Atelier d'Usinage Joly Concept Machine Shop
Atelier d'Usinage Joly Concept Machine Shop

Theoretical Machinist News

News: Site issues

The site is now running on a new server after being online for 9 years straight. Unfortunately, files got corrupted for some reason that I can’t explain. This justified updating the back end to a newer version of a Windows Server.

The tolerance calculators were no longer functional and there were a couple of small issues that were communicated to me by user via the link. This feedback is very welcomed, as are the positive comment of many users over the years for the use of It is always a pleasure to hear from you.

I also want to add that very few issues were reported over the results outputted by the Imperial thread calculator as well as the ISO Tolerance zone Calculator and ISO Tolerance Calculator. The algorithms are standing very well to the test of time. Thank you very much for your inputs.

Enjoy the site!

Martin - Februrary 17, 2024

News: Site changes

Hello fellow web site users... It has been a while since I worked on the site. I am starting my own machine shop, Joly concept, and in the process of making promotional material for the later I moved some stuff from there to The true position Calculator. I am also publishing an unfinished version of a Metric Thread Calculator... by very popular demand. It is still a work in progress but good enough to use as is. Please not that it is still a work in progress; these things are very complicated and take a great deal of time and effort to make and test out.

The social stuff at the bottom of the page is gone. It’s not something I got in the habit of keeping track of: Twitter, Facebook and Google.

The Phone apps are also no longer supported. It became very tedious to keep track of all the Android versions and iOS is something I would rather forget as a whole.

Another aspect of the site that is no longer supported is https://, I don't think it is necessary. When the site had a forum it was justified but since that is gone the need for secure browsing is no longer necessary.

Please consider sending machining work my way as I am just starting the business.

Enjoy the site!

Martin - December 8, 2019

News: Site redesign

The layout of the site has been change to make better use CCS styling overall. Although it’s not as optimal as I wished it would be, I still use inline style in some areas. I figure it is mostly due to the somewhat unique content or lack of knowledge on my part. Cleaning up the CSS styling of the will permit multiple styling for different screen sizes i.e. mobile devices.

Another change that is not apparent is the use the jQuery scripting API. The “PopUp charts” now work as initially envisioned. They appear as windows inside the browser. jQuery will eventually permit the use of input controls such as textboxes and selection box better suited to mobile devices. Until these things are implemented a mobile friendly versions of the site will not be available.

A new desktop app, JcTimer, for windows is available for download. I needed a timer utility a while back, so I created one and thought it might be useful to others. Unfortunately a code signing certificate doesn’t fit into the operational budget of the site. The code is unsigned and you will get a warning the publisher is not verified at installation time.

Martin – 05 March 2015

News: ISO Metric Tolerance

New ISO Metric Tolerance application is now online. This tool will calculate almost any possible ISO Metric tolerance Size/Deviation/Grade combination. Please note that due to the large amount of possible combination it is very difficult to properly test and validate all possible results. I found that the last ISO Tolerance Zone calculator was too limited in the choices of tolerance and made one that had much greater possibilities. It is, however, limited in functionality.

The Theoretical Machinist Chart for Windows® desktop download button is now fixed.

Martin – 06 April 2014

News: Website migration to new server

Unfortunately, migrating the website to a new server did not go as planned. The site was offline for several days due to configuration issues. I hope this wasn't too much of an inconvenience. Not everything is working correctly yet. Please be patient I am on the job and figuring things out. Thank you for you patience.

Martin – 08 January 2014

News: Joly Concept has a sister site; Joly Concept Banner. It is a Mechanical drafting and 3D modeling service. For those of you that have access to machines or just curious about mechanical drafting: A fully annotated drawing of a decorative cannon project that you can build yourself is available and free to download. (Le site est entièrement bilingue; anglais et français.)

Sales of the Smartphone apps are going well and easily cover the cost of running Thank you for your support!

