Rhino plugin BoltGen and external program BoltGenGUI (Graphical User Interface) are free programs that creates accurate Metric and English machine bolts of any length.  In addition, they create inside-thread-cutters and nuts.  Generated part Names (in Properties window) allow easy identification.  BoltGenGUI provides an easy-to-use Graphical User Interface.
 Makes Sockethead Capscrews, Flat head Machine screws, Flat head Capscrews, Oval Heads, Pan heads, and Hex Heads, or just threads without heads if desired.
Head drives include Torx, Philips, Allen and Hex wrench.
4 bolt styles can be created: threaded, without threads. and each as blocks.
Program is multilingual supporting English, Spanish, German, Czech, and Italian.  BoltGenGUI also supports French.
A second command in the plugin (BoltGenAN) is provided to make type AN Aircraft Bolts.  BoltGenGUI has this incorporated into the GUI.
For Rapid-Prototyping in the plugin version, an additional function is included to resize the Inside_Thread_Cutter called ThreadCutterScaler.  It allows resizing the cutter (or any object) in the WorldXY plane to increase thread slop.
Link for download:
Plugin version:  Download, unZip, and place in Rhinoceros Plug-in Folder.  In Rhino, choose Tools, Options, Plug-Ins, and Install BoltGen.
 Rhino commands are BoltGen, BoltGenAN, and ThreadCutterScaler  (also available from drop-down menu selections).
GUI version:  Download, unZip into temporary folder, and execute setup.exe.  The program may be executed from your Start menu, folder BoltGen.  Please see the Read Me.txt file in the download for more information.

Support Email: 4FQ.FLYS3S1Q4@ESL@
Plug-in rating:
Average: 5 (7 votes)
Title Release Notes
Updated version corrects metric flathead bolt angle
Failure fix and corrected Metric Flathead bolt angle to 90 degrees.  
Version: 1.76
Language: Any language
BoltGen 1.71 release
Now includes aircraft type AN bolts Fixed metric hex head size problem Minor other fixes  
Version: 1.71
Language: English
BoltGen Plug-in for Rhino
Fixed units scale problem with torx driver  
Version: 1.4
Language: English
Bolt and Screw Creation Program
Creates bolts faster by disabling draw during generation some minor bug fixes Added more correct head shape generation  
Version: Version 1.2 5/4/2013
Language: English
Homepage: McVan Aerospace


armac's picture

Read previous comments ... they tell how to unblock and install.

Hello?why my rhino 5 say your plugin boltgen block

It`s great. Thank you!

lopacki2's picture

I just downloaded this and must say I am thrilled. I have been designing a small table top shear for jewelry making and dreaded drawing all of the bolts for it. I just generated two diffrent bolts and now have twenty bolts in place in my drawing.

I had no problem installing the plug in with GUI and it works perfect.

Thank you very much for providing us this wonderful plug in.


All my best ........ Daniel Lopacki

armac's picture


  There are a few bolt formats where the information for heads is not available.  In those cases, I just make threads only and you can put your own head on the threads.  Please try different bolts to confirm that you are having trouble with the program and not the missing head info bolts.  15,000 other users around the world are not having any trouble with the program.  If your problem persists, first try downloading and replacing the plug-in.  If that does not clear up the problem, please let me know the details, including Rhino version, thread, length, head, etc. and I will try to find a solution.

Regards, Ray

Hi Ray,

The bolt heads are not generating.

Any idea as to why?




armac's picture


I do have an external GUI that uses Rhinoceros as a graphics engine and has a more friendly user interface (, but no buttons for the installed Plugin.  I am unable to send requests directly to the program since it was written in Visual Basic 6, so buttons can not control the program.  I am sorry.

Regards, Ray


Do want some icons, so boltgen can have a button bar?

What a great plug-in. Thank you!

armac's picture

Thank you for your feedback.  An error was recently corrected for metric flathead bolts ... the angle was 100 degrees and should be 90 degrees.  This was corrected in version 1.76 released May 16, 2014 in case you need an update.

file can be found at: under Resources tab.

Regards, Ray McKaig

Really good plugin! I love it. Good job! 

dr_d's picture

after copying the plug-in in without reading any directions, I also received this plugin is blocked; see


Here's the steps that worked to get it installed:

Close Rhino. 

Go to downloads folder.  

Unzip BoltGen 

right click, select properties

where it says this file might be blocked to protect computer because it came from another, click unblock

now open second explorer window; win+e

then navigate to the rhino plug-ins folder

drag the file from downloads to the plugins

select move/replace

start rhino, 

select file--> properties

then go to plug-ins

click install

find Boltgen.rhp

click ok..


MANY MANY THANKS FOR BOLTGEN!  It looks that it will be a big help for my daughter's landscape architecture project.



Rhino 5 64-bit on Win7

Brilliant, thanks!

armac's picture

To those having trouble installing the BoltGen Plug-in:

I have created an external GUI (Graphical User Interface) for BoltGen that should resolve your installation problems.  It is an external program that makes calls to Rhino, and uses a much better interface for bolt selections.

1. If the latest version of Rhino is not running, BoltGenGUI will launch it.  When closing BoltGen, Rhino will ask if you want to save your changes ... abort will keep Rhino running.

2.  If the latest version of Rhino is running, BoltGenGUI will use it.  Closing BoltGenGUI will not close Rhino.

Please download BoltGenGUI from

UnZIP and install like any other application using setup.exe.  Run it from the Start-Menu BoltGen folder.

Regards, Ray McKaig

I have tried this method, but still no joy in installing this plug in? Any suggestions?
It appears that the Plug-In has been locked and Rhino will not install - how is the plug-in unlocked?

how do use this program

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