Wooden Threads With Your Router Table

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Introduction: Wooden Threads With Your Router Table

About: If its practical, I have no use for it!

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 too 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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    41 Comments

    0
    atxcapps
    atxcapps

    4 months ago

    Great instructable! Like your others, very well written and clear instructions on every step. The end product is wonderful, I look forward to using this in an upcoming project. Thank you.

    0
    rschoenm
    rschoenm

    Reply 4 months ago

    Thank you! Let us know if you make some threads and if you have suggestions to improve the technique.

    0
    askjerry
    askjerry

    4 months ago

    I really like this project, very nicely done!
    I really need to do more with my 3D printer... I just get frustrated with it... 5 great prints then it gets all wonky and I have to adjust something... then maybe a few more good prints. Ahhh. With woodworking and machining... I always get the same results.
    But... I'll give this one a go... the results are well worth it, and I'll make a set for my neighbor... also a woodworker.

    0
    rschoenm
    rschoenm

    Reply 4 months ago

    Thank you! The 3D printed parts, especially the threads are a little tricky to print; and require a bit of sanding/shaping to work smoothly. Don't give up if the first print doesn't quite work. I did a few(+) prototypes first with different clearances etc. The threads don't have to be very accurate, they just need to turn without too much resistance.
    Let us know if you or your neighbor make any threads and if you have suggestions to improve the technique!

    3
    GiuseppeV8
    GiuseppeV8

    2 years 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 2 years 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 2 years 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 2 years 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
    mikej_w
    mikej_w

    Reply 4 months ago

    Putting the guide in the output is very hard to get right and is the main problem with using the router to make threads. You bypassed this by your thread guide on the input side, by placing a guide over the input dowel, which is the best part of this design. Thanks for writing the instructable, this is great!

    0
    rschoenm
    rschoenm

    Reply 4 months ago

    Thanks, the technique as described works very well for shorter threads. I need to experiment with some of these ideas and suggestions for longer dowel threads. But I've been sidetracked with large threads, spirals, and zippers! Not enough time in the day :-)
    Thanks again for your interest.

    0
    mvieke
    mvieke

    Tip 4 months ago

    Lovely instructable! I will definitely add this to my to-do list.
    Did you consider to add threads to the output of the dowel guide? I think this would let you make arbitrary length threads once you get it started.
    Thank you for sharing.

    thread.png
    0
    mikej_w
    mikej_w

    Reply 4 months ago

    Then you would have to line up the router bit exactly to make the threads line up with the output side, which would be difficult and require some other registration to make it line up. Not sure how to do that.

    0
    terrefirmax2
    terrefirmax2

    4 months ago

    I really like the aesthetic of different woods. Did I miss the part where you said what wood it is?

    0
    rschoenm
    rschoenm

    Reply 4 months ago

    Thanks! Maple, cherry, oak, mostly. Some walnut and poplar.

    0
    GFire
    GFire

    4 months ago

    Quite Impressive... I'll be attempting myself.

    0
    Kai SaerPren
    Kai SaerPren

    Question 6 months ago on Step 4

    Hi: I can see that this makes a very nice screw about twice the length of the thread sleeve. What if I want a threaded segment 12" long?
    be well
    K

    0
    rschoenm
    rschoenm

    Answer 6 months ago

    Thanks for your interest. I would do it like this: First, cut a 1 to 2 inch length of thread on the front of your long dowel. Then 3d print a dowel guide that has the same (interior) thread on the left side - past the v-groove bit. Mount this dowel guide and thread in the tip of your long dowel. Finally, use the new dowel guide to pull/turn your long dowel across the v-groove bit. You will have to cut the total depth of the thread in one pass for this to work. Good luck, let us know if you do this.

    0
    ProfessorJWN
    ProfessorJWN

    2 years ago on Step 5

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