Any metal workers in here?

[loply]

Hi folks,

Just looking for some quick metal working advice if anybody would care to help.

I'm in the process of building a devilishly useful and rather large machine and it involves a fair bit of metalwork.

First question: I bought an Evolution Rage cut-anything toothed blade for my compound mitre saw. Cut some 40x20x2 box section beautifully, then chopped a 40mm mild steel rod with ease (albeit quite slow), then tried another 40mm rod and it went a few mm then got rapidly blunt and is now unable to cut mild steel. Have I done something daft? Should I risk another one of these blades or would I be better off getting a second hand metal chopsaw with an abrasive blade? I honestly don't know the speed of my mitre saw but I presume it's whatever is standard, these blades are meant for 2,500rpm or less - was my saw possibly too fast?

Second question: I had to drill an on-axis hole down the middle of that 40mm mild steel tube. I don't have a lathe so I chopped off a 20mm long section of it, popped that on my pillar drill and drilled an 10.2mm hole into it, which I then tapped to M12. It ended up miles off-axis. I had centre punched the piece really well, and drilled straight in with the 10.2mm drill using lube, it cut easily but emerged on the other side in a different spot to where it went in. What should I do when I retry this? Should I have used a smaller drill first? Do I need to buy a spotter drill?

Cheers for any help!
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[warped one]

I'm a Fabricator if that helps. To me a metal worker does sheet metal I.e, Sheet metal worker.

Chop off saw-
It all depends on how hard you was pulling. If anyone is seen hanging off our chop saw (usually the sodding tinners) they get a lump of metal thrown in their general direction. If you were doing it too soft then there is the possibility for a hard spot to have formed. And for love nor money a normal cheap blade won't get through it.

If it is the sort of blad I am thinking of with the large cutting teeth, (Ours are about 2mm long) then get a scribe or similar and go around the whole blade and check each tooth, because they have a habit of picking up the swarf which comes out as little curls and getting wedged in their.

The compound blades are pretty crap, if the piece bounces then there is a chance of the blade exploding, and with little bits of disc flying around, it makes for one hell of a show. And they are only good for a few cuts aswel because they develop a hard spot, every now and then and after that they just won't cut at all, and are really only use for using as a Frisbee.

Drilling pipe-
We do alot of Stainless Steel hand rail, and are regarded as one of the best in the country by Kier and Mag so this is one of the things I am used to.

It is reasonably hard to get a hole to go perfectly through the middle of a pipe, I always use a center finder.

Like this:
https://web.media.mit.edu/~tim/pix/2003-3-23/0632c.JPG

Then to run your line across the pipe us a piece of angle which will give you a perfect straight line right down it.

If you don't have any angle you and be a rough arse and just wrap your tape around it and over lap both ends by about 100mm and make sure they are inline then draw round it and use the cetre finder again.

Anything over 8mm we use a 6mm pilot then go up to the correct size. If anything it saves the life of your drills, and the monogamy of having to sharpen the sodding things every 5 minutes.

Hope this helps.
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amnesia - Never in the history of usernames has one been more accurate. Warped indeed. You sir are a fecking oddball.

[SoND]

[warped one]

Ha Ha, I missed that bit.

As Sond said, Bandsaw.
Even with a 9inch there is a chance of a bite, and you'll end up with a nasty bump on the noggin to explain to the O/H and mates down the pub.

Can't you just take it too, a Fab shop locally?
We always have people come in off the street and asking up to chop a section down and most of the time they just give us a smoke or a few quid whilst we are doing it.

Then we can show you how do drill pip properly.
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amnesia - Never in the history of usernames has one been more accurate. Warped indeed. You sir are a fecking oddball.

[Pete.]

You might have blunted the blade by using too light a cut or you might have cooked it by going too heavy.

If you have a lot of that 40mm bar to cut you're better off using a bandsaw or power hacksaw. The cut from the chop-saw is not likely to be perfectly square across the bar for starters.
To drill a through-hole concentric you really need to find a lathe, because for the inexperienced, trying to drill and tap it on-axis after you have cut it with the chop-saw is not going to yield good results.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[SoND]

[MaybeGuy]

are you using coolant with the saw blade?

as for the drilling, try a pilot hole. start with a 4mm bit, or a slightly more bodgey way is to use a slightly smaller than required drill bit (like a 9mm) and drill halfway on each side, then widen it using the 10.2. only if you've got limited sizes available.

imo starting with a 10.2 with just a centrepunch is too much depending on the material. look at the tip of the drill. it's not a perfect point. ie: a tiny flat bit, may not look like much, but that's what's causing it to wander about and fuck your shit up. the pilot hole would clear the flat bit allowing a straight cut.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Pete.]

