Hello

"tungsten carbide or diamond grit coated or carborundum?"

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

I have decided upon a Dremel type of tool, perhaps with some lubricant
on the work piece, and adjustable speed. I think a grinding type of
bit, e.g. a 3mm cylindrical "burr", will suit. This is the sort of bit
shape I hope to try:

http://i.ebayimg.com/images/g/7xsAAO...wQ/s-l1600.jpg

or

https://cdn.ecommercedns.uk/files/2/...d-cylinder.jpg

I can buy them made from tungsten carbide, or diamond grit coated, or
the "carborundum" type of grinding stone.

Which is likely to be best? I can see that the cost of any of the types
if affordable for me and I don't need to make hundreds of cuts - I want
to use which is going to give me the least heating distortion and is
likely to be the fastest to cut.

Thanks for any advice on which type to choose!

DDS

On 2/3/2017 12:24 PM, Duncan DiSaudelli wrote:
Hello

"tungsten carbide or diamond grit coated or carborundum?"

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

I have decided upon a Dremel type of tool, perhaps with some lubricant
on the work piece, and adjustable speed. I think a grinding type of
bit, e.g. a 3mm cylindrical "burr", will suit. This is the sort of bit
shape I hope to try:

http://i.ebayimg.com/images/g/7xsAAO...wQ/s-l1600.jpg

or

https://cdn.ecommercedns.uk/files/2/...d-cylinder.jpg


I can buy them made from tungsten carbide, or diamond grit coated, or
the "carborundum" type of grinding stone.

Which is likely to be best? I can see that the cost of any of the types
if affordable for me and I don't need to make hundreds of cuts - I want
to use which is going to give me the least heating distortion and is
likely to be the fastest to cut.

Thanks for any advice on which type to choose!

DDS

The problem I always have with burrs and grindstones is keeping them on
track.

All 18-8 stainless steels are buggers for finishing with hand-held
tools. The curved shape implies some work hardening, but the original
sheet will have already been work hardened by rolling. The benefit from
the shaping means that it will be much stiffer than a flat sheet, hence
on balance easier to work.

If it was thicker, I think I might rough them out with a slitting disk
in a 125 mm angle grinder. At 0.5 mm, I'd be inclined to start by using
a Dremel with the fibre-reinforced slitting disk, without lubricant. The
disks won't last all that long. I say no lubricant because of the
difficulty of maintaining supply. You will get the fastest cut using the
thin, brittle, non-reinforced disks but they will break if you apply any
out-of-plane load.

One you have roughed out the cut, I would use a cylindrical abrasive
bit. The ones which fit a dremel will be rather small for cleaning up a
peripheral length of half a metre. You would be better off with a die
grinder, and abrasive bits perhaps 25 mm diameter.

You might be able to do the stage between Dremel "rough cut" and Dremel
"final finish" using a standard grinding disk on a 125 mm angle grinder.
Much faster metal removal. Some care needed!

0.5 mm is *probably* just too thick to use a shears. You can get
"Gilbow" type shears with curved blades to help making curved rather
than straight cuts.

IIRC this "universal" type will also cut curves, at a price!

https://www.amazon.co.uk/dp/B01MTR42...=gilbow+shears

Might be worth checking if you happen to have a normal (straight) shears.

Hello newshound

"tungsten carbide or diamond grit coated or carborundum?"

The problem I always have with burrs and grindstones is keeping them
on track.

All 18-8 stainless steels are buggers for finishing with hand-held
tools.

peripheral length of half a metre. You would be better off with a
die grinder, and abrasive bits perhaps 25 mm diameter.


You've made some good points and your mentioning of "die grinder" has
shown me that this might be a better purchase than a dremel. I can see
some very affordable ones, and the bits for them are likely to be
heavier duty. I remember coming across the term before but I didn't
know what it meant. Now I can see it might suit me very nicely.

My plan is to fix the rotary tool (of whichever type I buy) to a bench
and then, by hand, introduce to the bit and then rotate the work piece
about its axis, in order to be able to control the feed rate. The axle
can be bolted to the same bench and I am confident that I will be able
to form a nice circle.

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).

Thanks


DDS

On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis@home wrote:
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA
This is the best solution by far.

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS

On Friday, 3 February 2017 12:24:13 UTC, Duncan DiSaudelli wrote:
Hello

"tungsten carbide or diamond grit coated or carborundum?"

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

I have decided upon a Dremel type of tool, perhaps with some lubricant
on the work piece, and adjustable speed. I think a grinding type of
bit, e.g. a 3mm cylindrical "burr", will suit. This is the sort of bit
shape I hope to try:

http://i.ebayimg.com/images/g/7xsAAO...wQ/s-l1600.jpg

or

https://cdn.ecommercedns.uk/files/2/...d-cylinder.jpg

I can buy them made from tungsten carbide, or diamond grit coated, or
the "carborundum" type of grinding stone.

