Cutting metal: fast, accurate and easy (1 simple DIY trick) | Auto Expert John Cadogan
HTML-код
- Опубликовано: 27 авг 2024
- VEVOR DISCOUNT! (Industrial & DIY tools at great prices.)
s.vevor.com/bf...
Portable bandsaw (table version): s.vevor.com/bf...
Portable bandsaw (handheld version): s.vevor.com/bf...
TCT metal chop saw: s.vevor.com/bf...
Get 5% off with code VVSALES
1-2-3 blocks (matched pair, precision-ground): amzn.to/4b4Gpau
Save thousands on a novated lease (Australia-only): autoexpert.com...
OLIGHT DISCOUNT! (Awesome torches.)
bit.ly/3zF5hCQ
12% off: Use code AEJC
BLUETTI DISCOUNT! (Portable 240-volt power & power failure protection.)
www.bluettipow...
Discount codes here: autoexpert.com...
Help support my independent reporting, securely, via Patreon: www.patreon.co...
Podcast (audio-only version, for listening in the car, etc.): anchor.fm/auto...
Save thousands on any new car (Australia-only): autoexpert.com...
AutoExpert discount roadside assistance package:
247roadservice...
Did you like this report? You can help support the channel, securely via PayPal: www.paypal.com...
Boilermaker here, I did structural steel for more than a decade (before moving on to other fabrication). Everything in this video is spot on, at least in as much as it's relevant for light sections for DIY jobs. We used different tools like cold saws and croppers, but the techniques are the same. We also used a lot of oxy-acetylene, plasma cutters etc. In all cases, repeatable accuracy is normally what you are looking for.
The only thing I will say, controlling distortion is matter of designing a weld procedure that minimises the distortion even without restraint. Restraint is only one tool in the tool box, the icing on the cake. The locked in stress needs to be limited to the weld, not inherent in the in the entire frame or structure.
I can certainly describe a weld procedure for RHS (or SHS as used here) that produces almost no distortion, but I'm not sure how many people watching this video would need it, and of those that do, how many of them actually know they need it enough to pay attention...
I really appreciate your comment, Chris - thank you very much for taking the time. (I should probably cut all my mitres at 47 degrees, and accept the shrink to 45 x 2 = 90 ... or thereabouts.) Respect for the work you do - it opened my mind when I was a young engineer.
@@AutoExpertJC Thanks, if more engineers spent some time on the tools their design work would be much better.
I was never a fan of over cutting mitres, but it does work. Mostly, it stops the apprentice from growing every frame by three or four millimetres. The other thing I told apprentices, is that as soon as you start putting enough heat into a job to weld it properly, you're going to have to deal with distortion. You want a full penetration weld but there's no point making the weld thicker than the material you are welding (either on the inside or the outside). You won't make it any stronger, because the weakest part is right next to the weld, but you might just cause a lot more distortion than you need to. So... minimum heat to get the job done, but no more. That's usually a matter of experience, and in college (ie TAFE when it was still a useful institution) we broke a lot of things we welded in a big press with a gauge on it, just to see how much it took to break it, and why it broke. Also for stick you couldn't hide slag inclusions from the instructor, and for GMAW (MIG) it was spatter inclusions in the root. Both are stress notches inside the weld.
Also weld sequence - for mitre joints the one that causes the most distortion is the inside fillet, so you do that first. If it's got nothing to pull against it can't go anywhere, but it will try to close your 90° a little, so your next weld is the side, from the fillet to the outside corner, and that tries to open the angle back up again because of the weld direction. Balance the distortion, and keep the stresses in the welds, not the frame.
On a lot of jobs we didn't weld the outside corner. It depended on what the job was. Often if something was going to be screwed into the frame, it was better to leave at least the outside weld of the lower mitres so that if moistures came in through the screw holes, it had a place to get out. It doesn't cause much distortion though, as long as you've welded the inside fillet and the two sides. A lot of beginners get the sequence wrong, for example tacking the outside corners to "hold it" without realising they are giving the distortion a fulcrum to get nasty with their frame geometry.
I certainly would like a description on weld sequencing either from yaself or JC.
