Removing cutlass bearing set screws

[rosssavage]

Started the replacement of my cutlass bearings today.

Both props off easy peasy, one woodruff key stuck in its slot but confidence is high by drilling and tapping a hole in the middle followed by a slide hammer.

Now the real problem - the bearings are retained by 16 (yes, 16!) stainless set screws. Got about 8 out (forgot to count..,) but absolutely predictably the rest are totally mullered with rounded out sockets. What really gets me is they were done by a 'professional' last time, who has either reinstalled knackered screws or more likely over tightened them with the wrong sized tool and ruined them...

So how to remove them?

Bought some screw extractors and cobalt drills today, leaving the screws to soak overnight in freeway penetrating oil.

What are the chances of successfully drilling out the set screws in situ with my battery drill? Removing the p brackets to do it on the bench is going to add a whole world of cost to what should be a quick job...

 

[essexboy]

Why do you need to remove the Woodruff key ? as it is on the taper wont the cutlass slide over it ?
Trying to drill through th bolts sounds frought with hassle ! what about drilling through the heads and then trying to shear or chisel the head off, that should take the load off and the trying a left handed drill. only other suggestion is a hot spanner,
(Welding gun )

 

[superheat6k]

Two are sufficient to lock the cutlass, but if it was loose in the housing then this might explain the extras this time around.

I would definitely avoid disturbing the P bracket, otherwise you will likely have to spend quite a bit of time achieving a decent alignment.

I would dril them out with the tapping size drill, so assuming they are M6, then drill 5mm. It won't matter if you go through the old cutlass. This might allow the threads to be recovered. If they are still holding the bearing then simply open up to the full OD of the thread.

Then re-locate with Loctite 601 bearign fit if the cutlass is loose, with the 8 decent holes. I would then plug the rest with some fibreglass filler or epoxy resin. I would also make a note of the locking method in the ships papers for future reference.

I used a large three legged puller with a suitable plate to push the old bearing put. If you can get to Hamble you are welcome to borrow it. The bearing must travel out asternwards as there will be a register preventing it moving out forwards.

 

[rosssavage]

Unfortunately there's a disc type rope cutter that won't come past the woodruff key, hence the requirement to remove it. That isn't really a concern though. The set screws are grub screws, so no chance of removing heads - the little blighters aren't even proud of the bracket surface, so everything has to be done down little holes...

Don't know why so many set screws.... I'll certainly only use two on the new bearings assuming they're a snug fit.

I have a special cutlass bearing puller so that's not a problem (many thanks for your gracious offer though), it's just the drilling of the stainless screws with a handheld drill that I'm a bit worried about.

 

[Keith-i]

With a decent sharp bit you can certainly drill them out with a cordless drill. Drill slowly with good pressure so that the bit bites properly and use some cutting fluid if you have it. Something similar happened on my p bracket and I ended up tapping a fresh hole the next size up for a larger grub screw.

 

[omega2]

With a decent "Made in Britain" drill bit you will have no trouble clearing them out, and then re tap the threads, to suit any new grub screws you fancy, you can also remove the old cutlass bearings before you start drilling this way the hole can be seen to be clear. Sorry almost a double post.

 

[rosssavage]

Thanks chaps. Renewed sense of optimism!!

 

[Neil_Y]

If grub screws are put in with epoxy this will hold them from coming loose and prevent corrosion. Use an epoxy that softens with heat, a low temperature one.

When you fit new bearings install them as a clearance fit so they will slide in and turn by hand and then use epoxy to hold them in place, no need for the grub screws then.

 

[rosssavage]

Well a mixed bag really!!! Success, eventually. Managed to get all the set screws out, but failed miserably with the disc type rope cutter set screw. Tried drilling but it wasn't happening... Rope cutter set with screw hole upwards and filled with cutting lubricant. Tried to pilot with 2.5mm cobalt drill, but nothing happened. Went up to about 3.2mm and again nothing!! Brand new sharp cobalt drills, immersed in a bath of lubricant, drill gearbox set to slow and run at about half speed with a firm (but not too firm!) pressure.

Nothing.

Tried many things, but in the end resorted to cutting the rope cutter off. I got through six hacksaw blades!!

Anyway, bearings now done, without removing shafts with the aid of this wonderous tool:

No connection, just very satisfied customer. Sooooo easy once the set screws are out!!