Help! Cutting steel.

[GB]

Help me please! I've bitten off more than I can chew.

My front door consists of a steel frame with removable glass panels. I need to fit a mortice lock into the steel upright section, but I am having loads of trouble cutting the steel. I previously drilled into the steel using an ordinary HSS bit without any particular trouble, so I thought that cutting into it would not be too hard. In fact, it's defeating me! It's blunting all my tools, and I'm making virtually no progress.

The particular section I am dealing with at the moment is around an inch thick. I need to cut a rectangle out about 7 x 1 cm, so the body of the lock can go though.

I have tried a hacksaw type blade in a jigsaw, and that works a bit, very slowly but the blade has been worn smooth already.

I tried a very expensive bimetal plunge blade for my multi tool, but that's also blunt now.

There isn't space to get a hacksaw in, plus I probably do not have the brawn to do it.

[Muddymike]

Help me please! I've bitten off more than I can chew.

Angle grinder with steel cutting disk.

Mike

[RobertL]

A door made of inch-thick steel! Is this a strong-room door or something?

Robert

[Capitol]

Try a grit jigsaw blade.

[Bill Wright]

Do you mean an inch thick, or an inch wide? Inch thick sounds like something they'd have at Fort Knox.

If it's fiddly how about a Dremel?

Bill

[sm_jamieson]

If you can drill it, drill lots of holes and join them up with a hacksaw ? Simon.

[Dave Liquorice]

1" thick? Really? Solid 1" thick or square section tube? 1" solid will give any saw type cutter something to think about. Buy several good quality HSS jagsaw blabdes, run the saw slow and lubricate well with light oil. Let the saw do the work, only gently pressure to keep the blade in contact with the work. It'll take ages...

If tube you ideally need a blade with a tooth pitch that has at least

3 teeth across the thickness of the tube wall.

Angle grinder unless it has a very small disc will barely have cut through by the time the upper cut is 7 cm long. Not to mention the heat.

Holes in a row just clear of each other is one way but how you stop the drill wandering in that thickness I'm not sure. I think you'd need some form of "pillar drill" arrangement to keep the drill steady and true. Again sharp drill (new ones *aren't* sharp), slowish speed, lubrication.

[GB]

The frame round the outside is indeed an inch thick.

It's hard to get any accuracy with that, but yes it's plan B.

I have a Dremel, and I tried the thin cutting discs, which last about ten seconds!

[Tricky Dicky]

Sounds like a cold chisel and big hammer job! Is there any reason why you c annot chain drill right through the inch thick frame then all you would nee d to do is remove enough of the metal between the holes with a chisel to ge t a file in then it's plenty of elbow grease.

Richard

[The Medway Handyman]

Dremel wouldn't cut it's way out of a paper bag.

[The Medway Handyman]

Perhaps the OP is a drug dealer?

[dennis]

Drill a row of 10mm holes with a HSS drill and then use a file to open it up. It isn't hard work you just take your time. Use a centre punch to start the drill and it will be easier.

[stephenten]

I think you might find its stainless steel rather than plain steel.

When you try drilling stainless steel with a HSS drill bit, the stainless steel actually work hardens due to the chromium present in stainless steel.

This is what blunts the HSS drill bits.

What you need is cobalt drill bits. They cost more than HSS bits and even then you need to take it slow and steady and avoid heat build up.

Screwfix sell a set for around 30 quid.

Stephen.

[misterroy]

he's putting the new lock on after the crew abseiled down and got through the last door easily

[Nightjar]

This is a useful guide to drilling stainless steel, if that is, indeed, what the door is made from:

[BobH]

That is the way I would do it, but I know nothing.

[fred]

You get accuracy by creating a guide/mask for the cutting disk and fixing it securely in place, this can be any piece of strip, angle or at a push piece of wood that you have lying around. If it wears out then make a new one.

Best disks to use are the really thin ones (1.6mm or so is the current thinnest I think) as it reduces the amount of material to be used and if you make the first cuts with a number of used ones then you will have plenty of reduced diameter ones that will be useful for cleaning out the last bits.

I will let you get on with the logistics but I am dubious about the material being 1" thick solid and generally fitting slotted mortice locks in steel frames and doors.

Good luck all the same though.

[Jeff Layman]

That's not my experience (although it was using a B&D copy of a Dremel about 20 years ago). I had to cut an awkward shape out of 3mm Stainless Steel sheet. It took some time using one of these:

But it worked out OK. Only thing I would say is that it is important to keep the cutter well lubricated with oil. Now and again it dried out and the cutter and SS glowed almost white hot for a few seconds until I applied some more oil. Didn't harm the sharpness of the TC cutter at all.

[F Murtz]

It would be helpful if you supplied a photo as no one believes that you have a solid one inch thick section of a door so as no one would know what the problem is it is hard to comment. The frame is probably hollow section and should be easily cut with hole saws, hack saws, drills files etc. Drills just need pressure and low speed (as much pressure as you can apply without breaking the drill) hole saws similar but with lubricant.

[Fredxxx]

Those are my thoughts. While such doors might be used in banks, I'm left struggling why anyone would choose or how you would hang a door of

400kg[1], and what the frame looks like! [1] 2m x 1m x 0.025m x 8,000kg/m^3