Like Jack, I have had good luck with Berea. Good service, good kits.

Also, I have used crafts supplies for years:

http://www.woodturnerscatalog.com/st...n_Making?Args=

While you shouldn't need to buy a new mandrel, make sure you buy new
bushings with the kits. Many kits offered from manufacturers look the
same, but aren't close enough to use parts universally.

If you are interested in close tolerances, use the bushings from each
vendor and keep them separate from one another in a zip lock back or
similar.

Robert