Probably a dumb question but ...

[sacfxdx]

Do leadpipes actually touch the slide inners? So all leadpipes for a given bore would have the same end diameter?

I have a XO 1240 bass that advertises a .571 bore (through the values?). I was wondering if .562 pipes would work in my horn. If anyone has specific knowledge about XO 1240s that would be appreciated.

Thanks

[hyperbolica]

Even though it has the bigger diameter in the valve tubing, it has the same 562 in at least the top slide where the leadpipe goes. Yes, the end of the leadpipe does or should touch the inside of the top inner slide tube. And yes, other 562 leadpipes should fit your horn - that is, aside from the threads on the end, those fall into a couple of specs. Not sure which one XO uses.

[Doug Elliott]

Many leadpipes are actually smaller by a few thousandths, partly because the slide tubes aren't always a consistent bore size all the way to the end. That's not a good thing, but it's the way it is.

[Kingfan]

Not a dumb question - better to ask now than to make a mistake later. I Googled your horn model and found some sites say it is .562 bore at the slides, some say .571. Have your local instrument tech check for sure. If you don't have somebody nearby or they are not open right now, see if you can borrow one or get a cheap one from a place like Harbor Freight or eBay. You can get one for as little as $7 plus tax https://www.ebay.com/itm/US-6-150mm-LCD ... E&LH_BIN=1
Good luck!

[sacfxdx]

Thanks for the replies. The XO has a weird arrangement for the lead pipe threads and nut.

[Kingfan]

Thanks for the replies. The XO has a weird arrangement for the lead pipe threads and nut.

That shouldn't stop you from measuring the crook end of the inner slide. That's how I verified my bass had a .562 bore.

[hornbuilder]

Doug is correct that pipes are a couple thou. smaller than the nominal slide bore. If the slide tube is .562", a pipe that is .562 is going to be pretty tight, so @ .560 or smaller is common.

Another thing to consider is that solder is eutectic. ie, it shrinks when it cools. So, while the slide tube may be .562, the area where it solders into the cork barrels may be slightly smaller.

Finally, the vast majority of leapipes are tapered on the inside "and" the outside, so, only the very end of the pipe touches the inner tube. There are a couple of makers (Yamaha and Monette that I know of) make some pipes that are cylindrical in the outside. These will obviously "fit" more of the inner slide.

[baileyman]

With a round taper like lots of drifts, or the tail end of some body hammers, or maybe a tuba mouthpiece shank(?), you could flare a loose pipe to snug it up. Insert the taper and twist back and forth a bit and try. I have heard some will wrap the end with plumber's tape. Similarly you can shrink a tight fit by rubbing the end long-wise against a flat hard surface while rotating the pipe. These things ain't sacred.

[jjenkins]

Thanks for the replies. The XO has a weird arrangement for the lead pipe threads and nut.

Not weird, just not as common as most one-piece leadpipes. The XO trombones use two-piece construction leadpipes similar to King trombones, except threaded.

[LeTromboniste]

Not a dumb question - better to ask now than to make a mistake later. I Googled your horn model and found some sites say it is .562 bore at the slides, some say .571. Have your local instrument tech check for sure. If you don't have somebody nearby or they are not open right now, see if you can borrow one or get a cheap one from a place like Harbor Freight or eBay. You can get one for as little as $7 plus tax https://www.ebay.com/itm/US-6-150mm-LCD ... E&LH_BIN=1
Good luck!

With a .01 resolution and ±.01 accuracy, those are pretty useless for accurate measurements.

[JohnL]

.01"/.1 mm? Phooey on that.

You can buy a stainless steel digital caliper from Harbor Freight for less than $20 that'll do +/- 0.001 in. or 0.03mm.

[timothy42b]

Not a dumb question - better to ask now than to make a mistake later. I Googled your horn model and found some sites say it is .562 bore at the slides, some say .571. Have your local instrument tech check for sure. If you don't have somebody nearby or they are not open right now, see if you can borrow one or get a cheap one from a place like Harbor Freight or eBay. You can get one for as little as $7 plus tax https://www.ebay.com/itm/US-6-150mm-LCD ... E&LH_BIN=1
Good luck!

With a .01 resolution and ±.01 accuracy, those are pretty useless for accurate measurements.

If a slide were perfectly round I'd think that might be a problem.

A slide ID might very well vary .05 depending on which chord you measured it.

[JohnL]

If a slide were perfectly round I'd think that might be a problem.

A slide ID might very well vary .05 depending on which chord you measured it.

Maybe .005" (~.13 mm), but .05" (~1.3 mm)? You could have the slide measure anywhere from .500" - .547" and still have room to spare.

OOH! The multi-bore trombone! Draw the inners with an oval cross-section on the ID - .500" in one direction and .562" in the other direction. The best of both worlds! From smallish tenor to a bass in one horn! Make the rest of the horn the same way (including oval ports in the rotors and an oval bell flare that measures 8" in one direction and 9.5' in the other.

[timothy42b]

OOH! The multi-bore trombone! Draw the inners with an oval cross-section on the ID - .500" in one direction and .562" in the other direction. The best of both worlds! From smallish tenor to a bass in one horn! Make the rest of the horn the same way (including oval ports in the rotors and an oval bell flare that measures 8" in one direction and 9.5' in the other.

I think you're onto something.

An oval slide - if only it could be done with a spiral bore - twist the oval as it goes down the tube - but then the outer slide wouldn't fit right.

[sacfxdx]

Boy. Doesn’t take long to morph a post into something different.

Good discussions. Carry on.

[JohnL]

OOH! The multi-bore trombone! Draw the inners with an oval cross-section on the ID - .500" in one direction and .562" in the other direction. The best of both worlds! From smallish tenor to a bass in one horn! Make the rest of the horn the same way (including oval ports in the rotors and an oval bell flare that measures 8" in one direction and 9.5' in the other.

I think you're onto something.

An oval slide - if only it could be done with a spiral bore - twist the oval as it goes down the tube - but then the outer slide wouldn't fit right.

The OD is round; you use an oval mandrel but a round die. No reason you couldn't give it a twist; it'd be similar to the button rifling approach they use on some gun barrels.

Another option would be to make the ID polygonal - basically like an Olds inner, but inside out. If you only had a few sides (say, 6) the difference between the max and min could be significant (I'm disinclined to do the math). The more sides, the closer to round it gets.

[harrisonreed]

No one has thought of having the mouthpiece go around the leadpipe, rather than into it, either.

Please send all royalties to me, as is my entitlement!

[LeTromboniste]

No one has thought of having the mouthpiece go around the leadpipe, rather than into it, either.

Please send all royalties to me, as is my entitlement!

I guess technically, the MADBone system has the male thread on the leadpipe side and female threads on the mouthpiece side.