Looking for Bronze Prop Shaft

[Marvin Hamon]

I've been told by my local prop shop that it is no longer possible to get a bronze prop shaft. This seems a little odd to me since I have seen several sources for bronze round stock but I do not know what type of bronze is best for this application. Would the standard silicon bronze be the correct choice? This is for the basic 1 inch shaft for a 28hp engine.

Thanks

[Marvin Hamon]

I've been told by my local prop shop that it is no longer possible to get a bronze prop shaft. This seems a little odd to me since I have seen several sources for bronze round stock but I do not know what type of bronze is best for this application. Would the standard silicon bronze be the correct choice? This is for the basic 1 inch shaft for a 28hp engine.

Thanks

[Marvin Hamon]

I've been told by my local prop shop that it is no longer possible to get a bronze prop shaft. This seems a little odd to me since I have seen several sources for bronze round stock but I do not know what type of bronze is best for this application. Would the standard silicon bronze be the correct choice? This is for the basic 1 inch shaft for a 28hp engine.

Thanks

[mmd]

Providing that the rest of the drivetrain is galvanically compatible and that a suitable alloy is used, there is no reason not to use silicon bronze (manganese bronze in another beast altogether). One cannot swap a high-tensile stainless shaft for a bronze one of similar size, however. What is the maximum RPM of your engine and what gear ratio gearbox are you using?

[mmd]

Providing that the rest of the drivetrain is galvanically compatible and that a suitable alloy is used, there is no reason not to use silicon bronze (manganese bronze in another beast altogether). One cannot swap a high-tensile stainless shaft for a bronze one of similar size, however. What is the maximum RPM of your engine and what gear ratio gearbox are you using?

[mmd]

Providing that the rest of the drivetrain is galvanically compatible and that a suitable alloy is used, there is no reason not to use silicon bronze (manganese bronze in another beast altogether). One cannot swap a high-tensile stainless shaft for a bronze one of similar size, however. What is the maximum RPM of your engine and what gear ratio gearbox are you using?

[cbob]

Marv, If the Local Prop Shop is the one in Richmond, you got the straight poop, can't say the same for the one close to you. I took out the original 20 year old, (in '79) worn 1" bronze shaft, driven direct at up to 1800 RPM, by a 31 HP Graymarine, 14 x 8 Hyde RH wheel. The Seattle shop that machined the new ss shaft told me the same story. (As I had left the bronze sample, I expected bronze). Less expensive and that bronze was no longer used, didn't say unavailable, however. That stainless one is still like new, even at the gland and Cutless, no electrolysis evident on the strut, wheel (45 year old), or stock or gudgeonseither. Don't know the recommended alloy, but that guy at the Propshop will. If you still want bronze, don't know if silicon or manganese? - Check out Atlas Metal Sales, Denver, add page 15 of Jan. Feb. WB. #176. Website www.atlasmetal.com. (http://www.atlasmetal.com.) Luck and a Happy New one, cbob

[cbob]

Marv, If the Local Prop Shop is the one in Richmond, you got the straight poop, can't say the same for the one close to you. I took out the original 20 year old, (in '79) worn 1" bronze shaft, driven direct at up to 1800 RPM, by a 31 HP Graymarine, 14 x 8 Hyde RH wheel. The Seattle shop that machined the new ss shaft told me the same story. (As I had left the bronze sample, I expected bronze). Less expensive and that bronze was no longer used, didn't say unavailable, however. That stainless one is still like new, even at the gland and Cutless, no electrolysis evident on the strut, wheel (45 year old), or stock or gudgeonseither. Don't know the recommended alloy, but that guy at the Propshop will. If you still want bronze, don't know if silicon or manganese? - Check out Atlas Metal Sales, Denver, add page 15 of Jan. Feb. WB. #176. Website www.atlasmetal.com. (http://www.atlasmetal.com.) Luck and a Happy New one, cbob

[cbob]

Marv, If the Local Prop Shop is the one in Richmond, you got the straight poop, can't say the same for the one close to you. I took out the original 20 year old, (in '79) worn 1" bronze shaft, driven direct at up to 1800 RPM, by a 31 HP Graymarine, 14 x 8 Hyde RH wheel. The Seattle shop that machined the new ss shaft told me the same story. (As I had left the bronze sample, I expected bronze). Less expensive and that bronze was no longer used, didn't say unavailable, however. That stainless one is still like new, even at the gland and Cutless, no electrolysis evident on the strut, wheel (45 year old), or stock or gudgeonseither. Don't know the recommended alloy, but that guy at the Propshop will. If you still want bronze, don't know if silicon or manganese? - Check out Atlas Metal Sales, Denver, add page 15 of Jan. Feb. WB. #176. Website www.atlasmetal.com. (http://www.atlasmetal.com.) Luck and a Happy New one, cbob

