This photo from the Mary Rose Museum shows four bobbins recovered from the ship. Made of ash, willow, alder and Scots pine, at least one may have been decorated with paint. All have three collars, one at either end, plus one positioned centrally, and are hollow with one solid end. Three were found with the original stopper. Unfortunately, no thread was found. I’ve covered my reproduction of the one in the front left here.
This one’s my interpretation in an arbitrary pale hardwood, hemp string and a veg-tanned leather pouch to stop the chalk dust getting over everything. It works brilliantly.
Here’s another example by Peter Follansbee.