B&B Precision_ hard part turning soft state prep

Here’s our advice on preparing your components in their soft state in order to get the best possible results in Hard Part Turning.

Right Parts for HPT?

To begin, it’s always important to make sure your parts are actually suited to Hard Part Turning. We’ve found that size and geometry do play a big role in the outcome of a finish and would advise that parts need to have a small length-to-diameter (L/D) ratio of no more than 4:1.

Consistency of Material

Reducing the stress on your tools is key, so while your materials are in their soft state it’s key to ensure that the sizing and consistency will match throughout. Although there is a range of materials that can be turned, one made of 59HRc will certainly machine differently to one at 62HRc. B&B would advise that even where variation is allowed, you should avoid it in order to boost effectiveness. It’s also important during soft stage to chamfer holes, keyways and slots.


As with any machining, consistency is one of the key factors that we look to achieve. With Hard Part Turning it’s important during the soft state prep to first perform soft machining. This will minimize surface imperfections, allow for a completely dry Hard Part Turning and also stabilise hardening effects.


The aim for during the soft state prep for Hard Part Turning is to avoid burrs, don’t enter or leave your cut abruptly, and try to ensure you keep close dimensional tolerances.

Out Of Your Capability?

Of course, if all of this sounds like too much trouble you could always sub-contract your Hard Part Turning to B&B Precision. We have dedicated machines manned by our team and remain massively cost effective in a competitive environment. We can handle every step of production from sourcing the material, to prepping it for HPT, right down to delivering it to your front door. Contact us by emailing mail@bandbprecision.co.uk or call 01484866386


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