Edwards MBDN 525"/.547" slide converted to .547"

[LarryPrestonRoberson]

I'm looking at the MBDN Edwards .525"/.547" dual-bore tenor trombone slide. I can purchase one at a very reasonable price. But it is non-returnable and of course there is a chance I may not like it. So, would it be a fairly straight-forward modification to convert it to a single bore .547" slide? In that case, the end goal would be to end up with the equivalent of a T-STDN. Again, it is available at a very favorable price. And by my reckoning, with parts and labor, it would still be more economical than purchasing a new Edwards .547" slide out-right.

Does the .525"/.547" dual bore slide share some of the same components with the medium (.525") and large bore slides (.547"), particularly the T-STDN? I'm specifically curious about the hand-grips/cork barrels, threaded lead-pipe receiver, and end crook. If so, it seems like it would just be a matter of swapping the upper (mouthpiece side) inner and outer tubes. I have asked Edwards about the shared components, but I'm awaiting a reply.

[bimmerman]

I can help! I have this slide, a STD, a .525-N, and once upon a time had a BCN.

Before altering one of these, I think I know where you're looking. Are the standard slides also available?

The .525 and .525/547 slides both use the .547 STD crook (not the bass crook). The leadpipe receiver is the same, and I believe the cork barrel is too. I have cut a .547 pipe down to use with the .525 side of the slide, and it does physically work, so that leads me to think you can just replace the slide tubes and get away with it.

That said....you have to cut the .547 pipe REALLY short, so there may be some other restriction there. I can take some calipers to the OD/IDs and confirm with science, but I am pretty sure the dual bore slide is just a .547 STDN with a .525 inner/outer tubes on the upper leg.

As another check, my .525 pipes thread into the .547 receiver just fine.

[LarryPrestonRoberson]

I can help!

You have—immensely so far.

The .525 and .525/547 slides both use the .547 STD crook (not the bass crook). The leadpipe receiver is the same...
As another check, my .525 pipes thread into the .547 receiver just fine.

These are critical pieces of information. Thanks!

and I believe the cork barrel is too...
I can take some calipers to the OD/IDs and confirm with science, but I am pretty sure the dual bore slide is just a .547 STDN with a .525 inner/outer tubes on the upper leg.

This is my suspicion as well. But if it isn't too much trouble I would appreciate confirmation.

Before altering one of these, I think I know where you're looking. Are the standard slides also available?

Yes, that is whay I am researching very carefully first. And you probably know where I'm looking. I don't see any T-STD or T-STDN on sale. But yes, they are available at full price with the wait time.

that leads me to think you can just replace the slide tubes and get away with it.

That is my hope. I really appreciate your help!

[bimmerman]

and I believe the cork barrel is too...
I can take some calipers to the OD/IDs and confirm with science, but I am pretty sure the dual bore slide is just a .547 STDN with a .525 inner/outer tubes on the upper leg.

This is my suspicion as well. But if it isn't too much trouble I would appreciate confirmation.

I couldn't find my calipers, but with a marked length of string, the circumferences of the .525 and .547 slide receiver parts are identical. My unaltered .547 pipes seem to bottom out where the .525 inner tube begins, which makes sense, while the .547 pipe that is trimmed to fit (basically, truncated somewhere before the taper venturi, maybe at) will go in just fine.

One interesting tidbit-- my father has the same .525/547 slide. On his, the inner tube is .522. On mine, it's ~.525--he actually measured his with internal micrometers, mine fits the cut down leadpipe better so I am assuming it's a larger ID.