[cbob]

Sorry, forgot. R. J Lehay, Bayview Dist. of the San Francisco Area, can probably do local supply if you know exactly what you want. For stainless, the Prop Shop should have it or get it, you may have to wait a while for either however, again, cbob

[cbob]

Sorry, forgot. R. J Lehay, Bayview Dist. of the San Francisco Area, can probably do local supply if you know exactly what you want. For stainless, the Prop Shop should have it or get it, you may have to wait a while for either however, again, cbob

[cbob]

Sorry, forgot. R. J Lehay, Bayview Dist. of the San Francisco Area, can probably do local supply if you know exactly what you want. For stainless, the Prop Shop should have it or get it, you may have to wait a while for either however, again, cbob

[Marvin Hamon]

Thanks for the information. I'm repowering so I will probably need a new shaft and that is why I am looking around. I'm interested in a bronze shaft because it is one of only 2 SS parts I have in the water. The other is the rudder shaft and if I ever have to replace that I would be thinking bronze too. If I had a choice it would be better to have all the metal that's in the water be the same to lower the odds of galvanic corrosion. The max shaft RPM would be 1800.

[Marvin Hamon]

Thanks for the information. I'm repowering so I will probably need a new shaft and that is why I am looking around. I'm interested in a bronze shaft because it is one of only 2 SS parts I have in the water. The other is the rudder shaft and if I ever have to replace that I would be thinking bronze too. If I had a choice it would be better to have all the metal that's in the water be the same to lower the odds of galvanic corrosion. The max shaft RPM would be 1800.

[Marvin Hamon]

Thanks for the information. I'm repowering so I will probably need a new shaft and that is why I am looking around. I'm interested in a bronze shaft because it is one of only 2 SS parts I have in the water. The other is the rudder shaft and if I ever have to replace that I would be thinking bronze too. If I had a choice it would be better to have all the metal that's in the water be the same to lower the odds of galvanic corrosion. The max shaft RPM would be 1800.

[mmd]

Not enough info yet for a freebie, Marvin. What is the gearbox ratio? (Gotta know what RPM the shaft is turning at)

[mmd]

Not enough info yet for a freebie, Marvin. What is the gearbox ratio? (Gotta know what RPM the shaft is turning at)

[mmd]

Not enough info yet for a freebie, Marvin. What is the gearbox ratio? (Gotta know what RPM the shaft is turning at)

[cbob]

Marv, More to my previous; assume you mean rudder stock rather than rudder shaft, anyway, those, stock and gudgeons mentioned on previous post, are bronze, also rudder blade bolting to stock. Did you find out anything at Atlas and R.J re. application and availibility? An effective bonding system should eleminate electrolysis problems which are very unlikely to present themselves due to metal potential differencees. Could you indicate where you got info. these metal nobility difference could cause problems? Happy New Year, again. cbob

[cbob]

Marv, More to my previous; assume you mean rudder stock rather than rudder shaft, anyway, those, stock and gudgeons mentioned on previous post, are bronze, also rudder blade bolting to stock. Did you find out anything at Atlas and R.J re. application and availibility? An effective bonding system should eleminate electrolysis problems which are very unlikely to present themselves due to metal potential differencees. Could you indicate where you got info. these metal nobility difference could cause problems? Happy New Year, again. cbob

[cbob]

Marv, More to my previous; assume you mean rudder stock rather than rudder shaft, anyway, those, stock and gudgeons mentioned on previous post, are bronze, also rudder blade bolting to stock. Did you find out anything at Atlas and R.J re. application and availibility? An effective bonding system should eleminate electrolysis problems which are very unlikely to present themselves due to metal potential differencees. Could you indicate where you got info. these metal nobility difference could cause problems? Happy New Year, again. cbob

[Ian Wright]

Monel metal would be a better choice than bronze imo, I'm pretty sure you can still find that,,,,,,
IanW

[Ian Wright]

Monel metal would be a better choice than bronze imo, I'm pretty sure you can still find that,,,,,,
IanW

[Ian Wright]

Monel metal would be a better choice than bronze imo, I'm pretty sure you can still find that,,,,,,
IanW

[Marvin Hamon]

mmd, the max shaft rpm would be 1800. If it makes a difference the gearbox is 2:1 and the engine max rpm is 3600.

cbob, I have not called any suppliers yet. I still don't think I have enough information on what type of bronze I need. A bonding system won't stop electrolysis between a bronze prop and a SS shaft as far as I know. Only a zinc will help you there. My source of information is a table of potential differences between metals in seawater and a few years working as an electrical engineer.