@@Chrisamic Gold Star comment. I wonder if us hacks start on the outside because we've got our inside clamped with a big magnet. Makes me think setup layout and technique might be more important than I give it credit for - I am normally worried that the shape is right, rather than where I can weld.
@@Chrisamic just wondering, unless I read it wrong, I think you are saying weld the inside fillet first - is that right??
I asked my TAFE instructor and he said that the inside one should be last.
Anyway I’m now checking what others suggest and found this one - ruclips.net/video/lL98oE2NaQg/видео.htmlsi=cj-ZVJhEEryZUTRk. Also said a to do inside fillet last.
Mmm??🤷🏻♂️🤷🏻♂️🤷🏻♂️🤷🏻♂️
Hey also this guy is a demon welder and says outside corner first, then side (in direction of inside to outside) on both sides, and last the inside fillet. ruclips.net/video/h5AOvZsC85Y/видео.htmlsi=cl3kU1jpBtE7IXKa
And TimWelds also does the same - see 7min. 30 sec mark…. ruclips.net/video/w_iqJDfbzMM/видео.htmlsi=LDZQAocARi7lnMIW
and see here at 5min mark - def says fillet last ruclips.net/video/SriCUkwofWA/видео.htmlsi=Fn0fjh3etqvrWRQt
I’m really enjoying these workshop videos you are producing - please continue with them John. Cheers.
No worries - will do.
John man, you have a gift for doing safety videos in a way that lends itself to the information being absorbed and implemented, even by the most bone-headed of us. Just the right amount of respect, comedy, fact, care, and reasoning to make it absorbable through the thickest of skulls. Would love to see more safety videos. This one and your two videos on ways to die from arc welding are prime examples. Thank you.
I purchased this bandsaw 18Month's ago because of all the reasons you've highlighted and it's simplified my fabrication processes .
Like you I got one, I was very over the flame thrower drop saw. Do u use any cutting fluid, spray can or bottle etc. regards Ron
Always good for a reminder on risk reduction. Eliminating the risk (i.e. where you choose to stand) is much better than relying on PPE to mitigate the risk and standing somewhere stupid.
Agreed.
AND: a bandsaw doesn't piss the neighbours off as much as a grinder does at 8.00pm on Wednesday night. Iron man suit here we come!
Pissing the neighbours off is under-rated.
If you think a grinder is loud, try a dry cut metal saw. 😂
Writing as a machinist, I see no reason to even try a metal cutting circular sawblade. We have this principle called cutting speed that applies to every material/tool combination. It so happens that carbide on steel has a rate of about 400 feet per minute. On a circular saw used on a milling machine, that translates into about 125 rpm for a 12" sawblade if carbide toothed.
So a cutoff saw running at a few thousand rpm far exceeds the proper guidelines for carbide tooling. Yeah, it will last a while on overspeed obviously, but it's just wrong unless you're sawing wood or aluminum. If the tips get dulled/chipped, that's the end of your true cuts and the blade is scrap.
And yet, they work well and last for hundreds of cuts on common tube, pipe, angle and flat bar. Go figure..
Just cancelled my order for a Milling Machine.. are you saying I’m wrong?
How much does the average milling machine weigh and cost anyhoo?
A fabricator on a building site can’t lug one of those about I would guess.. and the kind of work involved or required wouldn’t be too concerned about ‘cutting rates’. Carbide blades are ‘multi purpose’ and cut steel easily. The work I do requires accuracy but not the accuracy a milling machine or other quality engineering process demands. It’s a different environment where cutting speeds are irrelevant unless it takes too much time.
Carbide saws have their place.. just like the cutting speed tables have their place in your work environment..
I like these types of content, I wish there was more like it.
To stray away from cars for a while is not such a bad thing.
Being out in the workshop and being a Tony Stark for a day is a way to go.
Re: stop spacer: good idea.
If you're cutting a lot of one length, and don't want to use the 123 block spacer, place the stop against the front edge of the part. It only needs to grab a tiny bit of the part to act as a stop. This allows the part to tilt and fall away without jamming the saw.
