I almost always turn the power switch on, then tension the countershaft belt. Been doing it for about 15 years and have never encountered a problem. Slipping the belt is also handy when power tapping. Just be safe.
Matt
Slipping & tensioning the belt on a running motor to get efficient drive on the lathe used to be the norm when the load of a dead lathe was applied as it reduced the consumption power surge/spikes .......... that is now a thing of the long gone past due to injuries sustained .
Years ago I was in the British armed forces and was ordered to become the workshop safety guy as we had over a hundred mechanics electricians and metal workers at play daily . I had to go on endless health and safety at work ( HASAW courses ) .
One of the two day courses was at the nations Safety Inspectorate Institute facility that promulgated & enforced the factories and work place safety laws act of 1921 . They had a 100 x 200 foot black museum that held the bits of machinery etc. that caused fatalities. There were several small lathes in the hall that had pulled someone into the lathe , killed them or seriously injured them .
When you think about it Matt you are leaning over something that is going to be rotating and likely to pull in any loose clothing or you if you stumble /trip as you reach forward over the rotating parts.
Having the belts tensioned on a dead motor won't ever allow that to happen however remote you may think the chances are for you doing as you currently do.
.
Plus if like most people you have the stop start switch on the right hand side of the lathe you'll be out of line if anything flys off the lathe shafts, tool posts or off the chuck when you start it up . Heavy flying chuck keys & parts of the lathe coming out the chuck or off the tool post area at start up were part of the lethal items display .
Please reconsider what your doing , so that when you eventually die you have all the bits you came into the word with instead of having parts missing on the way out.
