Is it OK to have tool installed during spindle warm up?

The Pro-Tip video offered by Avid says No. But the prompt in Mach4 implies it is OK. Can someone offer expertise? If I have a tool installed, would it be wise to warm it up manually at very low RPMs first? Does tool size matter? I have the 4HP spindle. Thanks.

I try to avoid having a tool in the spindle whenever anything is heating or cooling, as I’ve had them lock themselves into the spindle before. Especially for ATC spindles, where the drawbar will draw the tool even further into the spindle if it can as the tool or spindle change diameter.

Noted and thanks for the reply.

I think it depends on your spindle.

I read the manual for my HITECO QD-1F and it says:

“Warm up cycle must be executed with inserted toolholder but without any tool and without performing any machining process.”

Despite that, I don’t want to have an empty tool holder dedicated to warm up, so I just warm it up with a tool and tool holder in it. I use a small bit, not a fatty 2" surfacing bit.