Best way to cut 40x10 steel bar ??

Guys, I am working on a project that requires lots of flat bar cuts at a specific angle while being square on the other axis so I purchased a cut-off saw with the expectation that it would cut square but it didn't. I did 3 cuts and all of them drifted away from the job the deeper the cut went, I checked if the head is square to the base and if anything it leans slightly towards the job as it cuts. So why does my saw cut a double mitre? Is it taking the path of least resistance as it contacts the metal at the left first so the thin wheel drifts right? Like drilling at an angled job, the drill will wander downhill? If so bending a 355mm wheel at speed sounds dangerous.Its around 1.5mm out of square across a 40mm cut, its quite obvious. The parts will be tack welded then power coated so gaps will look ugly in the finished product and I don't want to fill every fillet with weld and dress every weld, neat cuts will negate this need.

I read that disk quality makes a difference, I thought it would eat the mild steel easily. Can you use a non-abrasive wheel on 10mm steel? That sounds dangerous too.

What other saw would do this job? I was looking at a power hacksaw but finding a hydro-feed machine is not going to be cheap and its way too big for my work area ....

I don't want to hand finish every cut as this will take forever and allows more inaccuracy. What would you guys recommend?

 

we used these, but to get them to cut straight (same with abrasive) is not to put any weight on it while cutting.

 

if it really matters, water jet or laser cut.

Otherwise you need to hand finish every piece

or this

 

Bandsaw (power tool), hacksaw (hand tool). Looks as though you have hardened the steel at the end there (blue colour), too much energy being transferred into the steel.

 

Thats just a dearer version of my 355mm Ryobi (yes it was cheap), I cannot imagine that toothed blade chomping into steel bar .... I guess that's what it was made for

No its not that important, I just want it to turn out nice

I cant see a regular band saw working well and I would have to slide a 1.3m bar on its side to get the angle cut. Hack saw? Nah I will find a way to make the cut-off saw work, even if I have to tilt the bar to make the cut straight. Heat - maybe I will try to cut it slower.

That saw above might do it but I don't have one and cant fit one in my work space.

Cheers guys.

 

I assume you're using a bandsaw ?
For precise metal cutting, you need a cold saw.
More something like this:
https://www.ebay.com.au/itm/1662020...MI2PqftYP2jgMVzWwPAh2PJyoJEAQYAyABEgJpRfD_BwE

 

No, he's using a drop-saw. Not sure why he is even asking the question, the solution seems obvious.

An adjustable bandsaw if such a thing exists, a cold-saw as mentioned would be more appropriate. Just pony up the cash to have a metal worker do it for you, if it is a one off thing, unless you want to invest in the tools. You are definitely cutting to fast, the discolouration is not a good thing.

 

Sorry what is obvious? I didn't expect a cut-off saw (abrasive) to cut so shit

 

cold saw* or a horizontal band saw is the answer for this job. slow is the answer for accuracy over heating the steel will harden it, causing the blade to wander as it can't cut the hardened steel as easily as the soft unhardened steel. hence the problem with abrasive saws, they're a tool for rough, fast cuts, not accuracy.

won't be cheap though.

I've got oneadees
https://www.machineryhouse.com.au/b007

cuts square enough (any better needs a trip through the lathe or mill), used it on (biggest so far) 150mm dia round bar.


*cold saws use toothed blades, but slow speeds - hence the cold.

 

(5) Marketplace - Hafco CS275A Cold Saw | Facebook

cheap at the $500 asking price

same here

(5) Marketplace - Metal cutting off saw | Facebook

don't forget coolant if you want clean cuts and a long lasting blade

 

The problem with band saws is the precision of cut. You'll need machine that has some serious blades and doesn't play much left and right. Cold saw is precise but little slower. It depends on job requirements

 

ha - after I enquired about that first link, they've realised what a good price it was and added another grand nevertheless, it's the right tool for the job if you don't want to refinish it.

You might also like to try a ferrous tct blade for the same drop saw

Kango 254mm 48T Metal Mitre Saw Blade - Bunnings Australia
Diablo D1472CF 14-inch Steel Demon 72T Cermet II Carbide Ferrous Metal Saw Blade : Amazon.com.au: Home Improvement

You'll need to keep an eye on max speeds though and don't be too aggressive with leaning on it.

Another thought though - cheap cut off saws (for steel, timber, whatever) will angle off when you apply a load on them because of the flexibility in their cheap frames or play in the bearings. The only solution to this is to 'calibrate' them for having a load (kinda like a negative offset) and load them very lightly. It's a shit solution to the mantra "right tool for the job" though.

 

Band saw + sliding jig to maintain angle and depth?

 

Sounds like your using this with a disc










When you need this with a cold cut blade







like Spyder6052 already said you have to cut slow to avoid disc flex where as with a blade it wont flex as much giving you more control.



Back in the day i used to install alot of i beam h beams and lentils.... mostly for new doorways and when you were extending rooms. For the bulk of it i would just use a makita cold cut hand saw... it spun a bit slower than normal saws but cut steel like butter and was easy to use.... LOL i used to get alotta tradies running up to me on sites and actually grabbing me like i was about to make a mistake.... till i explained to them i was using a cold cut not a normal hand saw. It pretty much looked like a normal hand saw but an "old fashioned" one.

The truth is you can actually use a totally normal saw and cheap ass carbide blade to cut thick metal.... the blade will just die faster. Alot faster on i beams and such... but for thinner box metal beams it works in a pinch.

I'm not convinced a bandsaw or the slow "hacksaw" type machines are worth the cost in this instance or the drama.


Edit.... Don't be sticking a cold cut blade on that disc cutter....! like a grinder they spin one speed and way to fast!

 

Kinda late but as others have mentioned you'll be wanting to either get a good quality cold saw & the appropriate blades etc.

Or if your doing only an X amount for an 1 time thing, then cruise around to a few smaller metal cutting etc workshops & i'm sure you'll find 1 that will be happy to cut 'em.

Most small metal workshop's if they aren't overloaded at the time with work. Usually will be happy to do the work if it's not complicated, either for a small $ fee or even an slab of "Grandpa's Cough Medicine"

 

90% of your issue is cheap gear. Your going to have to get out a square, align the cutting disc to the cutting bed. 90 deg mark on cheap saws is often a degree or more out.
Don't force the cut, let the weight of the saw cut itself or the cheap light duty frame will twist.

 

Showing laser cutting in action:

(I saved the video in 2007 - I assume the gear would be a lot more impressive now)

https://drive.google.com/file/d/1Uv20gZV3nJAmNXoB2CuOb18k8QME7I5a/view?usp=sharing

 

Where are you ? I'm in Adel. If you are local to me, let me know how many you have and what angles you need. I can do it for you.

 

Just looking at the angle of the original cut, it looks exactly like every fucking jigsaw cut I have ever made. This is because I am too impatient and just push too hard, flexing the blade.I also agree the cut appears to be forced.