Do any of you machinists out there know if the common morse taper end mill holders are bored all the way through at the diameter of the bore that accepts the end mill? For instance, does a 3/8 end mill holder have a 3/8 bore all the way through. I'm looking for a way to make mandrels similar to the pen mandrels where the shaft slides through the morse taper and locks down at any length with a set screw.
Thanks

It sounds like you're looking for a collet chuck. They are open on both ends and available in several sizes.

All the universal morse taper pieces (eg. for jacobs chucks and pen mandels) I have seen are not bored through. They are tapped for threads only an inch or so back.

Christian

yep! I looked at my pen mandrels and they are not bored all the way through and have a set screw to attach the mandrel to the taper. I am having some mandrels made as we speak that are 1/4",3/8, 1/2 and taper .030 from front to back over the 12" length so that the wood can lock up tight onto the mandrel with our spinning on the mandrel. I let everyone know how it Works. I'm affraid that .030 is to much taper and I'll have to have it cut down to .015.