Which is likely to be best? I can see that the cost of any of the types
if affordable for me and I don't need to make hundreds of cuts - I want
to use which is going to give me the least heating distortion and is
likely to be the fastest to cut.

Thanks for any advice on which type to choose!

DDS

TC. Diamond coated die grinder bits too often have less fine diamond dust than a moth, and it comes off almost as easily.

I wouldn't nibble a curved surface, you'll get too much distortion.


NT

On 2/3/2017 8:20 PM, dennis@home wrote:
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I had one of them (from Machine Mart). The "bit" broke after rather
limited use and I couldn't get a replacement. They are certainly good on
steel or aluminium and should work on 0.5 stainless, but as I said
before it is a really difficult material to work with in this way.

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet

I can buy them made from tungsten carbide, or diamond grit coated, or
the "carborundum" type of grinding stone.

TC. Diamond coated die grinder bits too often have less fine diamond dust than a moth, and it comes off almost as easily.
I wouldn't nibble a curved surface, you'll get too much distortion.

Distortion: that's a good point. Thank you for the advice NT. I'll try
TC bits in a die grinder, and I will fix the grinder and rotate the
work-piece in order to do the circle. I can drill an entry hole and then
introduce the burr bit, and rotate slowly.

Thanks all for your help and suggestions.


DDS

On 2/4/2017 12:25 AM, wrote:
On Friday, 3 February 2017 12:24:13 UTC, Duncan DiSaudelli wrote:
Hello

"tungsten carbide or diamond grit coated or carborundum?"

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

I have decided upon a Dremel type of tool, perhaps with some lubricant
on the work piece, and adjustable speed. I think a grinding type of
bit, e.g. a 3mm cylindrical "burr", will suit. This is the sort of bit
shape I hope to try:

http://i.ebayimg.com/images/g/7xsAAO...wQ/s-l1600.jpg

or

https://cdn.ecommercedns.uk/files/2/...d-cylinder.jpg

I can buy them made from tungsten carbide, or diamond grit coated, or
the "carborundum" type of grinding stone.

Which is likely to be best? I can see that the cost of any of the types
if affordable for me and I don't need to make hundreds of cuts - I want
to use which is going to give me the least heating distortion and is
likely to be the fastest to cut.

Thanks for any advice on which type to choose!

DDS

TC. Diamond coated die grinder bits too often have less fine diamond dust than a moth, and it comes off almost as easily.

I wouldn't nibble a curved surface, you'll get too much distortion.


NT

It may be worth considering for roughing out, though. You will be able
to see how far the distortion extends from the cut, and (depending on
the application) it may be possible to re-form the edges to the original
profile.

In message . com,
lid writes
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I have one of those. Pretty aggressive for precision work and you
obviously need a supply of compressed air.

--
Tim Lamb

On 04/02/2017 10:35, Tim Lamb wrote:
In message . com,
lid writes
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well, and
thanks for the advice. I shall look into the cutting disks you mentioned
& I'll see what types of other cutting bits are available (I still think
a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I have one of those. Pretty aggressive for precision work and you
obviously need a supply of compressed air.


I have some air shears, they are aggressive.
I had a hand operated punch that worked well, its has gone somewhere but
I don't know where.

In article ,
Tim Lamb wrote:
In message . com,
lid writes
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well,
and thanks for the advice. I shall look into the cutting disks you
mentioned & I'll see what types of other cutting bits are available
(I still think a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I have one of those. Pretty aggressive for precision work and you
obviously need a supply of compressed air.

You can get hand operated nibblers too. Preferably one where you can buy
new jaws easily if cutting SS.

I've got a rather rare electric version - made by Hitachi. Does tend to
run away with you. ;-)

--
*I'm not as think as you drunk I am.

Dave Plowman London SW
To e-mail, change noise into sound.

On 03/02/2017 12:24, Duncan DiSaudelli wrote:
Hello

"tungsten carbide or diamond grit coated or carborundum?"

I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

Plasma cutter?

In article ,
Tim Lamb wrote:
In message . com,
lid writes
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well,
and thanks for the advice. I shall look into the cutting disks you
mentioned & I'll see what types of other cutting bits are available
(I still think a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I have one of those. Pretty aggressive for precision work and you
obviously need a supply of compressed air.

To avoid the need for compressed air couldn't you use an electric drill
nibbler attachment? eg:
https://www.amazon.co.uk/Sealey-SNA9.../dp/B003OXBPJA

Alan

--


Using an ARMX6

In article , Duncan DiSaudelli
scribeth thus
https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS


Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment


--
Tony Sayer

In message , tony sayer
writes
In article , Duncan DiSaudelli
scribeth thus
https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS


Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)

--
Tim Lamb

On 2/5/2017 11:33 AM, Alan Dawes wrote:
In article ,
Tim Lamb wrote:
In message . com,
lid writes
On 03/02/2017 19:35, Duncan DiSaudelli wrote:

I think a die grinder with suitable clamping should work very well,
and thanks for the advice. I shall look into the cutting disks you
mentioned & I'll see what types of other cutting bits are available
(I still think a burr approach might well suit this particular task).



