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phillybarbour
04-12-2013, 05:46
I need to drill a hole in my water tank to fit a new valve, what type of drill should I use, just a little worried about it cracking. Any advice great fully received, thanks.

hippy travels
04-12-2013, 06:53
What size hole do you need to put in the tank and whats the tank made out of ?

Siimplyloco
04-12-2013, 07:00
That's funny, I was just about to write exactly the same question!
John

David & Ann
04-12-2013, 07:07
I expect the tank will be made of plastic as mine is, so a high speed drill HS type would be the best. Simply speaking a normal drill. If the hole is to be quite large begin with a small drill which will act as a lead for opening up the hole with a larger drill.

tiderus
04-12-2013, 07:07
You would be best with a tank cutter, or hole saw like this one on ebay.

19064

Ebay No. 290696478302

Cuts wood, plastic, or metal.

Rgd's Graham.

red ted
04-12-2013, 07:16
You would be best with a tank cutter, or hole saw like this one on ebay.

19064

Ebay No. 290696478302

Cuts wood, plastic, or metal.

Rgd's Graham.tank cutter is perfect,put masking tape where you are going to dril and try to mark, score or scratch were the drill will enter,just so the drill bit will not fly in all directions

ricc
04-12-2013, 07:19
You would be best with a tank cutter, or hole saw like this one on ebay.

19064

Ebay No. 290696478302

Cuts wood, plastic, or metal.

Rgd's Graham.

bear in mind thats only half the holesaw... it screws on a holder with a 6mm pilot drrill up the middle. the same holder takes various sized outer cutters.

the pilot drill holds the outer in place in the work so you only get one chance to make the right sized hole, you cant enlarge it later with a bigger holesaw.... but you can ream it out with a conecut.

holesaws work best cutting slowly , you need a drill with a variable speed trigger that actually works at low speed. summit hard like stainless steel will blunt the teeth or even knock them off if you go too fast. plastic or fibreglass is easy.

QFour
04-12-2013, 07:46
Dremel works really well. You need a steady hand but they are great for large holes. I have cut a lot of holes in plastic with one. Whichever way you do it don't let it get hot and melt the plastic.

Alf
04-12-2013, 08:31
Most valves would need a 20mm hole you could buy a holesaw to the correct size or a stepped cone drill either will need a pilot hole both types of cutter will leave a build up of swarf that needs carefully removal with a sharp blade, if this is the water tank for the van make sure you remove all the cutting swarf from inside the tank by flushing out the tank it's a good idea to glue the locknut and tap in place as well it's surprising the amount of taps that come loose and leak and it's difficult to do this at a later date

Alf




I need to drill a hole in my water tank to fit a new valve, what type of drill should I use, just a little worried about it cracking. Any advice great fully received, thanks.

Bopper
04-12-2013, 11:08
When I fitted my water system in my self build I used a variable hole cutter I bought from Lidll. There are three brass "Drills" in the packet a small, medium and large. Each of these drills have stepped cutters and I can highly recommend them. I have used them since fitting my tank on many many applications.

See pic and Ebay item 291011139846


19067

hextal
04-12-2013, 11:15
those step drills are awesome - particularly for cutting through metal.

the holesaws should be fine for that - as others have said - don'r forget the arbour

runnach
04-12-2013, 19:06
If you can get hand inside tank/vessel and, metal/plastic not too thick, Q-Max cutters are excellent.

https://www.google.co.uk/search?q=q-max+cutter&source=lnms&tbm=isch&sa=X&ei=lYqfUubtI6SS7AbKiIGYDQ&ved=0CAcQ_AUoAQ&biw=1280&bih=704

n brown
04-12-2013, 19:24
If you can get hand inside tank/vessel and, metal/plastic not too thick, Q-Max cutters are excellent.

https://www.google.co.uk/search?q=q-max+cutter&source=lnms&tbm=isch&sa=X&ei=lYqfUubtI6SS7AbKiIGYDQ&ved=0CAcQ_AUoAQ&biw=1280&bih=704 +1 for these

Siimplyloco
04-12-2013, 19:32
As any time served machinist will tell the uninitiated, a helical drill is perfectly OK for thin metal, provided the cutting edge is backed off with a grindstone or diamond file first. A spade drill is fine as well, as it has no helix to 'bite' into the material. Step drills, often coated with what they tell you is titanium, have only been generally available in recent times - since my 1960's apprenticeship anyway - and are very good provided one is not too ambitious and the material is soft enough to allow the drill to cut properly - there is very little top rake or clearance.

Without wishing to be a Smart A**, a little knowledge can be dangerous, and is usually expensive for the guy getting the advice.....
John

maxi77
04-12-2013, 19:53
Over the years I have used all sorts of things for drilling holes, has any one else used a twist drill in a brace and bit. The stepped cutters are fin as long as the material is thinner than the steps, but in my experience are better used in a drill press. Holesaws are wonderful and and I really extended my collection when m,aking a black water holding tank for my last boat. If you can flush the tank out after drilling you don't need to worry about swarf but if you cant slow speeds and plenty of grease can prevent most if not all the swarf falling into the tank. Back in the days of the brace and bit we used tank cutters for large holes and they are fine for plastic tanks with care but murder on sheet metal

Tezza33
04-12-2013, 20:26
Some good advice on this thread but whichever method you use let the drill do the work, if you press too hard there is a danger of splitting, warm conditions help as well

phillybarbour
05-12-2013, 06:15
Thanks for the various tips to all, the tank is plastic and hole is 25mm.

maxi77
05-12-2013, 09:06
Thanks for the various tips to all, the tank is plastic and hole is 25mm.

You could get away with a flat wood bit but needs care or a holesaw, but it is well worth the investment in the
proper holsaw not the cheap many on one holder type which rarely make a circular hole

Fazerloz
05-12-2013, 11:45
Nip round to your local engineering workshop 1 hole easy to get at in a plastic tank we would do it for nowt,:cheers: not worth buying the holesaw for.


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