Holes in a boat:

[DeanS]

I will need to cut a hole in the roof for a stove flue, a gas heater flue, an extractor fan in the shower/toilet.

I'll need to cut holes for the shower drainage, the basin drain, the kitchen sink drain.

 

I'm also going to link to this thread from my blog for anyone attempting a sailaway build of their own, so any info on holesaw sizes, best practice etc is appreciated:) I'm a complete novice, but I've used holesaws before. Interested in how it's done on a curved roof though.

[Guest]

I will need to cut a hole in the roof for a stove flue, a gas heater flue, an extractor fan in the shower/toilet.

I'll need to cut holes for the shower drainage, the basin drain, the kitchen sink drain.

 

I'm also going to link to this thread from my blog for anyone attempting a sailaway build of their own, so any info on holesaw sizes, best practice etc is appreciated:) I'm a complete novice, but I've used holesaws before. Interested in how it's done on a curved roof though.

Very briefly:

 

For sink drains etc. Starrett (the yellow ones) holecutters are best IMHO, use plenty lube, slowwww drill. Even milk is better than no lube. Starrett cutters reasonable price on fleabay, good electrical/plumbers wholesalers sell them. Used properly they last for donkeys years.

 

edit: tip when using any holecutter; use a dormer 6.5mm drill first, then just use the centre drill in cutter as a guide. If you use the centre drill to cut guide hole, the cutter can slam into the material and knock teeth off cutter. Bitter voice of experience.

 

Big holes in roof I chain drilled with 6.5 mm dormer drill bit, then jigsawed out with quality steel jigsaw blades. I went through a few blades, but it was surprisingly easy. Take your time.

 

example:

http://www.amazon.co.uk/s/?ie=UTF8&keywords=starrett+holesaw&tag=googhydr-21&index=diy&hvadid=9008506366&hvpos=1t3&hvexid=&hvnetw=g&hvrand=5652444421059017654&hvpone=&hvptwo=&hvqmt=b&ref=pd_sl_22c81j5f7l_b

Edited June 5, 2012 by Guest

[Chalky]

Same as Catweasel. I bought my hole saws from B&Q. Black & Decker drill let go (smoke etc) so I bought a cheap £10 B&Q drill which I treated as a disposable item. Worked perfectly with no problems.

 

For a Jigsaw I bought a B&Q one on clearance(£12) with a free set of blades. I thought that it'd do one job and then be scrap however apart from severely bending the base plate on the jigsaw it worked perfectly and the free blade cut the hole without a problem.

 

One tip. Remember the old adage - measure twice (at least), cut once.

Edited June 5, 2012 by Chalky

[Guest]

... also don't underestimate how noisy a process this can be

 

- so consider your neighbours and where you do it, and personally being that close I would use ear defenders/plugs....

[DeanS]

 

and here I was thinking I have to use a BEEEEEEEEEG holesaw to cut those flue holes. JIG SAW.....doh!!!!!!!!!!

[blackrose]

For large holes on a curved roof I wouldn't use a holesaw. I tried it with a 4" hole and even though I had a sidehandle on the drill, as soon as any part of the holesaw hits the steel the torque almost rips the drill out of your hands.

 

Mark out the hole, drill small holes all around the circumference and then use a jigsaw to join the dots. Avoid cutting though any frames underneath.

Edited June 5, 2012 by blackrose

[bargemast]

For bigger sized holes, I've always used my MAKITA jig-saw with good blades, lots of oil and not too hard pushing.

 

Only 1 hole drilled to enter the jig-saw blade, to be perfectly honest I never expected the MAKITA to survive long like this, but it seems to be (I hope) ever lasting.

 

Another idea, much easier is asking the shell-builder to make all the holes for you, which will take only minutes with their plasma-cutter, of course this is only possible if you know exactly where they have to be made.

 

Peter.

[Guest]

For bigger sized holes, I've always used my MAKITA jig-saw with good blades, lots of oil and not too hard pushing.

 

Only 1 hole drilled to enter the jig-saw blade, to be perfectly honest I never expected the MAKITA to survive long like this, but it seems to be (I hope) ever lasting.

