Table Saw Drum Mill

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Introduction: Table Saw Drum Mill

About: Business System Admin M-F ... Drum shop side hustle on Sat ... DIY enthusiast in spare time. I have a full workshop in my basement, which continuously evolves, as does my interests and skill level. I enjoy ma…

Last year I made a new drum shell roller jig for my cabinet saw, so this year I wanted to try a milling attachment idea for rounding the outside face of stave and segmented shells.

There are two common methods rounding these types of drums:
1. Turning them on a lathe manually or with an auto feed setup.
2. Using a router and a DIY jig.

I wanted to determine whether or not it could be done with a table saw and dado stack.

This build is a departure from my usual process, because while I have visualized how the parts assemble, none of the measurements were determined. I'm fitting the parts and notating the measurements as I go, which I'll list in the final step for those interested.

Supplies

3/4" plywood
Screws
Dowels segments
Carriage bolts
5/8" acme rod and nuts
Star knobs

Step 1: Riser Panels

For the front and back panels of what I'm calling the risers, I wanted a dado for a spacer which lands right above the roller jig fences sides. Cutting the dado into the larger panel ensures that it will line up once divided into smaller panels. As you can see in Fig. 1, I cut it on the wrong edge. Fig. 2 is the correct edge.

I didn't have a dado stack for my cabinet saw at this time, so I just made several passes with a 3/16" blade until I had a perfect fit.

The large panels were broken down into a single panel for the inside and two for the outside to span the gusset. This gap doubles as the slot for the threaded axis rod, which will make more sense down the road.

The parts were clamped to the roller jig side in order to get an accurate width measurement for the spacer and top cap.

Step 2: Top Caps and Locking Knob Holes

For the top caps, I opted for rabbet joints. While I had the risers mocked up, I took the time to mark screw hole locations [Fig. 2].

While fabricating the roller jig, I incorporated two captive T-nuts in order to secure future attachments. At that time I made a setup block, which I managed to not lose [Fig. 3]. I used this block to mark the hole locations and then drilled through holes with a small bit.

With that hole as a guide, I used a Forstner bit and drilled a 3/4" on the inside face - deep enough to accommodate a rubber O-ring. This will be the retention ring for the future knobs. The through hole was then enlarged to 5/16".

Step 3: Bearing Blocks

Next parts are the bearing blocks and an auto feed block. These are all 11 7/16" x 3".

Bearing Blocks
These will be the hubs for the threaded rod/axle/spinny bit, as well as the height adjustment to accommodate various shell diameters.
Hole: 1 3/8" hole drilled with a Forstner bit to the depth of the bearing [7/16"] - then a 5/8" through hole.
Grooves: 3/4" groove 1" in from each side - 3/8" depth.
Note: Mating grooves get cut into the inside face of the outside panels and the sides are mirror images, so pay attention. This will make sense down the afore mentioned road.
A section of 3/4" plywood gets glued into the groove and once cured, a 5/16" centered hole is drilled.

Auto Advance Block
Hole: 1" hole drilled with a Forstner bit to the depth of the nut [1/2"] - then a 5/8" through hole.
The shape of the nut is then traced and material removed with a chisel until the nut has a nice friction fit.

Hole Note: The holes aren't centered - they are inline with the straddled gusset, which is purposefully inline with the center of the table saw arbor.

Step 4: Panel Slots

The back panels have the fabricated gap, but the front panel is solid and therefore needs a slot cut.

Once the location was laid out, the top and bottom of the slot was established by drilling a 3/4" hole. The slot was then cut with a 3/4" router bit and you'll notice I took my time to set up and clamp several blocks to the router table top [Figs. 2&3].
The fence is set for the offset/location of the slot. The boards on each side are the stop points for the slot. The board at the front keeps the work piece tight against the fence [Figs. 2&3].

The outside panels then need 5/16" in slots for carriage bolts and I used a similar clamped block setup [Fig. 4].

The last picture should give you a good idea of how the bearing blocks and outside panels integrate.

Step 5: Knobs

For the knobs, I'm using 2" long sections of 2" diameter poplar dowel stock, which were cut using my small parts crosscut sled on the table saw.

Center is found using my shop made dowel center finding jig. 7/8" hole drilled with a Forstner bit to a depth around 3/4" - then a 5/16" through hole.

The carriage bolt was seated with a socket and a hammer and the hole plugged with a section of 7/8" dowel. Once the glue cured, the plug was sanded flush and sharp edges rounded over using the oscillating belt sander.

