Project Stave Snare Drum, 13 x 5.5

[Seth Dolcourt]

Hi,

I've posted 2 completed snare drums, and today, I'm starting another. This time, I'm going to tell a much longer story. It will take some number of weekends from this point forward to finish the story.

How many of you would like to receive free, 200 year old, highly figured sugar maple in the mail? Sounds too good to be true. In exchange for sending one of my stave shells to a member of a drum forum, he sent back this box full of charm as "rental payment." I should rent my drums more often!

canadian_sugah_1.jpg


Never look a gift horse in the mouth. Or so the expression goes. The blocks were too narrow for anything but a 10" diameter drum, and lacking a No. 6000 Lie-Veritas PowerDelta Wood Stretching mechanism, I just glued some walnut stripes to one edge to fatten the width.

sugar_spice_stripes.jpg


I needed quite a bit of time to run each block through my router table equipped with a 11.25 degree chamfer bit, but with the angle dialed in and the width of each block at 2.60" exactly, I've glued up a 13.125" diameter x 6" tall drum blank.

sugar_spice_stripes_clamped.jpg


Using one of my gizmos to safely edge a ragged-edge blank, the blank is now 5.5" tall, and the edges are 90 degrees to the face and co-planer to each other.

sugar_spice_edged.jpg

[Seth Dolcourt]

So....let's turn this shell!

If you've seen my other stave drum posts, I've not gone into much detail about how I do it. Today, I photo-document my turning process.

Barbell for a weakling? Guilty as charged. No, it's the heart of my whole drum lathe. A central axle pierces two MDF disks. The axle is precision 1" aluminum flagpole tubing.

axle_clamp1.jpg


Perhaps it looks like a kludge, but it works. Some fat head screws press the shaft collar tight to the disk. Some brass shims in the right place makes the MDF disk as close to 90 degrees to the shaft as possible. I know, there are lotsa holes there, but the important part are the holes labeled OK...All Thread goes through these holes, keep reading...

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It's woodworking, not metal working! .000" is great, but a few thou off here or there won't cause any harm. In this shot, I'm pretty darn close.

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The drum shell is positioned

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The other disk is installed onto the shaft

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Some All-Thread

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Inserted through 3 holes, each 120 degrees from each other. Make the nuts finger tight.

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All done. Ready for the next step.

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[Seth Dolcourt]

The central axle is right and true. Even if it ain't, it is, since all things spinny revolve around it. The job here is to get the shell as centered as possible. The reason is wall thickness - I'll be turning the inside of the shell later on, and if I do a good job centering the shell, I'll have lots of wall thickness later on, to determine how much I want to lathe away.


Did you know if you remove the router from your router table, you have a nice, big hole in which to drop a long tube into?

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Like so.

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View from the top, the job is to best center the shell.

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Eyeballing is good, but a Lee Valley caliper used in depth mode is better. Generally, the distance from the edge of the shell to the disk was about .43", give or take, measured at NSEW compass points, on both sides of the shell. If I was off by .01" at any point, that's fine.

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This picture shows the final steps. Lock the disks to the axle, tighten the nuts on the All Thread. The shell ain't moving from this spot.

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[Seth Dolcourt]

What follows is the fussiest part of my whole work flow. Done right, turning is a breeze.

If the axle and disk are the heart of my turning jig, the stands are the body. Simple book-ends, but there is a plate with 2 precision bearings very close to each other, and they cradle the axle. The plates are bolted to allow infinite adjustment vertically, giving my jig a general capacity of 10" - 26" diameter. Yes, 13" of swing!

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Clearly, with the axle sitting on both sets of bearings, the shell is a little tippy.

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On the stand where the drum is higher, I simply loosen two bolts holding the plate, and tap, tap, tap.

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Pretty good, and this is eyeballed. (Some of you already have a notion in your mind. Keep that thought.)

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Just a top-down view of the axle cradled by the bearings. If there was only a way to lock that axle into place, to prevent it from lifting or shifting.

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Skateboard wheels. All they have to do is press down. They are mounted on their own plate.

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Some steel angle, and I've installed UHMW slick tape. Some aluminum angle is epoxied onto the steel angle, and I just screw down into the stand. (Some of you have another notion, related to that first notion. Just keep it to yourself for now.)

The distance between the tabs allow for making drums from 4" tall to about 10" tall. That means I only need one setting for all of my snare drums.

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One step not photo'd, but important anyway. After I edged the drum, I marked some Stop Cutting lines. As mentioned, the rough blank is 13.125". Why? Because a shell is 1/8" undersized from nominal. This 13" shell will actually be 12 7/8" diameter, when finished. Why? Because commercially available drum heads are themselves the nominal size, so the drum shell needs to be a bit smaller to fit inside the metal hoop to which the plastic drum head is bonded.

So...I measured in from the edge of my shell 1/8", and 180 degrees from that line, did it again. Measuring the gap, I verified 12 7/8" between the marks. This is one of the marks on the right side of the drum....

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[Seth Dolcourt]

...and this is the Stop Cutting line on the left side of the shell.

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Mount the router on the rails (that aluminum plate slides really nice on the UHMW slick tape!) and make darn sure the router remains unplugged for this next step!

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Extend the router bit until it touches one of the Stop Cutting lines on one side of the shell.

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Move the router to the other side of the shell, and check it against a Stop Cutting line there. I'm really close, but not entirely 100% precise to the line. Adjust the bearing plates if needed to get yourself really close. You don't have to be exactly on. (Stop nagging, I know, I know. Don't worry, it'll be OK.)