 

Another idea, much easier is asking the shell-builder to make all the holes for you, which will take only minutes with their plasma-cutter, of course this is only possible if you know exactly where they have to be made.

 

Peter.

I have seen others drill just one hole and jigsaw as you describe without problems. I chain drilled to give my cheapo Argos jigsaw a chance, though it is still fine 8 years, several projects and much abuse on!

 

I agree with Blackrose that you will fight with a large holesaw, and an extremely slow drill would be needed.

[bizzard]

If you've not done it before,chain drill,because on steel of that thickness if the jig-saw wanders off line its a devil of a job to get it back on track and you'll probably have to stop and start again in the other direction and hope to meet up with the first cut that went off line.Keep the job flooded with oil.

I use an enormous old Wolf very low geared drill with extended hand holds to power large hole cutters kept flooded with oil but have to seriously hang on to it in case it suddenly picks up and whirls me around like a helicopter blade,flinging off my shoes and everything.

[PaulD]

I will need to cut a hole in the roof for a stove flue, a gas heater flue, an extractor fan in the shower/toilet.

I'll need to cut holes for the shower drainage, the basin drain, the kitchen sink drain.

 

I'm also going to link to this thread from my blog for anyone attempting a sailaway build of their own, so any info on holesaw sizes, best practice etc is appreciated:) I'm a complete novice, but I've used holesaws before. Interested in how it's done on a curved roof though.

 

From your blog it looks like your sailaway shell is still under construction. If so it would be a good idea to get any big holes cut by the builder using a gas or plasma torch.

 

Scary thing is when you have finished the fit out and have nothing to do.

 

Paul

[NBMike]

I used bosch T345XF blades. they cost more but will cut though steel roof and braces too if you happen to be unlucky enough to find one in the way. Jigsaws throw hot metal shards all over the place. If you cut metal with a jigsaw, wear safety specs.Don't ask me how I know this!

Mike

[Guest]

From your blog it looks like your sailaway shell is still under construction. If so it would be a good idea to get any big holes cut by the builder using a gas or plasma torch.

 

Scary thing is when you have finished the fit out and have nothing to do.

 

Paul

Are they ever finished?

 

I used bosch T345XF blades. they cost more but will cut though steel roof and braces too if you happen to be unlucky enough to find one in the way. Jigsaws throw hot metal shards all over the place. If you cut metal with a jigsaw, wear safety specs.Don't ask me how I know this!

Mike

I am 99% certain I used Bosch blades too. They were more expensive but very good.

 

Eye protection is a very good point too. I like those full face visor type shields when grinding, drilling and power sawing steel. My son had a grinding wheel explode in his face last year, and it made a hole in his face. Not trying to be a scare mongerer, but have seen a nasty accident, and prefer the visor type protection.

 

I keep a big magnet handy when cutting steel so I can quickly gather up the swarf.

[DeanS]

Thanks for all the tips.

 

No idea what a chain drill is. (yet.will google)

Cant tell the boat builder to cut the holes, as I KNOW if I do, I'll stuff up the dimensions/positions. I need to SEE the things in place before going through the roof.

 

Guess it's going to have to be a variable speed jigsaw...lots of lubricant, and a good line to follow.

 

If it's for a stove, would the collar be bolted on ...(more holes ?...as well as some form of waterproofing sealer....that can stand the heat...what stops the rain finding it's way between collar and roof...etc.

 

For a gas heater, there's normally a plastic collar for the outside. Do you just use some form of sealer for that.

 

Thanks all.

[Bat & Frog]

Hi Dean, by chain drill I think they mean lots of small holes then join up with jigsaw. If you google you'll get some strange item ! I went for the single hole and jigsaw option and had no problem.

It is worth the time before its floored & sprayfoamed to go through and and fully measure where all strengthening ribs, floor joists etc. are. That way you can try and jiggle things around and plan underfloor pumps etc avoiding supports. Take as many photos as possible, you never know when you want to remember hidden details !

[STUBAG]

I will need to cut a hole in the roof for a stove flue, a gas heater flue, an extractor fan in the shower/toilet.

I'll need to cut holes for the shower drainage, the basin drain, the kitchen sink drain.

