Router lathe for stave drums

[Scally]

I have been making a few stave drums and it takes a long time to get them round.

The more staves you have the easier it is to shape the square joints round but the more joints there are to get right and glue together.

I usually plane the high points then work up through the grits. It is steady work and the drums aren't perfectly round either.

Recently I found this jig using a router on a big frame that holds the rough drum shell. It was made by Koko on the drumshed forum.

This is my attempt.
MDF ends with 4 long threaded rods to hold the ends together. It can be adjusted for quite long drums.
Bearings are attached to each of the ends. You change their location to suit the diameter you need.
A set of round mdf templates are clamp bolted to the rough shell then mounted in the bearings.
Adjust the ends and the bearings to hold the shell.
The router runs on angled aluminium rails fixed to the top of the jig.

Shallow router cuts are made as you rotate the drum shell by hand (at this stage).

I have given it a short test and it looks fine.

It can be used to rout the inside of the shell by putting a set of rails inside the shell. I haven't added that yet.

Any comments and suggestions for improvement are welcome.

[Wongo]

I always wanted to something crazy like that, and you have finally done it for me. Here, have a greenie. :D

Love your work.

[Scally]

You're a champ.

But the credit goes to Koko.
I have made one before to round a square board, about 50mmx50mm. A drilled on one end was used to rotate the rod.

I couldn't wait for the weekend. This afternoon I tried it on the small drum shell in the above pics.
The shell is 24cm diameter by 40cm long with 24 staves(I think?).
Dry blackbutt reject floorboards.

It feels secure in the jig.
A little stiff to rotate.
Bigger bearings would help and smaller washers that don't put tension on the bearings.

I used a dishing router bit because it has a flat bottom cutting edge and round corners.
It took a dozen or more very shallow cuts. It still bites a bit.
Automating the rotation with a drill or similar would be an improvement. Then I could hold the router with two hands. It would feel better than doing it with one hand on the router and one rotating the drum.
I did about a dozen shallow cuts. Ended up covered in chips!

The finish still had slight scollops.
I used a ROS with 50# through to 240# while rotating the drum and it gave a very good finish.

Overall it took about and hour to do the routing and sanding and I was taking it steady.

Doing it by hand is hard work and it would take me a couple of days to get a reasonable finish.

This is much quicker, much easier and gives a much better result.

Know i want to do more....

Go on Scott......get yourself a sheet of mdf, threaded rod and a cheap skateboard.

[tea lady]

Very cool.:2tsup:

[joe greiner]

Inverted, and on a router table, might be more stable. Also, if the ends are to be discarded, or if their centres can be later wasted, dead centres can be made from all-thread mounted on the jig plates. Or if otherwise, temporary waste blocks can be attached to the ends, and still use the dead centres.

Have a squint here for a variation: http://www.woodworkforums.ubeaut.com.au/showthread.php?t=57412

Joe

[Scally]

Yes Tea Lady, I think so too.

That sounds interesting Joe.
I followed about 10% of what you are suggesting.

Can you give me some more details please?

The ends would be reused but the template bolted/clamped to the shell would be new for each shell. It needs to be close to the finished diameter.

I have never done any turning so I am not sure what a dead centre is.

[joe greiner]

Yes Tea Lady, I think so too.

That sounds interesting Joe.
I followed about 10% of what you are suggesting.

Can you give me some more details please?

The ends would be reused but the template bolted/clamped to the shell would be new for each shell. It needs to be close to the finished diameter.

I have never done any turning so I am not sure what a dead centre is.

Here goes, Scally: The apparatus supporting the router looked somewhat unstable, unless it were attached to your end plates. If the end plates rode on a router table, with the router below, it would be less likely to receive off-axis cutting. The "bookends" in my link served the same purpose. (They were inverted for cutting, with some lath strips across the "tops" for smooth running inverted on the router table.)

