Seized screws

T

Tomaret

Well-Known Member
Joined
8 Oct 2014
Messages
680
Visit site
My Lewmar 43ST winch is scoured to a plate which in turn is screwed through the grip deck into an aluminium plate. I can’t get to the back of the plate. The screws holding the plate in place may have been in place since the boat was built in 1989 but now I need to remove them. The screw heads are ph3, and using the correct screwdriver I have failed to move any of them. I’ve sprayed WD40 in the hope that it would seep down the screw hole but it had had no effect. Grateful for any other ideas, please.
 
PB Blaster, this was the only stuff that freed off some extremely stubborn manifold bolts before i considered cutting gear, its American but available on ebay & amazon, link below:

PB Blaster
 
I have seldom failed with PlusGas, though in one case I had to leave it for a week. Wd40 is well known to be ineffective. Alternatively, ther are the methods which use heat but I haven't had to do this, though it might prove necessary.
 
GrahamD said:
Can you use an impact driver?
Click to expand...
An impact driver is a lot more use on seized screws than WD40 or similar. The problem with penetrating lubricants is that the driver is more likely to slip, and chew up the screw head up even more, If used correctly the impact driver can just "crack" the corrosion, and free it instantly.
 
Heat everything up, as much as possible without melting the deck. The product you need to get in the threads is called 'Penetrating Oil' you can still buy it in normal bottles, like the old 3 in 1 bottles.
Make sure the phillips recesses in the screws are spotless with no grit, and buy a quality bit not Chinese.
A smear of fine valve grinding paste on the bit will stop it camming itself out of the screw.
A hand held inpact driver hit sharply with a 2lb club hammer, when all is hot, should do it.
If not, drill them out.
 
Good advice above. Use penetrating fluid, use an impact driver but if that doesn't work then drill the screws out .... but use a left-hand drill bit as that is also likely to unscrew the screw even before it gets through the head.

Richard
 
elton said:
An impact driver is a lot more use on seized screws than WD40 or similar. The problem with penetrating lubricants is that the driver is more likely to slip, and chew up the screw head up even more, If used correctly the impact driver can just "crack" the corrosion, and free it instantly.
Click to expand...

Also, a couple of gentle taps in the tightening direction can help to break the bond before the serious attempts to undo.
 
RichardS said:
Good advice above. Use penetrating fluid, use an impact driver but if that doesn't work then drill the screws out .... but use a left-hand drill bit as that is also likely to unscrew the screw even before it gets through the head.

Richard
Click to expand...

Good grief; where do you get one of those, short of resorting to an anti-matter universe? (I know screw extractors have an anti-clockwise tapered spiral.)

Mike.
 
mjcoon said:
Good grief; where do you get one of those, short of resorting to an anti-matter universe? (I know screw extractors have an anti-clockwise tapered spiral.)

Mike.
Click to expand...

Any half decent engineering equipment suppliers or many places on line,

( Normal drill bits, and screw threads, are left handed in the southern hemisphere where even sundials run the opposite way. ;) )
 
VicS said:
Any half decent engineering equipment suppliers or many places on line,

( Normal drill bits, and screw threads, are left handed in the southern hemisphere where even sundials run the opposite way. ;) )
Click to expand...

What, no links? And you'd also need a drill that works in reverse, though drills that double as screwdrivers often unscrew. And a chuck that does not loosen if run backwards... Those antipodeans must go down their plugholes widdershins in frustration!

(My late mother visited the southern hemisphere without noticing that the sun went into reverse. But she probably took her N hemisphere watch with her!)

Mike.
 
mjcoon said:
What, no links? And you'd also need a drill that works in reverse, though drills that double as screwdrivers often unscrew. And a chuck that does not loosen if run backwards... Those antipodeans must go down their plugholes widdershins in frustration!

(My late mother visited the southern hemisphere without noticing that the sun went into reverse. But she probably took her N hemisphere watch with her!)

Mike.
Click to expand...

As Vic says, a full set off left-hand/anticlockwise HSS bits can be easily bought over the internet. You do need a drill which will run anticlockwise but all my portable drills do that. The chucks are designed not to loosen when run anticlockwise as I guess that there wouldn't be any point it providing the facility if it couldn't be used. :)

13Pcs HSS Left Hand Drill Bit and Screw Extractor Set Titanium Nitride Coated | eBay

Richard
 
Just to report back that an impact driver, penetrating fluid, value grinding paste and a hammer worked a treat!

Again, many thanks for the helpful advice.

Mark
 
VicS said:
Any half decent engineering equipment suppliers or many places on line,

( Normal drill bits, and screw threads, are left handed in the southern hemisphere where even sundials run the opposite way. ;) )
Click to expand...

Thats where I have been going wrong all the time. I am still using the drills that came with me when I left the UK.

I looked at RichardS posting but it seems that supply will not send to South Africa which don't help me.:(
 
You must log in or register to reply here.

Share this page

Top