Martin – 10 December 2013


Partial redesign of the look of the site. Finally got around to changing the left side Main Menu to a drop down style menu interface located at the top of the page. This is leave more room for the actual content. This was necessary because of the width of the new ISO metric tolerance calculator web application that is wider than initially anticipated. A change to the look of the site is something I wanted to do for a while now as well.

ISO Metric tolerance calculator is now online. It is at Version 1.0. If you find any bug or have any issues with it, please contact me. Your feedback is very appreciated. The explanation of how it works is incomplete. This will be added later while the kinks get smoothed out.

The ISO Metric tolerance calculator was started a long time ago. The development of all the Smartphone and desktop apps put this project on hold much longer than expected. This is the reason the site did not show any changes for such a long time.

Martin - 27 June 2013


theoreticalMachinist for Windows Screenshots

The Theoretical Machinist Charts app has been updated to version 1.3. A drill tip height calculator and 2 Tap drill size calculator were added. Some colors were added to some charts and the help system was changed to make room for other tools that will be added in the future.

The drill point tip calculator was an effort to gain some experience in generating dynamic graphical representations. This experience will be helpful for later app projects.

I will go back to developing for the site. All this app development; Windows, android and iOS has taken me off site development for a long time now. Stay tuned for other tools to be added to the site shortly.

Martin - 11 June 2013

Site News:

The site has been at a standstill for a while now. I do wish I could spend more time on it but there are still some other projects I have to work on before committing time to major changes and updates to The about page has been updated. The information about me was kind of vague so I updated it to tell you more about what I actually do for a living and the things I know about. A linked-in button to my account there was also added.

Sales of the Smartphone apps are going well and is very much appreciated. These revenues will pay for the server operating costs for a while but I will have to find other means to pay for the server uptime. The usual way is with advertising, and this is a great segue to the next section of the news...

New software:

theoreticalMachinist for Windows Screenshots

Finally finished the Theoretical Machinist Chart for Windows® desktop freely downloadable software. this is free ad-based software. For now it is only a "Decimal Equivalents" chart but, if I see that it is popular and can be monetized. It will probably be updated with more functionality in the future. Something similar to the Smartphone apps. This app is fully multithreaded and should run very smoothly. The software should notify you if any updates are available. Although, none are planned for the immediate future. The application retrieves Ad content from and displays it at the bottom portion of the window. It requires and internet connection at start-up for this purpose.

theoreticalMachinist for Windows Screenshots

During the development of the "Theoretical Machinist Chart for Windows desktop" app. I had to make a small file checksum generator: Theoretical Machinist checksum Generator, Windows desktop software application. this is also available for download. It creates MD5, SHA1, SHA256, SHA384 and SHA512 hashes and has a handy hash comparison feature. The largest file I created a hash for was around 8 Gigabytes and I am uncertain what is the largest file that it can take as input. There are many app of this nature on the internet but the simple interface and usage might make it useful for some of you.

Site security:

The SSL security of the site was updated to turn off SSL 2.0 and reorder the priority of the cryptographic cipher suits used. This was done to counter the BEAST attack on SSL that was disclosed in 2011. now gets an "A" for SSL security on Qualys® SSL LABS Server Test page.

I am not expert on internet security and cryptography, but from what I have read so far. There is no such thing as being 100% secure over the internet.

Last Minute update:

Unfortunately I was unable to get a code signing certificate to sign the code for the new desktop apps. If you decide to download and install the "Windows desktop apps" you will get a warning that the publisher is unknown. I will do my best to resolve the situation as soon as possible.

Martin - 07 April 2013


The projects I have been working on for the past few months are almost complete. You can see what it was all about on the /SmartphoneApps page of this site. It has taken a great deal more time to complete than expected. you might have noticed the lack of changes to the site. Once everything is complete, App-wise, I will be updating the look and adding features and correcting some issues here and there.