Live or dead centres provide a conical surface to engage a divot in the end of the workpiece, commonly used on the tailstocks of wood or metal lathes. The distinction between live and dead, is that the live centres have a bearing to support the rotating centre, so that the cone point doesn't rub in the divot; in a dead centre (much easier to make), the cone is allowed to gently rub in the divot. At high speed, the divot may be lubricated to reduce friction; at low, or negligible, speeds, this is less critical and lubrication can be safely ignored. One advantage of using such centres, is that the central axis location is better controlled. Your rollers need to be very accurately placed to achieve such control.

My four-wheel steady rest (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=68735 ) is my current avatar. To use it for hollowing vases and such, I support the workpiece with the tailstock, and adjust the wheels to intimately contact the already-rounded portion of the workpiece, then remove the tailstock. Because the wheels are adjustable, it occasionally gets knocked out of alignment by a combination of forces, but I can usually re-find the central axis.

Upon reflection, your rollers might be usable for non-circular shapes (e.g. ovals), but the geometry could get weird right quick, I think.

If your router support is attached to your end plates, it's more stable than it first appeared, and you can probably ignore most of what I've said, unless you want to remember it.

Cheers,
Joe

[Scally]

Thanks Joe.

I have seen a jig with a big rod through the centre and supported by a bearing around each end.

This solves the problem of having my bearings parallel.

I drilled all the holes before assembling the jig. I clamps both end pieces together so everything was even.
Of course I will need to pull it to pieces to drill holes for the next drum(s).

The jig is pretty stable but you wouldn't call it rigid. The rails across the top to guide the router do help stiffen it up.
You also need a good surface to sit the jig on and you wouldn't want to move it part way through the routing. You would probably twist it a bit.

It isn't like a good lathe.

If I made up the dead centres for the router table I would need to extend the top of the router table. Some of my drums are pretty long - nearly 900mm so far.

I would like to try a cone shaped drum and a conga drum.
My head can't work out how the locate the bearings/router to do them.

There is always something else to work on.
Cheers.

[Scally]

Here are a couple more pics of Koko's jig.

You can see how he uses the router to do the inside of a drum shell in the first pic.

The second shows a pully that he uses to rotate the shell while routing.
He clamps a drill to the jig and runs a belt to the pully.
I think he says it rotates the drum about 12 times per minute.
Nice and slow.

[Scally]

Attached are two more pics from Koko's jig.

The first is with the drill set up to rotate the shell.
The belt is a push bike tube.
Inside is a rubber wheel that runs against the shell.
It is all adjustable for different diameter shells.

The second is a dust hose fitted to remove dust when routing the inside of the shell. It would be hard to rout without a dust extractor because the shell would fill with dust and cover the cutting surface.

[44Ronin]

Scally interested in making me a shell or two?

[Scally]

I am keen to make several now I have the jig set up.

I have requests for three sets of dunduns that will fill in a few hours over Christmas.

And I would like to try some shaped drums and experiment with different timbers.

What type of drums are you interested in?
Dimensions, timber, finish......

[44Ronin]

I am keen to make several now I have the jig set up.

I have requests for three sets of dunduns that will fill in a few hours over Christmas.

And I would like to try some shaped drums and experiment with different timbers.

What type of drums are you interested in?
Dimensions, timber, finish......

I was thinking woods like jarrah, tasmanian blackwood and png rosewood, purpleheart, rosegum.

Looking for snare drum shells - a 13.875" diametershell fits a 14" drumhead. 3/8" or 1/2" Stave/Shell thickness is fine.

Depth of shells of 4", 5.5", 6.5".

I like low sheen satin finishes.

[Scally]

I like your choice of timbers.

It would be straightforward to make the shells.

It might take some trial and error to get exactly 13.875". What tolerence is there?

My preference is to start with thicker shells. They can be made thinner but I think 1/2" plus would be stronger.

Danish oil would give a good satin finish and it is easy to maintain.

[44Ronin]

I like your choice of timbers.

It would be straightforward to make the shells.

It might take some trial and error to get exactly 13.875". What tolerence is there?

