Lapping a Valve

edcon1981 · 10-02-2008, 04:25 PM

Hey guys,

My '56 ambassador has a bit of hesitation on the first valve. It only does it after about five minutes of playing, then the valve gets hung up intermittently for 1-2 seconds... you know, just enough to throw you off. the valve itself does have a slight wear spot around the bottom of it, but nothing showing in the casing, and yes the serial numbers match.

is this something that i can fix on my own, or at least attempt to; or would you suggest getting it professionally done?

if you think it can be fixed in house, how would i go about doing said operation?

Firestas'1 · 10-02-2008, 04:36 PM

I think Old Lou would be the one to ask about this.

Brekelefuw · 10-02-2008, 04:54 PM

Lapping is the last thing you want to do when repairing valves. Only do it when other options have been tried. Lapping removes material, so if you make a mistake you have to replate the valves to get it back to tolerance.
If the valve casing is slightly warped that will make the valve hang. This could be caused by a knock to the 1st valve slide or a knock to the valve casing itself. Take the valve out and look through the casing and see if there are any shiny spots. Those shiny spots are where the casing is out of shape.
Rebounding the casing back into shape with a mandrel made to fit the size of the case would be my first attempt to repair. If that doesn't work, and I know where the valve is binding in the case, I might use this special tool to slowly burnish that area back into shape. Then if that doesn't work I will consider a small amount of lapping.
It also might be the valve piston itself that is a little bent.
Since you say it only happens after playing for a bit, maybe (and I don't know how much it actually affects the metal) the heat makes the trumpet expand just enough to cause the valves to be tighter. I doubt this is the problem though because I don't think the heat of your breathe can affect it significantly enough.

Wipe your valve casings and valves dry with a soft cloth and then apply oil. If there is any water in the valves when you apply oil, the oil sits on top of the water and it doesn't work correctly. Similar things happen on trombone. When a student loads up their slide with slide grease or slide-o-mix or whatever product they use, it will cause the slide to bind. They need to apply only a small amount for it to be effective.

MFfan · 10-02-2008, 10:09 PM

Sounds somewhat similar to the piston problem with a used cornet I bought, might have been the Ambassador or the
Roth. The first valve would hang up intermittently, towards the top of th stroke. OldLou thought , from my description, there was probably some chaffing on the bottom edge of the piston, from maybe some one dropping the piston on the floor.

We get together occaisionally and he was able to inspect it and that is what it was. He advised me to get some 2000, at least grade of fine sandpaper and carefully sand the edge of the piston, not touching the side of the piston. That was successful in wearing the burr on the bottom edge after some time working on it and no problems since. There are a lot of things that can hang up the piston, as has been mentioned. Good luck on your repair.

edcon1981 · 10-03-2008, 08:33 AM

sounds like i'd be better off just taking it to a repair shop. the local sam ash does repairs, anybody know their reputation?

oldlou · 10-03-2008, 10:04 AM

Quote:

Originally Posted by MFfan

Sounds somewhat similar to the piston problem with a used cornet I bought, might have been the Ambassador or the
Roth. The first valve would hang up intermittently, towards the top of th stroke. OldLou thought , from my description, there was probably some chaffing on the bottom edge of the piston, from maybe some one dropping the piston on the floor.

We get together occaisionally and he was able to inspect it and that is what it was. He advised me to get some 2000, at least grade of fine sandpaper and carefully sand the edge of the piston, not touching the side of the piston. That was successful in wearing the burr on the bottom edge after some time working on it and no problems since. There are a lot of things that can hang up the piston, as has been mentioned. Good luck on your repair.

David; that was your Holton Collegiate cornet.

For the rest of the readers, this sort of repair is usually quite simple, ,BUT, it does require an inspection by an experienced technician. The repair is usually quite inexpensive.

OLDLOU>>

edcon1981 · 10-06-2008, 01:27 PM

thanx guys. i'll let you know how it turns out.

10-02-2008, 04:25 PM	#1
edcon1981 Mezzo Forte User Join Date: Jun 2008 Location: South Philly Posts: 856	Lapping a Valve Hey guys, My '56 ambassador has a bit of hesitation on the first valve. It only does it after about five minutes of playing, then the valve gets hung up intermittently for 1-2 seconds... you know, just enough to throw you off. the valve itself does have a slight wear spot around the bottom of it, but nothing showing in the casing, and yes the serial numbers match. is this something that i can fix on my own, or at least attempt to; or would you suggest getting it professionally done? if you think it can be fixed in house, how would i go about doing said operation? __________________ Ed Con... 1890's (est) LeFever "691" Cornet 1910 Grand Rapids Inst. Co. "USA Line" Baritone 1920's (est) Harwood "Artist Solo Model" Cornet 1954 Olds (LA) "Ambassador" Cornet 1956 Olds (EF) "Ambassador" Trumpet 1989 Selmer "Bundy" Trumpet 2007 Kanstul "KSB100" 3-Valve Bugle "Villains always have antidotes... they're funny that way. "

