Holton Trumpet Serial Number Chart ((TOP))
Vintage and used trombones can usually be dated by serial number. Trombones will have the serial number either on the back of the hand slide or on the neck receiver where it attaches to the handslide. Sometimes the serial number will be on both the handslide and the neck receiver. Vintage King Trombones, H.N. White Era will often have the serial number on the tuning slide, but not always. Here is what we have seen at our shop by brand/maker:
Holton Trumpet Serial Number Chart
Conn (before 1970) Handslide Tennon below threads, outer handslide (lower outer tube at the top in back), No serial on Bell section, but model number is on bell. You can find more helpful information on the Conn Loyalist Website
This are the most commonly seen vintage brands, obviously not a complete list. We do keep an archive of sold instruments on our website here and try to photograph the serial numbers. Here is a link to the archive of previously sold trombones on our website. -exchange.com/archive-of-sold
All other data is highly suspect: there are no existing Kohlert serial number charts. Keeping this in mind, I'd say this chart is accurate by no more than +- 5 years, except for the years I just indicated.