Drilling diesel tank

olam

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I need to drill a hole in the top of a stainless tank for a fuel pickup,problem is the tank is half full.
whilst i would not dream of doing this with petrol,any thoughts on cordless drill with diesel fumes ,Fire risk or not?
 

30boat

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I think that if you start with a small drill and then enlarge the hole with larger ones the metal won't heat up to dangerous levels.The drills must be very sharp. There will be swarf falling into the tank too.
 

rogerthebodger

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Done it several times on my mild steel tanks when full with diesel. The 2 issued to consider is as LS said type to prevent the swarf from getting into the tank. I did that with a magnet but a magnet will not work with stainless. Also when drilling stainless drill at slow speed, battery drill is OK and keep the drill cutting with high pressure. I you start with a small drill then enlarge do not go up in too small increments as the drill tend to rub or dig in and not cut properly.
 

David2452

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Not a problem, I do it regularluy for heater standpipes even with 25mm hole saws, plenty of heavy grease to absorb the swarf and. With stainless pauses to allow the heat to disapatete if needs be, good quality bit and you will be fine.
 

olam

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Thanks all,
I 'm not worried about the swarf,with a hole saw not much chance of it going in the tank till the last bit which i can be careful with.
Just not sure of igniting fumes,figure diesel is quite hard to light up.
Thanks David for your comment,i'll pick up a good bit.
 

TonyBuckley

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rogerthebodger

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Big difference between welding and drilling a smallish hole in stainless steel.

I would a battery drill as the speed would be much lower than a mains drill which is what you meed to drill stainless and anyway if the drill point got too hod it would work harden the stainless making it almost impossible to drill even with power tools.

You may be able to drill thin stainless with a breast hand drill but not the small carpenters type.
 

Trundlebug

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There are no problems drilling a stainless tank even with a power drill, the "fumes" (vapour) are / is not a problem and there is little risk of igniting it / them.

The best drill bit material for stainless is cobalt, so if you have a number of holes to drill and haven't yet bought a suitable bit, get a cobalt one.

Alternatively if you just have one or maybe two holes to make, a fresh and sharp HSS bit will do it, with the provisos as stated above keep it cutting and don't let it get warm (i.e. go at low speed). HSS will go blunt quite quickly though when drilling stainless.

You'll struggle to get enough cutting power and consistency with a hand drill, I would advise against it. And you're more likely to break the bit (depending upon dia, but definitely below 5mm) when using a hand drill, because you'll struggle to maintain even pressure and steady direction whilst turning the handle.
A well charged cordless drill should be OK but it will drain the battery quite a lot.

Agree with the comments above re, swarf. Best to try and remove any that falls in if possible, it could end up blocking the fuel pick-up pipe and causing intermittent problems - a PITA to resolve.
 
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macnorton

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Use grease to collect swarf and take your time as already stated, diesel fumes are only a problem when the fuel is hot. (throw a lighted cigarette into a cup of diesel and it will go out!)
 

pvb

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There'll be no problem using a cordless drill. It won't explode. You could use grease to collect swarf, but I think I'd just have a vacuum cleaner tube next to the drill bit.
 

Lakesailor

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Problem with grease is that once you have broken through, the bigger dills will drop swarf into the tank. I used an engineer's magnet when drilling through this hole on a rocker cover. But as pointed out, that was mild steel. The hole went into a void behind oil baffles, so I couldn't reach clean out afterwards.

Drillinghole.jpg



See how much swarf I caught

swarfcollected.jpg
 

olam

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Did the job today,bi-metal hole saw,lots of grease,drilled till it was almost though then put a screwdriver in the centre
hole,levered and it came out like a ring pull,no swarf in tank.
Down side is adding a new feed pipe didn't cure the fault,no fuel pumping to the heater.
Thanks for replies.
 

Davegriff

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As a small aside, I knew a chap once who would weld rusty/rotten tanks on road tankers by filling the tank to the brim with fuel, ensure the lid was tightly closed, light the leaking fuel, then happily weld a patch. I'm talking fuel delivery tanks, petrol, kero and diesel. Scary.
 

30boat

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As a small aside, I knew a chap once who would weld rusty/rotten tanks on road tankers by filling the tank to the brim with fuel, ensure the lid was tightly closed, light the leaking fuel, then happily weld a patch. I'm talking fuel delivery tanks, petrol, kero and diesel. Scary.

The thought alone makes me cringe.
 
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