Restoration of my Sonor Force 2001

Ok guys I'm desperate!

I just tried to put some heads on the drums - they don't fit anymore.
(Only on my 8" and 20" drum)

I don't really know why, because the veneer I put on is MUCH thinner than the wrap was.
The veneer was 0.5mm and even got thinner while sanding.
The wrap was about 0.8mm.

WHAT HAPPENED THERE?
I'm getting some kind of nervous as I NEED this kit saturday.
I tried different heads, no success..

WHAT TO DO?!
 
David, did you consider the finish? Finishing the shells added some coating so while the coating may be pretty thin it could have added enough to make the heads not fit any more. It can't be too much of a difference though.

I'd try to gently rework just enough of the shell edges to make the heads fit. "Rework" = to just polish it gently, this might be enough.
 
David, did you consider the finish? Finishing the shells added some coating so while the coating may be pretty thin it could have added enough to make the heads not fit any more. It can't be too much of a difference though.

I'd try to gently rework just enough of the shell edges to make the heads fit. "Rework" = to just polish it gently, this might be enough.
This is most valid, but also consider a possible change of shape/expansion due to the wrap being removed. Are the shells still round?
 
Thanks guys!


@ Arky: I don't think that the finish adds so much.. It looks like the shell is 5mm too big now.. Since we did only 4 layers of clear laquer I don't think it's enough.

@ Andy: I will check if the shells are still round. If not, what can I do to get them round again? Any easiest way?
 
Thanks guys!


@ Arky: I don't think that the finish adds so much.. It looks like the shell is 5mm too big now.. Since we did only 4 layers of clear laquer I don't think it's enough.

@ Andy: I will check if the shells are still round. If not, what can I do to get them round again? Any easiest way?
Shit! 5mm too big? Wow, that's a lot. Check for roundness, then get back to me. I'm leaving out for band practice soon though (based on my performance Saturday, much needed)
 
Ok I tried to measure from lug to lug on my 14" drum.

Position 1: 35.5mm
Pos 2.: 35.2
Pos 3: 35.3
Pos 4: 35.4

It really looks like they're not round anymore.
Even if I put the head on, on some places there's space and on some spaces the head is tight as hell..

// EDIT
Andy, how about this:
I could try to cut some round wood plates and put them into the shell and then put some cords around the shell again to put some pressure on it.. do you think it would last?
 
Ok I tried to measure from lug to lug on my 14" drum.

Position 1: 35.5mm
Pos 2.: 35.2
Pos 3: 35.3
Pos 4: 35.4

It really looks like they're not round anymore.
Even if I put the head on, on some places there's space and on some spaces the head is tight as hell..

// EDIT
Andy, how about this:
I could try to cut some round wood plates and put them into the shell and then put some cords around the shell again to put some pressure on it.. do you think it would last?

So sorry to hear of your despair David, I've been following this thread for a few days now, bummer about the roundness of some of the shells, that must be the (unfortunate) end result of removing the wrap.

Yes, you'll need some kind of pressure to the shell to regain it's round shape, your best bet would be to be able to put the head back on, hopefully the shell will regain its roundness.

I've got an idea, try one of these quick release attachment to put pressure on the shell, put the belt at the top of the shell, but low enough for the head to fit fully on the shell, put the head on the shell, and very gently apply some pressure (put some protection as to not mark the shell), once the head fits, put the hoop on, tune the drum and leave the belt on for a few days, this might do the trick, but be ever so gentle when applying the pressure. The same apply for the reso side of the shell...

This is the quick release belt I'm talking about...
sangle-a-cliquet-5-m-basique-auto.jpg


You should find some in DIY stores.

EDIT: You want to put both belts (top and bottom) together to avoid possible breakage, to much pressure at one end of the shell could be fatal to the drum!!!
 
Hey Henri,

thanks for the kind words and the advice!


I just put some heads (top + bottom) on my 10" and 12" drum and put the screws really tight (especially were the shell is "too wide")..
We'll see tomorrow evening what happened...

No belts yet..
 
Ok I tried to measure from lug to lug on my 14" drum.

Position 1: 35.5mm
Pos 2.: 35.2
Pos 3: 35.3
Pos 4: 35.4

It really looks like they're not round anymore.
Even if I put the head on, on some places there's space and on some spaces the head is tight as hell..

// EDIT
Andy, how about this:
I could try to cut some round wood plates and put them into the shell and then put some cords around the shell again to put some pressure on it.. do you think it would last?
Hi David, sorry, just back from band practice.

I don't understand your measurements. Did you measure from one lug to the next around the circumference? This is not a good guide to roundness. Some drift in the drilling is inevitable, & TBH, those measurements sound typical & not a cause for concern. You need to measure accurately diagonally across the shell from bearing edge peak to peak.

That said, the fact that your heads are showing uneven contact pretty much suggests your shells aren't round. The photo doesn't tell me much, other than the head is some considerable distance away from seating correctly. A wrap becomes part of the shell, & in many cases, acts as a stabilising element in the construction. It's removal can equate to warping & expansion. Unfortunately, I think your shells are suffering from both, although that's difficult to confirm without inspecting them myself.

