Wooden Threads With Your Router Table

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Introduction: Wooden Threads With Your Router Table

I haven’t had much luck with the commercial tap and die sets for making wooden threads. It seems like the cutting knife in the die is the weak spot, it just doesn’t last for me or leaves a rough thread. So I decided to make my own threading jig for my router table. This wooden thread-making jig uses 3d printed parts to reliably create threads on a wooden dowel to make wooden screws for toys or jigs. The included files are for a 3/4 inch screw with a 6 TPI thread. (TPI = threads per inch). You can easily adapt the idea for other size dowels and threads.

Equipment:

  • 3D Printer
  • Router Table
  • V-Groove Router Bit, 60 degrees
  • 3/4 inch Tap - 6 TPI

Supplies:

  • 3/4 inch hardwood dowels
  • hardwood to make wooden hex nuts, mounting plates, etc

Step 1: 3d Printed Parts

3d print the four parts: the dowel guide, the thread box, the thread sleeve, and the set-up block. If you don't have a 3d printer use your local maker space or send the files off to a commercial 3d print shop. I designed the parts using Autodesk Fusion 360.

After printing the parts make sure the thread sleeve screws smoothly thru the thread box, and the dowel fits snug into the thread sleeve.

Use the set-up block to set the router bit height and distance from the fence.

The dowel guide clamps to the router table fence over the v-groove bit. The thread box clamps to the fence to the right of the bit (infeed).

Insert the dowel into the thread sleeve and then thread both into the thread box. When turning the dowel it will advance across the v-groove bit at the 6 TPI rate while the v-groove bit cuts the threads. If the dowel slips in the thread sleeve wrap the dowel with one or two layers of scotch tape to attach firmly.

Edit 7/3/2020:

Attached are new stl files for the 3d printed parts. They include all jig parts for 1/2”-8TPI screws and for 3/4”-6TPI screws, including setup blocks to get you started.

Step 2: Set-Up

The tip of the v-groove bit should be at 16 mm above the table, and 22.5 mm from the fence for the 3/4"-6TPI screw. For the 1/2"-8TPI screw set the tip of the v-groove bit at 13 mm above the table and 17 mm from the fence. You will have to experiment a little for the best cutting height. Mount the dowel guide and thread box on the router table as shown in the previous step. The thread sleeve should be positioned and fixed on the dowel so that the front of the dowel is at the tip of the v-groove bit.

Use a hardwood dowel with a straight grain. I am showing an oak dowel bought at the hardware store for this Instructable. A long dowel that extends beyond the router table edge is easiest to handle when turning the dowel.

The pictures should explain the positioning to start the cut.

Step 3: Cutting the Thread

Now start the router and turn the dowel to slowly advance it to cut the thread. The first part of the thread could be a little off until the dowel enters the dowel guide hole to the left of the bit (It has not been a problem for me). Keep turning until you have your desired screw length but stop before the thread sleeve exits the thread box on the far side. With the setup as shown you’ll get a thread length of about 3 inches. For longer screws you’ll have to 3d print a longer thread box. Everything else will be the same.

Step 4: Clean-up and Fine-Tuning

After cutting the screw clean up with a light sanding of the threads. Try the screw with the 3d printed sample nut. Attached is the file. As mentioned before, setting the exact height of the v-groove router bit above the table is very critical! If the thread-fit on the nut is too tight you need to raise the v-groove router bit by a very small amount. For a fit that is to loose lower the router bit. Even with the set-up block from step 1 you may need to do a little fine-tuning. The pictures above show a dowel with a perfect thread and a dowel where the bit was set too low; it does not fit the threads in the nuts.

Once you find the 'perfect' setting you can use a piece of hardwood to cut a v-groove into a set-up block for future reference.

Maple dowels and cherry dowels cut beautiful threads. Oak dowels and poplar dowels from the hardware store cut well with little chip-out. Birch dowels and pine dowels do not work well. I haven't tried any other hardwood dowels, so let me know your results if you try walnut, hickory, mahagony, etc.

Step 5: Wood Taps

To make a threaded wooden nut you need to get a tap like this and follow their instructions:

https://www.grizzly.com/products/Grizzly-Wood-Thre...

https://woodworker.com/12-diameter-taper-tap-mssu-...

Drill a 5/8 inch hole for a 3/4 inch tap, then use the tap to thread the hole as in the pictures. Use the 3d printed screw (file attached) and nut to mark the outline of the wooden nut. Then cut on a bandsaw and sand to the lines. Round all edges with a light touch.

To make a bolt head use a Forstner bit to drill half way into your wood block. Then mark the outline of the head as before , cut on the bandsaw, and sand. Finally glue the threaded bolt into the head.

Step 6: Be Creative!

Now that you have a bunch of wooden screws and nuts you can make beautiful construction sets or other toys for children. Look at some of my ideas in the pictures. I am working on a larger wooden construction set using these screws and nuts, with wooden wrenches, screwdrivers, a workbench, etc.

All pieces are finished with food-grade mineral oil.

Use the same technique to make larger diameter screws for clamps or bench vises.

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    28 Discussions

    0
    ProfessorJWN
    ProfessorJWN

    10 days ago on Step 5

    That’s likely the best instructable I have seen! Great work! Very innovative.

