Cutting Stainless Steel

[alanrichey]

Before I get my angry grinder out and my new 1mm cutting wheel, to cut holes in the side of the car for some vents there is one thing I am not sure of. Should the leading edge of the cutting wheel be going upwards or downwards ?

 

Logic tells me it should be downwards so all the sparks go underneath the sheet, and assuming the sheet is resting on something it will be pushed down on to the support rather than trying to lift it up, but is it that important ?

 

Also, I have seen some cars with vents in the bonnet sides and some further down in the body of the car. Any differences ?

 

Al

[Dave R]

Masking tape, mark out with magic marker. As long as the sheet is suported, so it can't escape you will be fine

[Stewart]

I found the easy way was to cover the area with masking tape mark out the shape and cut with a grinding wheel on a dremel and it surprised me how easy it was.

[steve in stockport]

You want it cutting so that it fires all the sparks and debris away from you, definitely not pleasant the other way round.

Practice on an offcut first and get used to the feel of the way it operates.

 

Also remember measure at least twice and cut once.

[Bob Tucker]

Cut towards the direction of rotation.

If it grabs it will kick back towards the cut & stop.

If you cut the other way, when it grabs it will skid along the new uncut metal

& carry on making a mess.....I know....

[kevin the chicken]

I have cut stainless with an angry grinder with no problems. I always use the thinnest disc I can get my hands on even if I do use several of them up as it is easier to be more accurate and if you do wander off slightly it won't be as bad as if you are using a thicker one. Cover the rest of the car up with something to stop hot sparks marking paintwork or interior and watch your skin on the sharp edges.

I would have thought that the vents would be better higher up as after all heat rises but wherever they are it should increase airflow. Can you not cut with some aviation snips or is it too thick. A dremmel sounds like a good idea for control and accuracy, I have some to fit in my bonnet, may go this way myself

[fry61]

I see what Bob above is saying but I think his method leads to very rapid disc wear --i;e very short life -- I have always used the thin s/steel - inox discs in a wiping cut -- the disc lasts a long time & there is no risk of the disc grabbing the work -- but as he said get a firm grip on your a/grinder to prevent running over parent metal that's not to be cut.

 

Invest in a leather apron -- I did after setting fire to shirts & jumpers.

 

Tool of choice for accurate cuts is 18volt 4.5" DeWalt Battery Angle Grinder -- much less kick on start-up.

Edited September 8, 2015 by florin metal works

[Guest mower man]

Got to agree with everything said above ,the big things are eye protection and patience ! mick

[Bob Tucker]

Dont let the sparks get onto any glass....

[cb750]

Just done mine using angry grinder and 1mm inox disc. Cut both with 1 disc and hardly any wear. Took it steady and had no problems. Didn't do it on the car, put one side of the bonnet down on the lawn, the other supported on my Workmate and had my wife hold it firmly into place. Both wearing safety gear!!

 

I wanted to get mine as far back as possible as my carb intake is there but was limited to the position as the pedal box enclosure was in the way and the inside of the vent would have fouled on it. I have the passenger side one facing forward and the drivers side pointing to the rear to create a cross flow. I put a post up about this recently. Seems to work!

[richardm6994]

 

 

Invest in a leather apron -- I did after setting fire to shirts & jumpers.

 

 

 

+1......especially if you're doing lots of grinding and cutting. I've lost count how many teeshirts I melted without even noticing until the grinder was switched off.

 

Also (from personal experience), the 1mm cutting discs go through your fingers like a laser beam through butter........be careful and don't take risks.

[alanrichey]

Thanks everyone, lots of good advice. Unfortunately no-one has actually answered my question. Although Bob (Tucker) came close with "Cut towards the direction of rotation". Unfortunately I don't know what that actually means.

 

So here is the question pictorially:

 

 

And Bob (florin), what do you mean by a 'wiping cut' ? not heard that expression before.

 

Al

Edited September 8, 2015 by alanrichey

[philshelton]

As its an abrasive wheel it will cut in either direction. I think the method Bob is talking about is to go back and forth across the material cutting a little bit deeper each time till it cuts through.

[richardm6994]

It will be fine in either direction however I tend to find I have better cut-control over the angry grinder when pulling against the disc rotation.

[fry61]

With your pic I would have the disc as viewed rotating clockwise -- anti-clock makes for rapid disc wear & liable to snag. This is opposite to how a milling or router cutter would be presented to the work ( I think ) This is what I meant by "wiping cut " the angle of cut & rotation makes the disc wipe the work as the disc is brought into play.

 

Does that make sense?? Hope so.