Screws for windows

[jessie]

Has anyone fitted Caldwell windows, the ordinary one that are fitted by screwing them to the surrounding metal? I'm struggling to find self tapping screws that will work and have a small enough head to fit the rubber trim over them.

[Mike Hurley]

Maybe ask Caldwells if they have them? B&Q, Wickes etc.

[jessie]

Thanks Mike, that was my plan for tomorrow but in general i've had quicker responses on here. I've looked in a few shops, but the heads are too big.

[Tony Brooks]

Sounds as if the holes in the cabin side may be oversize for the screws needed to fit the trim. If needs must maybe drill new holes in a different place so you can use smaller screws. However on many boats the screws do not screw into the cabin side,they screw into the wooden framing behind it so the hole sin the cabin side are much larger than the screw needs if it is to grip the metal.

 

Trouble is the wood often rots and sometimes so does the hole in the steel. Then it really does need new holes drilling and the old ones treating for rust, filling and painting.

2 minutes ago, jessie said:

I've looked in a few shops, but the heads are too big.

 

When I did my windows I went to a local fixing supplier but did have to buy a box.

[David Mack]

9 minutes ago, jessie said:

Has anyone fitted Caldwell windows, the ordinary one that are fitted by screwing them to the surrounding metal? I'm struggling to find self tapping screws that will work and have a small enough head to fit the rubber trim over them.

My windows are fixed with woodscrews passing through the steel into the wooden window liners. You should find a wider choice of woodscrew.

[jessie]

Thanks Tony, they are door windows and will be screwed into the metal plate of the door, holes not yet drilled as screws not yet sourced, its more a problem finding screws with a head that will fit into the channel on the window and still allow the trim to be fitted over them

2 minutes ago, David Mack said:

My windows are fixed with woodscrews passing through the steel into the wooden window liners. You should find a wider choice of woodscrew.

Hadn't thought of doing it that way, but it would work as the doors are lined with inch thick ash...thanks David, i'll look into wood screws.

[Tony Brooks]

8 minutes ago, jessie said:

Thanks Tony, they are door windows and will be screwed into the metal plate of the door, holes not yet drilled as screws not yet sourced, its more a problem finding screws with a head that will fit into the channel on the window and still allow the trim to be fitted over them

 

 

Have you thought about pop-rivets? They have a nice flat head and as you need to drill the holes can choose small ones. If you go that way it would be best to buy a decent pop-rivet gun, the bent metal ones are rubbish.

 

If you use aluminum rivets they are easier to "pop", can be drilled out more easily, and may act as an anode to have a marginal effect on corrosion around the hole.

Edited April 10, 2022 by Tony Brooks

[David Mack]

You will sometimes see countersunk machine screws with nuts on the inside suggested. Which is fine when you first fit them, but a real pain if you should ever need to remove a window.

[jessie]

7 minutes ago, Tony Brooks said:

 

Have you thought about pop-rivets? They have a nice flat head and as you need to drill the holes can choose small ones. If you go that way it would be best to buy a decent pop-rivet gun, the bent metal ones are rubbish.

 

If you use aluminum rivets they are easier to "pop", can be drilled out more easily, and may act as an anode to have a marginal effect on corrosion around the hole.

Would that work with the steel door being lined with 1 inch of wood? i'm not sure the rivet would have room to go through and flatten out on the inside of the door, or have i misunderstood what you mean?

4 minutes ago, David Mack said:

You will sometimes see countersunk machine screws with nuts on the inside suggested. Which is fine when you first fit them, but a real pain if you should ever need to remove a window.

yeah, i think it would all have been a lot simpler if the doors weren't lined, but i can't remove the lining without wrecking it 🙄

[Tony Brooks]

2 minutes ago, jessie said:

Would that work with the steel door being lined with 1 inch of wood? i'm not sure the rivet would have room to go through and flatten out on the inside of the door, or have i misunderstood what you mean?

yeah, i think it would all have been a lot simpler if the doors weren't lined, but i can't remove the lining without wrecking it 🙄

 

I think they would push the wood out of the way but I would test it first on some scrap wood and steel. If the steel is thick enough then drill and tap it so you can use small machine screws.