My preference is to start with thicker shells. They can be made thinner but I think 1/2" plus would be stronger.

Danish oil would give a good satin finish and it is easy to maintain.


1/2" or even 3/4" shell thickness is fine. Whatever you're comfortable with.

You don't need spot on tolerance with the diameter. Anywhere on or between 13 & 3/4 to 13 & 7/8 and I'm happy. If the shell is larger in diameter than 13 & 7/8, chances are the industry standard (mylar) drumheads will be tight fitting and prevent the drum from sounding good. Conversely, if the shell is any smaller than 13 & 3/4 it will be hard to get the tension casings to line up with the hoops.

I like this kind of snare bed

http://i48.photobucket.com/albums/f249/jcymbal/snares/RKedge003.jpg

[Scally]

Thanks for the 1/8th" tolerance???

I have just cut up two sets of staves. I will see how I go with the diameter.

From the pic of your shell it appears to be:

45 degree bevel inside
2-3mm flat
then a 8mm roundover.

Does that sound right?

Is that a ply shell?

A stave shell shouldn't need the internal hoops for strength.
What are the reasons for them?

What hardware do you intend to fit?

[44Ronin]

From the pic of your shell it appears to be:

45 degree bevel inside
2-3mm flat
then a 8mm roundover.

Does that sound right?



The picture was just a reference for the type of snare bed I like.

Here's another example of snare beds....

http://www.mikedrums.com/tuning/oaksnarebed67.jpg







Is that a ply shell?

A stave shell shouldn't need the internal hoops for strength.
What are the reasons for them?That drum from the photo is a steambent shell - They are notorious for going out of round. They require reinforcement rings to keep in round. It is for this exact reason that ply drum shells are the industry standard as they replaced steambent construction methods back in the 1920's.

Some companies still make Steambent drums, but they are rare - Here is an example of the steambent construction method in the first half of the video.

YouTube - [How It's Made] Drum Shells


As far as hardware is concerned, i'll order from a supplier

classic tube lugs

http://www.drummaker.com/pix/tblga.jpg

a piston style snare strainer

http://www.sfdrumco.com/rclassthrow-1.jpg

triple flanged hoops

http://www.drumfactorydirect.com/bmz_cache/1/15f03bdae70bf62ce00006e2958b9081.image.182x160.jpg

[Scally]

I found a pic of a drum being shaped on a router table.
I think it is similar to what you were talking about Joe?

After I get my jig running better, I might give it a go. It would certainly be easier to get the drum centered.

I made a big sanding disc to flatten the edges of the drums. It does a good job but is a handful to use.

This is the latest drum from the router lathe. 600mm long by 400mm diameter. It felt heavy in the jig and didn't roll very easily.

There are three more in progress and a set of Snare shell glued up.

Plenty of opportunity for refining the jig!!

[joe greiner]

I found a pic of a drum being shaped on a router table.
I think it is similar to what you were talking about Joe?


Actually, Scally, that looks better than the contraption I used. My spiral cage wasn't hollow, thus the need for the dead centres and the holding frame. Your hollow shells allow the use of the centre rod with end blocks. For best purchase, I think the staves should be all the same length, perhaps a little longer to enable final trimming to length. Thanks for finding it.

Joe

[Scally]

Joe, I understand about your solid spiral cage.

I cut the staves about a cm over length for the glue up.

The big disc sander is then used to get the ends nice and flat.
This gives me good contact with the end templates.

[Scally]

I have four drums finished on the Stave router jig.

The big shells take a bit of work to rotate them with one hand and control the router with the other.

On the Jamo Jamo dununba, I routed the inside as well. I didn't try to get it perfect, jut take the steps away from the staves.
The shed and me were covered in sawdust.
This would be a good 'outside job'.

I sanded a 45 degree bevel on the inside of the rims them used a roundover bit on the router table to get the outside profile.
It did a good job because the rim was nice and flat and the weight on the drums kept it firmly on the table.

Everything was sanded to 240 grit then give a light coat of danish oil all over.