Looking for ideas of joinery

[Rhythm House Drums]

I added a photo to try and help explain what I'm after. I have a new idea for a drum but not sure how the joinery will work. I will essentially have two hollow forms, a barrel and a cone that I want to join into one piece. I've done this before with a much less aggressive angle and just used dowels, but with the angle so sharp, I'm not sure I'll have enough room to use a dowel efficiently. I also thought about a type of rabbit, so the pieces would fit on like a box top and then just glue them.. but I'm not quite sure how I'd make that work. Maybe I'd route the ends of each stave before glue up? It's end grain to end grain so I need to do something more than just glue. The rabbit method would make my glue ups have to be perfect in order for that to work.

 

[Mark Gottesman]

I have never built a drum, but what your doing looks like a hopper used in grain and milling operations. Have you thought about making the drum with a bent stave. You could build a sliding saw jig to cut the tapers and just have vertical long grain joints.

Or if you want to use that sort of joint, you could probably rig up a way to route a circumferential groove and use glue in a thin spline. Maybe made from a thick veneer.

Luthiers use similar building techniques to bend sides and bind the edges.

I'm sure someone will be along shortly who has a useful idea. :gar-La;

 

[pviser]

Great question! On this one, I'll sit back and read the ideas of others.

 

[Rhythm House Drums]

Thanks for the response... I am actually in the process of building a steam box with a wall paper steamer for the purpose of bending the stave so I have one solid stave along the whole top half (instead of the two sections that I'm trying to join up). But I'm sure there will be a huge learning curve with that as well, especially if I'm trying to do a tight bend and have it uniform in 20 some pieces. I like the idea of the solid stave better, but I also have other applications where I'd like info on a best way to make this type of joint. I was thinking if I had a lathe I could do a rabbit or lap joint on each piece... IF.. But that's a little while down on the list of things to get... Also wondering if a finger joint would work, or if it would be impossible to match it up..

 

[CDPeters]

I think would try a splined miter in each stave, with the spline set close to the inside edge of the joint.

C.

 

[Ben325e]

It seems to be similar to what is achieved with a splined miter, just with a different angle.

1. Divide and mark the cylinder's circumference into even sections.

2. Tape the cylinder to the cone (and glue the two together, but I don't know that it would help much), with the tape being between each mark. I'd probably have 12 or
16 sections depending on the circumference of the cylinder.

3. Set the cylinder and cone in a crosscut sled, with the long axis of the cylinder being parallel to the direction of cut.

4. Tip the assembly forward so that the joint of the cone and cylinder is the only thing resting on the crosscut sled. Attach blocking to the sled so that it is providing stable support for the assembly.

5. Rotate the assembly to each mark and rip a slot into it with the crosscut sled.

6. Assuming you use a full kerf blade, glue 1/8" strips of wood into the slots.

7. After the glue dries, use a handplane to reduce the strips on the outside flush with the cone and the cylinder. I'd leave the ribs on the inside... they'll probably look neat. Or, a 1/8" or 1/4" chisel will flush the insides.


If you want the length of the strip to extend the same amount into the cylinder as it does the cone, then measure the angle of the cylinder. Lets say it's 130 degrees. With the joint of the cylinder and cone resting on the crosscut sled, the angle of the cylinder to the surface of the sled should be 25 degrees [(180 - (angle of cone to cylinder))/2]

I'd probably use a quality combination blade for the cut - something with ATB teeth plus a flat raker tooth to ensure a flat bottomed cut so that you don't have little batwing holes that go past the spline when it is made flush with the drum. Perhaps use some tape where the blade will exit the cut to help reduce tearout to a minimum.


HTH


Ben

 

[Rhythm House Drums]

I think would try a splined miter in each stave, with the spline set close to the inside edge of the joint

So you're saying to connect the end grain of the straight stave to the angled stave with a splined miter for each of the staves, and then glue up the form (bowl), instead of what I was trying which is to glue up two forms and then connect them? I like this idea, a lot more time consuming than I was thinking.. and a totally different approach, but I do think it will work and be really stable.

 

[Rhythm House Drums]

Sweet... thanks Ben. I like that Idea! Now on to that cross cut sled I've been meaning to build

 

[CDPeters]

That would work Ben - and maybe add a bit of decorative touch if contrasting wood where used for the spline.

