selftapping screws?

[arlow11]

hi all i want to screw down my water tank filling thing my boat has fine long screws to screw down the mushroom vents where do i get these?

thanks

[Nickhlx]

hi all i want to screw down my water tank filling thing my boat has fine long screws to screw down the mushroom vents where do i get these?

thanks

 

 

If you mean "studding" - almost any good hardware shop / B and Q etc - sold by the ? metre in various diameters and materials - cut to length required

 

Nick

[ChrisPy]

it doesn't sound like you have holes that are already drilled and tapped. so you need more than just the screws.

[O'Mali]

Try screwfix

 

http://www.screwfix.com/search.do;jsession...earchbutton.y=5

[Bones]

I got mine from Eynsham - oxon fastenings clickyand they are wicked! They drill the hole and self tap all by themselves click here. See if there is a good old fashioned fastenings/fixings shop near you and ask them!

[Nickhlx]

I got mine from Eynsham - oxon fastenings clickyand they are wicked! They drill the hole and self tap all by themselves click here. See if there is a good old fashioned fastenings/fixings shop near you and ask them!

 

 

Self-drilling and threading screws for thin metal / wood are also used by contractors that put up false ceilings - the ones that have those ? 600mm square tiles, frequently found in shops and offices - Plasterboard screws are similar - needle sharp with hardened points - and coated to prevent rust when they get wet from the skim coat

 

Also from B and Q or Screwfix

 

Nick

Edited April 3, 2009 by Nickhlx

[ChrisPy]

I got mine from Eynsham - oxon fastenings clickyand they are wicked! They drill the hole and self tap all by themselves click here. See if there is a good old fashioned fastenings/fixings shop near you and ask them!

it seems unlikely that they will work on 4 or 6mm steel which is likely what the water tank top is made of.

[Dave H]

Hi Majortom,

 

I used the hex head version to secure my side hatch. Very easy to work with using an 18volt drill with a 10mm socket in the chuck. Nipped up with a spanner afterwards of course.....

 

Regards

 

Dave

[Mac49]

Mine is fastened down with brass m4 screws, but you'd have to tap the thread.

As Bones says, might be worth looking for a local engineering merchants that might sell you half a dozen (or electrical wholesaler for these screws). The problem with screwfix etc is if it's not a job you're going to do often you'll end up with 96 spare screws! I've found my local shop very helpful when looking for odd nuts or bolts (they must love it when i walk through the door, another 40p sale)

Rick

[Ex- Member]

I've bought small amounts from e-bay in the past, engineering screws etc. Your better off tapping and screwing IMP especially if 6mm steel involved.

 

Tapping is a lot easier than it might seem. You can get 3 piece sets drill bit and 2 taps, all done by screwdriver drill, I can recommend these from Axminster power tools. Got them in M4-5-6 mm still got all three sets and tapped a lot of holes.

 

http://www.axminster.co.uk/product-Riss-HS...l-Set-22622.htm

Edited April 3, 2009 by Julynian

[ChrisPy]

Most holes are in locations where I can't swing the tap-holder, so I've been cheating - 8mm tap fitted in a variable speed drill and go very gently. Manage average 8 holes before it breaks. Buy lots of spares of the sizes you use. (Don't buy a set, you won't need most of them).

Edited April 3, 2009 by ChrisPy

[Mac49]

Most holes are in locations where I can't swing the tap-holder, so I've been cheating - 8mm tap fitted in a variable speed drill and go very gently. Manage about 8 holes before it breaks.

I don't think the guy who did my heating had a tap holder, he did all the threads like that! I've since done it myself a few times, like you say, in awkward locations.

 

Aldi sometimes sell tap & die sets cheap(£5 ish?), I got mine just to do 4 threads to fit my nav lights but they've ended up lasting a lot longer than i'd expected doing quite a few jobs on the boat (despite me using the drill with them occasionally!)

Rick

[Ex- Member]

Most holes are in locations where I can't swing the tap-holder, so I've been cheating - 8mm tap fitted in a variable speed drill and go very gently. Manage average 8 holes before it breaks. Buy lots of spares of the sizes you use. (Don't buy a set, you won't need most of them).

 

The sets allow a 2 stage tap before the final tap thread you require and supply you with the correct size drill bit. The sets I have have sucessfully drill and tapped dozens of holes without a problem or any breakage to taps although 1 have replaced drill bits. It does take a bit longer with the sets having to change bits, but you can simply drill straight through with each stage tap, so not putting the drill in reverse all the time and risk breaking the tap.

 

I used a single 6mm hand tap on the pidgeon hatch below total 80 holes, I did buy 2 taps thinking one wouldn't be enough but surprisingly did the lot and could do many more. If I only managed 8 holes per tap I would be wondering what i was doing wrong or question the quality of the tap.

 

 

 

This was also really handy, a Tap Wrench Aligner which probably helps in protecting the tap from being stressed laterally and of course dead square threads for the screws.

 

 

http://www.axminster.co.uk/product.asp?pf_...le=1&jump=0

[ChrisPy]

by "sets" I meant a boxed set of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc., most of which you will never need.

[Ex- Member]

by "sets" I meant a boxed set of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc., most of which you will never need.

 

Ahhh Got you, yeah you're right, half will never be used.

[Mac49]

by "sets" I meant a boxed set of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc., most of which you will never need.

The set I meant just has M3,4,5,6 which i've used all of them , but they also do a massive set with loads of non metric stuff and metric probably upto m12 which would have gone unused. I just borrowed a 8mm tap for the two holes i needed it for.

[RLWP]

I used a single 6mm hand tap on the pidgeon hatch below total 80 holes, I did buy 2 taps thinking one wouldn't be enough but surprisingly did the lot and could do many more.