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Here, I attach my hand-crank. Not pictured, but I've clamped the stands to the table, and added a few cross braces to stiffen the works up. You'll see those annoying metal braces later.

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[Seth Dolcourt]

Time to turn, which is what you all paid your admission to see.


I set a depth of cut that juuuust removes the peaks of the miters and an ephemeral amount of the flats. For the advanced wood workers, is this a climbing cut, and if so, why?

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Some more action shots of the first bit of lathing. The pink is rosin paper, which I've taped to the router base plate to act as shrouding for the chips that are flung from the bit.

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All done with the first round of cutting. Note the mess that it makes.

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A close up. All in all, the cut quality isn't too bad. Do you like the figure? Sweet, huh?

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So....all that side conversation. This is what that was about. Here is a flexible sewing tape showing the circumference of the right side of the shell.

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Here's the left side. Not bad for eyeballing, right? But, I can do better, and for a number of reasons including crafter's pride, I want to eliminate any taper. How do I do it?

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Easy. Shim the side with the smaller diameter. Two bits of .007" under each track. See? I told you it would be OK.

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Keep track of the Stop Cutting lines. I have plenty of meat left.

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[Seth Dolcourt]

Let's take another round of cutting, and check the circumference again. This is the left, 41" minus...

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and the right. 41" minus ! Hummm, baby! That's pretty good. No more taper.

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The arrow is my real Stop Cutting line, the little one is to be ignored. Keep cutting until you reach the line.

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With the shell still on the lathe, a flat wood block with a cork pad and 120 grit sandpaper wrapped around it makes simple work of removing the machine marks.

You see some of my shop notes written on the metal brace - 39.5, 39 5/8. By calculation, 12.875" x 3.1415926 = 39.51" is the circumference I need. By practice, 39 5/8" is actually the circumference I need. Here's why.

That flexible sewing tape has thickness, 1/64". If I measured 39.5", that would be the circumference on the *outside* of the tape, but the shell is *inside* the tape - and would be under the 12 7/8" target. Ahhh! Didn't think of that, eh? (Actually, I got burned on that very thing.) So, add a 1/16" to the circumference for tape thickness, add another 1/16" for material to be sanded away, and there you go - 1/8" over 39.5, hence, 39 5/8. And I was dead on.

lathe12.jpg

[Seth Dolcourt]

I'm done for this weekend, but let's wrap it up.


Here' the shell, ready to be removed from the lathe.

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Lifting away the clamping disk.

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The outside turning is done. Stay tuned for the next installment of this stave drum project. Thanks!

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[Salem Ganzhorn]

I have read some of your other projects and had no idea what your process was. Only that it produced some seriously cool looking cylinders .

Thanks for letting us in on your secrets!
Salem

[Joe A Faulkner]

I've never dreamed of instrument making, but I find this process extremely interesting. Thank you documenting this and sharing it here. I look forward to the next your next post.

[Seth Dolcourt]

I have read some of your other projects and had no idea what your process was. Only that it produced some seriously cool looking cylinders .

Thanks for letting us in on your secrets!
Salem

I've never dreamed of instrument making, but I find this process extremely interesting. Thank you documenting this and sharing it here. I look forward to the next your next post.

Hi, guys,

Thanks for your comments.

At its core, instrument making requires many of the same basic steps as furniture - wood selection, wood prep, milling and assembly. Without the elemental woodworking skills, this is a difficult project. Nothing on here is mortise and tenon'd, of course, but the knowledge and practice of all those classic woodworking joints make the formation of a simple but highly accurate long grain bevel that much easier to execute consistently, 32 or 40 times in the case of a 16 or 20 stave shell.

Cheers,

Seth

[Jim Becker]

Very educational, Seth!

[Mark Wyatt]

That is pretty wild. Thanks for the post. I'd love to see a video .

[Gerry Grzadzinski]

For the advanced wood workers, is this a climbing cut, and if so, why?

Depends on which way the drum is turning. If the top is turning away from the camera, then it's a climb cut. The reason being that if the drum were stationary, and you were pulling the router toward the camera, the router would have a tendency to climb along the parts, due to the bit grabbing the wood and pushing the router. With a conventional cut, you're pushing the bit into the wood, so it has not tendency to grab the wood.

Nice job, btw.

[Seth Dolcourt]

Very educational, Seth!

Thank you. I hope I'm at least giving back what I'm taking from SMC; I've seen plenty of good ideas here, thanks to people who openly share.

That is pretty wild. Thanks for the post. I'd love to see a video .

I've been thinking about it. I have a bunch of little stories I shot about using my edging gizmo, I might break down and buy some video editing software and see if I can stitch it together.

Depends on which way the drum is turning. If the top is turning away from the camera, then it's a climb cut. The reason being that if the drum were stationary, and you were pulling the router toward the camera, the router would have a tendency to climb along the parts, due to the bit grabbing the wood and pushing the router. With a conventional cut, you're pushing the bit into the wood, so it has not tendency to grab the wood.

Nice job, btw.

Thanks, Gerry. And I'm awarding you full points, for taking a crack at the answer, here's 10 for 10, just for playing the game!

Yes, the top is turning away from the camera. It's as simple as I've found that climb cutting reduces tear-out significantly. A 12" diameter walnut drum turned into a hairy dog when taking a conventional cut, so I go with the climb cut.

The depth of cut is 1/16" or less. Any bigger, and the router bit will grab like crazy and have its way with the shell. Bad news! Using a motor drive might tame that tendency; for now, the hand crank gets the job done. I feel so....Roy Underhill.....