OK, what to do. Your plan to gently force the head onto the shell is a good idea, but you should tension each screw evenly, not apply greater pressure to the pinch points. You're effectively trying to get the shell to follow the form of the head, so you don't want that to be uneven. Once tensioned evenly, place the shells in a warm place, preferably at a higher temperature than they've been used to. Although this seems counter intuitive (you expect things to shrink when chilled), it will help the shell to adjust. Hopefully, that will pull them into the round. Getting them round is critical, even if they're still over size. If you get them into round, but they're still too big, then I'm afraid you're into removing some thickness behind the head collar to allow the head to seat without hindrance. It may take some time for the shells to respond to gentle persuasion from the heads. Just overnight will likely not be enough.

I'm worried about this event David. If your photo is representative of just how far out the shell is, then this is quite unexpectedly excessive. Keep me updated before resorting to drastic measures. You'll be surprised by just how much wood can move.
 
Hi David, sorry, just back from band practice.

I don't understand your measurements. Did you measure from one lug to the next around the circumference? This is not a good guide to roundness. Some drift in the drilling is inevitable, & TBH, those measurements sound typical & not a cause for concern. You need to measure accurately diagonally across the shell from bearing edge peak to peak.

That said, the fact that your heads are showing uneven contact pretty much suggests your shells aren't round. The photo doesn't tell me much, other than the head is some considerable distance away from seating correctly. A wrap becomes part of the shell, & in many cases, acts as a stabilising element in the construction. It's removal can equate to warping & expansion. Unfortunately, I think your shells are suffering from both, although that's difficult to confirm without inspecting them myself.

OK, what to do. Your plan to gently force the head onto the shell is a good idea, but you should tension each screw evenly, not apply greater pressure to the pinch points. You're effectively trying to get the shell to follow the form of the head, so you don't want that to be uneven. Once tensioned evenly, place the shells in a warm place, preferably at a higher temperature than they've been used to. Although this seems counter intuitive (you expect things to shrink when chilled), it will help the shell to adjust. Hopefully, that will pull them into the round. Getting them round is critical, even if they're still over size. If you get them into round, but they're still too big, then I'm afraid you're into removing some thickness behind the head collar to allow the head to seat without hindrance. It may take some time for the shells to respond to gentle persuasion from the heads. Just overnight will likely not be enough.

I'm worried about this event David. If your photo is representative of just how far out the shell is, then this is quite unexpectedly excessive. Keep me updated before resorting to drastic measures. You'll be surprised by just how much wood can move.

Hi Andy,

no problem! I'm grateful for your help anyway!

Sorry for confusing - yes, I measured from the bearing edges, not from the lugs. I just used the lugs to get the right position.

I just put each screw to equal tension and placed them in my room in front of heater.. It should get pretty warm in here..
Damn I really hope that the damn wood will move back again.. It would be more than just a pitty if these shells wouldn't work.. :(


I'll keep you updated!!
 
Hi Andy,

no problem! I'm grateful for your help anyway!

Sorry for confusing - yes, I measured from the bearing edges, not from the lugs. I just used the lugs to get the right position.

I just put each screw to equal tension and placed them in my room in front of heater.. It should get pretty warm in here..
Damn I really hope that the damn wood will move back again.. It would be more than just a pitty if these shells wouldn't work.. :(


I'll keep you updated!!
David, in front of the heater = no. In a warm space = yes. They need to be at an even temperature all around the shell.

Thanks for the explanation on the measurements, but it still doesn't add up. Are your measurements in Centimeters not Millimeters?
 
David, in front of the heater = no. In a warm space = yes. They need to be at an even temperature all around the shell.

Thanks for the explanation on the measurements, but it still doesn't add up. Are your measurements in Centimeters not Millimeters?

Ok - moved them!

Sorry... I was pretty tired and frustrated yesterday, I guess I wrote some sh*t here..
The measurements are in centimeters!
 
Ok - moved them!

Sorry... I was pretty tired and frustrated yesterday, I guess I wrote some sh*t here..
The measurements are in centimeters!
No problem David. OK, so your shells are about 1/8" out of round. Frankly, that's just about standard for all but better intermediate & higher end kits. It could do with improving for sure, but it's not a deal breaker. It would seem the over sizing is the bigger problem. Check them later today & see if there's any improvement + report back.

Andy.
 
Kalma.. Keep in mind, these are a KHS/Mapex product.. shells, fittings.. etc. Their production was still so-so in those years so maybe that is part of the shell problem.. Just a suggestion.
 
Ok I just had a little "loosening" session with my 10" drum.
I put of the head and I'm not sure but I guess it's not really better yet.. I put the head on and again tightened the screws on..

Maybe I can do something to increase the pressure?
 
Ok I just had a little "loosening" session with my 10" drum.
I put of the head and I'm not sure but I guess it's not really better yet.. I put the head on and again tightened the screws on..

Maybe I can do something to increase the pressure?
I'm hopefully speaking to Dean this evening. I'll put this past him, & see if he has any suggestions. He's the man on this stuff!
 
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