How to get hashed set screws out of P Bracket?

RobW

RobW

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Hi folks
I need some words of wisdom on how to progress.
We have a bit of play in the cutlass bearing (p bracket type), on our Hunter Horizon 27, so after crane out, I have so far managed without too much of a fight, to remove the prop, disconnect the shaft at the inboard end, drop the rudder and extract the shaft, HOWEVER when it came time to extract the set screws from the side of the P-bracket, things have started to go wrong!

The two set screws are recessed hex type, they are not bronze - look like s/steel (?), but they seem very soft. The slightest attempt at removal has rounded off the inside edges without really having been able to apply any kind of force - which means I am now stuffed and can' t really see a way forward without drilling them out, which could / will easily damage the thread in the bracket. (Also tried a bit of heat, but made no difference really).

1) Anyone know of any kind of tool that might grip and help extract these?
2) Where can I buy new set-screws if I ever get these ones out - and what should they be made of - s/steel?

I guess I may be looking at drilling them out and then retapping the thread - anyone got any better ideas? (Never had to do anything like this before so a bit nervous about it!)

Any advice or words of encouragement much appreciated!

(I want my boat with an outboard back!).

Rob
 
Two possibilities:-

Firstly, have you got the correct size allen key to fit your grub screws? They might not be metric sizes. the key should fit with no wobble. If the grub screws are an odd size, you could find a slightly larger allen key and carefully grind it down to fit exactly.

secondly, it is very important to dig out all the old paint lying in the hex socket so that the key will fit to the full depth.

Cheers! Neil
 
Usually if you drill the, as you have pointed out, relatively soft S/S Allen screw, but with a not too big a drill bit, then 'Easy-Out' is your friend. Stainless in Bronze should be no problem.
 
In retrospect ( and possibly still now) a blowlamp might soften the muck in the hex socket so you could clean it out with a very fine jewellers screwdriver. Then decent penetrating oil over several days. Then more heat to the P.

Failing that, I would probably cut away the cutlass bearing in segments. There may even be enough grub-screw protruding inside to get a grip on.

Personally I wouldn't be too worried about drilling them out. I would start with a drill a bit smaller than the threaded hole which would centre in the hex recess. With any luck the grub screw will come out as you drill. At worst just retap if necessary slightly larger.

Vic
 
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RobW said:
1) Anyone know of any kind of tool that might grip and help extract these?
2) Where can I buy new set-screws if I ever get these ones out - and what should they be made of - s/steel?

I guess I may be looking at drilling them out and then retapping the thread - anyone got any better ideas? (Never had to do anything like this before so a bit nervous about it!)

Any advice or words of encouragement much appreciated!
Click to expand...

I had the same problem with the grub screws on my propeller. They were stainless steel and the hexagonal head looked like it was an insert that had been pressed inside the screw. Like yours, this disintegrated very easily when moderate torque was applied. I was lucky because I could just get a small (worn) disc on a Dremel onto the head and cut a slot for a screwdriver. After cleaning up the thread (good advice earlier) I managed to remove the damaged screw.

I didn't want to repeat the process so a friend made me some new grub screws on his lathe using a normal screw for the thread part. In your case, all you need to do is chop the head off an appropriately sized s/s machine screw so that the screw is the correct length, cut a slot in the top for a screwdriver and file off any rough edges.

Edit: I'm not an engineer and there may be a good reason why a slot headed screw can't be tightened enough into your P bracket but it works on my propeller.
 
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1) The grub screw hole must be cleared with a split pin remover or similar pick type tool of any paint/debris in it.

2) The Allen Key MUST be a VERY tight fit in the grub screw. If you get it tight enough the Allen Key itself will bend before the key slips in the grub screw.
As others have said you may need to grind down an over size Key to get the required tight fit. Do not assume a Metric Key will be tight enough fit in a Metric grub screw, unless you buy a quality key eg Snap On expect to be grinding. Be careful not to destroy the Key hardness by over heating caused by grinding.
I sometimes use a ground off shortened stub of a key so I can put a socket racket driver on the end, you get more torque.