I was thinking of a blind spline, perpendicular to the joint plane and parallel to drum circumference - and yes Kevin that is what I was thinking. If you split the angle in half, then you could run both sets of staves on one setup, then set up for the spline cuts and do all of them with one setup. Then it's just a matter of glue up...

C.

 

[Ben325e]

It doesn't have to be on a sled. You could even do it with a handsaw or a router (but I'd make a jig for a router...). A handsaw would be easy, you would just need splines the thickness of the kerf.

Edit: if you did use the crosssled, you could even tilt the blade so that the spline, after it was leveled with the cone and cylinder, would actually form a curve. The pattern going around the drum would be this : (((((((((((((

If you turned the drum around after you cut the first set and cut another set, you could make the pattern do several things: () () () () or )( )( )( )( or the curved sections could intersect each other, all depending on your spacing.

 

[Rhythm House Drums]

It might even look cool if I used a contrasting wood spline and made the miter cut with a dado set at 1/4 or 1/2 inch even, and just use some big splines. I've been wanting to buy a dado set The staves are usually around 2" wide each... depending on the size of the drum, so if I'm using 24 staves I could put a spline in the center of every other one... might have to try this!

 

[Rhythm House Drums]

you can see my excitement with all the smilies... You all are posting as I'm typing

I'm thinking some yellow heart splines on a walnut drum...

 

[Ben325e]

Just look out for tearout with the inside chippers on the dado set when they exit the cut. They are usually pretty aggressive. Also, the outside cutters on a dado set often times leave 'batwings' which could extend past the yellowheart splines. The height of the batwings on a typical flat dado divided by the sine of the angle at which the cylinder was tilted would be the length of the batwings when cut at an angle.

 

[ehpoole]

Another option, if you are accustomed to using dowels is to just go ahead and use dowels. Only in this case don't bother making it a blind dowel. That is, drill the hole from outside the complete essembly, in the same plane as the straight sides, use a drill press (and forstner bit) to drill straight through the cone into the side panel, then drive a solid dowel (no flutes or spirals) into the hole. Trim the dowel flush to the conical section with a flush-trim saw, sharp chisel or hand plane. We tend to fall into the trap of believing that dowels must always be hidden from view, but just as with splines they can be incorporated into a project as functional design elements as well. If need be, you can temporarily hold the assembly together for drilling with a few 23ga pins (or very small brads) -- just locate them where you will not need to drill trough them.

The pattern left behind will be that of a series of ovals where the trimmed dowels are visible. If you drill in a consistent equi-distant pattern around the cone then this can actually be an interesting design element. You could even use a contrasting wood for the dowels if you wish to draw more attention to the design element OR you can use dowels of the same species as the cone and they will be much less prominent.

 

[Gofor]

Another option:

Add a third piece between the barrel side and the cone piece. This piece is wedge shaped at the angle you want them to meet, so it will allow more meat to insert a spline in both surfaces (the mating surface to the barrel stave and the mating surface to the cone stave). After they are glued you can sand the protruding edges smooth or to a flowing curve. If this interim spline piece is a contrasting wood, it can add a decorative element to it as well.

If the barrel and cone meet at a 45 degree angle, the wedge piece would be a 45 degree wedge, shoved in far enough to allow a 1/4" deep spline groove in both top and bottom. The ends of the barrel and cone pieces would be square.

As the staves are only 2" wide, there should not be any wood movement issues. One advantage is that this could be easily mass-produced on a table saw; no new equipment needed.Another advantage is that both the barrel and cone staves can be the same thickness.

Go

 

[Gofor]

decided I had better add a quick drawing:

Hope this helps. Dimensions are based on 5/8" thick staves. Easily adjusted for bigger spline or different dimensions, angles, etc.

Go

 

[Ben325e]

After all these great replies and complex methods we'll probably check back on the thread later to find that Rythmhousedrums used the new mini pocket hole jig and screws from Kreg and they worked perfectly

 

[CDPeters]

Nice Mark, I like it!

 

[zapdafish]

http://www.eagleamerica.com/product/v190-2865/ea_-_glue_joints


dunno if any of these types of bits would work