Founded over 40 years ago, Stroud-based Howdon Power Transmission Ltd (HPT — www.howdon.co.uk) is the originator of the ‘Wedge Pin’ system for mechanical overload protection; patented in 1978, it remains central to the company’s range of Wedgegard torque limiters; and with such a well-established product, it could be expected that the company’s R&D activity was minimal, but that is far from the case, with new applications arising on a regular basis and frequent product updates taking place.

The Wedge Pin is effectively a ‘mechanical fuse’, designed to act as a weak link when a certain torque is reached, thereby preventing serious damage to rotary power transmission systems.

While production of the standard part is undertaken by long-term sub-contract partners, HPT needed greater flexibility and versatility when it came to machining for R&D, as well as low-volume production to meet urgent demand for bespoke Wedge Pins for particular applications.

Company founder and managing director Howard Miles said: “Our products cover a wide range of applications — from steel mills through food production to on-vehicle installations — and we are constantly looking to develop the design; and while sub-contract manufacture for production is ideal for us, we needed to react faster when it came to product development and testing.”

The search for suitable machine tools led to Burlescombe-based XYZ Machine Tools (www.xyzmachinetools.com) — just down the M5 motorway — where HPT had a demonstration of an XYZ SLX 1630 ProTurn lathe.

Works manager Neil Hussey was won over by the ProtoTrak control and its ease of use, which lends itself to the one-off and low-volume machining that he had in mind.

He said: “The ProtoTrak control is ideal for our needs. I can quickly generate programs at the machine from initial sketches of a part, while the ‘Traking and Verify’ capability of the control gives me the confidence that the first-off will be correct — without any fear of collisions when the cycle start button is pressed.”

Prismatic machining
With turning capacity taken care of, HPT’s attention switched to milling capability; and given the size and type of work undertaken by the company, the machine chosen was an XYZ 1000 LR vertical machining centre.

This features linear rail technology for axis travel, providing a lower-cost introduction to machining-centre ownership, although price was not a major consideration for HPT.

Mr Miles said: “Performance and specification were our main priorities when choosing a machining centre. We also wanted the security of local support and training, which we get from XYZ Machine Tools.

Mr Hussey had one day of training at XYZ, and we still have two days of free training left, which we will undertake on-site here when we need it. So far, we are managing to achieve everything we want with the machines and knowledge that we have.”

Backing up HPT’s decision to go for XYZ 1000 LR is the machine’s specification and performance. As standard, it features a 13kW 8,000rev/min spindle, a work envelope of 1,000 x 500 x 500mm and a 1,060 x 500mm table.

Also specified was the option of a fourth-axis unit, to increase versatility and productivity, along with a 24-position arm-type tool magazine.

Mr Hussey said: “It seemed like a sensible option to specify. We have a machining centre that is quick to program and set up, so to be constantly changing tools would be time-consuming. Keeping the magazine full with a variety of tools makes change-overs even quicker.”

HPT has a world-wide customer base, with significant sales in the USA, Africa and mainland Europe, as well as the UK.

Marketing and sales manager Chris Issac concluded: “As a member of the Made in Britain organisation, Howdon Power Transmission is rightly proud of the fact that its products go to customers around the world.

“Our brand is well-known, thanks to its longevity, but we are aware that we need to keep innovating and developing our products. Having this in-house machining capability enhances our ability to do that, by shortening the time to market for new ideas and bespoke offerings for customers.”