Hempstead & Johnson Ltd
Specialist Machining Services
We offer a comprehensive range of CNC turning and CNC milling services for both one-off prototypes and bulk production
We have over 30 years’ experience in precision CNC machining
We are one of the UK’s long-standing providers of specialist machining services. Our factory in Buckinghamshire is equipped with the latest in CNC technology to provide quick turnaround of both small or large quantities of precision machined components.
H&J offer the following CNC and conventional services:
- CNC Turning
- CNC Milling
- Conventional Milling
- Conventional Turning
- Vertical Boring
We constantly update services to keep abreast of recent advances in material development and specialise in the machining of:
- Silicon carbide and nitride
- Advanced zirconia ceramics
- Carbon fibre
- Metal matrix composites
- Single sapphire crystal.
Ceramic components are commonly used within the aircraft and defence industries for bearings, seals, and laser boxes for guidance systems.
Common Ceramic Materials Ground
- Zirconium (Extremely hard)
- Aluminium Oxide (Soft)
- Technox 300 (Soft)
If you need a close tolerance on your ceramic parts, this comes as standard. Using a metal-bonded diamond wheel that we dress carefully, close tolerances of +/- 0.005 mm can be achieved.
We also use plated Diamond wheels (mainly used for bores) with a minimum bore diameter of 1mm.
We can cut internal and external threads and drill ceramics.
We can dress resinoid diamond wheels of various grades to achieve high finishes – mainly used on carbides (Tungsten) and extremely hard grade ceramics. Up to 350 mm diameter material can be handled and in square form up to 400 mm.
Past customers have included Marconi Engineering, ENV Engineering and British Aerospace.
H&J offer precision CNC milling and turning. As well as working to conventional drawings, we can work with DXF, IGES and PDF files, sent either by e-mail or supplied on disc.
We work with various materials, including steel, aluminium, brass, copper, plastic, and exotics, such as titanium and gunmetal.
Our strength is our experience of working with different materials in many diverse industries. We also source welding, fabrication and finishing, enabling us to offer you a complete service.
We also specialise in taking cast components and finish machining all surfaces to tight tolerances and surface finish requirements.
We work with many tough materials such as tungsten carbide, HSS tool steel and hardened steel to produce components that require high tolerances and accuracy.
We are able to achieve these tight tolerances on small parts working by having a highly skilled workforce with over 30 years of experience in precision engineering.
We machine to customers drawings and designs, with either free issue supplied components, or we supply part complete
Current we are able to produce small units and both volume of established components.
We are also happy to work with engineers and customers to produce one-off samples for R&D development and prototypes.
We have a range of precision measuring equipment including CMM.
C of C is produced when required.
We work with a large range of industries some of which include, automotive aftermarket and components, global process industries, secondary process machinery, air compressors, filtration equipment and various types of mechanical seals.
We have a range of partners who we have relationships with over the past 20 years and work with and are able to provide the following seamless SUBCON for your components:
- EDM, Wire eroding and Sparking
- Chemi Black, Magnesium Phosphate
- Fine grinding
- Fine diamond toolmaking
Prices are based on individual requirements.
Don’t throw away your old cutters and special drills. Let us give them a new lease of life and save you time and money.
We pride ourselves on our ability to recover and refurbish tools that are considered too damaged or worn to be of any further use. The cost savings are significant over purchasing new tools.
The tools operate exactly as if they were the original item at a fraction of the cost. You get your machines up and running quickly, and you save on inventory.
We can refurbish the following types of drills and cutters.
- End mills
- Special cutters
- Slitting Cutters
- Plus, many more
- Regrinds on standard and special cutters.
- Manufacture of specialist drills, reamers, and cutters.
- Full heat treatment – hardening, normalising and tempering
- Specialist grinding of sub-assemblies
- Power steering sleeves and pinions for the motor industry.
Need More Information?
For a free quote, or to find out more about any of our precision engineering services, call us now on 01494 444971, or