Modular Fiddle Assembly Instructions

A modular, open source, 3D printed acoustic violin.

www.openfabpdx.com

#ModularFiddle

BodyTuners

BridgeStrings

NeckTruss Rod

Tail PieceChin Rest

Assembly ProcessThe Modular Fiddle is easy to assemble and requires no adhesives, fasteners, or other joining parts.

The assembly process takes about an hour.

1. Gather Materials2. Prepare Body – deburr and prep Body part.3. Prepare Neck – deburr and prep Neck part.4. Prepare Pegbox – deburr and prep Pegbox and install tuners. 5. Clean joints and join parts – gently file joints on all parts to achieve a smooth, consistent fit. Assemble Pegbox, Neck, and

Body parts together, install truss rods.6. Install tailpiece and strings – install stock violin tailpiece and 4/4 strings. 7. Install Bridge and chin rest8. Final Setup

WEAR SAFETY GLASSES AS NEEDED

1. Gather MaterialsModular Fiddle BOM Buy your parts locally whenever possible! Tell your local music shop about the project and what you're up to. You never know what kind of collaboration, feedback, or support could result.

9/25/2018Amazon links on this BOM are affiliate links. I have mixed feelings about this. It means that OpenFab gets a small percentage of the Amazon sale (usually about 4%) if the product is purchased via the link. If you plan to buy on Amazon, please use these links to support further development. Please purchase your parts locally if possible. Thank you!

Part Name Quantity Type Manufacturer Mfg Part Number Supplier Supplier Part # Unit Cost Total Cost Notes (lead time, print settings, etc)

Neck 1 Printed OpenFab PDX OpenFab PDX Print 3 loops with .4mm nozzle (skin thickness at least 1mm). Infill >= 15%.

Pegbox 1 Printed OpenFab PDX OpenFab PDX Print 3 loops with .4mm nozzle (skin thickness at least 1mm). Infill >= 15%.

Body 1 Printed OpenFab PDX OpenFab PDX 363g Print 3 loops with .4mm nozzle (skin thickness at least 1.2mm). Infill >= 15%.

Bridge 1 Printed OpenFab PDX OpenFab PDX 1g Print 3 loops with .4mm nozzle (skin thickness at least 1mm). Infill >= 15%.

Ukelele Friction Tuners, Grover 88B or Sta-Tite

4W 1 Purchased Grover 88B, 4W Amazon88B ASIN:

B000X31R4W $35 $35 Sta-Tite 4W also an option. ASIN B003A67WHU, link: https://amzn.to/2Ih2RAy

Medium Tension Synthetic Core 4/4

Violin Strings 1 PurchasedThomastik-Infeld

Alphayue AL100 Amazon ASIN: B012BMSANS $22 $22 Any 4/4 (full size) set of violin strings will work

4/4 Violin Tail Piece 1 Purchased Wittner 918119 Amazon ASIN: B00HGDRSB8 $17 $17 Other 4/4 tail pieces should work just fine

4/4 Violin Chin Rest 1 Purchased Wittner 250111 Amazon ASIN: B0009SXWLC $23.0 $23.0 Other 4/4 chin rests may or may not work. Test before you buy if possible.

Carbon Fiber Tube, 6x8x330mm 2 Purchased Arris N/A Amazon ASIN: B00TF8UW9C $7.5 $15

It seems like only one tube is necessary (through the neck). Time will tell if the body is stiff enough.

TOOLS• Needle-nose pliers• Small files (triangular is particularly helpful)• Deburring tool (much easier and safer than a

knife for cleaning parts)• Exacto knife• Sandpaper (I use 220 and 600 grit)• Safety glasses• Calipers or a decent ruler• Sharpie

2. Prepare Body

Remove supports from Body using needle nose pliers. Use a deburring tool, exacto, or file to remove any leftover bits from supports. Gently clean up F holes.

Clean off skirt and deburr edges where they contacted your build plate.

Check truss rod holes at front and rear. The carbon fiber tube should enter the holes by hand with moderate force. I drill mine out (significantly) with a 5/16” bit.

3. Prepare Neck

Remove supports from Neck using needle nose pliers. Use a deburring tool, exacto, or file to remove any leftover bits from supports.

Clean off skirt and deburr edges where they contacted your build plate.

Gently file fingerboard edges to round them off. Then sand the fingerboard and neck as much as desired. The smoother the fingerboard the better!

Check both truss rod paths (fingerboard truss and body truss) to make sure the carbon fiber tubes slide in and out without much force. These holes are sized larger than the Body’s and should not require drilling.

4. Prepare Pegbox

If needed, clean off skirt and deburr edges where they contacted your build plate.

Check peg hole fit – if needed, use a deburring tool or exacto to open up the holes a bit.

The Ukelele friction tuners are very easy to install. If needed, press in the bushings for the tuners. The Grover 88B (shown, left) do not use bushings, and simply tighten down on the Pegbox. The Grover 4W uses bushings you press in.

Fasten the tuners to the Pegbox and tighten them until they are seated and turn with firm force. You will probably need to re-tighten the tuners several times as the parts settle. (Less true for the 88B)

5. Clean Joints and Join Parts

All parts should slide together with some friction, but should not require high force or impact to install or remove parts. That said, it is OK to remove the Neck by tapping it carefully near the joint with a small hammer (or tapping it on a table).

Carefully file the joints on all parts as needed to achieve a good fit. Do not file too much!

Slide all parts together – feeling good? Great! Slide the carbon fiber truss rod through the Pegbox and to the end of the Neck.

Slide the Body truss rod entirely throughthe Body. Make it flush with the Neckinterface, then slide the Neck into place. Push the truss rod the rest of the way, until just sub-flush at the endpin. R5 and later Necks have an open through hole so you can push this rod back out as needed.

6. Install Tail Piece and Strings

Install strings from lowest to highest. (G to E)

Hook the ball end into the tail piece, then set the tail piece loop around the end button. Pass the string through the left close tuner and tighten counter-clockwise. Tighten, without the bridge, until there is enough tension to hold the tail piece in place.

The two left tuners tighten by turning counter-clockwise. The two right tuners tighten by turning clockwise. This is also shown in the image at right.

Repeat process with D, A, and E strings.

7. Install Bridge and Chin Rest

Slide the bridge under the strings and pivot it up to support string tension. The bridge should be centered, and the distance from nut to bridge should measure about 330mm.

Check that the strings sit OK in the nut and bridge grooves. You may need to file these down to hold the strings securely or to lower the action of the strings. Don’t worry about that just yet.

Fasten the chin rest in the appropriate position.

8. Final SetupTighten the strings to full tension, tuning from G to E. Then check the height of your strings at the end of the fingerboard.

While these heights are not critical, your instrument will play better and sound better if string heights are properly adjusted. Ideally your highest (E) string is 3.5mm above the fingerboard and the lowest (G) string is 5.5mm.

File the bridge grooves as needed to improve the string heights. I file my nut grooves as well, but I do it by feel and not by measurement.

Record your string height measurements. In a week, check them again and file the bridge as needed.

Additional design work may be needed for the bridge to attain proper string height!

This is the nut. It prints with grooves, but you may want to file them a bit deeper.

Nice work!!

Thank you for building a Modular Fiddle! Please share the instrument far and wide!

Post a picture or video and tag it #ModularFiddle

Got feedback? Share it on the Google Group: http://ow.ly/yXJAV

You can also email David with questions, ideas, or complaints. David@openfabpdx.com

Now go play some tunes!