Joined: 28 Jun 2013 Posts: 13 Location: The Woodlands, Texas
Posted: Sat Mar 20, 2021 7:21 am Post subject:
This is a good thread and the numbers submitted match up very well with my measurements. It is also interesting to note that most leadpipes that I have measured from manufacturers are right at 8-5/8" long.
Two important things about leadpipes that come to mind (beyond the venturi measurement) are: 1) the taper shape and 2) the measurement of the end of the leadpipe. Here is a chart with a variety of leadpipes measured down the tube. The '64 Benge MLP follows a traditional Schilke-style linear taper, but with a large venturi opening, this Blackburn leadpipe starts small but has a very fast and early taper, the 8335LA starts big and is fairly linear and the Bach 25 ('74 Bach #37) is fairly small and slow. Also note the leadpipe exit. I was surprised to see how many leadpipes, that I had measured, exit at .451" - .456"
Joined: 02 Sep 2005 Posts: 2827 Location: Littleton, MA
Posted: Fri Mar 26, 2021 5:24 am Post subject:
Thank you Lou for sharing the graphic of leadpipe tapers. I've always thought it important to include what occurs after the venturi. Much like the mouthpieces throat (bore size) only tells part of the story, the backbore shape and volume, shank engagement (gap) helps to complete the story.
Here are a couple more venturi sizes to add to the conversation.
"Barn era" Getzen Super Deluxe Copper Temp bell and copper leadpipe, venturi .333", receiver gap with Bach 3C mouthpiece at .373"
Bach 190 .401" bore Eb replacement leadpipe venturi .316", receiver gap with Bach 3C mouthpiece .178"
I hope this is helpful. _________________ James Becker
Brass Repair Specialist Since 1977
Osmun Music Inc.
77 Powdermill Road Rt.62
Acton, MA 01720
www.osmun.com
Joined: 24 Feb 2008 Posts: 2642 Location: vista ca
Posted: Sun Mar 28, 2021 9:03 am Post subject:
If you had the 80J with a bigger venturi it would basically (i think) be a B700 Large bore. The B700 has the lighter bracing and a whopping 358 (mine anyway) venturi. It plays great, especially soft dynamics. The sound is very dark, and with a shallow mouthpiece the sound is very bright. It's bigger than i can handle. But the pitch and response really are good. I would think the big venturi might make it hard to play soft, but no. _________________ Mouthpiece Maker
vintage Trumpet design enthusiast
www.meeuwsenmouthpieces.com www.youtube.com/lipshurt
Joined: 12 Jun 2011 Posts: 3663 Location: Pacifica, CA, USA
Posted: Sun Mar 28, 2021 12:27 pm Post subject:
Most Benge pipes are about 9 1/8" long. That's the other length that's popular in trumpet design. Bach, Calicchio and others are the shorter length mentioned; 8 5/8" - 8 3/4". _________________ "Strive for tone." -John Coppola
Edwards X-13
ACB MV3C /ACB A1/26 backbore
https://yourbrass.com/
Joined: 07 Feb 2014 Posts: 94 Location: Goodyear, Arizona
Posted: Sun Mar 28, 2021 12:42 pm Post subject:
This is by far the most intriguing lead pipe discussion that I have seen. I am particularly impressed by the graph showing the internal changes in the lead pipes. This is something that I never knew existed since I have never really studied the mechanics of lead pipes. I always naively thought that the lead pipe started out at the the receiver and then had some unique formula for a direct taper to the tuning slide.
Will someone with insight explain how these internal changes are made in the lead pipes and is there some sort of a formula that manufactures use to establish the changes for resistance and note production?
Just how is a lead pipe formed? _________________ agroovin48
Alan Cahill
1933 Conn Victor 80A Cornet
King Legend 2070
Adams A1V2
Joined: 21 Jan 2020 Posts: 204 Location: NW of ORD
Posted: Sun Mar 28, 2021 3:51 pm Post subject: Leadpipe Venturi Catalog
Same for me, I have found this subject really intriguing. I think it interests the mechanical engineer in me as much as the trumpet player.
