Segmental Bend Developer

As a fabricator of 40+ years, the last 30 or so as the workshop manager, I have constantly used trigonometry etc. to calculate cones, segmental bends and much more. Nowadays I am constantly asked by the fabricators to calculate developed lengths etc. to save them the time and effort of laying it out. I have developed this app so that they can do it for themselves and therefore save “MY TIME”.

This segmental/lobster back bend developer app contains more features than the one included in the Fabricators Handbook.

It develops a 90 degree bend as standard or you can enter any bend angle you require.

Enter a minimum of one full segment, or up to as many full segments as you require. The half segments are added automatically. The norm for most 90 degree segmental bends is five full segments plus two halves, this will gives a good flow through the bend.

This developer will also develops a wrap template, just enter the outside diameter etc. and a nominal thickness of say 0.0001, this will produce a wrap pattern when developed. A wrap template is marked on paper cut to shape and then placed around pre-rolled plate or pipe, the shape is then transferred onto the material for cutting, the template can be used many times.

Either outside or inside weld bevels can be selected for thicker materials i.e. thicker than 3 mm or 1/8 inch. Select inside weld bevels or outside weld bevels depending upon your welding sequence, one option must be selected for the pattern to be developed accurately.

Patterns can be developed in inches or millimeters, select the option you require.


To Use:- Select ins or mms, enter pipe outside diameter, bend radius, number of full segments, material thickness and bend angle (90 degree is default, but any angle can be entered ) .
Press/touch Develop button/icon, developed length, pitch dimension and developed lengths for A, B, C, D, E etc. will be displayed. A drawing will also be displayed, this drawing is for reference only, showing what the developed half pattern will look like and the positions of the developing lines.

I hope that from your feedback/comments I will be able to add extra relevant features and amendments in future editions.