3) If others before you have Muppeted your screw than its Screw Extractor time. The ones illustrated are the older version. A much better one in my exprience is the GRABIT damaged screw and bolt remover. One size removes fastners/bolts/screws 5 -14mm and 2-8 grade hardness plus SS

Do NOT use high speed with these, slow is better and gives far better control and grip

I get mine on web, they are currently tackling over 50 snapped steel bolts set into an alloy frame 50 years old with excellent results. ( Joys of British 50s engineering design no wonder we lost our industry, my Sadler is full of similar engineering no nos)



Brian
 
If the hex holes are gone ,first of all I'd try an easy out on the set screws. It probably wont work but you will have tried it.
I wouldn't try tapping in a torx bit or anything else as you might damage or losen the p bracket.
Other suggestions about grinding down a bigger key are good
If your shaft is out you could try cutting the cutless bearing with a hacksaw and collapsing it inwards. You might find you can then get it out and screw the set screws in the way rather than out. If all that fails you could file down the ends of the set screw just leave them there and drill new holes and tap new threads in the p bracket for new screws.
Plenty if set screws avaialble on ebay. I would go for cone point ones in 316 stainless.

I had to drill new holes and tap mine a couple of years ago. It's not nearly as difficult as you might think
 
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I have never had any success with screw extractors. The 6mm screws holding my cutless bearing had to be drilled out and that stripped the threads in the bracket. I simply inserted the new cutless bearing then carefully drilled it 5mm and tapped the holes 6mm. I then secured it with screws that are just long enough to penetrate the shell of the bearing and no longer.
 
A good bet is to drill absolutely centre (easier said than done, try a centre punch first) and then drill out (new bit for accuracy) to well-shy of the threads, leaving just the husk of the set screw in.
The easy-out type removers will work best then, gripping on the remains of the set screw which may flop around the extractor and almost fall out, but leave the bracket threads untouched.

Hopefully.
 
VicMallows said:
Failing that, I would probably cut away the cutlass bearing in segments. There may even be enough grub-screw protruding inside to get a grip on.

Personally I wouldn't be too worried about drilling them out. I would start with a drill a bit smaller than the threaded hole which would centre in the hex recess. With any luck the grub screw will come out as you drill. At worst just retap if necessary slightly larger.

Vic
Click to expand...

This is your best bet, and use a shiny new drill bit to make life as easy as possible. Going up a thread size may be a good idea anyway if the head is that easy to strip.
 
A left hand drill and heat MIGHT get them out without damaging the threads but I would just drill them out then drill NEW HOLES nearby using the correct size of drill for the tap and tap them to the same size as the exisitng set screws.

This is not something that is critical on location.

It is not difficult unless you have a SS P bracket.
 
Brake fluid and an E-Z Out got the snapped off brittle steel bolts out of my aluminium Honda CB900 cyninder-block with astonishing ease!

If you can find a way to soak the screws in brake fluid for a few hours, it will find its way between the threads and lubricate them. Brake fluid is the best stuff for this job.

The EZ-Out or other variants is just a left handed tap that cuts a strong tapered thread in the hole that you will have drilled and locks itself into the same, you can then apply torque by means of a tap-wrench.

If you still have some screw head to play with, maybe you don't need the EZ-Out (I've lost mine and would need to go out and buy another if I was in the same position as you) and you could try with a bigger key or ramming in a torx bit etc..

Good luck and don't despair. My wife's 1967 FIAT 500 once spat out one of its spark plugs, threads and all! It was a simple enough operation to bore out the hole and insert a helicoil.
 
Had the same problem last year, so after retapping decided to cut a bolt to the same length and fitted that, hoping it will work in a few years time.
 
About these Allen Keys....
They are sold in kits as L shapes, which often turn out to be worse than useless because the slightest tilt and the socket gets mashed.
I have been meaning to ask this question on the forum...any alternatives to these, like allen key holders for example ?
An ideal tool would be an Allen Key with a handle, like an old fashioned gimlet.
 
VO5 said:
About these Allen Keys....
They are sold in kits as L shapes, which often turn out to be worse than useless because the slightest tilt and the socket gets mashed.
I have been meaning to ask this question on the forum...any alternatives to these, like allen key holders for example ?
An ideal tool would be an Allen Key with a handle, like an old fashioned gimlet.
Click to expand...

T-handle allen/hex drivers are available from most good tool vendors, as are allen/hex driver bits to fit socket ratchets. However, a decent quality branded L-shaped key is good enough for 95% of needs; Unbrako for preference, although there are plenty of other quality tool brands to pick, Facom, Snap-on, Teng, etc.
 
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