1988 C34 Mk1 #647, Universal M25XP
My boat is on the hard now for bottom paint, hull polish etc.
Decided to do maintenance on the PSS Dripless Shaft Seal ie replace bellows, hose clamps,O-rings, set screws.
I had several areas of difficulty but can deal only with one in each post.
A: Cutlass Bearing
My yard had the same tool for cutlass bearing removal shown in Mainsheet's article 'A New Prop Shaft' on his website:
http://www.pbase.com/mainecruising/new_shaft
It's a beauty and really beefy (will handle shafts up to two inches). Mine came out easily. With the cutlass out, and the shaft coupling off, the shaft slid out easily clearing the rudder by 1/4 inch.
My problem is this:
I clean the shaft with an abrasive bristle cone in a cordless drill. Works great and leaves the shaft nice and shiny. With the shaft out, when I slide the new cutlass on it seems much looser than I expected. If I stand the shaft upright, the cutlass will slide easily down the shaft (gravity). I can feel the play between the bearing and shaft. The old bearing (quite worn) will not do this.
Pic 1807 shows the shaft section which sits in the cutlass. The grooves are caused (I think) by small critters (barnicles) which grow between the ribs of the cutlass all winter. When I run the motor and turn the shaft, the tiny calcium shell cuts a groove. I can see the hard bits in the old cutlass at the right places. The grooves are not caused by the two set screws securing the cutlass (not in the right places). I don't think these grooves affect the operation of the cutlass.
(NOTE my first attempt at posting this was rejected because I could not shrink the pic's enough. This second attempt has only the first pic but the following description of the remaining three gives the general idea.)
Pic1816 is a shaft measurement (caliper reading) off the cutlass site. I get 998 or 999 (thousandths) over most of the length of the shaft.
Pic 1824 shows 999 at the cutlass site.
Pic1821 shows 997 in one of the grooves. Another showed 996 but they are only grooves, not lengthwise disturbances.
I have taken the shaft and cutlass back to the chandlers and tried another bearing they had in stock: same thing! These are the same bearings you all use:
Johnson Cutless Bearings 1" x 1&1/4" x 4". Manufactured by DURAMAX MARINE.
Question A1: Is this a problem? Does the cutlass rubber swell or expand a bit when submerged (like nylon) to become a tighter fit? I'm worried this situation might cause a lot of vibration.
Thanks
Roger : The cutlass rubber is not going to swell! Is there any chance of you trying the new cutlass bearing on another 1" shaft (stainless or bronze)?
The new cutlass bearing should fit snug on the shaft.
Thanks Ron. I'll look around, see if I can find another shaft.
I called tech support at Duramax (440-834-5400). Very helpful. Says there should be clearance 3-8 thousandths between top of the nitrile rubber ribs and the shaft for water film. If you hold the bearing on the shaft between thumb and forefinger, and push with thumb (at 6'oclock), you should clearly see space at 12 o'clock. I'm relieved.
Roger, you can post more pictures in subsequent "Replies".
Thanks Stu. This is pic 1824 referenced above.
I wonder if the fit to the shaft will improve once it is pressed into place?
Hi,
As Roland said, this is exactly what I was going to answer you.
You are trying the bearing loose on your shaft, but remember that when you will put it in the support, being press fit, will 'squweeze' it.
The ID of the bearing won't be the same, and fit between the bearing and shaft will become good.
Quote from: patrice on May 28, 2014, 12:48:25 PM
Hi,
As Roland said, this is exactly what I was going to answer you.
You are trying the bearing loose on your shaft, but remember that when you will put it in the support, being press fit, will 'squweeze' it.
The ID of the bearing won't be the same, and fit between the bearing and shaft will become good.
I hate to disagree Patrice, but I don't see any way that the metal bearing sleeve will signinificatly compress in radius after fitting.
Press fit tolerances are very, very small.
Here is a thread on the subject that agrees with my hypotheses that the bearing ID will be reduced when it is pressed into the housing:
http://www.cruisersforum.com/forums/f55/cutlass-bearing-1830.html
Just to give you a rough idea,
Take your caliper and measure the OD of the bearing, and measure the ID hole where you will install the bearing. Say this will give you the compression you will end up on the bearing.
Measure the OD of the shaft and the ID of the bearing. This will give you the play dimension.
Now take your play measure minus the compression value = this will give you the final play you will get.
Again, this is not accurate procedure, but will give you a ROUGH estimate.
From my machinists handbook under press fit for no rotational forces.