 

I'm also going to link to this thread from my blog for anyone attempting a sailaway build of their own, so any info on holesaw sizes, best practice etc is appreciated:) I'm a complete novice, but I've used holesaws before. Interested in how it's done on a curved roof though.

 

Dean, if you're fitting it out where I think you bought the shell, nip next door and ask me if you can use our plasma cutter under supervision!

[the grinch]

nought wrong with a wheeel brace and bit and half a hacksaw blade!! thats how i cut both engine exhaust and back cabin collar! only took me 6 hours! LOL

[Chalky]

... also don't underestimate how noisy a process this can be

 

- so consider your neighbours and where you do it, and personally being that close I would use ear defenders/plugs....

 

 

We cut the holes for the roof vents whilst moving the boat from Lime Kilns on the Ashby to Fenny Compton. Gennie running on the front deck, me on the roof with jigsaw, drill and roof vents, and a friend steering. Interesting going under some of the bridges however we weren't anywhere long enough to annoy any one.

[Guest]

nought wrong with a wheeel brace and bit and half a hacksaw blade!! thats how i cut both engine exhaust and back cabin collar! only took me 6 hours! LOL

We still have an elderly "Stanley" chest brace at work which has two different gear ratios. It is quite amazing what can be drilled with that. So long as the bits are kept sharp, it can drill some serious stuff.

 

In Fred Dibnah's book, he describes how he spent (IIRC) two years of his evenings hand drilling the boiler plate for his beloved steam engine.

 

We cut the holes for the roof vents whilst moving the boat from Lime Kilns on the Ashby to Fenny Compton. Gennie running on the front deck, me on the roof with jigsaw, drill and roof vents, and a friend steering. Interesting going under some of the bridges however we weren't anywhere long enough to annoy any one.

I like your style a bloke was rubbing a NB roof down a couple of years ago with a random orbital whilst on the move. He was covered in blue dust from head to foot, so we christened him "Smurf."

[system 4-50]

I will be very interested in any tips you come up with for working out where the hole should be. Trying to extrapolate from the top of eg the Morco to the sprayfoamed ceiling I'm finding very difficult.

[Ray]

And don't forget to brush and re-brush the roof to remove even the minutest amount of swarf or you'll live to regret it. Don't ask me how I know (but we'd had our roof painted before we cut the hole for the flue)!

[Biggles]

If you are still in the early stages of your build. I would seriously suggest you buy a hole saw kit. You will use it time and time again for things you have yet to discover.

 

IMO its one of the most essential bits of kit to have around. I got mine from Screwfix it was about £45 and is still going strong having replaced only the 2" one due to wear.

 

I agree with the pre drilling tip earlier.

[Monkey 1]

I will be very interested in any tips you come up with for working out where the hole should be. Trying to extrapolate from the top of eg the Morco to the sprayfoamed ceiling I'm finding very difficult.

 

I'll be doing the same job shortly, I was planning on using a plumb line positioned on the ceiling so it hangs to the centre of the stove collar, then pop a small hole through the roof from inside, Then measure the large hole on the outside from that. Assuming I can keep the boat reasonably level!

[ditchcrawler]

If you are still in the early stages of your build. I would seriously suggest you buy a hole saw kit. You will use it time and time again for things you have yet to discover.

 

IMO its one of the most essential bits of kit to have around. I got mine from Screwfix it was about £45 and is still going strong having replaced only the 2" one due to wear.

 

I agree with the pre drilling tip earlier.

And get a bottle of this http://www.rocol.com/products/view/126/rtd-liquid-metal-cutting-lubricant one bottle will do all you want and will save your bits

[DeanS]

Dean, if you're fitting it out where I think you bought the shell, nip next door and ask me if you can use our plasma cutter under supervision!

 

Hi Stuart.

You're a gentleman. I'll be fitting it out up in Manchester, so no worries...I'll manage with the jigsaw....even if I break 10 blades...

[Guest]

And don't forget to brush and re-brush the roof to remove even the minutest amount of swarf or you'll live to regret it. Don't ask me how I know (but we'd had our roof painted before we cut the hole for the flue)!

Big magnet!