    0
    rschoenm
    rschoenm

    Reply 10 days ago

    Thank you so much! That's very kind of you.

    1
    AraY18
    AraY18

    22 days ago

    Nice job! I've searched for various ways of doing this (general search and lumberjocks) the problem most have is the creation of the initial jig is pretty complex or needs to be very precise, nice use of 3d printing to get around that. Don't suppose you have the fusion 360 source file(s) you could upload so others can make changes? (stls are hard to work with) Again awesome work!

    1
    rschoenm
    rschoenm

    Reply 22 days ago

    Thanks! Let me work on the Fusion 360 files, they are kind of messy. Lots of trial and error. Also, I never found 'official' specs for wooden threads, so I measured (from the tap) and eyeballed as well as I could. The 60 degree v-groove bit looks (and works) well. If you know what the specs are for wood threads please let me know.
    For the thread sleeve and thread box you could use any thread type you wish as long as it is 6 TPI (for 3/4"). Essentially you transfer 6 TPI from the thread sleeve/box to the dowel. I modeled the thread in Fusion 360 with a coil (triangular-external) and tweaked until it worked.

    0
    AraY18
    AraY18

    Reply 22 days ago

    No problem, appreciate the effort. As for 'official' specs, I'm not really sure, but I'd assume it's likely more of an acme type thread (like lead screws on 3d printers/some cnc routers) with a single start. Believe that profile exists in the thread feature in 360, create a cylinder, create thread, choose the 'modeled' option and the acme profile. https://www.engineersedge.com/hardware/external_ac...

    Looking at the Lake Erie kit seems to confirm that but it's just a guess from the images. https://www.lakeerietoolworks.com/products/wood-vi... Way to poor to afford something like that lol

    1
    rschoenm
    rschoenm

    Reply 18 days ago

    I redesigned the Fusion 360 3d files, they are a lot simpler and cleaner now. From these files you can make your own modifications. Please note that the dimension changed from the original Instructable. With these parts the v-groove bit needs to be set 15.5 to 16 mm above the table and 22.5 mm from the fence. The new set-up block will take care of that, but remember to ‘fine-tune’ the setting. When you find the perfect setting cut yourself a set-up block from hardwood.

    The thread box & sleeve are now based on a standard ANSI UNC 1-3/8” - 6 thread that can be modeled in Fusion 360. The thread sleeve is big enough to accommodate a 1” dowel if you change the Fusion 360 files accordingly.

    Happy threading!

    0
    AraY18
    AraY18

    Reply 17 days ago

    Awesome, and much appreciated. Thank you for taking the time!

    0
    JohnW539
    JohnW539

    21 days ago

    Really nice method!

    0
    rschoenm
    rschoenm

    Reply 21 days ago

    Thanks!

    0
    Josh MacKinnon
    Josh MacKinnon

    22 days ago

    Wow! Absolutely ingenious!

    0
    rschoenm
    rschoenm

    Reply 21 days ago

    Thanks!

    2
    rschoenm
    rschoenm

    22 days ago

    Hello, I did some laser engraved decorations on these bolts!

    IMG_9963D.jpeg
    3
    GiuseppeV8
    GiuseppeV8

    23 days ago

    Great idea! May I suggest to put a tapped piece at the exit of the router, so that the threaded piece can screw in it and you don't have to worry about the length of the adapter and can thread as long as you want? (Sorry for my bad english).

    0
    rschoenm
    rschoenm

    Reply 23 days ago

    That is a good idea and I started out that way. My problem was that I could not cut the initial two or so threads well enough to fit into a tapped piece at the router exit (left of the bit). A little practice probably would have helped.

    So maybe to cut a long thread you could do this: start with the technique as shown in my Instructable to cut two or three threads (turns) at the tip of the dowel. Then unclamp the whole setup, remove the thread sleeve, and replace my dowel guide with one that has the left side tapped at 6 TPI. Remount everything, slip in the dowel to match the prior thread at the router bit, and proceed. I’ll try that sometime.

    Thanks for the idea.

    0
    amdijefri
    amdijefri

    Reply 22 days ago

    Perhaps putting a “nut” of wood you have tapped at the entry point to the exit side of the dowel guide would let you verify both fit and cut very long threads? Create a cavity (in the dowel guide on the right end of the left side where threaded dowel will first enter) large enough to place a square nut. I hope that makes sense.

    0
    rschoenm
    rschoenm

    Reply 22 days ago

    It does make sense, and I'll try it sometime later. I'm still concerned that you have to cut the first one or two turns 'freehand' until they enter the threads on the left. If they don't quite match the pitch you'll get stuck. Again, thanks for the suggestion.

    0
    mmeichle
    mmeichle

    22 days ago

    Really. really clever! What about making the parts from something like aluminum and selling as alternative to taps and dies?

    0
    rschoenm
    rschoenm

    Reply 22 days ago

    Thanks! Anyone who wants to improve and make these parts commercially from metal or molded plastic, be my guest. Still need the taps, though.

    1
    BaznSuz
    BaznSuz

    22 days ago on Step 6

    Disappointing. Should be re-titled "Using a 3D Printer to Make the Parts for Making Wooden threads with a Router"

    1
    amdijefri
    amdijefri

    Reply 22 days ago

    C'mon… practically any project requires a jig of some sort.