TheoreticalMachinist Charts is now in the Smartphone Apps business! please support this site by buying the App. It is an application that displays common Machinist charts; Decimal equivalence, Tap drill sizes for Cutting taps, Cold forming taps and Pipe threads. A great deal of work has went into their creation. iOS, Android and Windows phone 7 devices are all supported.

My initial idea was: "I'll just make an app that shows a couple of charts... How hard could it be". It turns out that the learning curve was somewhat steeper than I expected.

Creating the data was a big undertaking, I didn't want there to be too little nor too much of it and it had to be correct. How to display all that data was a bit more difficult than expected, some devices have large screens, others have small ones, will it fit, is the text too small, will it slow the device down to a crawl.

It has to look good. Artwork is very important. You basically end up looking at almost every pixel individually, is there enough contrast, do the colors clash and the most important of all... Does it look cool?

Writing all the text was a lot more work than expected. Writing doesn't come naturally to me so I had to spend a great deal of time writing and re-reading everything . Translating it all into French , reading and re-reading all of that as well.

The actual coding was the biggest challenge. The apps are all written in their native language. Objective-C for iOS devices. Java for Android and C# for the windows phone 7 platform... I won't go into the details but I assure you there were a great many "details" to figure out. I did build it in a way that more charts could be added later on as updates.

Support this site. Buy the Smartphone apps.

Martin - 26 September 2012


The site has been at a standstill for a while now. I have been working on other projects that are coming to an end soon. I should get back to refreshing and updating the site fully shortly. Those other projects have taken a great deal more time than expected.

The SSL certificate has expired and I haven't settled on a new certificate provider. I have had a temporary one issued in the mean time. Since doesn't generate any revenues, I am reluctant on spending a great deal of money on a feature that is mostly unused; the "Forums" section of the site. It is a simple case of keeping costs of operations down. I will be shopping around for something suitable to the needs of the site and the certificate should change again shortly.

Martin - 15 August 2012


There was a minor bug when the Unified National Imperial Thread Calculator was updated a few days ago. A function wasn't compatible with IE version 8 and less. everything is back to normal. Sorry if it was an inconvenience to anyone. Thank you to the folks at for the quick fix.

As you might have noticed, The unified thread calculator page was updated. The UI was redone. The interface now uses JavaScript and feels quicker and it is less demanding on the server. It also is more SEO friendly due to having less cryptic code having to get loaded every time you visit the page.

The math isn't quite finished yet. There is still things to tweak here and there. The results are not perfect yet but very close to being exact. The issues lie within the V-Shape portion of the results. It is somewhat of a minor detail.

Martin - 01 March 2012


I finally got around to updating the Unified National Imperial Thread Calculator. It now does internal threads and the class "1A" issue has also been resolved. All results are calculated based on my best interpretation of the specification. That said, the specification is based on tabulated data: tables of values. There are still small discrepancies in the order of .0001" to .0003" compared to reference thread charts. I will leave the math as it is for now because I find that it is good enough for general usage. The results are not perfect but very close to the dimensions of the official specification.

The thread calculator is not final. It does not check the validity of the thread that is being computed. You can enter almost any combination of; diameter, pitch, class and series and it will compute it to the best Unified National specification of Standard thread designations. But it doesn't guarantee that the particular thread is a valid designation. If you choose a designation from a list of standard threads, the values should be correct or very close to specs you would find in reference manuals.

If you do have a special thread to calculate, start by selecting a standard thread that is closest to the one you want to compute and try different series designation; UN, UNC, UNF, UNEF, UNS. Compare the outcome of the calculations. Try to use the 2A and 2B classes of thread as much as possible.

Other data about the thread form such as; root and crest radius, Max/Min minor diameters that do not seem standard will be explained when the interface will be redone and the help section updated.

