# Drum rounding help needed



## jontheodore (Jun 16, 2008)

Hello all, I've been looking around here for a while and have finally joined up. I've just gotten into custom drum making, primarily in stave and segmented style drums, see pictures. I love making them and have gotten it down to a science thanks to a few test shells. However my problem lies with the rounding of the drums.

I unfortunately dont have a lathe, I would love one, but dont have the space or money for one at the moment. I do have a plunge router however, and have seen bowls and such made with routers, so I was hoping to adapt some of that to my dillema.

What I'm hoping you guys can help me with is to create a rig that can be used to round the outside and inside of my drums. And to hopefully use only one rig to accomadate all drum diameter sizes.

That being said, I'm not against say two rigs, one for rounding the inside, and one for rounding the outside, or even two rigs for say drums from 8-14" in diameter, and 16-28" in diameter. Im just trying to stay away from a rig for every drum size. And If any of my other tools can be used for this, even better, (at the moment, i have a sliding compound mitre saw, table saw, bandsaw, planer, router, rotozip, drills,)

I was also thinking of rounding the inside of the smaller drums using a drum sander attachment for a drill press, but if theres a better way I'd love to hear it.

I would like to thank you all in advance for any advice you may have, or if you know a link to a post that discussed something like this, I'd love to read it. I tried the search but didnt exactly know what to search for.


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## Mike (Nov 22, 2004)

Jon, the limitation you face is the depth of cut. I have yet to see a straight bit longer than a 4" cutting length. Using a circle cutting jig you could easily smooth the inside and outside diameters enough to install the drum heads. Would the rest of the shape effect the sound? Several members have built custom belt sanders and you could build one that would allow the finished edges of your drum to roll on tracks on each side of the sanding belt. This would give you the OD finished round. I can picture using two rollers mounted on a piece of plywood to support the OD rounded drum with an additional custom belt sander mounted to sand the ID. It would run a couple hundred bucks to build these items so unless you are serious about production I think it is not a worth while endeavor. What about building your drums using shorter sections stacked and glued? Sections would be about 6" tall or shorter depending on the bit used.


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## harrysin (Jan 15, 2007)

It's obvious that you have the construction as illustrated off to a fine art, in which case I would suggest that you produce planter boxes and wishing wells for which there is a ready market.
If however you still wish to make round drums, then I would suggest that each "Layer" is rounded individually by making a circle out of MDF so that it touches the flats, pin it in place and using a straight bearing cutter, rout around the circumference as shown in this crude but quick demonstration.
For the insides rout or cut a hole in a sheet of MDF so that it touches the corners and pin it in place and then rout the inside not forgetting that we now rotate the assy. in a clockwise direction whereas the outside was rotated in an anti-clockwise direction. I realise that separate templates are required for each size, however they are so quick and easy to make that it shouldn't be a problem.


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## chippypah (Dec 24, 2007)

Hi Jon,
Here are a couple pictures, is this what you are trying to make ?. In my opinion the only way this can be done with precision, is on a lathe.
Cheers
Pete


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## bobj3 (Jan 17, 2006)

Hi jontheodore


http://www.routerforums.com/31880-post21.html
http://www.grizzly.com/catalog/2008/Main/522

You may want to drop a PM or email to Andy and ask him how he did it..

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jontheodore said:


> Hello all, I've been looking around here for a while and have finally joined up. I've just gotten into custom drum making, primarily in stave and segmented style drums, see pictures. I love making them and have gotten it down to a science thanks to a few test shells. However my problem lies with the rounding of the drums.
> 
> I unfortunately dont have a lathe, I would love one, but dont have the space or money for one at the moment. I do have a plunge router however, and have seen bowls and such made with routers, so I was hoping to adapt some of that to my dillema.
> 
> ...


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## rstermer (Apr 22, 2008)

Jon- I have an idea that might help. I think you need to first use a circle cutting jig to round off both ends of the drum leaving the center section rough. That will give you a couple of smooth diameters to work with. Make sure both smooth sections have the same height.

