Cutting bearing edges without marring/chipping the exterior

drumco1547

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Hi guys-

Been practicing on some old really crappy shells.

I cut some edges on a snare shell yesterday with a brand new bit and the outside pass really checked up and chipped the outer ply.

Now, I did not tape the outside and the drum itself was a very cheap beech thing with pretty crappy quality.

No wrap.

I ran the outer edge clockwise, interior edge counter clockwise.

My question, for when I eventually step up and start cutting "real" shells- how do you prevent that?
 

Tommy D

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Depending on the bit size I run my router between 16k-25k rpms. Big bits go slower. Small ones faster. Depending on the wood type you either have to run it quickly or can go at a smoother pace and avoid burning. I take small cuts at a time. It takes me probably 6 or 7 cuts to make the final edge on just one side, so 14 or 15 total cuts to complete an edge. Always run your material in to the blade as opposed to running it with the blade. This will keep the bit pulling the material towards it as opposed to kicking it out. I mask the exterior and put tape on the router bearing itself if the inside of the shell is finished.

Some woods just are a pain to cut though. some really soft woods catch and pull out leaving a not-so-perfect cut. That usually requires faster router speeds, but the soft wood burns easily so you have to cut little bits at a time and do them relatively quickly so it comes out clean.

It just takes a bit of time, more experience on different shells and on the job training to get it. I recommend going slowly taking little cuts at a time to get a feel for how the shell responds to the cutting. Some are a dream to cut, others are more sensitive and need more attention.
 

drumco1547

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Tommy this is outstanding info. I really appreciate you taking the time to lay that out.

The 45 degree bit I'm using is new, it's a half inch shank and the diameter is 1.5".

When you say 15 cuts per edge, is that a drum with reinforcement rings or just the standard thickness shell with no rings?

I will put this into practice. Thanks again.

I may try to order some junker shells and just see what happens with each. Ludwig, Slingerland, maybe some MIJ stuff to see what different constructs and different woods like to do.

Many variables!

Thanks a ton-
 

Tommy D

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No need to buy different shells. Just test on your current shell. Go just a little bit at a time. You will be able to see how the wood responds to the cutting on your very first pass.

As for how many cuts it takes me, thats just how I do it. I do everything by eye so if I am trying to hit my cut to end right at the second ply line, then I go little by little until I hit that. Always cut the outside cut first. Thats the one that will be interacting with the head and that one is more important than the inner cut. If I want a really sharp apex on my edge, it may only take me 3 or 4 cuts to get close with the inner 45 (or 30 or 60... whatever), but the last little bit may take me 3 more tries to nail it. A rounded apex is pretty much the same idea, but you don't have to be 100% perfect since you will likely be blending the two cuts together with hand sanding. Also, if you are doing a whole set, do all the shells at the same time with the same router settings. If it is a 5 piece, set your router, cut all 5 shells on that setting, adjust the router, cut them all again, and so on and so on. This way all your shells are getting the exact same bearing edge on them. If you want graduated bearing edges, maybe do the all at the same time, but start dropping out shells as you go deeper with your blade. Cutting edges for me can sometimes take all day and I need to find ways of getting consistent and timely results.

Dont even get me started on old Ludwigs or Slingerlands with re-rings. I hate working on these shells. Those old bearing edges look to have been cut with a machete. There's no real way to get a uniform apex on those shells because the re-rings are of inconsistent thickness and they have random deep gouges taken out on them in various places. I just try to get somewhat close and blend the rest with sanding blocks. You do the best you can. They always end up being better than they came from the factory, but they are no where near as perfect as a modern shell.
 

drumco1547

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Understood. I may have gotten too aggressive with that first pass.

I had been doing the outer edge clockwise around the bit, and the inner edge counter clockwise around the bit.

Lots to learn.

When you say that you hit your cut ending right on the 2nd ply line, can you explain a couple things there?

1) Is this on a 3 ply or 6 ply or any in general?
2) Do you just stop the edge where the ply begins (right on the border) or do you try to hit it so the edge is dead center?

Thanks Tommy- I'll get it eventually!
 

amosguy

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If you are practicing on old crappy shells, then just start again on the same edge with multiple cuts as recommended. Not gonna matter much on finished depth anyway. That way you know if your technique is getting better.
 

Tommy D

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Understood. I may have gotten too aggressive with that first pass.

I had been doing the outer edge clockwise around the bit, and the inner edge counter clockwise around the bit.

Lots to learn.

When you say that you hit your cut ending right on the 2nd ply line, can you explain a couple things there?

1) Is this on a 3 ply or 6 ply or any in general?
2) Do you just stop the edge where the ply begins (right on the border) or do you try to hit it so the edge is dead center?

Thanks Tommy- I'll get it eventually!

There is no exact science to this. It all depends on how you want the drum to sound. Roundovers, double 45's, baseball bat, or single 45 degree edges all change how the drum is going to sound. As the person cutting the edges you are choosing how that drum is going to sound. When I say "cut to the second ply" it's just to be as an example. Am I cutting that with a 45 degree bit, an 1/8" round over, a 3/16" round over or a 1/4" roundover. Is it on a thin 6 ply shell or a thick 8 ply shell? There are lots of things that can influence what type of edge you may want to put on a drum. I mean, there are some times where I want to only cut through the first ply and a half for my outer edge and cut the inner edge so I have a half ply flat spot that I can smooth out with sanding to give me a pseudo Tama style edge.

That's why I recommend you go slow at it. Take off a little at a time, see how the wood reacts, see if you need to up the speed of your bit or the speed of your rotation on the shell to get that right blend of clean cutting without burning. Turn the shell opposite the rotation of the blade. If that is clockwise or counter that's fine. The only time I have ever needed to cut an edge with a climb cut is on some early 80's Tama Superstars with the white painted interiors. The paint on the interiors was chipping when cutting the inner edge, so I did a climb cut on my last pass which only took off like 1/64th of an inch of material, but it left the paint unchipped. Climb cutting in general is kind of dangerous so best to avoid it unless absolutely necessary.
 
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