Olds R20 single bore slide mod

JoshE · by **JoshE** » 2025-03-09 11:02 a.m.

Hi all, has anybody here experimented with a single bore slide on an Olds R-20? Possibly a .508" slide. I love the my R-20 , but the slots can be squirrely and very wide. Are there any slide sections out there that might pair well?

I have an A-20 and R-20 and everything is interchangeable, and for this discussion specifically the hand slide/tenon. Is it reasonable that a good tech could take the tenon from the the A-20, pair it with another slide, and get good results?

Thanks!

Posaunus · by **Posaunus** » 2025-03-10 2:52 a.m.

The R-20 (Recording w/ F-attachment) is dual-bore 0.495" / 0.510".

What single-bore diameter would you like to use? 0.508"?

JoshE · by **JoshE** » 2025-03-11 11:15 a.m.

I am thinking a 0.508" slide, but if anybody's tried anything else I'd like to hear their thoughts

UrbanaDave · by **UrbanaDave** » 2025-06-13 6:34 a.m.

While I think Olds made some single bore slides, I'm thinking the tenon might not be interchangeable. Also, the slide width may not be as wide as on the R-15/20. Did you ever move forward with this? I've wondered the same about my R-15. Maybe JohnL can share some thoughts?

Doug_Elliott · by **Doug_Elliott** » 2025-06-13 11:44 a.m.

I developed a backbore for my mouthpieces that makes the dual bore feel more like a single bore and takes care the "slots can be squirrely and very wide" situation.

UrbanaDave · 2025-06-13 4:23 p.m.

Thanks for sharing this, Doug! I've been using your D2.5 Olds shank w with your c+ cup on my 485/500 Olds horns and your D3.0 Olds shank w your D cup on my R-15/R-20 495/510. Are those shank/slide match ups in line with what you had in mind when you designed them? Glad this strand was here. Not meaning to hijack it, but I did want to ask you that.

Doug_Elliott · by **Doug_Elliott** » 2025-06-13 5:19 p.m.

I would expect the 2.5 to be best on both of those horns.

However,

With the various slide bore sizes in that range, and .508 and .509, it can be a fine line between too tight, just right, and too open.

UrbanaDave · by **UrbanaDave** » 2025-06-13 6:45 p.m.

Good to know. Thanks!

JohnL · by **JohnL** » 2025-06-14 2:38 a.m.

Olds built some single-bore .500" slides with tenons that will fit a Recording, but they're uncommon models.

Should you wish to pursue having a single-bore slide built, I'd suggest King 3B parts (inners and outers; maybe the end crook, too.

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Olds R20 single bore slide mod