 

Of course, you only managed with one tap because you bought two. If you had bought only one, it would have broken off in the most visible and inconvenient hole leaving a dead hard bit of metal to puzzle over.

 

It's like looking for a spanner that has hidden itself in the middle of a job. Don't bother. Go and find an alternative spanner and you will find the missing one lying visible where you were working when you get back!

 

Richard

 

It's the tool daemons you know

[arlow11]

not 100 persent what to do think the 6mm will possibly be a little much for selftappers or maybe not? I do have a tap and die set but its draper and has only one tap per size so i think its for re cutting the worse senario is a snapped tap right at the bottom said bottom think i might buy a set from julynians link still theres no room for swingin so will have to be in the cordless

thanks guys..........and bones

also many more questions

like gas pipe how is this normally done is it ok to cut holes on the gas locker some sort of protective gromit through the hull with copper pipe into the galley into hob and cooker using the least amount of fittings,with a gas tap on the pointy end so i can isolate so i dont blow up (i do have some gas and plumbing experience)are solderd fitings more risky due to vibration?

thanks

[ChrisPy]

like gas pipe how is this normally done is it ok to cut holes on the gas locker some sort of protective gromit through the hull with copper pipe into the galley into hob and cooker using the least amount of fittings,with a gas tap on the pointy end so i can isolate so i dont blow up (i do have some gas and plumbing experience)are solderd fitings more risky due to vibration?

thanks

you definitely need to research gas installation before you proceed. BSS Guide download and Calormarine websites are the best starting points.

[NB Alnwick]

Most holes are in locations where I can't swing the tap-holder, so I've been cheating - 8mm tap fitted in a variable speed drill and go very gently. Manage average 8 holes before it breaks. Buy lots of spares of the sizes you use. (Don't buy a set, you won't need most of them).

 

Forty years ago I would have sneered at such a suggestion but I have to admit that, while re-wiring Alnwick's engine room, that is exactly how I have done it and, although I broke two drills, I suffered no broken taps whilst fixing some three dozen odd brass 'P' clips with 4,5,6 and 8mm machine screws.

 

Initially, I fell on this method in desperation when I dropped my smallest tap wrench in the cut - using a B&D cordless drill with the triple benefits of variable low speeds, variable torque settings and the ability to reverse, I soon found that tapping these small metric threads became an absolute doddle - the other benefit of this method is that it is much easier to start the thread at 90^o to the work surface.

 

The most critical thing is to use the correct drill size - I used 3.2mm (1/8") for M4, 4.2mm for M5, 5.0mm for M6 and 6.8mm for M8 - also, I found that anything less than British made High Speed Steel drill bits will break very quickly. I got my HSS drills and taps through eBay and they were delivered the day after I bought them with 'Buy-it-now' - that is one of the real benefits of eBay.

 

Finally, although a reversible drill is really useful - don't try drilling holes in steel with the thing in reverse - it doesn't work!

[colin stone]

Winzer Wurth Zebra screws are self tapping into 6mm steel easily and 10mm with care.

[NB Alnwick]

Winzer Wurth Zebra screws are self tapping into 6mm steel easily and 10mm with care.

 

The only problem I see with modern self-tapping devices is that, to be any good, they need to be made from hardened steel which invariably attracts rust, eventually if not immediately. They are also more difficult to remove and re-assemble should the need arise. That is why I prefer to drill and tap, then use traditional bolts or machine screws made from stainless steel or brass.

[Hairy-Neil]

Stainless steel screws will become difficult to remove in short order in exposed conditions if screwed into mild steel. It's the old dissimilar corrosion thingy again. Copper grease helps medium term.

 

 

There are taps available, specially designed for machine tapping. They have helical flutes similar to drill bits.

[Timleech]

Stainless steel screws will become difficult to remove in short order in exposed conditions if screwed into mild steel. It's the old dissimilar corrosion thingy again. Copper grease helps medium term.

 

 

There are taps available, specially designed for machine tapping. They have helical flutes similar to drill bits.

 

 

These are really handy, use them in a hex screwdriver bit holder, they come individually or in sets with or without the matching hex shank drill bit, there are also combined drill-tap-countersink in the same hex format though I've never tried them:-

 

http://uk.rs-online.com/web/search/searchB...t&R=0828151

 

Tim

[Ex- Member]

not 100 persent what to do think the 6mm will possibly be a little much for selftappers or maybe not? I do have a tap and die set but its draper and has only one tap per size so i think its for re cutting the worse senario is a snapped tap right at the bottom said bottom think i might buy a set from julynians link still theres no room for swingin so will have to be in the cordless

thanks guys..........and bones

also many more questions

like gas pipe how is this normally done is it ok to cut holes on the gas locker some sort of protective gromit through the hull with copper pipe into the galley into hob and cooker using the least amount of fittings,with a gas tap on the pointy end so i can isolate so i dont blow up (i do have some gas and plumbing experience)are solderd fitings more risky due to vibration?

thanks

 

I think externally you can go through seat lockers with a hole for the gas pipe, but of course protect the pipe and or gromet the hole. Where the copper pipe enters into the boat a bulkhead fitting must be used. I used this company as they seemed to have all the different sized fittings for converting to metric. They have the full gamut for LPG fitting too inc bubble tester.

 

Scroll down the list for bulkhead fitting sizes.

 

http://www.bes.co.uk/products/145b.asp

 

No soldering for gas fitting all compression. You will need gas taps for isolation, would strongly advise bubble tester too, might be compulsary now anyway not sure. You must avoid un-necessary joints, I got away with using one straight joiner between bulkhead and cooker.

 

I did ours 4 years ago so some things might well have changed.

Edited April 4, 2009 by Julynian