Need 24" square reference table, sort of

[Bill LeMay]

I'm a total newbie, but here goes. I want to build and repair drums. My biggest challenge is getting trued bearing edges, which are the rims of the cylinders on which the heads sit. Their quality greatly affects the sustain and clarity of the drum's tone. I have some Gretsch drums which are otherwise in decent shape, but the edges are quite wavy.

Looking around, industrial reference tables would be overkill, as I don't need anything that precise; I mean we're talking drums, not musical instruments! :) Some people recommend a sheet of glass as an inexpensive reference table. This would be plenty flat for me I'm sure, but my intended approach would be to shine a light from the inside of the drum shell to reveal the irregularities. I don't think a glass table would work well for this.

My 24" square requirement would allow me to set the entire shell of a 24" diameter drum on a flat surface.

I welcome any ideas. Thanks,

Bill

[Dave Falkenstein]

Perhaps the Festool Multifunction Table would provide what you are seeking:

http://www.festoolusa.com/category.aspx?ID=9

You can buy the table in a "Basic" configutation, without the fence and Guide Rail. The table is made with extruded aluminum sides and a top of MDF with a pattern of holes for using clamps of various types and sizes. Clamps can also be used in the side channels. The top is quite flat and stable. Would this table siut your needs?

[lou sansone]

I would think good quality 3/4 baltic birch or MDF would be flat enough.
lou

[Charlie Plesums]

If you want something especially stiff as well as flat, build a torsion box table, often called "assembly" tables among woodworkers. Basically it is like an I beam, where a thin layer on the top and bottom become extremely strong and flat if they are held apart, and glued in place, by a set of supports (often a grid of thin wood), or in cheap doors, held apart by cardboard.

An old flat door may solve your problem.

[Ken Fitzgerald]

Welcome to the Creek Bill! A neat place to exchange information and obtain opinions!

[Matt Meiser]

Either a torsion box with MDF surfaces, or maybe a piece of granite countertop?

[Brett Baldwin]

Welcome Bill.

I'd think that the MDF suggestions would be the practical way to go. Plenty flat for the precision you are looking for and very economical as well as easily replaceable. I'm thinking that a lipped table top that you could drop your 24"x24" MDF surface into would make an easily renewable work surface. Hope that gives you some useful ideas.

[Jamie Buxton]

Can you quantify how flat you need? For instance, if the table were flat within 1/32", would that be good enough? Or do you need flatness to .005"? Or what?

[Bill LeMay]

Thanks for the ideas. For the curious, here is a web page that talks about bearing edges. These guys have a slick machine for cutting bearing edges. There is a link that shows a video of the machine in action.

http://www.drumfoundry.com/zen/index.php?main_page=perfect

Bill

[Norman Hitt]

Thanks for the ideas. For the curious, here is a web page that talks about bearing edges. These guys have a slick machine for cutting bearing edges. There is a link that shows a video of the machine in action.

http://www.drumfoundry.com/zen/index.php?main_page=perfect

Bill

In addition to the suggestions mentioned above, If you don't want to make a flat top yourself, by laminating MDF and covering it with plastic laminate on both sides so it will remain flat, (like we make router table tops and table saw extension tables/wings, then look at WoodCraft and they sell a produce that is 3/4" Baltic Birch plywood that has a phenolic laminate on both sides and is very flat. You can get this in sizes up to 2' x 4' from them. You would probably want to seal the edges to eliminate any moisture from swelling it around the edges over time.

[Tom Jones III]

One thing commonly overlooked, I use the granite countertop piece that is cut out for a double kitchen sink. The piece is garbage to the installers but it is very flat and very hard yet small enough to put away against a wall in your shop.

[Jamie Buxton]

Thanks for the ideas. For the curious, here is a web page that talks about bearing edges. These guys have a slick machine for cutting bearing edges. There is a link that shows a video of the machine in action.

http://www.drumfoundry.com/zen/index.php?main_page=perfect

Bill

Bill, besides being cool and quick, that machine also takes care of the issue of making sure the bearing edge is flat. They spin the drum blank on a turntable and hold that router at some fixed distance above the turntable. As long as the turntable doesn't bounce, and the drum doesn't rock on the turntable, the milled edge of the drum comes out flat. Notice that it doesn't matter if the turntable top is flat.

