Threading Machine and my first kitless pen

Signed-In Members Don't See This Ad

TG Design

Member
Joined
Jan 22, 2018
Messages
244
Location
Dayton, Oh
I was inspired by Bruce Robbins (aka BRobbins629) to build a device to machine square threads in pen caps and bodies. After reading through his “Incredible Threading Machine” tutorial, I decided to build a dedicated threading machine/fixture. (not sure what to call my version yet)

My plan is to use a Dremel and a 4 jaw chuck. The 4 jaw chuck is threaded 8TPI-1", I so purchased an 8TPI-1" rod and a couple of nuts. I mounted the threaded rod, nuts, and chuck in some Delrin. I made a turning handle and mounted that assembly to some t-track. I then mounted the Dremel and an linear positioner to the t-track. I found the Dremel holding fixture on Thingiverse and printed it out, that was a huge score!

I tested the fixture with a scrap piece of acrylic (yellow in the pictures), per Bruce's guidance I added 0.040" to the caps ID to determine the bodies OD. Here is my formula: Body threads = Cap ID + 0.040". The micrometer on the linear positioner allows me to precisely touch (zero) the cap or pen body and then cut 0.020" deep threads. I slowly turn the crank and the Dremel bit #199 cuts the threads (0.010" increment steps). It's INCREDIBLE, now I know why Bruce named his version that. It's very smooth and the threads are very tight. I had to sand the external threads a little(maybe .002"), just a little fine tuning and rounded the first thread.

After successful threading of a piece of acrylic, I thought, "what about some wood threads?" This lead me to my first kitless pen, to be honest, it was not planned. I had a few kitless pen ideas running through my head, so after cutting some threads in some Cocobolo. (I used that because I know it's dense and assumed it would hold threads nice.) The threads turned out nice, after a little tuning I was able to get the grain to match once it was screwed together. That’s the nice thing about a single thread, it stops in the same place each time.

Why stop now? So I made a clip out of titanium, the pen top out of aluminum with a socket cap screw to hold the clip. I decided to put a 5 sided 1/4 twist on the body and made the section out of aluminum to hold a pencil tip roller-ball cartridge. The end of the pen is also aluminum. I bead blasted the aluminum and titanium to a matte finish and polished the very top and bottom. The 1/4 turn 5 sided twist encourages the pen to be rotated, this really makes the chatoyance of the Cocobolo to flip.

Lessons learned:
I need a small vertical mill; all the aluminum pieces were made by hand using a hacksaw, lathe, files, drill press, 6-32 tap and sand paper.

Sanding the aluminum next to the wood caused the aluminum dust to contaminate the wood. I put tape on the wood to keep it clean.

Titanium is not easy to work with, it does not cut or sand very well. White sparks!

Titanium does not cold form very well; I broke the first clip trying to bend a 90deg angle. Use a torch!

Just do it, you never know what you can create. This is not what I imagined my first kitless pen to look like, not too bad for not having any real plans, just trying to work out some proof of concepts.

Thank you Bruce for the inspiration!

Questions or comments welcome.
 

Attachments

  • 1TG.jpg
    1TG.jpg
    179 KB · Views: 461
  • 2TG.jpg
    2TG.jpg
    219.1 KB · Views: 400
  • 3TG.jpg
    3TG.jpg
    185.2 KB · Views: 384
  • 4TG.jpg
    4TG.jpg
    110.4 KB · Views: 406
  • 5TG.jpg
    5TG.jpg
    140.8 KB · Views: 347
  • 6TG.jpg
    6TG.jpg
    105.6 KB · Views: 335
  • 7TG.jpg
    7TG.jpg
    86.8 KB · Views: 254
  • 8TG.jpg
    8TG.jpg
    89.7 KB · Views: 268
Signed-In Members Don't See This Ad

magpens

Member
Joined
Feb 2, 2011
Messages
13,303
Location
Coquitlam, BC, Canada
That is really neat !!!! . Congratulations !!!

Too bad you are a month late for the BASH kitless contest ... you very well could have won !

What would be the kerf for the Dremel 199 cutter ... I assume it is 1/16" because your thread pitch is 1/8"

BTW ... the orange pieces holding the Dremel ... can they be bought or did you make them ?


EDIT: I later saw that you got the design for the orange pieces online and then printed these pieces yourself. So you must have a 3-D printer.
 
Last edited:

TG Design

Member
Joined
Jan 22, 2018
Messages
244
Location
Dayton, Oh
Thank you Mal. I was busy making the threading machine during the Bash, just didn’t get it done in time.

The file to 3D print orange fixture holding the Dremel was found on Thingiverse, I had a buddy at work print it for me. PM me if you need one.


Sent from my iPhone using Penturners.org mobile app
 

dogcatcher

Member
Joined
Jul 4, 2007
Messages
2,021
Location
TX, NM or on the road
Excellent job. If you want a 60 degree cutter, you can file the Dremel 199 on both sides while it is running with a diamond card. I cut a block of wood at 60 degrees and mounted a diamond card on it. Then "eyeballed" it to the center and then "ground the other side. Buy extra 199's, you will probably need them.
 

TG Design

Member
Joined
Jan 22, 2018
Messages
244
Location
Dayton, Oh
Great machine! And if you add a second linear positioner in the axis, you can make double or triple thread...



Interesting, I am wondering what double or triple square thread would look like. I made the chuck carriage adjustable, it slides back and forth by loosening 4 thumbs bolts. I assume I could cut the first set of threads, move the chuck back so the cutter starts 180degs off? I can make some stops on the t-track to return. Very interesting!
 

