I just paid to have my cutlass bearing replaced. I ordered direct from the manufacturer and was sure that it was correct for my boat. After the installation I noticed some up and down play...about the same as before it was installed. There is no side to side play. The machanic is a bit confused on this and I am wondering if there is something else that can be done to eliminate the play. Comments
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Dimensional problems with cutless
Normal 'play' on a cutless bearing is 0.003" per inch of shaft diameter. Cutless bearings are installed via an "intereference fit" and these dimensional anomalies must be taken into account when replacing. Inotherwords, you need a micrometer to correctly measure (to thousandths of an inch) the diameter of the shaft and the inside diameter of the 'housing' in which the bearing fits. When all is finished with the installation you want an operating clearance of the bearing to the shaft at approximately 0.003 inches bearing clearance per one inch of shaft diameter. When you 'press' the bearing into the 'housing' the diameter of the bearing 'closes - down' .... the bearing is larger than the housing and that intereference dimension has to be subtracted from the bearing when not installed. If your bearing to shaft clearance is too large, you can either install a new bearing of the proper 'outside diameter' dimensions or sometimes put thin shims into the bore of the housing. In all probability your shaft has abraded down in diameter hence the extra clearance noted. Shafting that has worn down can be 'plated' back to proper dimensions in spectialty shops who do such additive 'plating' or metal deposition. Each bearing manufacturer will list the installed *dry* clearance. Put a surface gage near the shaft and wiggle it up and down and side to side to see if the actual installed clearance is 'close' to the 'installed clearance' specification. Cutless bearings when dry shouldnt be a 'tight' fit on the shaft .... these are hydrodynamic bearings that require a bit of water to be between the shaft and the bearing to work properly. The 'secret' with such plain journal bearings is that the 'press fit' into the housing will affect the final installed inside diameter and operating clearance. hope this helps.
Normal 'play' on a cutless bearing is 0.003" per inch of shaft diameter. Cutless bearings are installed via an "intereference fit" and these dimensional anomalies must be taken into account when replacing. Inotherwords, you need a micrometer to correctly measure (to thousandths of an inch) the diameter of the shaft and the inside diameter of the 'housing' in which the bearing fits. When all is finished with the installation you want an operating clearance of the bearing to the shaft at approximately 0.003 inches bearing clearance per one inch of shaft diameter. When you 'press' the bearing into the 'housing' the diameter of the bearing 'closes - down' .... the bearing is larger than the housing and that intereference dimension has to be subtracted from the bearing when not installed. If your bearing to shaft clearance is too large, you can either install a new bearing of the proper 'outside diameter' dimensions or sometimes put thin shims into the bore of the housing. In all probability your shaft has abraded down in diameter hence the extra clearance noted. Shafting that has worn down can be 'plated' back to proper dimensions in spectialty shops who do such additive 'plating' or metal deposition. Each bearing manufacturer will list the installed *dry* clearance. Put a surface gage near the shaft and wiggle it up and down and side to side to see if the actual installed clearance is 'close' to the 'installed clearance' specification. Cutless bearings when dry shouldnt be a 'tight' fit on the shaft .... these are hydrodynamic bearings that require a bit of water to be between the shaft and the bearing to work properly. The 'secret' with such plain journal bearings is that the 'press fit' into the housing will affect the final installed inside diameter and operating clearance. hope this helps.
Check Roundness
Ensure that the passage in the strut is round. Maybe it was worn on the bottom of the old bearing and when the new bearing was fit into it (assuming that it is nylon, delron, etc.) it may have taken the oval shape and left the up/down slack. The shaft should fit with no play whatsoever. I think I just said the same thing as RichH.
Ensure that the passage in the strut is round. Maybe it was worn on the bottom of the old bearing and when the new bearing was fit into it (assuming that it is nylon, delron, etc.) it may have taken the oval shape and left the up/down slack. The shaft should fit with no play whatsoever. I think I just said the same thing as RichH.
Rich, what do you do for a living? Launch Space
shuttles? Guys like me order up a new cutlass based on the size of the shaft. The length should be pretty much standard. We get the old one out as need-be. That means loosening SET SCREWS. And then tapping the new bearing into place. The method used depends on the pre-work done. (was the shaft removed) Then tightening the SET SCREWS! And if the old cutlass was rapidly worn, engine alignment is a must. But we save the micrometers for our hotrod engines.
shuttles? Guys like me order up a new cutlass based on the size of the shaft. The length should be pretty much standard. We get the old one out as need-be. That means loosening SET SCREWS. And then tapping the new bearing into place. The method used depends on the pre-work done. (was the shaft removed) Then tightening the SET SCREWS! And if the old cutlass was rapidly worn, engine alignment is a must. But we save the micrometers for our hotrod engines.
