I've played Conn valve trombones (based on 6H), I own an Olds (basically, the same valveset as the "marching trombone" with an 8 inch yellow brass bell (with fairly fancy engraving) - NOT the same bell as Ambassador, Special, Super, or Recording.
note: VERY FEW Olds small-shank trombones feature 8-inch bells. Most are 7-1/2 inch with the "Recording" typically being (though small shank) 8-1/2 inch.
I had previously never played a King.
I've heard (??) that some of the Kings were 2B-based and some were 3B-based.
This one seems to be a 3B-based bell section with a 2B-based (.480" bore) valve section.
The 3rd piston was dragging (which is why it was brought in).
I never quite figured out what was wrong (other than it was NOT the casing) so I continued to take out scuff marks on the piston (spots that were NOT simply vertical contact lines, but individual spots) with 1000 grit (followed up by 1500 grit) oiled paper UNTIL (finally) the piston stopped dragging (VERY subtle removal of material).
The guides also were flopping around (failing to make the next 90 degrees for tightness) so I took a needle file to the #3 guide track in the casing (just in "case" the corner of the guide was dragging against a rough track edge).
I suggested removing all oil residue and putting thread glue on the guide threads (obviously, with the guide oriented properly) but I preferred to NOT do that myself, as I wanted him to walk out with the piston NOT dragging (as opposed to telling him to "wait for the glue to dry").
Anyway, It's not dragging now, and still offers a nice suction or compression release (again: EXTREMELY subtle removal of material).
I don't like pissy-@$$ jobs like this (whereby something is "almost" right, but one has to continue to dick with it).
oh yeah:
My F. E. Olds and Son (original gleaming lacquer and original NICE case WITH playing slide also on board AND original brochure included) is a better instrument.
Also...I was going to undo his 3-piece King balancer for him. (They went back to the original style.)
I wrapped the knurled/threaded ring with a thick washcloth and tapped it with a rubber mallet.
Guess what? Freakin' nickel plating chipped off.
I have a vintage (same style) King balancer (from the 1960's...H. N. White era), and demonstrated for him me whacking on that same knurling with a STEEL dent hammer (no marks, and no damage to the nickel).
On his that nickel plated over yellow brass with NO COPPER STRIKE...so the nickel plating is just "hanging there".
...so many compromises in their final era of production (though a bit of fancy engraving added, here and there, along with a few fancy-@$$ cases).
I TESTED a (student model 606 .500" bore) playing slide on it. It was slightly too large, but - YET - DID bolt up ok, and the threaded DID engage.
I suspect that a 2B (OR VERY OLD student model 605, which was more like a 2B, whereas the 606 is a bit more like 3B) slide would have fit that bell section's receiver perfectly.