It seems like the use of bronze for prop shafts is now in the past so I'll just go with the flow and use SS but thanks to everyone for their input. I'm on to the next project, getting the engine bed ready for the new engine.

[Marvin Hamon]

mmd, the max shaft rpm would be 1800. If it makes a difference the gearbox is 2:1 and the engine max rpm is 3600.

cbob, I have not called any suppliers yet. I still don't think I have enough information on what type of bronze I need. A bonding system won't stop electrolysis between a bronze prop and a SS shaft as far as I know. Only a zinc will help you there. My source of information is a table of potential differences between metals in seawater and a few years working as an electrical engineer.

It seems like the use of bronze for prop shafts is now in the past so I'll just go with the flow and use SS but thanks to everyone for their input. I'm on to the next project, getting the engine bed ready for the new engine.

[Marvin Hamon]

mmd, the max shaft rpm would be 1800. If it makes a difference the gearbox is 2:1 and the engine max rpm is 3600.

cbob, I have not called any suppliers yet. I still don't think I have enough information on what type of bronze I need. A bonding system won't stop electrolysis between a bronze prop and a SS shaft as far as I know. Only a zinc will help you there. My source of information is a table of potential differences between metals in seawater and a few years working as an electrical engineer.

It seems like the use of bronze for prop shafts is now in the past so I'll just go with the flow and use SS but thanks to everyone for their input. I'm on to the next project, getting the engine bed ready for the new engine.

[cbob]

Marv, Like I said my 20+ year old SS (1") sahft is like new, and is there because the 20 year old bronze job was shot. The propeller is, I presume mag., bronze, Hyde feathering, been in the sea since '58, and although not like new, shows no pinking at the thin blade edges. The boat is thoroughly electrically bonded, with a zinc hanging over the side, The shaft has an oilite bronze contact arrangement to the shaft, and the ground to sea potential is maintained around 550 to 600 MV. Before you decide, check out wooden boats at Svend's, see what they have and ask about it, the owners I mean. Luck again, cbob

[cbob]

Marv, Like I said my 20+ year old SS (1") sahft is like new, and is there because the 20 year old bronze job was shot. The propeller is, I presume mag., bronze, Hyde feathering, been in the sea since '58, and although not like new, shows no pinking at the thin blade edges. The boat is thoroughly electrically bonded, with a zinc hanging over the side, The shaft has an oilite bronze contact arrangement to the shaft, and the ground to sea potential is maintained around 550 to 600 MV. Before you decide, check out wooden boats at Svend's, see what they have and ask about it, the owners I mean. Luck again, cbob

[cbob]

Marv, Like I said my 20+ year old SS (1") sahft is like new, and is there because the 20 year old bronze job was shot. The propeller is, I presume mag., bronze, Hyde feathering, been in the sea since '58, and although not like new, shows no pinking at the thin blade edges. The boat is thoroughly electrically bonded, with a zinc hanging over the side, The shaft has an oilite bronze contact arrangement to the shaft, and the ground to sea potential is maintained around 550 to 600 MV. Before you decide, check out wooden boats at Svend's, see what they have and ask about it, the owners I mean. Luck again, cbob

[Ken Liden]

Typical marine bronze shafting is usually called "tobin bronze". It has the same torsional shear yeild strength as 304 stainless ie about 20,000 psi. Stainless 304 has a higher modulus of elasticity than bronze ie 28,000,000 psi v/s 16,000,000. These two materials are at the bottom of the marine shafting charts.

[Ken Liden]

Typical marine bronze shafting is usually called "tobin bronze". It has the same torsional shear yeild strength as 304 stainless ie about 20,000 psi. Stainless 304 has a higher modulus of elasticity than bronze ie 28,000,000 psi v/s 16,000,000. These two materials are at the bottom of the marine shafting charts.

[Ken Liden]

Typical marine bronze shafting is usually called "tobin bronze". It has the same torsional shear yeild strength as 304 stainless ie about 20,000 psi. Stainless 304 has a higher modulus of elasticity than bronze ie 28,000,000 psi v/s 16,000,000. These two materials are at the bottom of the marine shafting charts.