The other nice thing the machine does is cut the correct profile on the edge of the drum. You haven't mentioned this issue, but after you get your drum top flat on your reference table, you still have the problem of machining that profile.

So how 'bout solving both problems for yourself by making a manual version of their machine? When I say "manual", I mean it works like that video, but you manually lower the router into the drum blank, and you manually rotate the turntable. It should be pretty easy to build. You'd need a turntable and a router. If you're posting here, you probably already have the router, so you only need to find or make the turntable.

[Alan Turner]

Jamie,
My thoughts exactly. A carefully made jig to hold the router firm and horizontal seems pretty doable for a drum lover.

[Jamie Buxton]

To make a turntable, you might start with a lazy susan bearing. One source is http://wwhardware.com/catalog.cfm/GroupID/Lazy%20Susans/CatID/Flat%20Lazy%20Susan%20Bearings/showprod/1.

[chester stidham]

How about this use glass it's flat and cheap put some type of marker like blueing dye on it set your drum on top and spin it remove the spots with ink by sanding then repeat untill you get even crovrige of the ink then you well have a very flat edge for a little investment.

[Bill LeMay]

Bill, besides being cool and quick, that machine also takes care of the issue of making sure the bearing edge is flat.


Yes their solution is quite elegant.


So how 'bout solving both problems for yourself by making a manual version of their machine? When I say "manual", I mean it works like that video, but you manually lower the router into the drum blank, and you manually rotate the turntable. It should be pretty easy to build. You'd need a turntable and a router. If you're posting here, you probably already have the router, so you only need to find or make the turntable.

I'm less of a woodworker than you give me credit for. :) But I do have a router. I took a stab at making a jig to orbit my router over a drum shell (not a finished drum, so I could experiment with impunity). Unfortunately it didn't pan out - the shell was unusually thick (7/8") and I couldn't get a router bit to take out enough wood. It would have taken lots of passes and my jig was not robust enough to sustain all those setups. Like I said, I'm a newbie.

I'd like to build a bearing edge cutter like theirs. Is that sort of router bit easy to be find? To be honest I never saw one like that before.

Thanks to all for your ideas and encouragement.

Bill

[Jamie Buxton]

I'd like to build a bearing edge cutter like theirs. Is that sort of router bit easy to be find? To be honest I never saw one like that before.




Bill --
They undoubtedly have had custom bits fabricated, and that makes sense for production work. For small shops, those profiles may require two passes with two different standard bits. You might check out bit specialists like Eagle America (www.eagleamerica.com) or MLCS (mlcswoodworking.com) for odd shapes.

[Norman Hitt]

Thanks for the ideas. For the curious, here is a web page that talks about bearing edges. These guys have a slick machine for cutting bearing edges. There is a link that shows a video of the machine in action.

http://www.drumfoundry.com/zen/index.php?main_page=perfect

Bill

Bill, in the video clip, it appears that the bit they are using for this particular edge, is a "Bullnose" bit. Many bit mfrs. make these in different radius sizes. For some of the other edges they show, they would have to use bit with a different profile, or in your case, you could probably use a combination of more than one bit to get the edge you desired.

NOW.....the problem you have is to make a jig to make it work.:confused: :confused: You could take two pieces of MDF, and I would suggest covering both sides with laminate, or better yet, use some of the plywood with the phenolic already laminated on both sides that I mentioned in my earlier post, and then drill a 1/4" hole through both pieces in the center to insert a steel or brass pin to make the turn table. Using the hole in the center attach a router circle cutting jig, and cut one piece of the laminated plywood in a circle for the top piece of the turntable. Also, use the circle jig with a sharp pointed centering bit, (or similar bit) and make a series of "concentric circle light" scratches and then mark them with a permanent marker pen, wiping off the excess to leave a fine line, which will aid you in centering the drum for the edging operation. Wax the two mating surfaces of these pieces for easier turning. You would then need to make a series of slots in that top piece for attaching whatever clamping devices you want to use to hold the drum in place.

Next, you would need to make a jig to mount the router in a 90* position to the table. It should be a two piece jig that is adjustable vertically, and would be fastened to the bottom sheet of ply via bolts that are adjustable horizontally in slots in the bottom piece. you can get an idea of how to do this by looking at the cheap one offered by MLCS in many of their sale flyers.

Hope this will give you some ideas.:)