All a Matter of Dimensioning: Online Thread Calculation from Bornemann

Whether they are used in plant construction, mechanical engineering or tool manufacturing, in demanding production processes, under water or in outer space: spindles and threads are often subject to extreme requirements. When it comes to thread dimensions, development departments require experienced engineers and technicians from as early as the prototyping stage.

Establishing the lowest possible thread dimensions with the optimum load bearing capacity clears the path for compact custom designs in mechanical engineering while also minimising material use. This calls for a huge amount of computing work. Dense formula sets or home-made Excel spreadsheets are often used alongside expensive software. The more custom the thread, the more complex the dimensioning. Likewise, custom solutions will quickly require two or three experts for calculations, simulations, adjustments and recalculations. These investments are especially justified in safety-critical solutions for lifting, medical and conveying technology. These calculations require long, hard days in the office, and any doubts will result in time-consuming optimisations that extend the duration of a project.

Bornemann is now launching a new free-to-use online calculation tool for thread dimensioning. In just a few steps, users can define custom thread profiles for any conceivable application. Enter the axial load, overall length, thread length and bearing distance – with the option of choosing the material and lubrication specifications if desired.

Whether you need standard threaded spindles or leadscrews, trapezoidal threads or trapezoidal thread spindles, buttress threads, round threads or high helix screws: dimensioning is carried out automatically with no need for notebooks full of formulas or Excel spreadsheets. You can change any factors and then change them again. In practice, this makes thread creation much faster, easier and safer – even if thread dimensioning is not part of a company’s daily business or is being done for the first time for an innovative custom tool.

The First Question to Start with: What is the Thread Supposed to Do?

The calculator at https://www.bornemann-gewindetechnik.de/en/screw-dimensioning-tool/ can be accessed by anyone, provides reliable results and creates the basis for in-depth consultation on tailored custom solutions.

It was programmed by the thread experts at Bornemann, combining widely accessible formulas with their decades of experience in the field of highly specialised thread technology. Bornemann gave some long-standing customers the opportunity to look behind the curtain as early as the testing and development phase.

Erik Säfsten, an expert in lifting solutions and CEO of the Scandinavian company Dendro Lift, subjected the new calculator to intensive testing along with his engineers:

We produce highly customised lifting systems with very heavy loads. The Bornemann dimensioning tool makes my engineers work much, much easier. It lets you determine the right thread sizes in an uncomplicated way. If one of the variables changes, the tool automatically calculates the effect on all the other parameters. When designing custom systems, that gives us much greater security and lets us make much quicker progress. Nicely done! We are delighted to work with the Bornemann calculator: if my engineers are happy, then I’m happy, too!

— Erik Säfsten, CEO Dendro Lift

Calculating threads – no need for paper, formula sets or error-prone Excel spreadsheets.

Whether you are a student, technician or experienced custom machine engineer: With its clear structure and convenient dropdown menus, the thread dimensioning tool is an intuitive, step-by-step system that helps you understand the complex relationships between various parameters and opens your eyes to the paths towards new solutions. Users can calculate the smallest suitable thread size or are free to select their optimum size from a spectrum.

For quick results, there are just a few predefined mandatory fields: the axial load in kilonewtons, the distance between bearings in millimetres and the overall length and thread length of the spindles in millimetres.

You can define load types including alternating loads, dynamic or static compressive loads or dynamic or static tensile loads at the top, as well as the support type for the spindle in the combinations: fixed bearing/free, simple bearing/simple bearing, fixed bearing/simple bearing and fixed bearing/fixed bearing.

Define your materials at the same time

Based on the application and area of use, the choice of materials can be of decisive importance, especially for round, high helix and trapezoidal threads, leadscrews and trapezoidal thread spindles. For its threaded spindles, Bornemann uses only high-quality steel and tried and tested steel alloys. Eight different steel qualities are provided in the calculator drop-down list.

Depending on the area of application and load factor, there are 17 different materials to choose from for the leadscrew nuts: from red bronze, grey iron, bronze, multi-allow bronze or a special bronze such as Ampco, to plastics with strong sliding properties.

If you want, you can define a specific safety factor with regard to the tensile stress. A value of 1.25 is always preset, which means protection against overloading is automatically integrated into the dimensioning.

You can also select the thread type before confirming your entries. Users can choose from a wide range of designs including trapezoidal threads, buttress threads, round threads, metric threads, inch unit threads and Whitworth threads for water installations and pneumatic applications, for example.

All the important information can be read in one glance

The calculated values are based on a round nut, square nut or flange nut and a simple threaded spindle with no machining of the journals.

The calculator checks the self-locking properties of the thread during both movement and start-up. Users can further optimise and amend all the basic parameters, including the nominal dimension, pitch or number of threads, as needed, and update their calculations with a click of the mouse.

You are provided with important recommendations, tips and special features at all times. Issues such as surface pressure are addressed, correlations to the permissible operating speed are clarified and empirical formulas, tolerances and quality factors are explained. Values for buckling, strength tests, drive torque, drive power and holding torque are all provided.

All your values can be saved with a screenshot, transferred to a CAD programme, printed out and discussed with colleagues.

The calculator operates in accordance with the latest DIN and ISO design standards. There is no inference of a legally binding guarantee of specific properties or suitability for a particular application. For binding advice before placing an order or commencing production, users are invited to contact us directly and open a request for consultation, which conveniently can also be done by clicking the link on the page.

About Bornemann Gewindetechnik

Bornemann Gewindetechnik (www.bornemann.de) has been producing threaded spindles and nuts according to international standards for more than 50 years now. We produce custom solutions for lifting technology and hydraulic steelwork applications, platform equipment and gate valves for dams, to name just a few. Alongside challenging high-precision work on buttress threads, feedscrews and multi-start threads, we also focus on the production of large, ready-to-install trapezoidal thread spindles and nut sets. Behind all this is German engineering expertise, which we have now incorporated into the development of our powerful online thread dimensioning calculator: It makes thread dimensioning faster, easier and safer for beginners and professionals alike