Cutting holes in 6mm plate

[JimM]

Hi all

I need to cut a couple of 67mm holes in some 6mm plate. Toolstation do jigsaw blades that claim to cope with that sort of thickness (T118B for 2.5-6.0mm and T123X for 1.5-10mm) but is a jigsaw really up to the job or will it just die, chew up blades etc

Cheers

Jim

 

[Baz-Cem]

What about those metal cutting hole saws with alot off cutting fluid.

 

[Endacy]

See my exhaust thread, I cut a 52mm hole in 6mm stainless with a Starrett hole saw + arbor (they are bi-metal and rated for stainless). Took all day but that's because my drill kept overheating due to the slow speed, a pillar drill would work, it stated 80rpm for stainless, very slow...

 

[Drains]

As Baz-Cem says, a metal cutting hole saw, lots of cutting fluid/paste/oil, and a slow speed drill. Dont try it on a high speed drill cos it'll all go pear shaped.

Or a broacher, as shown off by Welderpaul last week - a magnetic based drill type machine with a HSS cutter that cuts out a plug of steel. You could hire one.

I have an old Wolf drill ( a proper piece of wolf kit) which I use for just this kind of job. It's about a 600 rpm (or perhaps less - I'm not sure), high torque machine, and if it grabs it can break your wrist. So I hang on hard. (I like to remind it before we start that i'm the boss, and respect is due )

Si

 

[Hitch]

A 67mm hole will be too tight for a normal width jigsaw blade to cope with, especially in metal.
Id go down the holesaw route if its only a few.

Bahco holesaws are one or the best, but the Screwfix ownbrand ones are pretty good

 

[JimM]

Cheers guys, poking around the garage I found a box of cheapy, market stall hole saws, unbelievably one of which is 67mm Sure they are going to be crap but hopefully I'll get the 2 cuts I need out of it

Silly question but can I use 3in1 or WD40 as a cutting fluid, all I've got knocking around at the moment ?

Cheers

Jim

 

[Hitch]

3in1 will work better than wd40....

Or even gearbox oil or engine oils works good.

 

[irondarren]

ive done a 150mm hole in a bit of 6mm with a hole saw, drill doing about 180 rpm, as slow as it goes. Took a long time to do it but it worked

 

[JimM]

The slowest my pillar drill goes is 550rpm, I'll give it a shot and see how I get on.

If it's a dismal failure, I might try and find someone with a cutting torch, the hole doesn't have to be particularly neat or overly accurate (within 3 or 4 mm will be OK) Could a torch get near this.

In case you're interested, it's only to make a hub puller like this

http://members.visi.net/~kohout/hubpull.html

Couldn't find a similar flange !

Cheers

 

[shenion]

Look at a Harmonic Balancer Puller. It is designed to bolt on with a 3 or 4 bolt pattern and has a bolt with a bearing in the middle.

Mine cost $20, used it for all kinds of things. Oh, and the harmonic balancer I bought it for slid right off

 

[Welderpaul]

Or.....
Centre punch the middle of the hole you want to cut out.
Scribe the circle with a pair of dividers
'Stitch drill' out the hole with a 5mm bit, keeping just inside the scribed line - a long series of small holes
Knock out the middle
Use a half-round file to file the edges down to your scribed line

Probably quicker than watching a hole saw go round and round for hours on end?

 

[JimM]

A quick update.

Got home tonight and gave the cheapy hole saw a go, took a while but eventually it did manage to cut both holes, although it was really struggling by the end.

Can't complain though the set only cost £5, I bought it to cut a hole in the hot water tank years ago, used it again for some downlighters and the 2 holes today. One of those rare cases where cheap tools have actually been a good buy !

Thanks to everyone for their advice

Cheers

Jim

 

[scarecrow]

Or.....
Centre punch the middle of the hole you want to cut out.
Scribe the circle with a pair of dividers
'Stitch drill' out the hole with a 5mm bit, keeping just inside the scribed line - a long series of small holes
Knock out the middle
Use a half-round file to file the edges down to your scribed line

Probably quicker than watching a hole saw go round and round for hours on end?

That sounds awfully like work to the powertool generation
well I also have to put my hand up as I had to cut a hole in some box gutters today I just popped the small rod in the welder turned it up good and high probably quicker than a half round file