Maybe something like this?

https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

I have one of those. Pretty aggressive for precision work and you
obviously need a supply of compressed air.

To avoid the need for compressed air couldn't you use an electric drill
nibbler attachment? eg:
https://www.amazon.co.uk/Sealey-SNA9.../dp/B003OXBPJA

Alan

Probably a bit fiddly compared with a purpose-built tool, whether manual
or powered.

There are two sorts of devices described as nibbler

https://en.wikipedia.org/wiki/Nibbler

The "shears" type is OK for making a linear cut, the punch and die type
which takes out a little rectangle at a time is best if you are cutting
out "features" like a square recess or a T-feature.

In message ,
newshound writes
There are two sorts of devices described as nibbler

https://en.wikipedia.org/wiki/Nibbler

The "shears" type is OK for making a linear cut, the punch and die type
which takes out a little rectangle at a time is best if you are cutting
out "features" like a square recess or a T-feature.

Anyone still have their Gosscut metal shears?

--
Tim Lamb

In article , Tim Lamb
scribeth thus
In message , tony sayer
writes
In article , Duncan DiSaudelli
scribeth thus
https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS


Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)


Big magnet
--
Tony Sayer

In article , Tim Lamb
scribeth thus
In message ,
newshound writes
There are two sorts of devices described as nibbler

https://en.wikipedia.org/wiki/Nibbler

The "shears" type is OK for making a linear cut, the punch and die type
which takes out a little rectangle at a time is best if you are cutting
out "features" like a square recess or a T-feature.

Anyone still have their Gosscut metal shears?


Yes! Had those things since waay back in the 60's or maybe early 70,s

And they still cut fine!
--
Tony Sayer

On Mon, 6 Feb 2017 11:15:44 +0000, tony sayer
wrote:



Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)


Big magnet

If it is a magnetic stainless steel.

G.Harman

In article ,
tony sayer wrote:
In article , Tim Lamb
scribeth thus
In message , tony sayer
writes
In article , Duncan DiSaudelli
scribeth thus
https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS


Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)


Big magnet

Yup. One of the speakers on my old Rover as I discovered after having a
new rear wing fitted. The type of car speaker with a concentric tweeter -
so no grill over the pole pieces. Which filled up nicely. ;-)

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

On 2/6/2017 12:40 PM, wrote:
On Mon, 6 Feb 2017 11:15:44 +0000, tony sayer
wrote:



Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)


Big magnet

If it is a magnetic stainless steel.

G.Harman

But 304 isn't.

In message , "Dave Plowman (News)"
writes
In article ,
tony sayer wrote:
In article , Tim Lamb
scribeth thus
In message , tony sayer
writes
In article , Duncan DiSaudelli
scribeth thus
https://www.amazon.co.uk/Silverline-.../dp/B000LFW9XA

dennis, F Murtz - I didn't realise that that sort of "nibbler" would be
as affordable. I will see if it would work for my particular set of
circumstances. Thanks for the suggestion and recommendation.

DDS


Had a go using some air power tools in a garage a while ago, that above
seems like a very good investment

You'll end up with a shed floor covered in tiny 1/8th. Moon chips:-)


Big magnet

Yup. One of the speakers on my old Rover as I discovered after having a
new rear wing fitted. The type of car speaker with a concentric tweeter -
so no grill over the pole pieces. Which filled up nicely. ;-)

A discovery from 55 years ago (apprentice tour of duty in the instrument
dept.) a sharp steel pointed tool (broken dart ideal) is that you can
pick out bits of steel from a circular magnet.

Presumably the magnetic field is stronger at the point.


--
Tim Lamb

In message , tony sayer
writes
In article , Tim Lamb
scribeth thus
In message ,
newshound writes
There are two sorts of devices described as nibbler

https://en.wikipedia.org/wiki/Nibbler

The "shears" type is OK for making a linear cut, the punch and die type
which takes out a little rectangle at a time is best if you are cutting
out "features" like a square recess or a T-feature.

Anyone still have their Gosscut metal shears?


Yes! Had those things since waay back in the 60's or maybe early 70,s

And they still cut fine!

Saw mine today:-) Gathering dust on a workshop shelf. Only one *S* I
note. Fine tool if you only wanted to cut in a straight line.


--
Tim Lamb

On Fri, 3 Feb 2017 12:24:10 +0000, Duncan DiSaudelli
wrote:


I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

Go and chat to your local water jet cutting workshop.

On 06/02/2017 22:17, Peter Parry wrote:
On Fri, 3 Feb 2017 12:24:10 +0000, Duncan DiSaudelli
wrote:


I need to cut a couple of circular holes (150mm dia) in some 0.5mm thick
"304" grade stainless steel sheet which has been formed into a curved
shape and polished (which I think means it has likely been work hardened).

Go and chat to your local water jet cutting workshop.

Chemical etching comes to mind as well.