Mr Lupton's Econ Engineering was doing so well that he could invest pounds 500,000 in a factory on the edge of Ripon in North Yorkshire.
It seemed a worthwhile risk, despite the change of government in 1979. "I anticipated the boom ending," he recalls. "The price we were selling at couldn't go on. We expected the market to shrink, but not to stop dead altogether."
The date when Sir Geoffrey Howe swung his axe and cut deep into local council spending is etched into the Lupton memory. "On 14 March 1981 we had pounds 1,280,000 of spreaders on quote. By the end of the month we were down to pounds 200,000."
When the factory finally opened it was staffed by just three people. The workforce had shrunk from 115 to 35 within a month. "This was a team I'd built up over 11 years. I knew them all by Christian name. Making so many of them redundant did not make me very popular. I had no idea what I was going to do with the building, but when you're in a position like that you can either defend or attack."
His rivals were also suffering from the savage cuts in public spending. The market leader, Atkinson's of Clitheroe, Lancashire, a subsidiary of Cammel Laird, was losing pounds 10,000 a month. Mr Lupton contacted the group chairman and persuaded him to sell Atkinson's for less than half price.
He gambled on a slow revival in the market that duly arrived when local authorities began to realise that slashing vehicle replacement programmes was a false economy. Econ Engineering now employs 137 people, has a turnover of pounds 5.5m and supplies 85 per cent of the salt spreaders used on British roads.
They are now very much the core of a business that began when this son of a Wharfedale farmer developed a mechanical hedge flailer 40 years ago. He was 19.
Modified agricultural spreaders were largely used to grit the roads until 1970, when Mr Lupton developed a purpose-built device that would spread the salt more accurately. "We started with the slogan 'Don't grit the gutter'," he says.
Always a keen student of political trends, he was ready to exploit the local government reorganisation of 1974 and the massive growth in spending that went with it.
Local government is considerably more cost-conscious in 1996. Road gritting in many areas has been sub-contracted to companies determined to account for almost every grain of salt.
Ten years ago it was spread at the rate of 40 grams a square metre. Now it is down to less than 20 grams and the target is even lower.
Accuracy is the key, and for that Mr Lupton had to invest heavily in state-of-the-art technology. Money from the sale of his other factories in the late 1980s property boom has come in very handy. "This is a business with low unit sales," he explains, "but there's profit in servicing parts and technological development."
A key development in recent times has been the installation in the driver's cab of a sensor, called SCAM, which monitors salt output. Technology originally designed to guide Cruise missiles and rockets has been adapted for use on cold roads.
One way or another, cuts have played a big part in the development of Econ Engineering: local authority cuts at the beginning of the 1980s and military cuts at the end. For motorists at least, the company's products have helped to keep some of the discontent out of winter.