Removing stripped grub screws

[vyv_cox]

Surely the big solid clamp thing is a casting? Is there any way to check it's stainless, please?

If it was plated brass a small drilling would identify the unmistakeable colour of brass/bronze. However, every one of these fittings that I have ever seen has been stainless and I do not recall seeing a brass one. I have many cast stainless ones.
Stainless Steel and Cast Range | Baseline Marine Products Ltd

 

[PaulRainbow]

I have similar in one of the clamps that holds my bimini together, the lower of the two:

It has been so extremely uncooperative so far that I'm dubious whether an extractor will work. Which is weird, because it seems to be stainless steel and presumably the clamp body is a brass casting? Also strange how it seems to be surrounded by more corrosion than the upper grub screw - I'd not noticed that before.

Heat it with a blow torch and knock a suitable sized Torx or spline tool into it. If that doesn't undo it, as Vyv suggests, drill it out. The heating will make it easier to drill, if you have to go that way.

 

[KevinV]

Is there a huge rush? Time is an oft-forgotten ally - soaking in Plusgas for a few weeks will do wonders. Seal the bottom edge and the only place for the fluid to go is through that thread.
A few cycles of heat on the clamp to expand it away from the screw will help a lot. Then bash in a torx - even just the bashing will help anyway.

 

[Boater Sam]

Whatever you used in the first place was not a good enough fit.
You are fortunate that there is a bit protruding, a long time tapping on them may well loosen the threads. Keep dosing with Plus Gas, not WD40.
Then get a really good fitting torques or allen bit.

 

[thinwater]

Lots of good ideas.

Cutting the fitting off is another possibility. Delicate work with a die grinder, depending on your expereince. Stop just short of through.

 

[CJTurner]

I did mine in on the cutlass bearing. A Dremil with stone bit resolved it quite easily, without ruining the thread. If you do resort to drilling, cobalt drill bits cut stainless very easily.

 

[KompetentKrew]

… every one of these fittings that I have ever seen has been stainless and I do not recall seeing a brass one. I have many cast stainless ones.
Stainless Steel and Cast Range | Baseline Marine Products Ltd

Thank you.

 

[SimonNZ]

I ended up buying new bimini clamps to solve @vyv_cox's problem.

While I was at it, I tried to find replacement grub screws for some other clamps that had missing ones. I couldn't find grub screws with a point (damage your chromed frame but at least they stay put-ish) anywhere, even at Blacks Fasteners (here in NZ, probably the biggest fastener suppliers). Blacks gave me a few without points for free because it wasn't worth raising an invoice for them.

 

[thinwater]

I did mine in on the cutlass bearing. A Dremil with stone bit resolved it quite easily, without ruining the thread. If you do resort to drilling, cobalt drill bits cut stainless very easily.

For those who do not know, a die grinder is basically a heavy duty Dremel. Most use 1/4" shank instead of 1/8" shank, and the speed is just a little lower. The cutting disks and stones are about twice as big. But very similar and good for reasonably delicate work.

 

[William_H]

OP should if possible find a similar grub screw in the structure. Look at it very closely. It is likely that what he thought was a hex socket was a spline drive. Get a set of so called tamper proof screw driver tips. he may find the correct tip. In which case he may be able get a drive onto the screw. As said with some sort of freeing agent or heat. As said if all else fails try drilling out. The heat of drilling will aid in removal. ol'will

 

[PaulRainbow]

OP should if possible find a similar grub screw in the structure.

You mean like the one an inch away from, see post #18

Look at it very closely. It is likely that what he thought was a hex socket was a spline drive. Get a set of so called tamper proof screw driver tips. he may find the correct tip. In which case he may be able get a drive onto the screw. As said with some sort of freeing agent or heat. As said if all else fails try drilling out. The heat of drilling will aid in removal. ol'will

Never seen bimini fitting with spline drive grub screws.

 

[penberth3]

OP should if possible find a similar grub screw in the structure. Look at it very closely. It is likely that what he thought was a hex socket was a spline drive. Get a set of so called tamper proof screw driver tips.....

I'll bet you a pound to a penny it wasn't spline drive. On a grub screw, really? And tamper proof spline drive, is there such a thing?

 

[rogerthebodger]

All stainless I think, which suggests galling as the culprit. If so, the two are welded together. Drilling out is the only answer.