Intereference fit.
The intereference fit holds the bearing in the housing, the set screws are there in case the housing gets so hot that the bearing doesnt fall out when the diameter/circumference changes due to the heat. The bearing should always larger in diameter than the housing by about 0.001" per inch of housing diameter. .... learned this back in the 'space race days' ;-)
The intereference fit holds the bearing in the housing, the set screws are there in case the housing gets so hot that the bearing doesnt fall out when the diameter/circumference changes due to the heat. The bearing should always larger in diameter than the housing by about 0.001" per inch of housing diameter. .... learned this back in the 'space race days' ;-)
Space Craft!
Never having tried to change the Cutless on a spacecraft I just do as Fred does. The shell on my 1" shaft bearing was tuphnol and VERY thin - making bearing extraction difficult. Hence I removed the "P" bracket and bored it out to 1 1/2" ID so now use a cutless with a thick bronze shell which is easy to remove without needing to pull the shaft. The size now is the bog standard 1 1/2" x 1" x 4" long and just about everyone stocks these - unlike Hunter's original fit.
Never having tried to change the Cutless on a spacecraft I just do as Fred does. The shell on my 1" shaft bearing was tuphnol and VERY thin - making bearing extraction difficult. Hence I removed the "P" bracket and bored it out to 1 1/2" ID so now use a cutless with a thick bronze shell which is easy to remove without needing to pull the shaft. The size now is the bog standard 1 1/2" x 1" x 4" long and just about everyone stocks these - unlike Hunter's original fit.
Yo Rich!
This excellent response is the reason why certain things like cutlass bearings need to be replaced by the yard. Amateurs need not apply.
This excellent response is the reason why certain things like cutlass bearings need to be replaced by the yard. Amateurs need not apply.
is it the correct bearing????
two years ago a friend had a sloppy loose fitting bearing replaced by the yard. his is a french built boat. hence metric. shortly ater new instalation lot of noticeable play again. yard had installed an american(non-metric size) bearing that was close but not correct. when proper size bearing was installed problem solved.
two years ago a friend had a sloppy loose fitting bearing replaced by the yard. his is a french built boat. hence metric. shortly ater new instalation lot of noticeable play again. yard had installed an american(non-metric size) bearing that was close but not correct. when proper size bearing was installed problem solved.
Tight fit for sure...
we had found in the archive the right size and model of cutlass bearing for our C30... Got a quote from the yard at 500.00$ CA to change it! Made up a tool, as found on the C30 Association website and changed the whole things in less than an hour...that's the way I like. GG
we had found in the archive the right size and model of cutlass bearing for our C30... Got a quote from the yard at 500.00$ CA to change it! Made up a tool, as found on the C30 Association website and changed the whole things in less than an hour...that's the way I like. GG
Not that hard
The entire process took me 45 minutes and most of that was looking for the tools. $500 is about $1000+ per hour for the yard. Can you say "licensed to steal"?
The entire process took me 45 minutes and most of that was looking for the tools. $500 is about $1000+ per hour for the yard. Can you say "licensed to steal"?
Yo Bill!
Re-read the original post.....a mechanic was paid to do the install. Even if David ordered the wrong sized bearing shouldn't the mechanic have caught the error before installing it. I think your recommendation puts too much faith in "professionals". Kevin
Re-read the original post.....a mechanic was paid to do the install. Even if David ordered the wrong sized bearing shouldn't the mechanic have caught the error before installing it. I think your recommendation puts too much faith in "professionals". Kevin
yeah bill
but did he use the right bearing. they are all numbered and if the numbers are wrong it may be metric. Is the boat or engine foreign?
but did he use the right bearing. they are all numbered and if the numbers are wrong it may be metric. Is the boat or engine foreign?
Space mechanics
and other experts, if you read the orginal post: "I noticed some up and down play..." how can you say that the bearing had the wrong diameter?? or that the shaft was worn out???. Paul Alkers' theory makes more sence to me.
and other experts, if you read the orginal post: "I noticed some up and down play..." how can you say that the bearing had the wrong diameter?? or that the shaft was worn out???. Paul Alkers' theory makes more sence to me.
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