Cutting holes - basic metal work query

[Anderzander]

I've found a hole in the end panel of my A-frame crossmember and it's quite a small area to get in and cut it square with a grinder.

I don't have a plasma cutter - so I wondered what other folk use in that sort of situation ?

I have a compressor and wondered if this is where an air saw would work ? Or is there a small air grinder ?

Apologies for the ignorance !

[Bowie69]

Die grinder, on air, very good access

[Anderzander]

Ahhh

And what kind of cutter would you use ? A burr or a stone ? Or something else ?

[Anderzander]

Oooo - they do little discs for them like this : http://pages.ebay.com/link/?nav=item.view&alt=web&id=271829468623

[bushwhacker]

Mini air grinder with a tool to take the left over thin disks when they get to small for the 41/2 grinder.

Or an air saw Draper do one that takes the long hacksaw blades full length or snapped shorter.

[Bowie69]

I like a good burr for that kind of work, very flexible

[GW8IZR]

Another useful tool is an air or electric file which also work well

[Anderzander]

Thanks for all this help folks

Can anyone point me to the mandrel (?) that will mount the discs to an air die grinder ?

There's probably quite a bit of material to take out with a burr or a file - so a small disc would be a good start.

[mickeyw]

Search Air cut off tool.

http://www.justoffbase.co.uk/Tool-Shop/Air-Cut-Off-Tools

I don't seem to be able to post a picture from my phone ?

[Bowie69]

Or.... you can buy just the'arbor', I know this is a yank site, but you get the idea:

http://www.harborfreight.com/1-4-quarter-inch-cut-off-wheel-arbor-for-die-grinder-93389.html

[secondjeremy]

Be careful when using adapted tools in die grinders - some of them go very fast - like more than twicce the speed of a 4.5 in angle grinder - or 10 to 20 times the speed of an electric drill. The problem is that things like grinder discs are safe to about 12,000 rpm (stated on the disc) and not safe to the speeds a die grinder can achieve. Same goes for things like wire brushes - steel bristles hurtling all over the place isn't a good idea.

[Anderzander]

That's a good call - though the discs I linked up to above were safe up to 20k. I will be mindful of the speed though.

[Anderzander]

Or.... you can buy just the'arbor', I know this is a yank site, but you get the idea:

http://www.harborfreight.com/1-4-quarter-inch-cut-off-wheel-arbor-for-die-grinder-93389.html

Something like that would be ideal - I've now just been given a basic die grinder. It comes with two sizes of 'chuck' ? And a few stones. I've a load of burrs which I inherited from my grandad - so if I can get the discs it would be good set for me.

[Anderzander]

Another useful tool is an air or electric file which also work well

There's some of these on eBay for around £40 - 10mm x 330 belts. They look super useful !

[Bowie69]

AFAIK they have either 18" or 1/4" chucks, most stuff is 1/4" from when I have been looking.

Free tools, always good

Burrs are amazingly fast, one with a sharp edge may get you by in the interim.

[GW8IZR]

There's some of these on eBay for around £40 - 10mm x 330 belts. They look super useful !

Yes, they make very short work of ripping recalcitrant defender front shock absorber nuts off in that hard to get to space ;-)

[Anderzander]

In further thoughts - the cut off tools come with a guard, something I'd be missing if I just bought a mandrel/arbour.

With safety in mind I think I'd better off just buy the tool.

I also quite like the look of the straight ones - like this :

[CwazyWabbit]

Not that I'm recommending running it without the guard, however with a straight die grinder and the arbor if a disc does decide to shatter you will be a lot less likely to be in the line of fire than if you were using an angle grinder.

[Anderzander]

I guess that depends the plane of the surface you are cutting ?

The reason I liked the idea of the one pictured is that I can cut into surfaces that are vertical and perpendicular to the cutter more easily.

Holding the normal angled ones against a flat surface would seem rather awkward ?

Pro's and cons to each - but I suspect the angle (die grinder type) may pose more issues than the other....

[JeffR]

Careful buying burrs from Ebay, most are made of chocolate, similarly most of the budget air saw blades from Ebay would be lucky to cut paper let alone metal. Shame you are not closer, could have loaned you either a cut off tool or die grinder.

[Lewis]

Must the hole be square?

Drilling a suitably sized round hole with a holesaw sounds like a lot less faff and hassle than most of the suggestions above. Your welder won't care what shape the patch is

[Anderzander]

It doesn't have to be square - but it's too big and irregular to be covered by a round hole.

An oval might work

More than just getting one for this instance though - it's all part of a skill set i want to develop and build up the equipment to go with it.

[studmuffin]

Agree with air tool but if space is really tight I have got through some bits of metal thicker than you would believe possible with a Dremel or similar. It just takes a lot of discs and patience. I also have a tiny hole cutter which fits onto a drill, but this only cuts up to 1.6mm in MS. All it needs is a 6mm drill hole for access but you can use it like a scroll saw.

[cackshifter]

The carbide burrs are really good in a die grinder, (ie branded ones not cheese ones) but they produce really nasty chips like hot sharp wire; you must wear good eye protection and when you finish grinding clean up before doing anything else. They are the worst splinters and they get everywhere. But they can reach places most other things can't.