Dormer Drills

[Guest]

My boat must be made of armour plating as it is a sod to drill.

 

Are Dormer HSS drills/taps still the best, or should I be looking at these fancy ones now available? Can these cobalt ones and the likes still be ground on an ordinary wheel? Are they better?

 

As an aside but out of curiosity, what the hell is a left handed drill bit used for? What does it do that a right hand one can't? Reason I ask is I have just seen some on Ebay.

 

Many thanks.

[carlt]

From the listing it looks like they are used for stud extraction.

[Guest]

From the listing it looks like they are used for stud extraction.

Cheers Carl. Of course, never considered that. Obvious innit?

[Timleech]

My boat must be made of armour plating as it is a sod to drill.

 

Are Dormer HSS drills/taps still the best, or should I be looking at these fancy ones now available? Can these cobalt ones and the likes still be ground on an ordinary wheel? Are they better?

 

As an aside but out of curiosity, what the hell is a left handed drill bit used for? What does it do that a right hand one can't? Reason I ask is I have just seen some on Ebay.

 

Many thanks.

 

Dormer are certainly among the best, Guhring is another good name, Cleveland are pretty good.

'cobalt' drills are AFAIAA made from a high-cobalt High Speed Steel, and are particularly good for stainless and other hard-to-work steels. I'm sure Dormer will have their own version, a good make of 'cobalt' drill will be better than a cheap drill labelled 'cobalt', there's a good chance that a good make of HSS drill might be better than a cheap 'cobalt' drill. I have a set of Presto cobalt drills for special occasions, which are excellent. I'd be amazed if you really had trouble drilling your boat shell with good quality HSS drills.

(as an aside, I've seen on two occasions people using the Hammer setting on their drill, with an ordinary drill bit into steel cabins, and wonder why their drill kept going blunt :lol: )

 

 

Tim

Edited July 17, 2010 by Timleech

[carlt]

(as an aside, I've seen on two occasions people using the Hammer setting on their drill, with an ordinary drill bit into steel cabins, and wonder why their drill kept going blunt :lol: )

 

 

Tim

Were they bleeding from the ears, too?

[alan_fincher]

(as an aside, I've seen on two occasions people using the Hammer setting on their drill, with an ordinary drill bit into steel cabins, and wonder why their drill kept going blunt :lol: )

Are you sure it's not a misguided attempt to tighten some loose rivet,s ( or possibly "rivets") ?

[nb Innisfree]

My boat must be made of armour plating as it is a sod to drill.

 

Are Dormer HSS drills/taps still the best, or should I be looking at these fancy ones now available? Can these cobalt ones and the likes still be ground on an ordinary wheel? Are they better?

 

As an aside but out of curiosity, what the hell is a left handed drill bit used for? What does it do that a right hand one can't? Reason I ask is I have just seen some on Ebay.

 

Many thanks.

 

Your shell has probably got a higher percentage of carbon in it, ours doesn't and cheap drills go through no prob. For you carbon drills might be a better bet than HSS as they are harder though you will have to watch they don't overheat which isn't much of a prob with HSS. Prob with cheap drills is their durability when abused but as they are cheap who cares?

[Justme]

Or you could have been drilling near where it was welded.

[WotEver]

Or you could have been drilling near where it was welded.

I guess he could, but mine's a pig to drill too. I watched with amazement as a fellow boater was ¹/₄ inch stitch-drilling his roof for a new chimney collar - in the time he'd taken to drill 4 holes I wouldn't have made one.

 

Tony

[GSer]

A good quality cutting oil/grease along with the correct drill speed should help lots, as soon as the drill bit gets too hot, it's downhill all the way

[WotEver]

A good quality cutting oil/grease along with the correct drill speed should help lots, as soon as the drill bit gets too hot, it's downhill all the way

I generally use 3in1 - is that a no-no? I've been known to use diesel too.

 

T.

[jake_crew]

Also most mains "black & decker" drills are far too fast, overheating the drill bit & hardening the steel.

 

A drill with a proper gearbox which will deliver just a few hundred RPM is best (OK speed does depend on drill size).

 

Use some lube, and push hard so that the drill is cutting into cold, unworked metal.

Edited July 19, 2010 by jake_crew

[GSer]

I generally use 3in1 - is that a no-no? I've been known to use diesel too.

 

T.

 

 

There is better stuff about, on steel, I tend to use CT90 oil (because I have some kicking about) or some really old cutting grease, usually one or the other works well, on most brasses and cast iron I use nothing, on copper or other soft sticky non ferrous metals I use white spirit (i know its dangerous but, hey ho, there you go) and on some plastics, water or a solution of fairy liquid and water works well.

 

All this is seat of the pants stuff and just what i've ended up using, so please don't come running if it all goes wrong

 

Paul

[nb Innisfree]

My boat must be made of armour plating as it is a sod to drill.

 

Are Dormer HSS drills/taps still the best, or should I be looking at these fancy ones now available? Can these cobalt ones and the likes still be ground on an ordinary wheel? Are they better?

 

As an aside but out of curiosity, what the hell is a left handed drill bit used for? What does it do that a right hand one can't? Reason I ask is I have just seen some on Ebay.

 

Many thanks.

 

Depending on where it is situated you could perhaps heat the spot to be drilled to cherry red for a few minutes and let it cool slowly, metal will then be softer.

[Timleech]

Depending on where it is situated you could perhaps heat the spot to be drilled to cherry red for a few minutes and let it cool slowly, metal will then be softer.

 

Dodgy thing to do with a cabin, apart from any fire risk it's quite likely to be a different shape afterwards, maybe not nicely flat any more.

'Mild' steel, as used for the vast majority of steel hulls and cabins, shouldn't acquire any significant hardness whatever heating & cooling it's subjected to (and therefore can't be softened much by annealing, as it can't have been hard in the first place). The exception might be where a boat has had a serious fire, and the red hot steel has been in contact with free carbon (eg charred wood) for a significant period, there is a chance then of some carbon being absorbed into the surface and 'case hardening' it.

(edit - if quenched suddenly by eg fire hose)

Tim

Edited July 19, 2010 by Timleech

[Guest]

Cheers everyone. I am convinced now that it is down to poor drills. Have ordered some Dormer ones so should be OK

 

Someone mentioned drilling the roof. I had no probs. whatsoever putting the chimney collar in, but the cabin sides are difficult.

[Byeckerslike]

Guhring is another good name - I totally agree, Guhring manufacture superb drills - the size of their manual would make very good ballast!

Colbolt drills are normally 8% Colbolt added to High Speed Steel drills and are normally referred to as HSCO drills.

 

 

Rob