Step 6: Assembly

I found that the easiest method for assembly, was the clamp the parts in place and use them to self-center themselves.

The spacer for instance. The two back panels were screwed in place with the knobs, the bearing blocks kept them square, and clamps held the space tight within the dado. Then I could drill pilot holes and secure the parts with screws [Fig. 2].
Note: Screw locations were laid out and countersinks drilled prior to this assembly.

The inside panel was then attached, followed by the top cap.

I finished all of the parts with a single coat of shellac. The bearing block runners/keys and mating slots received a liberal coat of paste wax

Then or course I found the risers a home base on the table saw sled/jig wall.

Note: The 1" at the top of the inside face serve two purposes.
1. They are inline with the bearing block slots and bolts, which makes it possible to actually remove the bolts and bearing blocks. I might want to modify them ... or might need to swap a bearing.
2. They allow me to hang the risers on the sled/jig wall.

Step 7: In Use Shots

The drum shell gets clamped between two round plates utilizing long carriage bolts and wooden blocks with imbedded T-nuts [easier to turn]. The acme rod is then threaded through the "infeed riser bearing", through the drum shell assembly, through the "outfeed riser bearing", and into the auto advance nut.

Loosening the two star knobs on each bearing block allows you to adjust the height. You don't need to be concerned with any gauges or racking ... just set a 1/4 board on the saw top and lower the assembly until the drum shell bottoms out.

The Verdict: It definitely works. Once I commit to cutting the acme thread to a shorter length, I think it will perform much better ... eliminate blade chatter. I'll also need a better crank handle.

Additional Uses: The auto advance block could be removed and jam nuts added so that a drum rotates in a fixed position. This could be used for cutting circumferential grooves for inlay banding.

Motorization: Jam nuts could be added to the end of the acme rod so that it could be turned with a drill.

Future: I plan on adding an attachment for milling the inside of the shell, but that will use a track and router.

Crazy Idea: I'd like to test an attachment which mills the outside of the drum using an Arbortech Turbo Plane. I just need one to fall off the back of a truck.

Dimensions
Inside Face: 16 3/4" x 11 7/16"
Outside Large Face: 16 3/4" x 6"
Outside Small Face: 16 3/4" x 4 3/4"
Top: 2 7/8" x 11 7/16"
Spacer: 2 1/8" x 11 7/16"
Knobs: 2" diameter x 2" length
Bearing Block: 3" x 11 7/16"

Step 8: Test Run Video

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    32 Comments

    0
    Works by Solo
    Works by Solo

    12 months ago

    Awesome project, Bryan! Congrats on the win.

    0
    ArthurJ5
    ArthurJ5

    1 year ago

    I need to get me one of these! Wow, great instructable. I make banjos and this jig would be perfect for shaping the case, actually multiple cases at once. I normally use a band saw and a router in a series of jigs.

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    Reply 1 year ago

    I would be interested in seeing your jigs. I have a router jig for the exterior, which I plan on revising/cannibalizing for a new version. I want it to be somewhat modular to do both exterior and interior and fit within my "jig system".

    0
    ArthurJ5
    ArthurJ5

    Reply 1 year ago

    My jigs are nothing special. Just a couple of circle cutting jigs, they are nothing like your set-up. I cut the rough circle on the band saw, then use a plunge router and a circle cutting jig to trim the outside smooth. The good thing about using a router is I get a great finish ready for light sanding. Then I use the same set-up for the inside of the ring. For deep cuts I start with the circle cutting jig then go to the router table and use bearing guided bits. I like your jig because it doesn’t require so many set-ups and I could make several banjo bodies at once.

    I’m anxiously awaiting your inside cutting jig instructable.

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    mbonifax
    mbonifax

    1 year ago

    Great, Easy enough, efficient enough

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    Reply 1 year ago

    Thank you. Much appreciated.

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    aterentiev
    aterentiev

    1 year ago

    Thank you for great describing! I've read somewhere that if you place the saw blade diagonally and not perpendicular to the rotating piece you'll get smoother results. Maybe you can check it.

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    jeanniel1
    jeanniel1

    Reply 1 year ago

    I've done that, too, for when we work on ceramics on the wheel. A diagonal does make a smoother surface versus the 90 degree blade.

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    Reply 1 year ago

    They might be talking about standard 3/16" - 1/8" blades that aren't ground for a flat bottom cut. I'm specifically using a flat bottom cutting dado stack - the blade is 3/4" wide.

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    ironarmadillo
    ironarmadillo

    1 year ago

    Very clever idea.

