Drilling stainless steel bolts

BlueChip

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My SL Sprint 1000 powered anchor windlesss has seized up and I need to get it off. Its bolted though from under the deck, I removed these, but the Windlass seems to be stuck down with sikaflex on my teak deck and i am unable to move it.
The motor/gearbox is bolted to the frame from underneath and I have loosened one of the allen head screws but three are impossible to move and I have damaged the head of two of them

Looks like I need to drill the heads off the screws - they are s/steel. Anyone got any tips of the best way to go about this?
 

Das_Boot

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If you can get a vice grip onto them try it. I know it has its limits depending on the size of the bolt but you would be amazed at what you can loosen using one.
 

StephenSails

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Cheap cobalt drill bits from screwfix work a treat, go really slowly and use some cutting compound as well if you can.
 

bugs

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I feel for you. I had a similar problem and it was a nightmare. The aluminium section on top had bound to the bearings and the bearing would not shift from the shaft coming up form the gear box. Even when i had the top moving and the bolts extracted it would not disassemble.

If you drill off the heads of the bolts you will still be left with the shaft of the bolt whose threads are obviously seized. Perhaps a vice grips will be enough to grip the remaining part of the bolt, assuming there is enough protruding.
You could consider using a bolt extraction tool (tapered drill like device with reverse thread). By drilling a suitable hole in the head of the bolt the bolt extractor can be tightened into the hole and provides you with enough grip to remove the bolt. The end of the bolt extractor has a square end which normally connects to a tap wrench. Bolt extractors are available in most tool shops. Id go for the coarse threaded version (i wiped fine threaded one on an m8 stainless bolt on a propellor once......)

Not sure of what materials you have but consider using heat too. If threadlocking compound was used the heat will break the bond. In fact it might be worth trying heat first. It may even help with disimilar materials.
 

cliff

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Before you go drilling anything take a look at a set of IRWIN nut/bolt removal "sockets". These look like ordinary sockets but the inner "hex" is in fact spiral and taper cut and designed to "screw" onto damaged nuts / bolts and grip tighter the more torque placed on them. They are no use for tightening nuts etc as the spiral runs the wrong way. I have used the smaller ones to remove Allen headed studs when I had rounded of the inner hex.
I bought a full set last year and they have more than repaid me is saved time and frustration when dismantling outboards, inboards and other rusty machinery.

Irwin Extractor here

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hammer.thumb.gif
 

bugs

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oh, forgot to mention.
I went through lots of drill bits like ,wellllll quickly....
I recommend spending a few quid on a tungsten carbide bit.
And use anti-sieze paste when you reassemble.
 

Graham_Wright

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Two other thoughts following my previous.
Try an impact driver (especially after heat as someone else recommended).

If all else fails and you can avoid setting fire to the boat, stick weld an extension on the bolt head.

The trouble with stainless is that it can cold weld to itself. Taps with a hammer (many in my experience) and simultaneous torque may work if you can still apply the torque.
 

reeac

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The best tip that I've had re. drilling SS is to make sure that there's some swarf coming off - if there isn't then the drill is just skimming over the surface and will become blunt almost immediately. Use a very low speed and heavy pressure and using any lubricant will simply require even more pressure so don't bother. Cobalt drills are frequently recommended but I'm told that HSS work quite well.
 

cameocrew

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Tungsten carbide drill +treflux cutting compound -careful starting as drill
will 'bounce' a little on damaged heads ( i use highest speed to start then slow
to drill head off) This combo goes tru SS like sh1t tru goose
 

BlueChip

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Thanks for all the tips, I'm fully equiped with everything suggested - and if all else fails a very big hammer!
Tomorrows the day - wish me luck
 

alienzdive

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If you are wanting to take it off and throw it away, get into it with a grinder, cut the whole thing into piecs or cut through a srew head.
 

Avocet

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You can sometimes get good results using a masonry drill with the tip ground like a HSS drill. They are quite difficult to grind ('cause they're very hard!) but once you've got a decent cutting edge on them they're pretty good for drilling hard materials.
 

BlueChip

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Thanks for all the replies - in the end I cut the heads of the bolts using a dremel and cutting wheel - went through the s/s like a hot knife through butter - still not get the thing apart though
 
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