Stainless stud in aluminium

[MM5AHO]

Wanting to overhaul the Simpson Lawrence anchor winch I needed to unbolt it from the deck. Its held by 4 x 10mm diam stainless studs into the bottom of the winch (aluminium) and through the deck.
Three studs came out OK, the fourth is siezed.

I have tried two nuts locked together to try to remove this, but have sheared the stud twice so far. There's still about 50mm stud left !

Any ideas on how to remove the stuck stud?

I have the winch off the boat now, and on the bench, being able to remove it with the offending stud still in it.

 

[srp]

There's still about 50mm stud left !
I have the winch off the boat now, and on the bench

That's a good start. If you can heat the exposed bit of the stud, preferably to red heat, it might expand enough further down in the seized portion to break the corrosion that holding it. Heat and a decent penetrating oil (maybe some ACF50 which some recommend) may just do it.

Don't even try to drill it out unless you have a decent pillar drill, and can bolt the winch onto the table at the right angle. If you can do this, start the 'drilling' with an end mill (very slow speed, plenty of cutting fluid and a firm pressure on the bit. Clean the swarf out of the hole frequently. Use an 8mm end mill, and centre it so you don't damage the thread. When you've managed to cut a decent depth with the end mill, change to a decent (ie new or newly sharpened) HSS drill bit to remove the remainder.

Two things not worth trying are drilling with a hand held drill (because the drill bit will wander off course, impossible to correct) and attempting to use stud extractors (which will break, and you won't get the extractor out).

 

[Fr J Hackett]

Best bet will be to cut off flush and then drill it out and Hellicoil the resultant hole and put in a new stud.

 

[SAMYL]

Drilling it out should only be attempted as a last resort. Stainless is difficult to drill at the best of times and a nightmare when in aluminium.
As above heat it up to to very hot and give it a good sound clip on the end with a hammer to shock it, not that hard that you will damage the aluminium though.
Clamp it as tight as you possibly can with good mole grips or in a vice if possible. Do NOT try to screw it out in one go, wiggle it back and foreward to loosen it whilst applying easing oil. Do not apply too much force, take your time and go gently. Only when it is quite loose try to unscrew it a bit at a time and keep screwing it back in and out again with lots of oil.
Best of luck.

 

[electrosys]

This is a common scenario with old Seagull engines.

The best method is to heat the ally around the stud. LOTS of heat - far more than you would imagine. Use 2 x locked nuts on the stud if there's still room - but don't use excessive force. If it won't budge - then MORE heat.

Another approach is to arc-weld a nut on top of the stud - it's the same principle, but in reverse - causing expansion of the ally (via the heated stud), then allowing the stud to cool.

Flood the thread with WD40 or the penetrating oil of your choice as soon as you get movement, then work back and forth ... you know the rest.

 

[vyv_cox]

I agree with most other posters. Heat is the best option and the 'weld a nut on' hint is probably the best of them as it puts high heat into the area where it is needed. Aluminium conducts heat so well that you would need to use a blowlamp on it for a very long time to heat sufficiently.

Drilling out a hard stud in a soft body is a very skilled activity. If you could mount the windlass solidly and use a pedestal drill you might get away with it but I wouldn't put money on it.

Chemical release methods that are sometimes suggested include Coca-Cola, sodium carbonate and caustic soda solution but success seems to be intermittent.

 

[boguing]

Leave a rag soaked in Ammonia on it for a day, keeping it wet. Breaks down corrosion in alloys of alu.

 

[Fr J Hackett]

The previous replies re the use of heat are quite correct it is a potential and the first way of extracting the stud. However it is perfectly possible with good drill bits a slow speed and a steady hand to drill out stainless studs by hand. I have twice done exactly that for the very same problem that the OP describes with a Lofrans windlass. Center punching first then a small pilot hole followed by drilling out with a series of drills. One occaision required the hole to be Hellicoiled and the other I was able to pick out the remains of the stud without damage to the existing threads. The process requires patientce a steady hand and the right tools but is achievable, perhaps it's because I come with an engineering background from family, education and a practical bent with more hours than I care to remember at work bench that I would say it can be done. It maybe not everyones first choice but if all else fails give it a go.