    I have a workshop similar to yours and I'm always looking for jigs and accessories I can build at need. This has been bookmarked!!!

    Considering the deflection in the acme threaded rod you're experiencing: Have you considered replacing the 5/8" rod with something more substantial like a 1" or 1 1/2" threaded rod.

    Another possibility is to not use an acme threaded rod, instead use a standard 1" or 1 1/2" all-thread rod. This would slow down your feed rate and maybe give you a better cut surface from the dado stack.

    I can also see this jig you've created used with a benchtop 4" x 36" sander in a vertical position to sand the surface uniformly smooth.

    One thing I've done in the past for turning long all-thread rod through nuts is to use a variable speed hand drill to turn the rod. Depending you how good you are at holding the drill trigger for an appropriate feed speed (which really shouldn't be a problem for accomplished woodworkers like yourself), could greatly decrease the rod deflection from having an offset crank.

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    Reply 1 year ago

    Great points.

    I did consider stepping up the 5/8" diameter. I decided against it because I already had 5/8" components (D shaft, stop collars, bearings) and I wanted to be able to interchange parts between jigs. Also, the price jumps up drastically. The 5'8" rod was around $25 I think. 1 1/2 jumps to around $125. I'm just a guy dinking around, so can't justify the cost.

    I have a 3/4' all thread rod, which I used for a clamping prototype and I personally experienced a lot of play between the rod and nuts - maybe the all tread is undersized or the thread density has variation. I went with Acme rod in order to eliminate that issue. I also purposely wanted less thread density, so I wouldn't be spinning a drum for days.

    Agreed on the drill. I quickly touched on that at the end. I was thinking maybe a coupling nut and jam nut - then a socket adapter for the drill.

    0
    ironarmadillo
    ironarmadillo

    Reply 1 year ago

    Yeah, those Acme thread prices can escalate real fast. I just checked
    those prices myself and it looks like McMaster-Carr has more
    reasonable prices for the 1" and 1 1/2" Acme rods, especially looking at the 3' lengths. (https://www.mcmaster.com/acme-threaded-rods/acme-lead-screws-and-nuts/thread-size~1-8/thread-size~1-1-2-5/).

    After watching your video, it looks like you could place the 2 risers closer together to stiffen the turning assembly, leaving just enough clearance on either side of the dado stack for your workpiece.

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    Reply 1 year ago

    McMaster-Carr - exactly. I went with the 6' length.

    I agree about the placement. If I get shorter carriage bolts, I can move them in and still maintain infeed/outfeed space.

    0
    ironarmadillo
    ironarmadillo

    Reply 1 year ago

    Sometimes it's your subconscious which comes up with a possible idea when you sleep on an interesting problem: What about moving the threaded rod to shift the entire jig (risers and all) and replacing the rod through the workpiece with a wood dowel or metal rod of greater diameter? You could place the risers within 1" of the sides of the workpiece (for clearance of the dado stack). You'd still need a crank on the workpiece rod to spin the workpiece. (My subconscious and I are still on relatively good terms since I retired 3 years ago).

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    Reply 1 year ago

    I think I see what you are saying - treat it like an entire carriage that is moved. I wouldn't be able to do that with this current set up as the sides are clamped to the table and built to auto align with the center of the arbor.
    It's an interesting design concept.

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    justcheckinm8.
    justcheckinm8.

    1 year ago

    With the rod level to the table, only the first blade in the stack is doing the work(?) If it was at a slight angle, with the rod at the right height above the last blade to achieve final diameter, then all blades in the stack get a go at cutting and being smaller cuts per blade, maybe reduce the chatter you mentioned.

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    Reply 1 year ago

    I don't think that exactly accurate based on the fact that the acme rod is 6 TPI. I'd have to put the camera closer for another test run to confirm. I think if you put in a standard blade, you would end up with a drum that had threads, which in itself would be interesting.
    The jig in its current state can't be put into an angle as the rod passes through two bearings and then the nut. There would be a misalignment/binding issue.

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    ANDRELAS
    ANDRELAS

    1 year ago

    Awesome ingenuity. Picture support rollers under the work piece to adjust depth.

    0
    zacker
    zacker

    1 year ago

    i can see this being used to round out a solid chunk or wood to make a solid, one piece shell too but youd need to make another jig to hollow it out on the inside. great job!!

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    Reply 1 year ago

    I'll be making a version of the "common" router jig for the inside of stave and segmented shells. The solid, one piece shells seem like a whole different animal. If they are anything like turned bowls, you'd be dealing with deformation and cracking. I'll have to look around for any drum builders using that method.