[Ryeland]

All my Caldwell windows are fitted with m4 countersunk head brass machine screws into drilled and tapped holes. Takes a bit longer but makes a good job. You can nip them up easily if any leaks occur due to the butyl rubber strip losing it's 'springyness'.

 

Richard 

[jessie]

Thanks @Ryeland I'll have a look for some of those, I think that's what was used for the air vents covers iirc, sounds like the best option if the trim will go on, it's a very narrow channel

 

[Cheshire cat]

When we had our boat repainted the windows were taken out. The original screws were no longer able to grab and tighten up in some of the holes. The painter tried using larger screws but the heads were too large and the shafts too long. 

 

I resorted to drilling the holes out and inserting the smallest plastic rawlplugs (yellow ones). I was then able to go back to the original sized screws. 

 

There is no rubber cover on my screw heads otherwise I would have considered redrilling the windows in a different place.

[GUMPY]

1 hour ago, Ryeland said:

All my Caldwell windows are fitted with m4 countersunk head brass machine screws into drilled and tapped holes. Takes a bit longer but makes a good job. You can nip them up easily if any leaks occur due to the butyl rubber strip losing it's 'springyness'.

 

Richard 

Similar to mine except I used stainless steel pan head machine screws.

Fitting windows with self tappers or pop rivets is a bodge.

Edited April 10, 2022 by Loddon

[Ronaldo47]

If you need reduced head height screws then go for flange head types. They have a wider, shallower head than ordinary screws and the excess width can be removed if this is a problem.

 

I have reduced the diameter of screw heads by gripping the threaded shank of the screw in the chuck of my cordless drill, and offering the head to my electric grindstone while rotating the drill chuck contrary to the rotation of the grindstone to increase the relative velocity between screw and stone. Only gentle pressure needs to be applied. 

 

 

Edited April 10, 2022 by Ronaldo47
Rearranged paragraphs for clarity, typos

[Cheshire cat]

5 hours ago, Ronaldo47 said:

If you need reduced head height screws then go for flange head types. They have a wider, shallower head than ordinary screws and the excess width can be removed if this is a problem.

 

I have reduced the diameter of screw heads by gripping the threaded shank of the screw in the chuck of my cordless drill, and offering the head to my electric grindstone while rotating the drill chuck contrary to the rotation of the grindstone to increase the relative velocity between screw and stone. Only gentle pressure needs to be applied. 

 

 

Do that 100 times and the jobs a good un 😁

5 hours ago, Loddon said:

Similar to mine except I used stainless steel pan head machine screws.

Fitting windows with self tappers or pop rivets is a bodge.

Well mine lasted 20 years without problems. Your solution requires threadng every hole. Over engineered. 😊

[Chris G]

7 hours ago, Ryeland said:

All my Caldwell windows are fitted with m4 countersunk head brass machine screws into drilled and tapped holes. Takes a bit longer but makes a good job. You can nip them up easily if any leaks occur due to the butyl rubber strip losing it's 'springyness'.

 

Richard 

Brass screws and aluminium frames sounds a seriously bad idea when it all gets damp.

[Peugeot 106]

Mine are Caldwell hopper type windows. I took them out and cleaned them up when I painted the boat. 

My windows were originally pop riveted and I drilled them out. I managed to drill the rivet holes with a tap drill which was only slightly bigger than the rivet holes and then tapped the holes.  I’m guessing the rivets were probably 4.8mm and the subsequent taps M5 but they could have been 3.2 mm rivets with M4 tap.  I held the tap in the drill on slow speed after drilling and lubricated the drill and tap well. I used stainless steel  half dome head machine screws with Allen key sockets and they look very neat. You can get all sorts of different heads for small machine screws. 

Get a couple of drills and taps as you are sure to break some. If the going is tough back off a little.  They are not expensive. You can also hold the Allen key in the drill if you cut off the arm. Be sure to try to hold the drill and tap square to the window though if the odd one is slightly out only you will notice.

you can buy taps, corresponding drills, lubricating paste and stainless machine screws with your chosen head from any decent engineering supplies normally over the counter for a few quid.

it was pretty easy and quick to do. I think that using rivets can lead to problems as you can’t adjust them. I used arboseal butyl tape and it worked very well.

