Disasemble the damper from your flu. Before reassembly add a washer to the outside where you first enter thru the pipe and put it on the turn stem. Then do the same internally on both ends to where there is no room for the damper to be able to move in either direction along the stem. Then on the stem outside at the pointed end add a 1/4 inch fat ringed washer with locking screw that has a allen key locking screw to lock the stem into place. This will not allow the stem to be moved in or out which means it will not be able to move horizontally as the washers internally fill all the extra space along the stem and the one outside in the beginning with the locking nut fat washer (not sure what to call it) . This has allowed me to exactly control the stem and damper with no wobble at all and that really helps to save on wood burning too fast due to wobbly dampers.
This is what you need to buy to be able to tighten up the center shaft of the damper with at the outside end . This picture though shows a bearing but it is really just a solid round fat washer with a locking key allen set screw. This was the closest thing i could find.
You will love how the control over the damper is exactly 100% unlike how normally heat alters the damper and makes it wobbly internally
Note: push the stem thru as tight as you can so that the damper is totally locked in place. Then tighten the locking fat washer with the locking screw with allen wrench. You may need to add two washers first before it goes thru the damper part and one at the end internally or one first and two after the damper internally. The point is to lock the damper in place so it can't move one fraction of an inch internally along the shaft / stem.
in west virginia now in a small town martinsburg growing lots of veggies.. thank you Jesus
PS: always seeking followers of Jesus