Thread: Cutting metal - angle grinder/ cut off saw or both

G'day.
I use a 115 mm angle grinder with a 60 grip flapper wheel to do all my grinding. The flaper wheels seem to last longer and cut better.

For cutting steel, I use a TCT steel cutting blade in a el cheapo GMC $49 drop saw intended for cutting wood. This saw gives a clean cut that is cool and clean. You don't have to clean up the cut.

Originally Posted by TomH

Good evening all,

I am about to enter the world of welding thanks to the GMC clearance through ebay. I did learn welding at tafe some time ago for a couple of days, and intend to practice solidly to develop my skills.

Whilst I own loads of woodworking tools I do not have many suitable for metal work. In a month or so I need to make the frame for an outdoor chair (my mum has the design), which will involve cutting RHS. I do not own an angle grinder or a cut off saw. It sounds like I definitely need the angle grinder to clean up welds, and was interested as to whether I could use the angle grinder to cut RHS to a sufficient degree of accuracy or do I need to purchase a cut off saw as well?

Cheers,

Tom

Hi Tom.
The two tools do different things. I own both. Put it this way, for a single cut now and then in not-too-thick stock, the grinder will get you by....but if you are cutting a number of lengths of steel, and especially box section or T section, the grinder is going to give you....let's say....issues.

The drop cut saws are cheap these days. I own a Makita one, and I'm still using the first disc it came with...and that's after a lot of cutting. I can send you some photos of a large steel shelving unit I made for my wife. Believe me...you wouldn't want to be making 100 cuts with an angle grinder. Also, consider the fact that you will likely be making butt welds and flllets. You want things to be very square, my friend. Spend the money and get a cut-off saw. You'll never regret it.

Cheers,
Big Mike

I also have both,

Maktec drop saw - orange cheaper version of blue makita works well.

Angle Grinder 4" very useful, got a twist knot wire wheel that screws on, can use for cleaning down surface rust etc. Also gets rid of spider webs etc on timber next to shed.

Agree with Big Mike's comments.

Originally Posted by glock40sw

G'day.
I use a 115 mm angle grinder with a 60 grip flapper wheel to do all my grinding. The flaper wheels seem to last longer and cut better.

I use flap wheels to clean up welds/edges etc, 40-60 grit for rough grinding and 80-120 for finishing before painting.

I also use a fine kerf (1 mm) cut off wheel permanently mounted in an old tablesaw. It makes more accurate cuts than an angle grinder and allows you to rip which is very useful. Overall it's probably not quite as accurate as a cut off saw but then again I can cut HSS with it!

If I were you I would start with a five inch angle grinder. With thin disks it eats through rhs and with a bit of practice it is easy to get square cuts. I rarely bother to get the cutoff saw out. I say 5" because they are so much more efficient than 4" yet you can still use them with one hand. I'd just get the angle grinder first and then if you want to get more into metalwork get a cut off saw. I like hitachi grinders and think they are a good place to start. I borrowed a cheaper brand once and the vibration made it very hard to control with any accuracy. I cant recommend thin wheels enough they make a huge difference
Ben

I agree, the 5" hitachi grinders are good value (we have one at work) but I wouldn't write the cheapies off quite so quickly. I have made many useful things with my 4 year old, 4" $39 Ozito angle grinder - no significant vibration difference compared to the 5" Hitachi and it could die tomorrow and it would have easily covered my costs. Hopefully something like a Hitachi should last somewhat longer.

Originally Posted by Canetoad

. . . . . yet you can still use them with one hand.

I would not recommend using any grinder, except perhaps a dremel, with one hand. I suggest holding the steel/metal in a vice or with clamps and using 2 hands.

Angle grinders are ever so handy, and the different array of discs and attachments you can put on them make them one the best power tools you can buy.

If your budget will extend to it, a cut-off saw is a god send if you need to do a number of cuts. However, the angle grinder will do the job... as will a hacksaw and file.


And I'm with BobL. Anyone publicly advocating using an angle grinder single handed needs their head read. (no offence meant, Canetoad) I know it's common place, and most of us have probably done it on more than one occasion, but recommending it to someone on a public forum, in this very litigous society we live in these days, is just asking for trouble.

Thanks for all the replies. I do have a hacksaw and files, but could think of better ways to spend my time than cutting metal!!