It was one of those rare jobs that went very well and they don’t leak.

i hope this helps

[Peugeot 106]

3 hours ago, Cheshire cat said:

Do that 100 times and the jobs a good un 😁

Well mine lasted 20 years without problems. Your solution requires threadng every hole. Over engineered. 😊

I found drilling and tapping with a cordless drill to be pretty quick. As the steel is relatively thin even hand tapping wouldn’t take long. I find tapping with the drill easier to keep everything square. Don’t ask me why but my hand seems to wobble when I hand tap.  I use the drill and tap method quite a lot  for fixing things rather than rivets or self tapping screws. I first saw a sheet metal worker do it and couldn’t believe how quick, simple and secure it was. I should have added that I used a “taper tap”. Probably the main issue is getting comfortable access which was easy for me as I was inside a barn

[MtB]

13 hours ago, Tony Brooks said:

Sounds as if the holes in the cabin side may be oversize for the screws needed to fit the trim. If needs must maybe drill new holes in a different place so you can use smaller screws.

 

Another approach when this happens that saves the need to drill new holes in different places is to repair the existing holes by fitting Rivnuts. Like a pop rivet you fasten through the old hole, with a screw thread in the centre:

 

 

 

 

 

https://www.ebay.co.uk/itm/162016486633?chn=ps&var=460986691709&norover=1&mkevt=1&mkrid=7101533165274578&mkcid=2&itemid=460986691709_162016486633&targetid=4585169652812020&device=c&mktype=&googleloc=&poi=&campaignid=412354547&mkgroupid=1305120599331881&rlsatarget=pla-4585169652812020&abcId=9300541&merchantid=87779&msclkid=a326b9f75de417e9011fdba43ed6fc23

[Tony Brooks]

7 hours ago, MtB said:

 

Another approach when this happens that saves the need to drill new holes in different places is to repair the existing holes by fitting Rivnuts. Like a pop rivet you fasten through the old hole, with a screw thread in the centre:

 

 

I did think about using those when I did my windows but the fun I had getting some of the old screws out made me decide there was too much chnace they would turn in the hole rather than have the screw undo the next time.

[GUMPY]

Rivnuts are fine for thin steel but the ones pictured only go up to 3mm cabin sides are normally 4mm😯

[Peugeot 106]

19 hours ago, Ronaldo47 said:

If you need reduced head height screws then go for flange head types. They have a wider, shallower head than ordinary screws and the excess width can be removed if this is a problem.

 

I have reduced the diameter of screw heads by gripping the threaded shank of the screw in the chuck of my cordless drill, and offering the head to my electric grindstone while rotating the drill chuck contrary to the rotation of the grindstone to increase the relative velocity between screw and stone. Only gentle pressure needs to be applied. 

 

 

Can I suggest that if you are still stuck because of the head size that you could take up this suggestion. You may be able to use emery paper instead of a grindstone. If you visit a proper “engineering supplies” company they are usually quite helpful (as well as being much cheaper than retail). They often have examples of screw heads on the counter. I would think that if you go for Allen key types that as the key slot is very small you could take quite a lot off the diameter and still have enough “meat” to turn.

Another suggestion would be to have a practice in a piece of scrap steel ( or hidden part of your boat but not below the water line or into any tanks!) That would be a confidence booster.

 

if you can tell us

1) maximum width and height of head you can accommodate 

2) diameter of hole left after you take a self tapper out. Or take the self tapper to a shop/supplier and compare to work out what size it is. That should give us the drilled hole size assuming they were correctly fitted originally

[jessie]

Thanks so much for all the advice and suggestions, I've ordered some 5mm taps, and 3.3 drill bits and stainless steel machine screws with countersink heads. I realised there is thickness in the frame to allow for countersinking and if they are too big I'll have the tapped hole and can try a different head.

There are currently no holes drilled in the doors, the windows came predrilled, so I can only tap the hole through the steel of the door but it's 4mm, so should hold.

When I was ordering I couldn't see any of the flange head type, I have seen them since but the order is in now. 

It's really good that you all took the time to offer help, thanks again.

[Peugeot 106]

Sounds good but the drill for M5 is 4.2mm. 3.2mm is for M4.

when I buy the taps I keep the taps and drills together ready for the next job so that I know I have the correct drill

let us know how you get on. I’m sure it will go ok if you think it through and go carefully

Foe this sort of job engineers supplies really are your friend as they have all the bits and bobs in one trade counter