 

[ghostlymoron]

If you've still got sufficient thread protruding - you're in with a chance. Lock 2 nuts together and use WD49 or diesel to penetrate the thread for a couple of hours then wiggle the thread back and forth till it gives a bit. Then more penetrating fluid, wait and repeat the process. Excessive force is not the answer (you'll only break the stud as you have found out), patience is the key, it could take several days as the fluid only works down the thread slowly. I'd be careful with heat as aluminium melts at fairly low temp - some heat would be good tho.

 

[Lodesman77]

My experience of this - rebuilding an Aries, all stainless in aluminium - is that a combination of heat and plus gas will work, given enough heating cycles. Heat up the stud as previous posters have said, and allow to cool. Apply plus gas. Repeat at least x5. Then use locked nuts/welded nut/pipe wrench...

 

[MM5AHO]

Update:

Thanks for many useful replies. This forum seems best at helping others from the experience of one who has been there before!

So I tried the heat, lots of heat and alternate WD40 after cooling. With the 2 locked nuts still could not budge it, so went to the serious stage of drilling it out. Mounting the whole winch on my pillar drill, and with the stud sawn off flush and filed flat, and a centre punch for alingment, I started with a 3mm dia bit and increased in 0.5mm dia steps up to 8.5mm.
Then I was able to peel the remaining thread out of the aluminium for about half the depth of the hole.
Next a tap of the right thread, removed the balance and cleaned up the internal thread.

So now four clean stud holes.
But I wish I'd closely inspected the rest of the winch first.
Its a Seawolf, and spares seem to be available at very few places, and at quite high prices.
To refurbish this winch will mean just over £300 in spare parts, and thats about half way towards a whole new winch.

So before doing that I'm looking at a new winch, hoping I might find something with about the same mounting arrangement in order to avoid new holes through the deck!

But I did get the stud out!

 

[Bosun Higgs]

Any ideas on how to remove the stuck stud?

Not difficult to do if you can apply serious heat to the ally. There is no way the stainless will resist if you get the ally warm enough but the problem is having the courage to go at it.

If you arent willing or there is something nearby that will be damaged by heat, then it isnt that difficult to drill out a stud. Start very carefully with a small diameter drill and preferably in a bench drill if you can manage it. Use a sharp new drill bit, drilling slowly with good pressure. Let the drill cool regularly and dont let swarf build up. Done carefully you wonyt even need to helicoil - you can usually get the last bits out without doing too much thread damage and can clean up the thread with a tap.

But try heat first

 

[Boo2]

Wanting to overhaul the Simpson Lawrence anchor winch I needed to unbolt it from the deck. Its held by 4 x 10mm diam stainless studs into the bottom of the winch (aluminium) and through the deck.
Three studs came out OK, the fourth is siezed.

I have tried two nuts locked together to try to remove this, but have sheared the stud twice so far. There's still about 50mm stud left !

Any ideas on how to remove the stuck stud?

I have the winch off the boat now, and on the bench, being able to remove it with the offending stud still in it.

If you try penetrating oil and so on as per other posters' ideas for loosening it without joy then the risk of shearing the stud is less important because you will need to cut the stump off anyway to drill it out.

If so then I'd proceed as follows : make up a jig from 3/8" plate steel with three holes in it. One hole over the stud you want to remove and the other two to bolt the jig down on the deck. Then drill the remains of the stud out with a hand drill using the jig to guide it, I don't see how you could use a pillar drill to do that. You could try starting with a centre drill as they are stiff and not prone to wander.

Good luck,

Boo2

Edit : Doh ! Should have read to the end...

 

[SAMYL]

Update:

Its a Seawolf, and spares seem to be available at very few places, and at quite high prices.
To refurbish this winch will mean just over £300 in spare parts, and thats about half way towards a whole new winch.

So before doing that I'm looking at a new winch, hoping I might find something with about the same mounting arrangement in order to avoid new holes through the deck!

But I did get the stud out!

I am assuming that the spares you will need are only bearings and seals so why are they so expensive unless you need some other bits and pieces.
Bearings and seals, both imperial and metric, are usually all available from good bearing stockists and at a fraction of the cost quoted from agents.

 

[Fr J Hackett]

Update:

Thanks for many useful replies. This forum seems best at helping others from the experience of one who has been there before!

