Telescopic Mast Prototype Development

About the project

Hi, I’m looking for a mechanical design engineer with practical hands-on experience in telescopic/sliding mechanisms, manufacturing, fabrication, and physical prototyping to help develop a compact telescopic mast. This is not simply a CAD modelling or rendering job. I need someone who can engineer the mechanism so that it can actually be manufactured, assembled, tested, and iterated. The final target is a lightweight telescopic mast carrying approximately a 400 g external payload, in addition to the weight of the moving mast sections. The target overall dimensions are approximately 250 mm maximum collapsed height, 1,300 mm total extended height, and less than 100 mm maximum assembled base outside diameter, including collars or other protruding hardware. The mast will operate vertically with the base rigidly mounted. The exact number of stages is not fixed and I would like the engineer to recommend the appropriate number of stages, diameters, wall thicknesses, overlaps, guide lengths, clearances, materials, and construction method. The mast must be non-locking and freely sliding, with no twist locks, lever clamps, manual locking collars, or other mechanisms that require manual release. It must also be non-rotating/anti-rotation so that the top stage maintains its orientation relative to the base during extension and retraction. We need smooth low-friction movement, low radial play and wobble, positive stage-retention and travel stops, and a practical method of assembly and disassembly. We are considering two possible approaches. The first option is a passive telescopic mast. In this version, the mast is only the structural and guiding assembly. We will provide our own internal lifting and retraction mechanism, which will push and pull the top stage. The passive mast therefore needs freely sliding stages, guidance, anti-rotation, stage retention, mechanical extension/retraction stops, and a continuous hollow passage through the center. Our current working target for this version is at least 30 mm clear internal bore through the smallest/top section, although this should be confirmed during the design phase. A mostly 3D-printed PETG functional prototype is acceptable for initial testing, and aluminium tubes combined with printed guide components may also be proposed if this is simpler or more reliable. The second option is an integrated pneumatic telescopic mast. In this version, the telescopic assembly itself provides both structural support and pneumatic lifting force. A lightweight single-acting pneumatic design with external cable-assisted retraction is acceptable if this simplifies the design and reduces weight. For this option, experience with pneumatic or hydraulic cylinders, telescopic cylinders, seals, wear rings, guide bushings, low-friction sliding stages, and pressure-containing assemblies would be valuable. I am not initially asking for complete detailed designs of both alternatives. I want your engineering assessment and recommendation on which approach is most practical for the dimensional and weight requirements. Before developing the complete mast, I want to start with a paid three-section functional prototype consisting of one fixed outer section and two moving sections, creating two telescopic interfaces. This initial prototype does not need to achieve the final 1,300 mm extended height. Its purpose is to prove the fundamental mechanical design before we invest in the complete mast. It should test smooth extension and retraction, guide and bearing arrangement, sliding clearances, anti-rotation, retained overlap, positive extension and retraction stops, stage retention, assembly and disassembly, radial play/wobble, and compatibility with our internal lifting mechanism or pneumatic sealing arrangement depending on the selected concept. The geometry and materials should be representative enough that a successful three-stage design can later be scaled to the complete mast. For the three-stage milestone, I require editable parametric native CAD in SolidWorks, Fusion 360, Inventor, or equivalent, plus STEP files for individual parts and the complete assembly. For all parts intended for additive manufacturing, I also require print-ready STL and/or 3MF files. The CAD package should include the complete assembly, fully collapsed configuration, fully extended configuration, sectional/cutaway views, and an exploded assembly view. I also require dimensioned 2D engineering drawings covering the important functional dimensions and manufacturing information, including critical tolerances and sliding clearances, OD and ID of each section, wall thicknesses, guide/bushing dimensions, stage travel, retained overlap, mechanical stop positions, anti-rotation geometry, mounting interfaces, and the assembly/disassembly method. Please include material recommendations, estimated total mass and moving mass, a bill of materials, and specifications for off-the-shelf fasteners or components wherever possible. For the 3D-printed prototype, please provide recommended material, print orientation, basic print settings, and any relevant DFM/DFAM recommendations. The design should account for actual FDM-printing tolerances and surface finish rather than assuming machined-metal clearances. Please also perform a basic interference/motion check of the assembly and provide a simple prototype test plan covering sliding force, extension/retraction, wobble, anti-rotation, stop operation, and repeated cycling. The first milestone must include one design revision after I physically test the prototype. If you offer physical prototyping services, please quote 3D printing, assembly, functional testing, and shipping separately. If you provide CAD and engineering only, that is also acceptable. When applying, please show at least one relevant telescopic or sliding mechanism that you personally designed. Examples could include telescopic masts/poles, telescopic cylinders, deployable mechanisms, lifting columns, linear sliding assemblies, pneumatic/hydraulic cylinders, or other nested sliding structures. I am particularly interested in projects that were actually manufactured and tested rather than only rendered in CAD. Please briefly explain what part of the mechanism you personally designed, whether it was manufactured, what problems were discovered during prototyping, and what design changes were made after physical testing. In your proposal, please provide your recommended initial approach, a fixed price for the three-stage engineering milestone, estimated completion time, whether you offer fabrication/testing, and an approximate cost range for developing the complete mast after the three-stage prototype has been successfully tested. This is an R&D prototype. The priority is practical mechanism engineering, smooth operation, low weight, compact packaging, manufacturability, and learning from physical testing—not appearance or rendering quality.

Skills required