I came across something like this recently. A friend called with a sprindle from a bench drilling machine and asked me to check as he was sure it was bent. I checked it Ok but when he reassembled the machine and fitted a chuck with a drill, there was a definate “throw” at the tip of the drill. My immediate and totally wrong impression was that someone had used a hammer to remove the chuck.
Another friend with more experience than me, removed the chuck and as best he could, cleaned out the taper socket in the drilling machine sprindle resulting in a much improved performance. When I saw this, I went into my tool store and extracted a No 2 MT reamer. Using hand pressure only, the bore was cleaned in seconds. The macnine now works well.
Never too old to learn.
Hope this is of some help.
Ray