Martin - 07 February 2012


It has been a while since any news has been posted but development of the site never stops. I've been tweaking things here and there such as changing the look of the site to a chamfered look instead of the rounded corners and taking care of other small issues. Learning new technologies is also time consuming but the effort has lead to the addition of the bolt circle calculator. It is the first app on the site that uses HTML 5 technology. It is still useable with non HTML 5 browsers but it was designed with this new technology in mind.

While developing the bolt circle calculator I figured out some algorithms for angle calculations. I added a decimal angle to and from sexagesimal: degrees, arc minutes and arc seconds, converter . It will also resort your entry to true sexagesimal: base 60 format.

The thread form calculator hasn't been receiving all the attention it deserves. I'm stuck on an issue but should get back to it soon. It really is confusing because of all the special cases in the "Unified National" thread specification. A major overhaul of the interface is also planned.

Martin - 21 january 2012


The style of the site has changed to chamfers. Corner radiuses were the initial idea but having pages with too many of them affect the performance on older and less powerful computers and devices. A couple of things here and there have also been tweaked but nothing major.

The unsecure components when browsing using https://, SSL, are fixed. There shouldn't be any warning about the site having unencrypted elements now. The culprits were the links to facebook, Google+ and twitter buttons. The issue was that was redirecting users to an unsecured link when using this site in an encrypted, secure, fashion. does not have access to any information of yours when using these links, when clicking on these buttons you deal directly with the respective site. only collects anonymous usage information for web site usage analytics: to the best of its knowledge. Some warnings still appear when coming back from the forums section. These issues will be looked into at a later date.

Some portions of the site now use HTML5 elements. You can see more about this on the graphical bolt circle calculator. There is only one component of that page that demands a browser that is HTML5 capable. the calculator portion of the page should still work if your browser isn't.

Martin - 21 December 2011


Most of the work being done these days is on the back end of the Unified thread data calculator. It is mainly memory optimization and building a framework that can be used for other kinds of thread forms. Nothing that is very apparent on the surface.

The help section has been updated. It answers some of the question I’ve had so far. I didn’t get enough feedback to do an actual FAQ. But that will also be added later on when I get more input from people.

I’ve added a Guest section in the forums where people can create new topics without the need to create an account in the hopes that it might get things going in there. My only worry is that it’ll get used by spammers and not by regular users of the site. I keep an eye on these things and messages of the sort will get deleted soon enough.

Martin - 11 September 2011


Not many things have change recently. By that I mean, no major additions to the site. Although you might have notices a couple of new selections added to the popup selector. I though having a list of common thread sizes and fractions would leave out the guesswork for people who are not familiar with threads and fractions. The input boxes are now color coded and a legend panel was added to make the use of the calculators more obvious.

I’ve started working on the Threads Unified Imperial calculator again recently. I have to get back into the “groove” of coding. Last time I did anything on that calculator, the site was still but a white blank page. I have to redo some of the things I thought was a “good” idea at the time.

Anonymous tracking data shows that is international! I was hoping it wouldn’t just be a Canadian thing. Canada, especially Québec, is a great place to live and all but the size of its population is somewhat small. I am natively French speaking and perfectly bilingual English speaking. Initially I wanted to make bilingual but having limited time and resources to spend on developing the site, I chose to go English only to reach as many people as possible. It is still something I would like to. But it is easier said than done.

Your feedback would be much appreciated. I’ve noticed that the forums usage is low. But I understand that creation of an account, username, password, registering and all is hassle. There are so many places on the internet that uses forums and comments and the likes. You can always email me at in French or English; I do read all my mail. Any correspondence in another language would be done with the help of translating software. They aren’t perfect yet but good enough to get the point across.

Site usage is still low by internet standards but I am very pleased with the activity I see so far. The site has only been online for less than 2 months.

Martin - 29 August 2011


Many things have changed since the last news entry. I’ve done a slight reorganization of the website layout. The home page is now a button style interface, something a little more eye catching than a page full of text. The news, what you are reading now, has been put in a separate page. It’s something I’ve wanted to do since the start of this project but nothing ever came to mind as to what I actually wanted as a landing page. So I had an idea last week and went with it. A help page has also been added but… Don’t go there for help just yet.

