ran my fingers around the bearing edge and noticed one section (about 5 inches long) is slightly bumpy or wavy. I can’t really see the bumps but I can feel them. And they are uniform so I can’t imagine any way these could have been made other than in the manufacturing process. Is that normal for this drum? I wonder if it’s the coating because it feels like the edge surface of a porcelain pan.

This is more a question of curiosity. I doubt it would affect the sound. Thanks!
 

KamaK

Platinum Member
Acrolites shipped in a student kit with a case and stand. The stand was lightweight and extended fairly high so that students could play standing up.

Fairly often, you would see Acrolites where someone bumped the stand and tipped it over, causing buckling that can be felt along the bearing edge but were otherwise fine cosmetically.

Remove both heads from your drum. Grab a ruler. Make sure it is round. Find a glass or slate table and make sure the batter side is completely level.

I've only ever successfully repaired one, and it was quite a bit of work because you need to push from the inside out with a fabricated jig. While the repair was successful, it was more effort than the drum was worth.
 

Push pull stroke

Platinum Member
Acrolites shipped in a student kit with a case and stand. The stand was lightweight and extended fairly high so that students could play standing up.

Fairly often, you would see Acrolites where someone bumped the stand and tipped it over, causing buckling that can be felt along the bearing edge but were otherwise fine cosmetically.

Remove both heads from your drum. Grab a ruler. Make sure it is round. Find a glass or slate table and make sure the batter side is completely level.

I've only ever successfully repaired one, and it was quite a bit of work because you need to push from the inside out with a fabricated jig. While the repair was successful, it was more effort than the drum was worth.
What kind of jig did you use?
 

KamaK

Platinum Member
What kind of jig did you use?
The short of it is, I cut a ~14" diameter circle out of 3/4" plywood, cut a 3" strip out of the middle, and used two lengths of threaded stock, 4 washers, and 4 nuts to fashion a rudimentary jack to push the indentation out evenly from the inside while I lovingly coaxed from the outside with a rubber mallet.

I'd only recommend it if you have the identical problem, have the parts laying around, and are handy at fabri-cobbling things of this sort...
 

Mr Farkle

Well-known member
Acrolites shipped in a student kit with a case and stand. The stand was lightweight and extended fairly high so that students could play standing up.

Fairly often, you would see Acrolites where someone bumped the stand and tipped it over, causing buckling that can be felt along the bearing edge but were otherwise fine cosmetically.

Remove both heads from your drum. Grab a ruler. Make sure it is round. Find a glass or slate table and make sure the batter side is completely level.

I've only ever successfully repaired one, and it was quite a bit of work because you need to push from the inside out with a fabricated jig. While the repair was successful, it was more effort than the drum was worth.
I’m impressed that you were able to make a jig to do that! I checked it on a glass surface (great idea) and it’s fine. It’s round too. I really think it’s manufacturing and would have never noticed without running my hand along the edge.
 
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