Thread: ripping 90x90 x2.5mm rhs

Hi Meadow,
The Triton could work, the only thing I would make sure of is that the first cut is on the face that has the weld bead inside it.
That way you will minimise how much the cut will close up and bind on the cutting disc, which it might do anyway just to be annoying.

Phil

Phil has a point - you probably need to be prepared with some wedges or pieces of stock your kerf width so that you can wedge the cut open.
If I'd had to do that a year or so ago I would probably have used the angle grinder and run the blade guard down a piece of something as a guide. Now I'd look at that and reach for the plasma cutter. Perhaps put a post on the welding forum and see if anyone nearby can help as it would be a very quick job for a PC.

Michael

I cut some universal column with a Makita 9-1/4" saw using a metal cut off disc successfully many years ago, but the heat from the sparks wrecked the return spring on the guard.
Depending on the length of cut required, I would probably use an angle grinder or circular saw against a fence of some sort, and probably do it over a few passes instead of trying to cut right through in one go.
The sparks will probably leave a messy deposit on the inside of your guard, which may be a bit of a problem.
I don't suppose unequal angle is available near your required size which could be welded together?.

Good luck with your project.

Alan...

I used a small woodworking table saw with an abrasive disk permanently mounted in it to cut metal for many years. However, unlike the triton, mine was belt driven so the metal and disk abrasive (at TS speed the disk wears at about twice the rate of an angle grinder and makes a large amount of abrasive dust) did not fall directly on the motor. For a few cuts I can't see why you can't do this with the triton but I would make sure the circular was cleaned up afterwards. It's not the metal so much as during the cutting process this forms relatively larger pieces compared to the wheel itself which forms a fine abrasive dust that will penetrate the innards of the circular motor and long terms can make a real mess.

Another problem I found with thin kerf abrasive wheels is that they can wander away from a straight line even when a fence or guide is use and as you will be cutting blind it will be difficult to see what is going on so you will have to stop and check periodically to see it is still on track. One way I found of keeping it on track was to pre cut a series of short cuts along the length of the piece by using the fence as guide and slowly dropping the metal onto the wheel every 100 mm or so. Then run the piece through and the cuts will help keep the wheel on track.

And definitely use wedges as suggested to keep the cut open.

Only last sunday did I retire my little table saw with the abrasive wheel. I cleaned and fixed it up and gave it to my son who has started to do a few woody things. In it's place in my shed is a 50A plasma cutter which would be the ideal thing to rip that SHS piece with.

I'd be using a plasma cutter for that task. Less dust, cleaner cuts and a lot faster.

Kennards used to hire out a 25amp unit from memory which had a built in compressor and was good for cuts up to 3mm at high speed. It could be run off a 10amp socket as well.

Failing that, a thin block of timber clamped down as a straight edge and a thin cut off disc would my choice - You're sticking so it's not like the cuts have to be perfect, especially if you're half decent with stick.

Best of luck

Cheers
Jon

Originally Posted by meadow street

G'day,

got an interesting situation where I may have to rip down a piece of rhs - 90x90x2.5 mm.

now, my first instinct is to fit an abrasive cutting disk to the circular saw on the triton and run it along the fence.


wise or not wise?


meadow

The cutting disc will more than likely pull off line and could jam the job against the guide.

Also cutting into thinish steel in one pass will tear the cutting disc to pieces very quickly.

The best way to use the Triton is to drop the cutting disc down until only 1 - 2 mill protrudes, add another guide if possible (wood and G clamps) so the job runs down a channel, then progressively grind down through the steel as you pass it over the cuttig disc.

I've cut plenty of steel this way. The cut will be perfect and the disc will last.

Just increase the disc height as the cut progresses on each pass.

Probably take about 2 or 3 passes for 2.5 mm.

The cuttings shouldn't worry the saw.

I use a cheap 1800 watt Black and Decker to cut steel and no problem.

Rob

Just to add my thoughts, I have a 9 inch Ryobi cs that has no other purpose. I have cut up to 6mm with this hand held, using a fence. I cut hard and fast. Anything else just wears the disk. I don't get sparks, but orange blobs, when it gets up to speed that is. There is still a problem with going off track, but I think this is due to my control more than anything else. I think the saw edge is not parallel to the disk. A feather stick would. help on the ts. I also have plenty of disk in the cut. This will reduce the flex. It surprises me that the guard spring still works. I lock the guard just above the work surface. It gets very hot and I don't want to touch it, even with gloves. In your case the work would be the guard.

Dean

Hacksaw

Meadow,

Where abouts in NSW are you?

Apologies for being OT, but Jon, did you ever get the gears sorted for your drill?

Michael

Originally Posted by Jon_77

Meadow,

Where abouts in NSW are you?

near Tamworth Jon.

ill need probably 6m ripped.

current thinking is gradual passes with the triton, or finding a plasma operator.

thanks for input everyone: )

the internal joiners are upwards of $20 to buy off the shelf, and I'll need about 18 -20 of them!

= 360$ -400$

i don't charge myself for time, so making them up is the go I reckon. The larger ones to fit a 150x50 are two tall lipped channels, spot welded. The smaller ones look like a rounded rhs section (not cattle rail) and of course is an unusual size.

Mind you, if I get the manufacturers name and location I may be able to wrangle something?

merry go rounds

meadow

Originally Posted by Michael G

Apologies for being OT, but Jon, did you ever get the gears sorted for your drill?

Michael

Wow, good memory Michael

Nope, I priced up the raw materials (about $100) but other things (reno's) took a priority so it's just sitting in a box for now.

Meadow - that's a shame, if you were in Sydney you could have used my plasma cutter. All the best with it

Cheers
Jon

Have you trialed, welding the box section? At 100 x 50 x 2.5 wt there's heaps of wall thickness to weld into.

Given that you prep and and square the butt weld edges correctly I foresee fewer problems than phaffing around with a saw trying to cut the inserts.

Also why couldn't you fish plate the long sides of the joint ? 150 x 80 x 2.5 would be more than adequate.

If it was my project,I would be ensuring that the butt weld surfaces were dressed to a clean shiny metal surface and square.

For butt welds, just set the butt edges about a millimeter apart and tack each corner using higher than normal amps and ensure edges are straight using a 1200mm level.

Weld across the short butt edges first and then do the long edges as this will help resist distortion.

Much quicker

Grahame

yes Gra,

i really would prefer to weld and plate the sides.

although it's 2mm not 2.5.

i guess I am getting caught up in the flooring system recommendations more than anything else.

ill do some experimental welds and see how things look and maybe ask a few more structural questions : )

regards