TG Design

Member
Joined
Jan 22, 2018
Messages
244
Location
Dayton, Oh
Excellent job. If you want a 60 degree cutter, you can file the Dremel 199 on both sides while it is running with a diamond card. I cut a block of wood at 60 degrees and mounted a diamond card on it. Then "eyeballed" it to the center and then "ground the other side. Buy extra 199's, you will probably need them.



Very cool idea, I was wondering where to find a 60deg cutter that small. I bought 10 #199’s the other day, supply chain risk management!
 

BRobbins629

Member
Joined
Mar 8, 2006
Messages
4,019
Location
Richmond, VA, USA.
Great machine! And if you add a second linear positioner in the axis, you can make double or triple thread...



Interesting, I am wondering what double or triple square thread would look like. I made the chuck carriage adjustable, it slides back and forth by loosening 4 thumbs bolts. I assume I could cut the first set of threads, move the chuck back so the cutter starts 180degs off? I can make some stops on the t-track to return. Very interesting!
It will work by indexing forward or back, half the thickness of the thread or double start, but you will then need a cutter with half the thickness. See end of tutorial for example.

http://content.penturners.org/library/tools_and_jigs/incredible_threading.pdf
 

Chief TomaToe

Member
Joined
Oct 6, 2017
Messages
262
Location
Bloomington, Indiana
My, my, my, this pen really impresses! I haven't seen too many kitless rollerball pens I like, but this is absolutely superb. The concept for the square threads is simple enough, but the actual implementation is where the challenge is! Fantastic piece of engineering here.
 
Joined
Mar 5, 2017
Messages
91
Location
Chesapeake, VA
I was inspired by Bruce Robbins (aka BRobbins629) to build a device to machine square threads in pen caps and bodies. After reading through his “Incredible Threading Machine” tutorial, I decided to build a dedicated threading machine/fixture. (not sure what to call my version yet)



My plan is to use a Dremel and a 4 jaw chuck. The 4 jaw chuck is threaded 8TPI-1", I so purchased an 8TPI-1" rod and a couple of nuts. I mounted the threaded rod, nuts, and chuck in some Delrin. I made a turning handle and mounted that assembly to some t-track. I then mounted the Dremel and an linear positioner to the t-track. I found the Dremel holding fixture on Thingiverse and printed it out, that was a huge score!



I tested the fixture with a scrap piece of acrylic (yellow in the pictures), per Bruce's guidance I added 0.040" to the caps ID to determine the bodies OD. Here is my formula: Body threads = Cap ID + 0.040". The micrometer on the linear positioner allows me to precisely touch (zero) the cap or pen body and then cut 0.020" deep threads. I slowly turn the crank and the Dremel bit #199 cuts the threads (0.010" increment steps). It's INCREDIBLE, now I know why Bruce named his version that. It's very smooth and the threads are very tight. I had to sand the external threads a little(maybe .002"), just a little fine tuning and rounded the first thread.



After successful threading of a piece of acrylic, I thought, "what about some wood threads?" This lead me to my first kitless pen, to be honest, it was not planned. I had a few kitless pen ideas running through my head, so after cutting some threads in some Cocobolo. (I used that because I know it's dense and assumed it would hold threads nice.) The threads turned out nice, after a little tuning I was able to get the grain to match once it was screwed together. That’s the nice thing about a single thread, it stops in the same place each time.



Why stop now? So I made a clip out of titanium, the pen top out of aluminum with a socket cap screw to hold the clip. I decided to put a 5 sided 1/4 twist on the body and made the section out of aluminum to hold a pencil tip roller-ball cartridge. The end of the pen is also aluminum. I bead blasted the aluminum and titanium to a matte finish and polished the very top and bottom. The 1/4 turn 5 sided twist encourages the pen to be rotated, this really makes the chatoyance of the Cocobolo to flip.



Lessons learned:

I need a small vertical mill; all the aluminum pieces were made by hand using a hacksaw, lathe, files, drill press, 6-32 tap and sand paper.



Sanding the aluminum next to the wood caused the aluminum dust to contaminate the wood. I put tape on the wood to keep it clean.



Titanium is not easy to work with, it does not cut or sand very well. White sparks!



Titanium does not cold form very well; I broke the first clip trying to bend a 90deg angle. Use a torch!



Just do it, you never know what you can create. This is not what I imagined my first kitless pen to look like, not too bad for not having any real plans, just trying to work out some proof of concepts.



Thank you Bruce for the inspiration!



Questions or comments welcome.



Question, so me what you have essentially built is a mini machine lathe no ? Check out Robert Smiths “Advance Machine Work” (1925) or the Atlas Lathe Manual (1940’s ??) should be able to find scanned copies online , I know for sure the site Scribd has them posted , check out chapters on thread forming


Sent from my iPhone using Tapatalk
 

dogcatcher

Member
Joined
Jul 4, 2007
Messages
2,021
Location
TX, NM or on the road
For some really neat items to use in creating tools and equipment, search "Machifit" on eBay.

For a cheap and pretty accurate cross slide (X Y Axis), search for "camera micro slider". These little jewels come in 2 and 4 way versions, if you buy the 4 way, it is actually only 2 of the 2 way versions. I have several, the quality is there even one the cheap ones. The more expensive are sometimes smoother operating.
 
Top Bottom