Would you remove a prop with an angle grinder?

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crown22

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Hi Everybody a follow on to my previous posts.An engineer and two other boat owners have confirmed that my prop has
been trashed by corrosion and needs to come off.An unsuccessful attempt yesterday with two of the three legs of the puller so tomorrow I will be attempting to cut off one of the blades to enable fitting of the third leg.Wind up the pressure and then the blowlamp comes out.If that fails then plan is to cut it off being careful not to damage the threaded part of the prop shaft and the keyway. Any other ideas gratefully received.
 
As its a three blade prop you should be able to use a three leg puller without cutting off blades unless the puller is just too small and weedy for the job. The sort of pullers sold for most small jobs are really not man enough for propellers.

Ask around to find out who has a really heavy duty one, and borrow it. Heating the prop with blowlamp then applying the puller and tightening it fully usually does the trick. Sometimes hitting the end of the forcing screw a sharp blow with a fair sized hammer is also useful.

As for using an angle grinder, its a last resort and not one I would want to try as you do not want to cut into the shaft.
 
At my club we use two very thick discs with a shaft slot cut into one of them , and three lengths of studding through 3 aligned holes in each to compress them. Not complex to make and stronger than the prop.
 
chewi said:
At my club we use two very thick discs with a shaft slot cut into one of them , and three lengths of studding through 3 aligned holes in each to compress them. Not complex to make and stronger than the prop.
Click to expand...

Exactly what my engineer in Marmaris uses. Home made and far better than any three leg puller. I think that a fair proportion of marine engineers will have made something similar. and the OP just needs to locate one.
 
Unless your prop is very small a blowlamp is not sufficient. Oxygen- propane or oxy-acetylene is required, especially on a breezy day if working outside. Three legged pullers rarely fit properly with blade overlap, as said above fabricate one with two steel plates and stud bar. Finally, use a decent sized hammer to shock it off the taper... no toffee hammers!
 
I've never yet failed to shift one with a puller with the right number of legs, though the slotted plate tool sounds better. Use a jubilee clip to hold the legs in place, and a good heavy hammer. Never fails, though may need some perseverance! As per my avatar maybe! Precision engineering with a Birmingham screwdriver.

Angle grinder? No. Too risky.

Heat? A propane blowtorch will not be powerful enough to heat that mass of metal enough to free it. Also you will almost certainly destroy the cutless bearing which may weld itself to the shaft....
 
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When I couldn't remove a tapered shaft my diesel fitter B-I-L (who worked on heavy earth-moving equipment) told me to get two heavy 3kg hammers, place one behind the prop "shaft" and give it a huge big hit on the opposite side with the other hammer. The shaft then came out easily using the puller. I assume it works a bit like squeezing an orange pip between your fingers to propel it.

Clive
 
When I couldn't remove a tapered shaft my diesel fitter B-I-L (who worked on heavy earth-moving equipment) told me to get two heavy 3kg hammers, place one behind the prop "shaft" and give it a huge big hit on the opposite side with the other hammer. The shaft then came out easily using the puller. I assume it works a bit like squeezing an orange pip between your fingers to propel it.

Clive
 
Thanks for the valuable information everybody.In particular the posting about the risk of damaging the cutlass bearing with too much heat.I will not be buying a blowlamp from B&Q today!.I have limited home workshop facilities to make the custom puller.If there is anybody near Lancaster who wants £100 over this weekend that would be great.The funny thing is that back in the day people used to remove their props to stop them being nicked.I wish somebody would nick mine without damaging the shaft!No forum rules broken I hope.
 
Jack it off.

Drill and tap two holes opposite each other in the prop hub.
Screw in threaded rods.
Get a solid piece of metal/bar/angle iron/box section
Drill holes to take the threaded rods from the prop
Weld a nut in the centre to take another threaded rod (or you can lock this with a nut either side of bar)
Either wind up the two outer bars to pull the prop or if you have the centre threaded rod in a fixed nut then wind this up to push against the end of the shaft.

Jacking off avoids any chance of slipping and or damage from the puller claws.
 
Why not get a decent blowlamp like a Rothenberger and apply heat to the prop for perhaps 15 minutes, give it a smack with a large hammer (to wake it up) and apply puller.
 
This one uses a jacking off approach with three threaded bars but two will do.
021813046.jpg
 
Jim@sea said:
Why not get a decent blowlamp like a Rothenberger and apply heat to the prop for perhaps 15 minutes, give it a smack with a large hammer (to wake it up) and apply puller.
Click to expand...

You shouldn't use or need hammers, the prop is a soft metal and shaft supports are fragile on most boats.
 
Burn the thing with a propane torche! Then sink it in a bucket with cold water, and try again with an appropriate puller! Unless the angle grinder user is skilled i wouldnt let him even think about it. I dont know about the hammer ..would this bent the shaft?
( i am a victim of angle grinder butcher who murdered old through hulls along with the hull )
 
In the absence of a good puller and or two good heavy hammers technique, which is sound practice, you could very, very carefully cut a slot in the prop boss start with the angle grinder and finish with an hacksaw to as close to the shaft as you dare then use a cold chisel and club hammer to open up the slot or stretch it. Do not apply the chisel vertically ie at right angles to the shaft but parallel to it. Any puller should then get it off if it does not come of with a tap at the back of the boss.
 
I found it easiest to remove the shaft, complete with prop, then take it to a man with decent workshop.
Then a combination of improvised puller and a sharp tap with a slide hammer and it popped off with no damage.
 
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