So I tried the heat, lots of heat and alternate WD40 after cooling. With the 2 locked nuts still could not budge it, so went to the serious stage of drilling it out. Mounting the whole winch on my pillar drill, and with the stud sawn off flush and filed flat, and a centre punch for alingment, I started with a 3mm dia bit and increased in 0.5mm dia steps up to 8.5mm.
Then I was able to peel the remaining thread out of the aluminium for about half the depth of the hole.
Next a tap of the right thread, removed the balance and cleaned up the internal thread.

So now four clean stud holes.
But I wish I'd closely inspected the rest of the winch first.
Its a Seawolf, and spares seem to be available at very few places, and at quite high prices.
To refurbish this winch will mean just over £300 in spare parts, and thats about half way towards a whole new winch.

So before doing that I'm looking at a new winch, hoping I might find something with about the same mounting arrangement in order to avoid new holes through the deck!

But I did get the stud out!

Well done, when brute force fails sound engineering often comes to the rescue:

 

[Boo2]

So I tried the heat, lots of heat and alternate WD40 after cooling. With the 2 locked nuts still could not budge it, so went to the serious stage of drilling it out. Mounting the whole winch on my pillar drill

Sorry, but I can't picture at all how you did this, did you take any pix ?

But I did get the stud out!

Congrats on that anyway,

Boo2

 

[MM5AHO]

I didn't take any pix, sorry.
But what I did was hacksaw off the stud close to the surface of the aluminium it was in, then carefully filed it smooth and flush. The using a centre punch, punched a starting point to drill from, and moved up progressively in drill bit sizes, drilling a little at a time. This meant less bit on the drill bit, removing only a little at a time, easier to control.
Stopping drilling where there is only stainless spiral left embedded in the aluminium in the V of the thread, this residue of stailess was more easily removed. That left a corroded aluminium internal thread which was cleaned with a tap, using same technique as drill bits, start smaller and work up to full size.

On prices for this obsolete winch, and worthwhileness of refurbishment.

See http://www.slspares.co.uk/parts.php?product=Seawolf+520+Windlass+
for some idea of spares pricing.
If I'm going to refurbish, I want t end up with an almost new winch. So the two gears with dodgy teeth must go, the plastic pawl release, new cones, washers, clutch, bearings, stainless cover, and a few other bits.
There's significant corrosion of the main aluminium block (hence stuck stud), I removed about 10mm of aluminium oxide / salts from the underside, and inside the geartrain cavity there's deep pitting. The gear train cover is very brittle. NOt sure what that material is, some type of fibeglass or similar, but its very easily damaged.


I can get a Lewmar Pro series 1000 for between £650 and £850 (quite a price variance for the same spec). Here's a solid block of stainless, and its heritage is the Simpson Lawrence ancestry that the Seawolf 520 came from originally. Not sure of the seawolf age, but SL closed about 10 years ago at least; the winch is probably about 1980's vintage. The original manual I have looks 1970's!!

 

[Stemar]

I can get a Lewmar Pro series 1000 for between £650 and £850 (quite a price variance for the same spec).

For that sort of money you could get an electric one. I don't know if it'd be big enough for your boat, or of adequate quality but, personally, as a confirmed lazy old bugger, I'd certainly give it a look!

 

[MM5AHO]

The Seawolf is electric, so is the Lewmar.
Boat is 10m (32ft), so there are all appropriate size. Boat is cabled for high current winch (15mmsq or something? bit like starter cables for a car).
Electric is mandatory. I'm co-owner with an octagenarian who sometimes sails solo!

 

[Neil]

Not difficult to do if you can apply serious heat to the ally. There is no way the stainless will resist if you get the ally warm enough but the problem is having the courage to go at it.

If you arent willing or there is something nearby that will be damaged by heat, then it isnt that difficult to drill out a stud. Start very carefully with a small diameter drill and preferably in a bench drill if you can manage it. Use a sharp new drill bit, drilling slowly with good pressure. Let the drill cool regularly and dont let swarf build up. Done carefully you wonyt even need to helicoil - you can usually get the last bits out without doing too much thread damage and can clean up the thread with a tap.

But try heat first

Of course it's not always convenient to heat up the workpiece or put it under a stand drill.

After having made one of the most unsuccessful attempts ever to hand drill out a sheered SS bolt from an outboard casing, I came across this:

http://www.quikcenter.com/index.html

Of course I'd wished I'd seen it first, but anyone used anything similar?