[loply]

Hi folks,

Thanks for the replies so far.

Those Rage blades claim to be able to cut steel up to 50mm thick, and the first 40mm bar did indeed cut fairly effortlessly... I didn't use coolant or lube as it's meant to be used without. I did let the blade cool occasionally though.

I might look on Gumtree for a used abrasive chopsaw. Are these any good? How much does a replacement disc cost and will 40mm bar be a difficult task even on one of these?
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[MaybeGuy]

that'll be why it blunted so quickly then. Surely the chop saw has a built in pump?

Theres not much you can get away with when working steel without coolant.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[SoND]

Rage saws are dry and highspeed, you don't use coolant with them.

It's probably advertised for 50mm hollow sections, not solid steel.

You can get your blades sharpened, if you stop cutting solid stuff it'll last a lot longer.

Solid bar will eat up an abrasive disc pretty quick and it will be just as noisy and slow.

It's not worth getting another saw just to cut a handful of bits, take your material to an engineering shop and ask them really nicely to put it in their bandsaw.
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[loply]

There's a bloke advertising a 'barely used' chopsaw with blade for £20 locally, I think I'll go and buy that and then I'll be able to finish my bits and bobs using it, and I'll attempt to resharpen the Rage blade.

I wouldn't mind owning a chopsaw anyway as the Rage blade is a bit scary for cutting M12 stud or othersuch small objects. It works but... You can imagine the fear...

How would I sharpen the Rage blade? Using a mini file and doing the obvious?
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[SoND]

There are people that do it professionally. The rage blades are tipped with tungsten carbide, you can give it a go but it's hard.

An abrasive chopsaw will be just as scary and dangerous! The cheaper saws don't tend to come with a vise built onto it so get clamps that fit.

Always clamp your work, those blades will cut through you like butter.

Safety goggles are preferable to glasses because chips can get under them easily.

Wear your ear plugs / defenders too. They're very fking loud as you've probably noticed and a hot spark in the ear isn't nice.

Safety nazi to the rescue!
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[MattHirst]

When drilling a pilot hole, you should never drill a pilot larger than the web of the drill you will be using to finish the hole.

As for drills wandering, that's where u-drills and spade drills are made of winnah. Cut steel like a hot knife through butter
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It's all fun and games until someone gets hurt, then it's bloody hilarious!!!

[loply]

I went over and saw the bloke who was advertising a chop saw for sale - £20 I got myself a decent nick thing with a fresh looking blade. Pretty big diameter.

It has a built in clamp which holds the workpiece really well, and I have to say the overall result was a lot more predictable, smooth and safe than using the Rage blade.

It also had a well designed route for the sparks to go, whereas the Rage flings stuff in every direction.

I think it's a lot better to be honest, and knowing that the discs are only a few quid to replace is reassuring.

Wish I hadn't bothered with the Rage blade now.
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[warped one]

Wait until you get a blade bounce then explode, your next post will be about how to dig parts of the disc out your garage wall and arse.
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amnesia - Never in the history of usernames has one been more accurate. Warped indeed. You sir are a fecking oddball.

[Pete.]

They are safe enough if you don't abuse them tbh. I don't like the noise or the mess but I never had one pop a blade. A cold cut saw is ideal for cutting such large bar but that's going to be way over budget.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[warped one]

Compound disc's are bloody dangerous.

If you have ever seen one go pop, you will know why the one at work is sat in the stores gathering dust.

They are bloody lethal.
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amnesia - Never in the history of usernames has one been more accurate. Warped indeed. You sir are a fecking oddball.

[MattHirst]

We have 3 at our work and they are used multiple times daily and get one hell of a lot of abuse.

I've yet to see a blade go and we regularly cut tool steel etc. We have even cut carbide re-inforced/solid carbide boring bars with it before, they take a lot of cutting but do-able.

If you are having blades go then you are either swinging on it to try and cut through really quickly, not clamping your work piece correctly so you are getting sideways movement (imo the most common cause of a disc breaking) or having a chip in the cutting edge of the wheel and not dressing the wheel before cutting your workpiece.
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It's all fun and games until someone gets hurt, then it's bloody hilarious!!!

[loply]

Do you need to dress abrasive cutting discs? What do you use?

I have a stoney/diamondy tool which is a red plastic handle with a cube of moonlike sparkly material on the end of it, which I use for reprofiling the grinding wheels on my bench grinder... Should I be using that to keep the chop saw blade square too?
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[SoND]

No, leave it be.
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."