0005/.0010
I would be curios what the actual inside\outside measurements for the parts are?
Guys : Reread the post as Roger's cutlass bearing is NOT pressed in, it is held in place by set screws!!!
What I asked Roger to do was to find out if the cutlass is the fit problem? and then to see if the shaft is the fit problem?!
A thought
Thanks everyone for all the input.
Some of the dimensions requested:
Old cutlass bearing: OD 1.248 to 1.250 (a few 1.247 and 1.253 spots!) Could have been distorted during push out.
New cutlass bearing: OD 1.250 everywhere
ID 1.007 to 1.008
Note this inside dimension is hard to measure (rib to rib) and it is only the first 1/2 inch into the bearing.
The shaft is 0.998 to 0.999"
The strut is very difficult to measure (at least for me). It is definitely not perfectly round. Think about it. Been in the water for 26 yrs, several bearing replacements - I can see the cut marks inside from the hack saws, who knows what pounding might have been applied.
Strut: ID lots of 1.248 to 1.250, a few 1.246 and even 1.253" Again the caliper only measures in the first 1/2 inch.
Patrice: I had thought about this earlier and expected (hoped) that the compressed bearing would be a little tighter on the shaft, BUT NOT MUCH. It does seem that it might be pretty hard to compress a tube.
Ron: I have not found another 1" shaft. FYI this bearing will definitely be a press fit. The yard want me to sand the inside of the strut with emery cloth. They think their big pusher might still have trouble. Even after about one hour's working on it, I can only get the bearing in about 3/4 inch (by hand). I don't expect I should ever be able to get it in very far by hand but it is still pretty tight. The set screws are insurance I think.
The old bearing can be pushed in by hand about 1 to 1&1/2 inches. I plan to keep working on the strut and when happy, install the shaft and use their tool to push in the bearing from the aft. I hope it all goes in tomorrow, maybe launch Sat. Will report on how it goes.
Hi Roger,
FWIW, after my 2nd season with the new boat I found a bit of play in my CB also. Although I do a realignment check every spring, I suspected that the Dealer didn't align properly and created some wear. Being a bit OCD, I decided to do what you did--I removed the old CB then ordered a Johnson Duramax. Found the same amount of play, so I called them and talked with an engineer. They provided the same info you posted: OD Tolerance is +/- .001, .002 Interferernce, .003-.008 ID tolerance. They also said there is tolerance for a water film. Since this didn't match my experience or what most will say about CB ID fit, I set about calling Morse (the other major manufacturer and the vendor Catalina uses) and ordering one of theirs. Same tolerances and same conversation. I then called the following: Buck Algonquin and Spartan in Maine. Finally I talked with Gerry Douglas. After all this, I installed the new Bearing and after a season found no play even though when I first installed it seemed to have the same play as the old one which based on my caliper readings were within spec of both CB vendors. Part of the reason for all my additional research and concern is because my shaft is fed through a Fiberglass skeg, not a strut and it is NOT press fit--this goes against all conventional wisdom. However after speaking with all of the above and in particular Gerry I had no choice but to trust that the slip fit plus set screws is by design. I have indeed found this to be the case. Sorry to provide all the extra info., but if your shaft is true and not scored where the Cutless should go, you should be fine per the CB engineers. Good luck and I apologize in advance if I confused the situation.
Roger : As far as I know there are only two types of struts:
1. A pressed in cutlass bearing held in by compression
2. A bearing that is held in by two set screws (usually the starboard side)
The pressed in bearing can not be inserted more than about 1/8"
while the setscrew bearing might be inserted up to a couple of inches and then pressed or tapped into position until seated.
I know of no pressed in bearing strut that also uses set screws - as the set screws are completely unnecessary!
If your shaft shows set screw impressions, someone (a dunce) turned the set screws in completely thru the cutlass casing and violated the rubber into the shaft!!
If your yard did this work, I'd recommend that you not have even have them do minor surgery unless you Life Insurance is paid up!
Don't know what else to tell you!! A few thoughts
Sorry everyone for not getting back right away. I put in the shaft and cutlass bearing (CB) Thurs morning May 29 using the yards skoocum tool STRUT PRO. I was a little sorry I worked so hard at sanding the inside of the strut with emory cloth. As I describe below, the CB went in quite easily. More on this later.
http://www.strutpro.com/
The order of things was as follows:
I did take the shaft and coupling to a machine shop for facing (dressing). Fits very nicely, can push it almost fully on, then some light tapping.