I would also really like to learn how the rate of expansion of the diameter of the leadpipe impacts playing characteristics. And maybe it is different for different players based on the airstream they create / use. _________________ Bach190ML43
Kanstul 1001
Bach NY7
Yamaha 631 Flugel
Joined: 12 Jun 2011 Posts: 3663 Location: Pacifica, CA, USA
Posted: Sun Mar 28, 2021 6:08 pm Post subject:
There is much of the magic, or failure in the taper. _________________ "Strive for tone." -John Coppola
Edwards X-13
ACB MV3C /ACB A1/26 backbore
https://yourbrass.com/
Will someone with insight explain how these internal changes are made in the lead pipes and is there some sort of a formula that manufactures use to establish the changes for resistance and note production?
Just how is a lead pipe formed?
Some people use math to determine the taper(s) they want. Some don't. Some use straight tapers and some use a series of different tapers over the length.
The thing about the math is that the rest of the horn has to be taken in to consideration because the bell taper will affect the balance as well.
The leadpipe I use on most of my models is one I machined freehand on my lathe with no math. It happened to work out great, but I have made many leadpipe shapes that weren't nearly as good.
A new bell shape I'm experimenting with doesn't work well with my regular leadpipe so I'm trying others to see if I can get the blow where I want it.
Over time and with many trials and errors, the builder gets to know the effects of changes in taper in certain spots. Measuring as many other pipes as possible also helps see the shapes that tend to work best.
Joined: 28 Jun 2013 Posts: 13 Location: The Woodlands, Texas
Posted: Mon Apr 12, 2021 2:47 pm Post subject:
Like Ewan Divitt says, they are either drawn on a mandrel with a drawing bench or made from sheet metal. I do the latter in brass, copper and bronze, though I hammer and roll on a generic tapered mandrel until straight and smooth. The precision of the final taper dimensions are a direct result of precision cuts on the sheet metal. Simple geometry (2*pi*r) produces the right diameter at the desired points down the tube.
Lately I have been experimenting with smaller venturi, with faster early tapers. (See the Blackburn 19 leadpipe example in the chart above)
As Ewan points out, the bell taper and leadpipe taper are co-dependent in both sound and blow. Rarely does a huge venturi and fast taper work well with an early bell flair. (Unless you are Arturo)
I am early in my observations, but learning fast. _________________ Lou Gagliardi
HighScream Brass - highscream.com
HighScream Brass Brio and Dolce Models
Yamaha YTR-8335 LA Bb
1994 Bach Stradivarius 43 Sterling Silver / 25-O
Courtois 154R Flugelhorn
GR Mouthpieces: WB-Classic, WB-Studio-M
Joined: 07 Feb 2014 Posts: 94 Location: Goodyear, Arizona
Posted: Mon Apr 12, 2021 7:09 pm Post subject:
High Screamer, will you post a simple diagram of what you are talking about so those of us who have limited mental capacity can see what you mean? Do you machine a mandrel to specs or cut a piece of sheet metal to specs and roll it around a mandrel? I still can not visualize it. _________________ agroovin48
Alan Cahill
1933 Conn Victor 80A Cornet
King Legend 2070
Adams A1V2
Joined: 28 Jun 2013 Posts: 13 Location: The Woodlands, Texas
Posted: Tue Apr 13, 2021 2:24 pm Post subject:
Quote:
High Screamer, will you post a simple diagram of what you are talking about so those of us who have limited mental capacity can see what you mean? Do you machine a mandrel to specs or cut a piece of sheet metal to specs and roll it around a mandrel? I still can not visualize it.
Here are some photos of a leadpipe from sheet brass:
1) cut to shape, 2) anneal, 3) shape on mandrel, 4) wrap with annealed wire to close joint, 5) brazed, 6) remove annealed wire, 7) file, hammer & roll smooth
Joined: 24 Dec 2018 Posts: 3367 Location: Endwell NY USA
Posted: Tue Apr 13, 2021 2:38 pm Post subject:
My understanding is that that mandrel is slightly smaller than the finished size and shape of the leadpipe ID. The mandrel serves as an undersized 'internal anvil' for the precisely sized and shaped sheet of brass to be formed around, and held during soldering of the seam. Then the mandrel provides the firm internal support for the final 'rounding' of the leadpipe by use of the small hammer seen in pictures 4, 5, and 6.