Good advice re the 5" angle grinder. I wouldn't want one any larger (the site I used to work at banned all 8" & 12" angle grinders due to the horrific injuries caused by these beasts), but the 4" ones would be too small. I was in Bunnings last year and a guy was bringing back an 6" angle grinder that was too small for the job. The Bunnings assistant in the tool store then advised him if he removed the guard he could use 8"+ blades on the same machine. I've heard some stupid advice given, but this one could have real life consequences, so I let him & store manager know.

It seems a grinder is pretty essential, so maybe I'll pick one up and see how good I am at cutting square - maybe santa can get one for Christmas if I start lobbying now.

Cheers,

Tom

Gidday

When i first started my trade as a welder/fabricator i was astounded at how accurate and often used a 9inch angle grinder is.You would be surprised how often there used and what there used to cut!

IF your cutting forget the smaller ones n drop saws a 9 inch will get you buy until you learn to become a surgeon with it n give more consistent accurate results.

Remember for the type of job your planning U really dont need super accurate cuts. If you get within 1 mil or so you'll be able to do a solid weld (butt or fillet) then tidy it up with a 80 grit flap disk on a 5inch!

If your going to be working with metal getting proficient on a 9inch is a skill well worth mastering

Regards Lou

Silly me. Sorry guys no I don't want to publically advocate using grinders one handed. I should have thought about what I was saying a bit better.

Ben

I found early on that the small grinders run through too many disks when cutting, for cutting I run a 14" cutoff saw, it's quick, accurate and simple for cutting mitres.

Mine is setup in a bench with a 6' long lead-in and 4' lead-out rack section so I can get the steel into the saw nice and straight and level. Makes cutting bulk steel so quick and handy.

For sundry cutting or off-site cutting I reckon it's worth using the 9" angle grinder. With a certain amount of common sense and care they are relatively safe to use and the blades last much longer than the smaller grinders, the depth of cut is much better as well.

The problem with using the 9" grinder for a lot of cutting is that the side-handle is not oriented the best way for machine control, in my case I made up a new side handle that runs out to the left (or up when the grinder is in the cutting position) and then out to the left - over the top of the wheel guard - this means that my left hand is in a position and orientation that gives much better control over the grinder.

I probably could be accused of overkill but I run the 14" fixed saw in the bench in the workshop, a 9" grinder permanently fitted with a cutting disk, a 9" grinder with a grinding wheel and a couple of 5" grinders with flap wheels. I've gathered these grinders over the years so now I don't lose time forever changing wheel types on a single grinder.

Originally Posted by Gavin Newman

I probably could be accused of overkill . . . . . .

Nah, sounds perfectly reasonable to me. I'm just jealous I don't have the room in my shed.

Originally Posted by TomH

I was in Bunnings last year and a guy was bringing back an 6" angle grinder that was too small for the job. The Bunnings assistant in the tool store then advised him if he removed the guard he could use 8"+ blades on the same machine. I've heard some stupid advice given, but this one could have real life consequences, so I let him & store manager know.

I read an OH&S report about a guy who did this. He is no longer with us.

Mike

Originally Posted by Gavin Newman

I found early on that the small grinders run through too many disks when cutting, for cutting I run a 14" cutoff saw, it's quick, accurate and simple for cutting mitres.

Mine is setup in a bench with a 6' long lead-in and 4' lead-out rack section so I can get the steel into the saw nice and straight and level. Makes cutting bulk steel so quick and handy.

For sundry cutting or off-site cutting I reckon it's worth using the 9" angle grinder. With a certain amount of common sense and care they are relatively safe to use and the blades last much longer than the smaller grinders, the depth of cut is much better as well.

The problem with using the 9" grinder for a lot of cutting is that the side-handle is not oriented the best way for machine control, in my case I made up a new side handle that runs out to the left (or up when the grinder is in the cutting position) and then out to the left - over the top of the wheel guard - this means that my left hand is in a position and orientation that gives much better control over the grinder.

I probably could be accused of overkill but I run the 14" fixed saw in the bench in the workshop, a 9" grinder permanently fitted with a cutting disk, a 9" grinder with a grinding wheel and a couple of 5" grinders with flap wheels. I've gathered these grinders over the years so now I don't lose time forever changing wheel types on a single grinder.

Just out of my curiosity when useing your 9" with your mod what side of the grinder are you standing when cutting,(blade side or gearbox).