This is what I was expecting from the anonymous analytics tracking I put into the site recently. I now have a better idea of where people tend to go and exit and such. This would explain the reorganization of the site. now has its SSL certificate! It doesn’t quite work the way I want it too yet but it permitted me to switch on “Create new registrations” in the forums. Logins and new registrations can only be done in SSL, “https://” mode. If you get a warning that “access is denied” when trying to login or create a new account, it’s because your connection to that portion of the site is not secured with SSL. You will have to either; go back to the main site and click on the “Forums” link or manually change “http://” to “https://” in your browsers address bar.

The main issue with SSL is that when you initially reach the site you’re in regular non-encrypted, “http://” mode. When you go to the forums, it switches to encrypted “https://” mode. So far so good; The problem is when coming back from the forums; it stays in “https://“ encrypted mode. The buttons for Facebook, Google+1, twitter and the anonymous analytics are not considered secure content. That explains why you get a warning about the website having non secured content while in “https://” mode. I’ll figure it out and fix that issue as soon as I can.

Martin - 13 August 2011


Basic cutting tap drill size chart now available in PopUp selector. now has a privacy policy.

Anonymous data tracking is slowly being implemented throughout the site. No personal information is collected. The anonymous data that is gathered will be used to better understand which part of the site get used more so I can better focus my attention on the areas that are popular. All aspects of the site are important to me but the time I can allocate to it is limited: I do have a day job. This information will also be important if advertising ever becomes a part of

New registrations to the Forums has been disabled until a secure SSL connection can be established between your computer and the Forums area of the site. There hasn't been any security issue since the launch of but since so many big named websites have been getting hacked lately. I prefer to take a Precautionary stance until I am satisfied with the security of the site.

Martin - 02 August 2011


Site progress... So far so good but still no SSL certificate.

I've started adding Glossary boxes on some pages to better describe the terminology that is used. It should give a better idea of their usage for to general public.

Martin - 28 July 2011


The site is now online and can be reached using; “”. I wanted to get the site up at the beginning of the month of July but things didn’t turn out the way they were supposed to. Setting up the server was more demanding than expected. It is the first time I setup a website. I’ll keep it discrete for now to see how things go.

Security is a major concern of mine. There is still the issue of not having an SSL certificate yet. If you want to use the Forums section, please be advised that the connection between your computer and the server is not secure and not encrypted. Do not create an account or sign in into the forums if you are using one of those “Free internet WiFi hotspot” like the ones at your favourite coffee shop or an airport. Reading the posts poses no security issue. If you’re not sure what I’m talking about… Just don’t use the Forums yet. The site will have an SSL certificate soon.

I am certain there will be some technical issues to resolve in the first few weeks of the website being online that will delay the creation of new content. I still find that it looks somewhat bare but considering just a year ago it was just an idea and that I knew absolutely nothing about websites, HTML, Servers and all that stuff… I find that it is good enough to publish.

Some parts of the site are still under construction and others are missing content; technical drawing and explanations of what the calculators do and how to use them. I decided not to wait and “put it out there” as it is. So stay tuned for new things to appear here and there from time to time. Enjoy the the site!

Martin - 25 July 2011


Welcome to! The site is in its initial launch stage as of July 2011. Features and fixes will be added gradually over time. Before moving too far along with the addition of new content, I will be working on the plumbing for a while to make sure everything is in working order. This is my initial attempt in building and administering a website and a lot of the dos and don’ts are still left to be learned.

I have more ideas of things I want to incorporate into the site. The basic functioning is how I envisioned it initially; Charts, calculators, forums, text and images to describe the usage. All the rest will come later on.

I have the impression that it will always be a work in progress.

Martin - 01 July 2011

Last Updated: 17 February 2024

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