10-02-2008, 04:36 PM	#2
Firestas'1 Piano User Join Date: Dec 2006 Location: New Jersey Posts: 467	Re: Lapping a Valve I think Old Lou would be the one to ask about this. __________________ Stan J. What is to reach the heart must come from above. If it does not, it will be nothing but notes, body without spirit. --Ludwig van Beethoven Music is God's best gift to man. The only art of heaven given to earth, the only art of earth we take to heaven. --Letitia Elizabeth Landon

10-02-2008, 04:54 PM	#3
Brekelefuw Forte User Join Date: Mar 2006 Location: Toronto Posts: 1,885	Re: Lapping a Valve Lapping is the last thing you want to do when repairing valves. Only do it when other options have been tried. Lapping removes material, so if you make a mistake you have to replate the valves to get it back to tolerance. If the valve casing is slightly warped that will make the valve hang. This could be caused by a knock to the 1st valve slide or a knock to the valve casing itself. Take the valve out and look through the casing and see if there are any shiny spots. Those shiny spots are where the casing is out of shape. Rebounding the casing back into shape with a mandrel made to fit the size of the case would be my first attempt to repair. If that doesn't work, and I know where the valve is binding in the case, I might use this special tool to slowly burnish that area back into shape. Then if that doesn't work I will consider a small amount of lapping. It also might be the valve piston itself that is a little bent. Since you say it only happens after playing for a bit, maybe (and I don't know how much it actually affects the metal) the heat makes the trumpet expand just enough to cause the valves to be tighter. I doubt this is the problem though because I don't think the heat of your breathe can affect it significantly enough. Wipe your valve casings and valves dry with a soft cloth and then apply oil. If there is any water in the valves when you apply oil, the oil sits on top of the water and it doesn't work correctly. Similar things happen on trombone. When a student loads up their slide with slide grease or slide-o-mix or whatever product they use, it will cause the slide to bind. They need to apply only a small amount for it to be effective.

10-02-2008, 10:09 PM	#4
MFfan Forte User Join Date: Sep 2006 Location: Kalamazoo, Michigan Posts: 2,122	Re: Lapping a Valve Sounds somewhat similar to the piston problem with a used cornet I bought, might have been the Ambassador or the Roth. The first valve would hang up intermittently, towards the top of th stroke. OldLou thought , from my description, there was probably some chaffing on the bottom edge of the piston, from maybe some one dropping the piston on the floor. We get together occaisionally and he was able to inspect it and that is what it was. He advised me to get some 2000, at least grade of fine sandpaper and carefully sand the edge of the piston, not touching the side of the piston. That was successful in wearing the burr on the bottom edge after some time working on it and no problems since. There are a lot of things that can hang up the piston, as has been mentioned. Good luck on your repair. __________________ Dave Rafferty 1953 Olds Ambassador (LA) 1966 Besson 2-20 (Silver) Lemar Trumpet (peashooter-Conn?) 55-56 York Artist Trumpet Besson 609 trumpet 1955-60 Besson 8-10 Trumpet 1948 Besson cornet 1946 King Master Cornet www.kalamazooconcertband.org

10-03-2008, 08:33 AM	#5
edcon1981 Mezzo Forte User Join Date: Jun 2008 Location: South Philly Posts: 856	Re: Lapping a Valve sounds like i'd be better off just taking it to a repair shop. the local sam ash does repairs, anybody know their reputation? __________________ Ed Con... 1890's (est) LeFever "691" Cornet 1910 Grand Rapids Inst. Co. "USA Line" Baritone 1920's (est) Harwood "Artist Solo Model" Cornet 1954 Olds (LA) "Ambassador" Cornet 1956 Olds (EF) "Ambassador" Trumpet 1989 Selmer "Bundy" Trumpet 2007 Kanstul "KSB100" 3-Valve Bugle "Villains always have antidotes... they're funny that way. "

10-06-2008, 01:27 PM	#7
edcon1981 Mezzo Forte User Join Date: Jun 2008 Location: South Philly Posts: 856	Re: Lapping a Valve thanx guys. i'll let you know how it turns out. __________________ Ed Con... 1890's (est) LeFever "691" Cornet 1910 Grand Rapids Inst. Co. "USA Line" Baritone 1920's (est) Harwood "Artist Solo Model" Cornet 1954 Olds (LA) "Ambassador" Cornet 1956 Olds (EF) "Ambassador" Trumpet 1989 Selmer "Bundy" Trumpet 2007 Kanstul "KSB100" 3-Valve Bugle "Villains always have antidotes... they're funny that way. "

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