Another statue by our local artist, Jason Thompson. The pieces are manufactured in iron using patterns of polystyrene. The statue is now situated at Tittesworth Reservoir, Meerbrook, Staffordshire. The commission was for Severn Trent Water as a centre piece to their educational centre.
H. Downs & Sons in more than a decade. The decline of the foundry industry over this period has forced the company to continually seek new customers and areas of promoting casting sales.
To expand the services and quality required by our customers, we first introduced computers to ‘track’ pattern equipment and production in 1992. Computers have helped on the design and technical side of production for the last 10 years.
Although technical information and drawings can be zipped over the Internet we can still experience problems with certain file extensions to drawings and often ask to adopt the KISS approach. We now ask for files to be sent in .jpeg .gif .tif or as a .pdf file to make sure we can open the drawings first time.
Six years ago Nigel Downs started our first Internet site through his interest in photography and computers. Statistics for the web site are quite impressive, the company doesn’t sell its own product and has to rely on new customers to replenish those that fade away. Therefore information to the customer is paramount.
The site is visited on average 71 times per day with the average visit lasting over 10 minutes. 15% of the traffic comes through the main index page; the remainder is generated through search engines such as Google, Yahoo, Microsoft and Alta Vista.
Feedback from the site produces at least one new company enquiry per week. Ratio of 500:1. More than 20% of viewers revisit the site looking at details of production, Art and the Ironbridge programme, which we worked in conjunction with the BBC’s Time Watch.
Pattern making is one of the most complicated areas in the production of castings, with several areas littered with pitfalls for the unwary.
First question is, how is it going to be made?
When this is decided a setout is drawn of the x-section of the casting, to this is added the contraction ratio. In the case of iron we have a contraction of 1:100; Steel is 1:60. So for each material the size of the pattern has to vary, the iron pattern 100 mm long has to be made 101 mm so it shrinks back to 100 mm. The pattern makers use special rulers with the contraction already built in, so if they measure 100 mm off the rule, the actual size in reality is 101 mm.
Next comes the machining allowance, this is drawn on to the set-out allowing 3-4 mm on castings with 250 mm dimensions and up to 20-25 mm on some of the larger castings This is to ensure any floating material within the casting will be machined out.
The bottom of a casting is generally cleaner than the top so there is less allowance on the bottom.
How are we going to core it out to put the holes in?, Do we have to split the pattern? What material are we making it from, a one off polystyrene, wood or repeatable resin?
Only when all these questions are answered do we continue. The pattern maker has to think backwards and upside down, in negative and yet still be positive.
Ni-Resist bar stock
One of our less frequent materials melted, owing to the cost of melting a small batch, is Ni–resist, a material described as a stainless iron with a chrome content of 1.5-2% and Nickel in the 18-22% range.
This iron has a good resistance to heat and corrosion. The company decided to stock various diameters from 25 mm to 150 mm in lengths of 300 mm as the delivery time can often be as long as 4-5 weeks.
By investing in stock we are now able to offer most sizes in this diameter range as an off the shelf option for those customers requiring breakdown material, which was wanted yesterday!!
Each bar, on one end, has cast identification of the bar size and the material, which is BS3468 Grade S2. Chemical and mechanical certification is also available for each bar.