How do I cut a 140mm circular hole through 5mm ply, without a jigsaw?

[prv]

Thankfully, this dismal weather hasn't made the lateness of my preparations too painful.

Dismal weather? It was glorious in Alderney the weekend before last, so it can't have been too bad in Chichester. Two weeks before that we had an excellent trip to Poole and back; bit chilly on the return journey as I recall but very pleasant overall. And the weekend before that is captured in Dylan's "Christchurch to Chichester" video in the other thread - hardly dismal there either.

Excuses, excuses!

Pete

 

[zzyyxx]

That blade's too wide to cut a 6" circle.

Pete

Then either get a smaller one, or gaffer tape one end of a hacksaw blade.

 

[Wunja]

How about using a router with a compass attachment?

 

[Greenheart]

How about using a router with a compass attachment?

Ah, but that would require the purchase of a router.

Dismal weather? ...we had an excellent trip to Poole and back; bit chilly on the return journey as I recall but very pleasant overall.

Hmm. I don't have a cabin to cower within, nor an Eberspacher. From "bit chilly", I infer hellish bone-chilling, drenching and dispiriting. I can wait!

 

[prv]

Then either get a smaller one, or gaffer tape one end of a hacksaw blade.

I'll use one of my wide selection of large holesaws, thanks . Or possibly the jigsaw.

Pete

 

[prv]

Hmm. I don't have a cabin to cower within, nor an Eberspacher. From "bit chilly", I infer hellish bone-chilling, drenching and dispiriting. I can wait!

I didn't realise you were planning to anchor overnight in the Dayglo Torpedo. We did run the heater that evening, and the previous morning my mate also insisted on me putting it on before he would get out of bed (though I was warm enough), but we were on deck all day and obviously weren't running the heater then.

Pete

 

[Greenheart]

I was only kidding Pete. And I know, I must hurry up with the repairs or half the season will have gone.

Although, by this date last year, it was still looking and feeling miserably cold, and the summer turned out to be one of the best.

 

[zzyyxx]

I'll use one of my wide selection of large holesaws, thanks . Or possibly the jigsaw.

I thought the challenge was to come up with a way to cut a hole without using any of the tools that are normally used for cutting holes?

 

[Greenheart]

Mainly, the difficulty is the absence of power-tools. Knives, hacksaws etc, I have in plenty.

Plastic explosive might do it. A shaped charge, as they use on bank-truck doors? Or so I've heard.

 

[Lakesailor]

That would have been my choice at the start of the osprey project......

 

[Greenheart]

Envy. Pure, sad envy. I'm off for an inspection of the Osp this evening, prior to screwing-in the new keelband. I did a remarkable job of centering all the screw-holes in the 3/8" band, using just the hand-drill.

 

[pvb]

Mainly, the difficulty is the absence of power-tools. Knives, hacksaws etc, I have in plenty.

Faced with the same constraint, I'd just drill a circle of holes and join them up with a pad saw (about £3 from lots of places) or a saw blade in a Stanley knife.

 

[Greenheart]

The ring of holes is likely to be my solution.

...a saw blade in a Stanley knife.

That...sounds like a reason for me to keep the paramedics on speed-dial...

 

[pvb]

That...sounds like a reason for me to keep the paramedics on speed-dial...

Ha! No more dangerous than a padsaw (or any of those power tool devices), and even cheaper. I keep one in my boat toolkit, and it often comes in handy.

 

[Jabs]

I thought the challenge was to come up with a way to cut a hole without using any of the tools that are normally used for cutting holes?

So maybe a brickies hammer then?

Just beat a hole to approximate dimensions.

Tony

 

[LittleSister]

Continuing the 'cutting a hole without using hole cutting tools' train of thought:

1) Paint the 140mm circle you want removed (on both sides of the ply) with epoxy or similar. Once hardened, submerge the ply in water for 24 hours. Lift it out and now set fire to the dry circle with a blow torch or similar.

2) Smear the circle you want removing with soft cheese, and paint the areas you don't want moving with mouse repellent. . .

 

[Greenheart]

I wish you could have seen how much of that post I read, before I began to smell a rat...or a mouse? :highly_amused:

 

[Poignard]

I had to install a new mushroom ventilator recently and it needed a larger diameter hole than the old one. Removal of the old one revealed a pear-shaped hole that had been made using the chain drilling and rasp techinque; a real botch up. I made the new (perfectly round) hole with a router, a bearing guided cutter and a template.

 

[alan_d]

I had to install a new mushroom ventilator recently and it needed a larger diameter hole than the old one. Removal of the old one revealed a pear-shaped hole that had been made using the chain drilling and rasp techinque; a real botch up. I made the new (perfectly round) hole with a router, a bearing guided cutter and a template.

I'm sure the quality of the ventilation will be superior through a perfectly circular hole.

 

[Lakesailor]

I used to to do everything to perfection. Then I realised how much of my life I was wasting. Now I limit it to the bits that matter and the bits you can see.