The taper of the leadpipe is determined by the precise cutting of the flat sheet brass. I don't think the mandrel is forced into the leadpipe to cause any internal 'stretching' or 'forming'. _________________ Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Joined: 07 Feb 2014 Posts: 94 Location: Goodyear, Arizona
Posted: Tue Apr 13, 2021 2:41 pm Post subject:
Thank you for the visual. That is what I needed. I can see that the mandrel is machined with the taper transition points and then wrapped with the sheet stock and shaped then brazed. Good lesson! _________________ agroovin48
Alan Cahill
1933 Conn Victor 80A Cornet
King Legend 2070
Adams A1V2
Joined: 28 Jun 2013 Posts: 13 Location: The Woodlands, Texas
Posted: Tue Apr 13, 2021 6:34 pm Post subject:
Quote:
The mandrel serves as an undersized 'internal anvil'
Jay you've got it. The mandrel is typically used for rolling out leadpipe dents. I got it from Allied or Votaw. When I am hammering or rolling on it, I work all the way on the small end of it so the pipe is loose and, as you say, it acts like an anvil while planishing or rolling.
Thanks Alan and Rusty.
In keeping with the OP, I will post more charts of some other leadpipes. I have others, including a Bach #7 from a Mt Vernon and a French Besson that I plan to measure. I'll share the charts. _________________ Lou Gagliardi
HighScream Brass - highscream.com
HighScream Brass Brio and Dolce Models
Yamaha YTR-8335 LA Bb
1994 Bach Stradivarius 43 Sterling Silver / 25-O
Courtois 154R Flugelhorn
GR Mouthpieces: WB-Classic, WB-Studio-M
My understanding is that that mandrel is slightly smaller than the finished size and shape of the leadpipe ID. The mandrel serves as an undersized 'internal anvil' for the precisely sized and shaped sheet of brass to be formed around, and held during soldering of the seam. Then the mandrel provides the firm internal support for the final 'rounding' of the leadpipe by use of the small hammer seen in pictures 4, 5, and 6.
The taper of the leadpipe is determined by the precise cutting of the flat sheet brass. I don't think the mandrel is forced into the leadpipe to cause any internal 'stretching' or 'forming'.
The size and shape of the mandrel determines the leadpipe inner dimensions.
Plainishing the seam of a brazed tube will widen the diameter of the tube. The type of seam (butt, scarf, toothed) will also change the methods used to get the seam smooth.
I personally don't believe you can make an accurate(repeatable) pipe without an accurate mandrel.
When I make my bell tubes, I hammer the seam smooth on an undersized mandrel and then burnish the entire tube down to the final bell mandrel to eliminate any stretching from hammering and make it easier to spin at later stages.
You would never braze a tube with the mandrel inside it for a few reasons.
The first being that it is a huge heatsink and will make doing a good seam way more difficult.
The second is that the mandrel will be damaged by the flux and heat and will rust and potentially warp depending on the type of steel used.
Joined: 26 May 2021 Posts: 2 Location: Salt Lake City
Posted: Tue Mar 01, 2022 12:56 pm Post subject:
James Becker wrote:
Thank you Lou for sharing the graphic of leadpipe tapers. I've always thought it important to include what occurs after the venturi. Much like the mouthpieces throat (bore size) only tells part of the story, the backbore shape and volume, shank engagement (gap) helps to complete the story.
Here are a couple more venturi sizes to add to the conversation.
"Barn era" Getzen Super Deluxe Copper Temp bell and copper leadpipe, venturi .333", receiver gap with Bach 3C mouthpiece at .373"
Bach 190 .401" bore Eb replacement leadpipe venturi .316", receiver gap with Bach 3C mouthpiece .178"
I hope this is helpful.
What do you mean by Barn era? I have a Copra-Temp as well from the 50s, and its gap is .406" with a Bach 1 1/2C (and .5" with a Monette). Also, there's practically no venturi. I don't have the means to measure the venturi, but there's hardly any visible difference between the inner diameter of the venturi compared to where it sits in the mouthpiece receiver.
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