Obsolete spare parts – why they disappear
Most manufacturers keep spare parts in stock for a limited period after a model goes out of production. After that the moulds are scrapped, and all that remains is whatever is left on dealers' shelves. For a machine or appliance that otherwise works, a small plastic part is often what decides whether it can be used any longer.
Typical examples are latches in dishwashers, drawer wheels, knobs, hinges, gearbox gears and brackets that have cracked at a screw. What these parts have in common is that the geometry is limited and the dimensions can be measured. That makes them well suited to a new 3D model, even when there is no drawing to start from. The pieces of a cracked part are often enough to recreate the whole shape.
It is not only old equipment. Appliances that are five to ten years old can lack spare parts too, because models are replaced often and stocks are kept small. Sometimes the part still exists but is only sold as part of a larger assembly, so a broken latch means buying the whole door. A new model of that one small part is then the sensible alternative.
Measuring a spare part without a drawing
We start by identifying the dimensions that control the function: hole patterns, shaft diameters, threads, distances between fixing points and faces that bear against other parts. These are measured with a digital calliper, micrometer, radius gauges and thread gauges. Freeform shapes, such as the curve of a knob, are photographed straight from above against a grid and traced to scale.
A worn sample lies about the most important dimensions. A shaft journal that has worn down or a hole that has gone oval is therefore measured at its least worn point, and we compare it with the mating part. It is often possible to work out a likely nominal size: a hole pattern of 31.9 mm in a European machine was almost certainly drawn as 32 mm. There is more on the methods in the guide measuring a part for CAD.
All dimensions go into a parametric model in which the driving dimensions are named. That makes it easy to change a hole pattern or a wall thickness after the trial fit without breaking the geometry. We often add a simple drawing with the critical dimensions too, so you can check the finished part yourself with a calliper.
Why the original failed
A spare part that is simply copied inherits the weakness of the original. So we look at the fracture surface before we model anything. A break at a sharp internal corner points to stress concentration, and we add a radius. Cracks around a screw hole often show that the screw was overtightened or the wall is too thin, which is solved with a sturdier screw boss or a metal washer.
Fatigue in snap fits is dealt with by a longer, tapered tongue that spreads the strain more evenly. Where a plastic part has worn against metal, a bushing in a different material can be better than making the whole part harder. Sometimes the improvement is as simple as moving a rib or adding a millimetre of wall thickness where it cannot be seen. With the delivery we briefly describe what has changed compared with the original and why, so you know what you are getting and can easily order another batch later.
The right material for replacement part manufacturing
For one-off parts, FDM 3D printing is usually the quickest way to make a spare part. PETG suits most indoor parts, ASA withstands sun and weather, and PA or carbon-fibre-reinforced PA gives stiffness and wear resistance to gears and brackets. TPU is used for dampers, seals and grip surfaces that need to be soft.
Metal parts, such as shafts and loaded brackets, we draw for turning or milling and help you find a machine shop. If you need hundreds of parts a year, adapting the model for injection moulding may pay off. Everything is built in the same parametric model, so changing the method does not mean starting again. If you already have a scanned mesh, we can rebuild it – read more under STL to STEP conversion.
Parts in contact with food, drinking water or high temperatures need specific materials and sometimes a different manufacturing method. So always tell us where the part sits and what it is exposed to. A knob on a cooker and a knob on a radio may look the same but need completely different materials.
Trial fit before the final files are delivered
The fit is always checked in the real world before the final files are delivered. We print a test part, you try it in place and tell us where it binds or is loose. The adjustment is made in the model, not by filing the part, so the next one is right first time.
This is also the stage where threads and press fits are confirmed. An M5 thread in plastic often holds better with a brass threaded insert than when cut directly into the material. As the customer, you are responsible for having the right to copy the part; a replacement part for your own machine is normally not a problem. Parts where almost no dimensions are known and the whole function has to be interpreted are handled as reverse engineering.
Measuring methods and typical accuracy
| Method | Use and guide value |
|---|---|
| Digital calliper | External, internal and depth dimensions – approx. ±0.02–0.05 mm depending on surface and technique |
| Outside micrometer | Shafts and pins – approx. ±0.005 mm |
| Thread gauge and major diameter | Metric thread to ISO 261 / ISO 68-1 or imperial thread |
| Radius gauge | Radii from approx. 1 to 25 mm |
| Photo against a grid, straight from above | Outlines and freeform shapes – approx. ±0.3–1 mm |
| Impression in modelling clay or a casting | Internal shapes the calliper cannot reach |
| Worn hole or worn shaft | Measure at the least worn point, round to the likely nominal size |
| Clearance in a printed sliding fit | approx. 0.2–0.4 mm on the diameter |
Guide values. Accuracy depends on the condition of the sample and how easily the surfaces can be reached.
What we need from you
- The broken part or all the pieces of it
- Photos straight from the front and side with a ruler or calliper in the picture
- Markings on the part: part number, material code (e.g. >PA6-GF30<) and manufacturer
- Make, model and year of the machine
- Dimensions of mating parts: the shaft, hole or screw the part sits on
- Where and how the part broke and how it is loaded
- Quantity and environment: outdoors, heat, moisture or food contact
Typical projects
- Latch and wheel for a dishwasher basket
- Knobs and buttons for a cooker and oven
- Gearbox gear for a kitchen machine
- Hinges for lids and doors
- Cracked bracket for a lamp or sensor
- Wheels and runners for a chest of drawers
- Housing for a power tool
- Lever and handle for farm implements
- Spacer and bushing for an older machine
- Clips and holders for a caravan
What affects price and lead time
- How complex the shape is – flat faces are quicker than freeform shapes
- Whether the sample is intact or has to be reconstructed from pieces
- Number of critical fits, threads and snap fits
- Whether you need a workshop drawing in addition to the 3D model
- Number of trial fits before the shape is approved
- Whether the part is to be reinforced or redesigned
What you get
- 3D model in STEP (editable) and STL or 3MF
- Parametric native file from Autodesk Fusion on request
- PDF drawing with critical dimensions and tolerances for a workshop
- Test print for a trial fit
- Finished 3D-printed parts in the chosen material (optional)
- Short description of reinforcements and material choice
Frequently asked questions
Can a spare part be made without a drawing?
Yes. Most plastic parts and simpler metal parts can be measured and remodelled in CAD. We need the part, its pieces or good photos with dimensions. The part can then be made by 3D printing, CNC machining or injection moulding.
Do I have to send you the part?
Not always. For simple parts, photos with a calliper in the picture and a few extra dimensions are often enough. For tight fits, gears and freeform shapes it is safest to send the part, and we return it after measuring.
Will the new part be as strong as the original?
Often stronger. We analyse why the original failed and reinforce exactly that area with radii, thicker walls or ribs. The material is chosen for load, temperature and environment.
What if the part does not fit first time?
That is why we make a test print. You try it and describe the deviation, and we adjust the model. The final files are only delivered once the fit is right.
Am I allowed to copy a manufacturer's spare part?
Making a replacement part for your own machine is normally not a problem. As the customer, you are responsible for having the right to copy the part, especially if it is to be resold. We do not recreate trademarks or logos.
How small can the parts you measure be?
Details down to a few millimetres can be measured with a micrometer and magnifier. Very fine features, such as fins thinner than 0.5 mm, may need to be simplified to be manufacturable.