Simple Prop Removal Tool

[Nonchalant1]

I had props changed at a yard in Sarasota and was amazed to see a guy pop the old props off easily with a big bronze nut device. It was simply a heavy bronze tube with threads on the inside on one end that match the prop shaft and capped on the other end with heavy solid bronze. He took the prop nuts off, screwed the big bronze tube on and hit the end of it with a handheld sledge. The props popped loose easily. I asked if that could affect the thrust bearings and he said that they're made to take much more thrust in that direction easily.

Have you guys used or seen these? It's a ton easier and much more simple than the prop puller I have always used.

Doug Shuman

 

[SKYCHENEY]

I can't really visualize it. Do you have any pictures?

 

[Nonchalant1]

Sky - no pics, but it just looks like a big thick bronze pipe, about 8 inches long and 4 inches wide with a 2" threaded hole in one end and closed on the other end with a heavy bronze cap. You screw it on, I believe a little short of actually touching the prop and hit it hard with an 8 lb sledge hammer, held in one hand on an 8 inch hammer handle. I was amazed to see them pop right off, because I've seen hydraulic prop pullers and all kinds of other heavy bolt & plate pullers that take time and work, but this took about 15 seconds.

I think that this prop puller is made by General Propeller in Bradenton, FL where I took my backup props to be tuned. These guys do lots of HUGE fancy props, have PropScan, etc. and also sell Propsmith and Algonac pullers.

I asked it this thing could be used underwater and he said it could, but the sound of hitting it under water would probably be bad for a diver's ears.

Doug

 

[SKYCHENEY]

So all of the force of the blow is taken by the threads on your shaft? Then the shock from the impact breaks the prop free from the taper? Sounds like it wouldn't be too good for the shaft, the threads, or the transmission.

 

[captddis]

I have one of the nut knockers. They work great1 I think I paid 125.00 for it from C+B Propellor. I will post a pic.

 

[Nonchalant1]

So all of the force of the blow is taken by the threads on your shaft? Then the shock from the impact breaks the prop free from the taper? Sounds like it wouldn't be too good for the shaft, the threads, or the transmission.

I wouldn't have any concern about the shaft threads because it uses all of the threads on a 2 inch stainless steel shaft against a bronze nut. The bronze would deform if anything would. The thrust bearings would be the only concern, but as he said, they're made to take large thrust in that direction.

 

[captddis]

 

[captddis]

 

[mike]

I can't think of a better way of berneling the transmission thrust bearing. On the Allison’s the bearing is marginal already, esp. if you have the ball-bearing configuration. It's less of an issue with the tapered roller bearing units, but still it is not a good practice. I rather pay the yard fee to use an appropriate puller, than risk damage to a transmission that will cost north of $5k to fix and install.

 

[captddis]

I can't think of a better way of berneling the transmission thrust bearing. On the Allison’s the bearing is marginal already, esp. if you have the ball-bearing configuration. It's less of an issue with the tapered roller bearing units, but still it is not a good practice. I rather pay the yard fee to use an appropriate puller, than risk damage to a transmission that will cost north of $5k to fix and install.

Then when the puller won't budge it the yard wacks it with a sledge.

 

[sgharford]

The full forward thrust of the prop is transmitted thru the thrust bearing. right? I would think if it could take 400hp+ of thrust it must be substantial and should be able to take a wack by hand held sledge pretty easily.

 

[J's Dream]

It's called a Prop Knocker...and it works very well. I kind of laughed at the idea when I first saw it. My friend worked for SeaRay's Product Development, and lent me the tool. I threaded it on the shaft, and hit it with a hammer 3 times like he said.

After I hit it, I unscrewed it, thinking what a stupid tool...it'll never get these props off...No sooner did I get the tool off, the prop was sliding off the shaft!

Needless to say, I was impressed...but still haven't spent the $100 to purchase one from General Propeller.

 

[Trojan]

The inursha has got to go and stop some place. That is all that the nut does is give you a place to hit.
I agree with Mike. That thrust bearing is designed to receive a constant rotating pressure. Any hitting on the bearing could cause a very small dimple in the bearing race or roller causing a premature failure. I don't like even hitting the end with the clamp type puller. The new props I have, have 3 holes drilled and tapped in the prop hub end. A special puller is used with these holes and just pulls the prop off. Very nice.

BILL

 

[saltshaker]

Then when the puller won't budge it the yard wacks it with a sledge.

Usually way too hard and continually. Seen that too many times to count. Seems that if used right, the nut buster would be less damaging.

 

[SKYCHENEY]

I have never had to hit this puller. I just keep tightening until she goes POP!

We made it up in the shop a few years ago. It will also push in/out cutlass bearings. Handy tool to have around.

 

[mike]

FWIW, angular contact thrust bearings are intended to take intermittent and continuous radial and axial loads, not excessive shock induced point contact. The amount of force delivered with a sledgehammer could well exceed the bearings material specs. Failure will not be immediate, but the initial damage will be done, and over time fatigue failure will occur. Check with any of the bearing companies (SKF etc), and you will see instructions on bearing installation cautioning to apply force only to the face of the non-loaded race. What may be easy for the yard can cost you big boat bucks. Have a homemade set-up similar to sky's using a 20-ton Hydraulic ram. It works well on both the props and the trans coupling. Further if you use the Tony Athens prop attachment method listed on the boat-diesel site, removal will be a cinch.

 

[ppat324]

Old faithful... ws

 

[captddis]

I am not going to debate for the next week, however I hate beating on things but I don't see how two wacks on the end of the nut is going to cause harm. The common way to pull shafts is with a 20 pound slide hammer. Onan and Kohler told you to use a hammer to shock the gen end off the shaft. Detroit diesel uses a sledge to shock off the harmonic balancer and cone.

What happens when a 60,000 lb boat hits bottom at speed or someone hits something hard and tulips the props or bends the shaft? That has to be a whole lot more stress on the bearings.

I have prop pullers too and often times they will not budge the prop even with a porta power maxed out to where the plates are bowing. Then go to heat, If that does not work then what? Oh yeah when using a puller and the prop comes loose and hits the nut on the end of the shaft with a violent clang, does'nt that send a shock up the shaft?

 

[Brian Degulis]

A properly fit prop that's been lapped on installation then tightened to spec which on a 2 1/2" shaft is over 800lbs of torque is never coming off without shocking (hitting) the shaft unless you heat it. If your getting if off with the puller alone then it wasn't put on correctly it's just that simple.

Brian

 

[Nonchalant1]

Old faithful... ws

Bill,

That's the prop puller I have and use. It works fine, but if one gets stuck I'd have to go borrow/rent a hydraulic version.

Doug