Coat the inside of strut with anti seize lubricant.
Insert shaft into strut and through shaft log. Go inside and install coupling and connect couplings hand tight. It will be off again later for PSS and stuff.
Hang Strut Pro on shaft: a bit tricky with one person, so I left the bearing off at first.
Back off the Strut Pro and let the aft end hang down. Insert CB by hand (I got it in about 3/4 inch. It prob works if you can only get it in 1/8 inch.
Bring the aft end of Strut Pro back into position, advance it in till the 1" horseshoe plate makes contact with the CB. As you drive in the CB you need to keep checking that the 1" horseshoe (drive plate) makes good even contact with each edge of the CB. At first the plate is positioned at the prop taper on the shaft so it won't automatically stay centered.
Start driving (turning the bolt heads). Apply some more anti seize to the outside of the CB. The Strut Pro is a powerful too (could push the B's off an elephant!) I actually drove the whole CB in by turning the large bolt heads by hand! Never used a wrench! The anti seize helped and the CB was cooled (frozen) but I don't think that helped much because dry fitting a cool CB didn't help much. I'm not too worried that I sanded off too much of inside of the strut. I could only ever insert it maybe an inch by hand and there are the two set screws. I was just surprised how effectively and effortlessly this tool pushed the CB in. Now that it's in, when I grab the shaft and push/pull athwart ship I can feel a tiny bit of play. I'm going to go with it.
Solstice:
Thanks for all the research. Seems to confirm where we're at.
Ron:
I hear you on press fit vs set screws. I think mine is definitely a press fit. No idea what FO's did. I expect someone (or their yard) added the set screws later (two on the port side). They look a little home made (don't go in perfectly straight). The grooves around my shaft are definitely not from the set screws (wrong place). At the set screw positions, there were no marks on the shaft. I can also see and feel small hard bits (calcium?) inside the old CB (between the ribs) at places that match the grooves.
Pic 1868: Strut Pro set up on shaft, CB not yet in place. More pics in additional "REPLIES"
Another view
Back off the Strut Pro. Insert CB by hand ; Got mine in 3/4 inch.
Guys : The Strut Pro tool is the same as C34 Fleet 12 bought for our fleet tool box. Many members of the fleet have saved $$ by pressing out the old cutless and pressing a new one themselves.
Rather than free drinks from our dues, the fleet purchases tool for the members to use.
A thought for the C34 Fleets!!
Pic 1873: Bring Strut back into position. Advance to contact CB. Apply more anti seize, Start driving!
Quote from: Ron Hill on May 30, 2014, 05:34:16 PM
I know of no pressed in bearing strut that also uses set screws - as the set screws are completely unnecessary!
If the builder actually builds to ABYC standards the cutlass bearings are all
supposed to be a "press fit". ABYC P-6 also requires a minimum of two set screws. Thus all cutlass bearings should both press fit AND have a minimum of two set screws which are also supposed to be "spotted" into the bearing shell.
Just to close this thread out, was the original shaft re-used?
Roland:
Yes I did use the original shaft. While it was out, I polished it with a cone bristle (abrasive) brush in a cordless drill over the entire length. It cleans up nicely (looks new). I wondered if that might have taken a thousandth off and contributed to the cutlass bearing sliding so easily but I don't think that was a problem. Anyway, it's in now; I'll report after I launch. I'm currently messing with significant engine mount/engine bed problems.
http://c34.org/bbs/index.php/topic,8080.0.html
You must freeze the bearing overnight (do not super cooo w/ dry ice!) to reduce the diameter and push it in as quickly as you can. Those instruction should have been with the bearing and the yard jockeys should know that.
Set screws are belt and suspenders, bearing is still a press fit.
As I said above, I did cool the bearing; freeze overnight, take to the yard (three min) in a coolie bag in freezer packs. That's why I got the STRUT PRO all set up without the CB in place, then backed off and dropped the back end so I could quickly insert the CB part way into the strut then bring the STRUT PRO back into position and drive it in. In my case no amount of cooling would have allowed me to push in the CB by hand. Most I could get was an inch+. Also it's bound to take 5-10 min so CB will warm up a fair bit.
Don't bother trying to cool the bearing for any reason, 0 deg F is not a relevant or significant temperature, -300F is.
On top of that the operation takes 30 min to press in the bearing... so how long will it remain at 0 deg F?
Only a few moments.
It's not necessary, the fit is tight and no match for any kind of press such as the strut pro or even the homemade one I used. Sorry to kick this one to the curb as it were.