Stainless ste grub screws tend to be much softer than normal grub screws as I found when fitting my PSS stern seals rotors

Try drilling them out

 

[William_H]

I'll bet you a pound to a penny it wasn't spline drive. On a grub screw, really? And tamper proof spline drive, is there such a thing?

You may well be right about OP's grub screw. However I may be misleading in describing the small kit I have of a variety of screw driver tips. (about 32 different ones) It contains spline drive (or is that Torx?)in a variety of sizes with a hole up the middle. Something like this
Pardon Our Interruption...
Yes from 50 years ago I regularly used a 4 spline drive on a radio knob grub screw and just on Saturday needed a 6 spline drive to remove in this case a screw on gas strut on my old Ford. It is not safe these days to assume what seems like a hex allen key drive is indeed that. ol'will

 

[vyv_cox]

Stainless ste grub screws tend to be much softer than normal grub screws as I found when fitting my PSS stern seals rotors

Try drilling them out

I assume they are not all made in the same way, or possibly not all of the same material. There are some on my stern arch that were too hard to drill, even with fresh out of the wrapper cobalt bits.

 

[mattonthesea]

Thanks everyone. I should probably have given some context: the boat is in Finland and I won't be there until May so no hurry. I am planning for what I need to take. The fitting was from Seashure before they ceased trading. The screw is at the bottom of the bar so I can't soak it although I could keep spraying.

It's entirely my fault. I mixed up my quality hex keys with my cheap supermarket ones and I didn't notice the change from turning to stripping; twice! I only put the bar up last June.

If they are that soft then I imagine I'll be able to drill them out. I'll take a left handed thread drill bit with me (well, several I suppose as I'm not sure of the size. M6?).

I'll also get a torx set (never come across these before but I have been foiled by an adjustment screw with that head!!!

There is an engineer in the yard and he is happy to lend tools so I think I've got it covered. What a wonderful place this is.

M

 

[mattonthesea]

Thanks everyone. I should probably have given some context: the boat is in Finland and I won't be there until May so no hurry. I am planning for what I need to take. The fitting was from Seashure before they ceased trading. The screw is at the bottom of the bar so I can't soak it although I could keep spraying.

It's entirely my fault. I mixed up my quality hex keys with my cheap supermarket ones and I didn't notice the change from turning to stripping; twice! I only put the bar up last June.

If they are that soft then I imagine I'll be able to drill them out. I'll take a left handed thread drill bit with me (well, several I suppose as I'm not sure of the size. M6?).

I'll also get a torx set (never come across these before but I have been foiled by an adjustment screw with that head!!!

There is an engineer in the yard and he is happy to lend tools so I think I've got it covered. What a wonderful place this is.

M

Next question: what size Torx bit set and who makes good quality? Would this be good?
https://www.screwfix.com/p/bosch-1-4-hex-shank-tx-impact-control-screwdriver-bits-8-piece-set/194fw

 

[Poignard]

Thanks everyone. I should probably have given some context: the boat is in Finland and I won't be there until May so no hurry. I am planning for what I need to take. The fitting was from Seashure before they ceased trading. The screw is at the bottom of the bar so I can't soak it although I could keep spraying.

It's entirely my fault. I mixed up my quality hex keys with my cheap supermarket ones and I didn't notice the change from turning to stripping; twice! I only put the bar up last June.

If they are that soft then I imagine I'll be able to drill them out. I'll take a left handed thread drill bit with me (well, several I suppose as I'm not sure of the size. M6?).

I'll also get a torx set (never come across these before but I have been foiled by an adjustment screw with that head!!!

There is an engineer in the yard and he is happy to lend tools so I think I've got it covered. What a wonderful place this is.

M

If you apply the PlusGas to the the upper side it will find its way round to the grubscrews. If you tape a bit of freezer bag around the fitting, the PG will have time to soak in.

 

[vyv_cox]

Next question: what size Torx bit set and who makes good quality? Would this be good?
https://www.screwfix.com/p/bosch-1-4-hex-shank-tx-impact-control-screwdriver-bits-8-piece-set/194fw

I think your grub screws will be very unusual to have Torx sockets, but they are not expensive. Those should be excellent: impact drive ones are tough and strong.

 

[Humblebee]

If you apply the PlusGas to the the upper side it will find its way round to the grubscrews. If you tape a bit of freezer bag around the fitting, the PG will have time to soak in.

Or a bit of electrical tape, masking tape or whatever, anything to keep the PG in place and let it soak in.