Next make a jig that consists of a flat plate with two slots routed along its length. There will be two crosspieces slightly wider than the distance between the 2 slots. The crosspieces will be connected to the plate via bolts through the slots and the crosspiece. The slots allow you to move the crosspieces closer or farther apart to accomodate various drum lengths. Each crosspiece will have a slot routed through it along its length. There will be 4 round pins having the same diameter (larger than the slot) 2 for each crosspiece and each pin the same length as the height of the smooth section you cut on the od of your drum. The pins are bolted to the crosspieces through the slots in the crosspieces. The slots in the crosspieces allow you to accomodate various drum diameters by moving the pins closer or farther apart. The height of the slots in the crosspieces above the plate is determined by the diameter of the largest drum you would like to make. Once it is all assembled the crosspieces are bolted to the plate, the pins are bolted to the inside of the crosspieces, 2 on each crosspiece and the drum is positioned on the jig so the smooth diameters you cut with the circle jig rest on the pins. Now the drum can be rotated as it rests on the pins. 

Next step- Make a router sled (see Bobj3's excellent posts on how to make) sized to fit your drums. If you design it right, you will be able to machine both the OD and maybe the ID using 1 sled. The jig could be built to accomodate any OD, but the minimum ID will be limited by the height of your router and the sled design, so I would suggest cutting the ID smooth while still in the ring state before gluing the rings together to form the drum would be a good idea at least for the smaller drum diameters the router/sled won't fit inside.

I know this is all pretty wordy but I hope I was able to convey the concept. If not, post your questions and I'll try to answer them.

Regards,
rstermer


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## jontheodore (Jun 16, 2008)

thank you all so much! sorry i didnt get back quicker, been really busy around here. But all of your ideas sound really good, this week im going to take a harder look into each. The one problem i see with harrysin's design, is for the stave drum, i probably wouldnt be able to do that because of the depth of cut, as mike said, but im definitely going to take a look at the sled idea.

But i also think i may have something in mind, it incorporates both an idea i saw on another drumsite, but changed a little bit with the way the drum is held. I'm going to try everything on the weekend and tell everyone how it goes! thanks again!


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## Microsuffer (Aug 7, 2008)

I think there is an easier way to do this. Don't glue up more than two layers at first. John Innskeep uses a collet and a bolt to rotate a layer pair against a bit on a router table. No template needed. I don't yet have URL posting rights. Just google 'black walnut banjo rim' and you should find his delightful web site.

Note, while Johns scheme is emminently workable, you could build much deeper assemblies if you glue successive layers of segments to a routed ring. Each new layer uses the previous layer for a template and eliminates the need for very long bits or complex template setups. You just need a straight bit longer than the first pair of layers are thick.


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## Peter Sanders (Sep 16, 2007)

Hi



jontheodore said:


> What I'm hoping you guys can help me with is to create a rig that can be used to round the outside and inside of my drums. And to hopefully use only one rig to accomodate all drum diameter sizes.
> 
> That being said, I'm not against say two rigs, one for rounding the inside, and one for rounding the outside, or even two rigs for say drums from 8-14" in diameter, and 16-28" in diameter. Im just trying to stay away from a rig for every drum size.


I gave this some thought.

After about five minutes I thought this concept could work for you .

The (very rough) drawings are not to scale, but hopefully provide enough detail for the concept to be understood.

The implementation of the design can be resolved in many ways with a range of materials. I have drawn my idea with timber construction in mind. Obviously feel free to use whatever you have and can work with.

I suggest for rigidity and accuracy that the "whole" unit be built single "base".

If you create a faceplate a little larger than the largest drum you intend to make, then this jig should be able to do all sizes, limited only by the height of the router and/or the diameter of the router base. If the router base is removable then that should make the use of the router in this jig a little easier.

The router could be mounted in any orientation you prefer. If you make the router mounting bracket offset and can rotate it 180 degrees you should be able to do both inside and outside by quickly rotating the router and repositioning the "jaws" appropriately.

I would recommend that the horizontal motion of the router be controlled by a threaded rod. This would improve the performance and ease of use of the jig.

I also recommend that you use a cove bit or similar rounded bit to ensure that a smooth surface is produced.

A three jaw version would probably be easier to work with. However using a four jaw could allow you to create "offset" drums - a weird idea though 

If your drum sizes are "fixed" then the jaws could be bolted to the faceplate and do not necessarily have to ride in "T" slots.

There are many other variables and alternatives to this jig. I hope this helps you a little. Feel free to post other messages or questions and I will do my best to help you.

ps. It would probably be MUCH better to mount the router arm on roller bearings for smooth motion and greater accuracy. Good quality draw slide??


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