In an early, simple hay tedder described in 1852 and manufactured in Edinburgh by the company of Mr. Slight, the two wheels, via a spur wheel and a pinion, drive a set of light wheels, the rake wheels; on these two rake wheels are mounted eight rakes, which pick up and disperse the hay.
It should be noted, how-ever, that only about 1 out of every 10 STEM workers has a high school diploma or less. Those with gradu-ate degrees in a STEM job earned more than $40 per hour, nearly $4.50 more per hour on average than those with non-STEM jobs.
Comparison with employment group. The 2016 full-time average hourly wage rate for industrial, electrical and construction trades, which includes sheet metal workers, is $28.00. The 2016 corresponding median weekly wage rate is $1,125, giving an approximate full-time annual salary for this employment group of $58,500. There are over 40,000 sheet metal workers working in Canada.