Some of the things you talk about come natural for me but still there is much for me to learn. Thanks for all these great videos.
20:42 - wow I am impressed - you have taken "measure once cut twice" to a whole new level.
Thank once again, for an informative presentation.
Just as a side comment, I recall that the preface of one of my engineering text books from the 1970s, stated that "Engineering is the art of making approximations."
I think it's the art of being 'close enough'.
An engineer is a guy who can do for a nickel what any fool can do for a dime. On one off projects I'm often the fool because it's easier to over build than to calculate. For repetitive cuts I'll build a jig. The real trick is getting welded structures straight and true. Sometimes takes some thought and bracing.
Stick the stop block on the clamp side of the saw. No need to worry about spacer blocks.
Then properly support the stock on the other end so that it doesn't drop when the cut finishes. You can buy cheap rollers that work quite well from Bunnings etc.
Don't wire wheel the inside of tube either. Use a file or buy a deburring tool ($10 from Bunnings, Supercheap etc).
Wire wheels have a habit of grabbing the workpiece and getting the required angle to strip a burr from inside a tube makes that more likely. You'll also be more likely to bend the wires more, making them break and fly off.
Weld order and direction also matters. Tack the inside corners of your miters, then tack in the supports then the outside corners (so you have a little extra material at the end to avoid melting the corner off). Weld the inside corners of the mitres, then run inside to outside top and bottom. Finish up the outside edge then go back through and do the supports.
If you're doing a lot of them or want a particularly good result it can also help to not fit the corners up at exactly 45 degrees. Cut them a little off so that you end up with them touching on the inside and have a 1mm or so root gap on the outside. The extra weld will pull it back out and if you get the balance just right (couple of test pieces will help) it'll come out at 90. The exact gap you want will depend on the material size, thickness, welder settings and so on.
Welding on just one side of a tube is also a recipe for pulling (IE the supports). Peening the weld can help on really small stuff, or you can heat a wedge with the thick part opposite the weld with an oxy on larger sections to correct it.
Above all, cheap material with huge internal residual stress will move around all over the place no matter what you do. So don't buy steel from Bunnings.
The trick to building something straight is to make it straight the first time, not to try to fix it after the fact. That comes from jigs that will take the stress of the material as it tries to pull and planning your order of operations.
I absolutely love the way you care about our safety! Thanks!
No worries Paul - thank you.
good safety awareness vid... I know growing up in the 70's and 80's we may not have practiced a lot of safe things, however workshop safe practices were instilled in us at school. seems we have to now reinforce that fundamental learning, 40 years later....
A lot of people just don't know the basics.
common sense sadly ain't that common@@AutoExpertJC
Love Your No BS frank & Honest Approach! Very Informative and Entertaining! Good On Ya Mate!
Great extra content. Thank you JC
No worries Justin - thanks for your interest.
This video is a nugget of gold. I liked it better that the EV and dumb ideas from zealots ones. Of course, what John says here about technique and safety applies equally to when you are cutting wood with a drop saw for a project. Just remember that for a cut piece to be accurate in length to the desired measurement, you have to account for half the width of the cut made by whatever saw you are using. More of these, please!
Thank you, Mark.
I suck at metal fab. I need more tricks. Please, keep on making those.
Thanks, John. Rooly appreciate these videos too. Cheers from WA
Hi John as a member of a model engineering club I will be telling the others of your video's for there sake as your information is great most of the guys are very good at what they do but this is a reminder of what we should do always and not kill our selves
Hi very cool teaching and metal working your still got work after all the EV s have left the planet cheers
Great video. I went to pipe welding academy. We had precise test plates and pipe and about half way through the semester the instructor told us that precise pieces in the field often didn't happen. So he taught how to deal with parts that didn't fit up.
Good tips John. I bought a cold cut saw a few years ago (can’t remember brand) for cutting mild steel in my home shop. Worked great for about 3 cuts then got so dull it was worthless. I figured I was doing something wrong so contacted a guy I knew that ran a fabrication shop in town. He had bought the same cold cut saw as me and said his did the same thing and he had gone back to using the old abrasive chop saw.
I brought one a few years ago and haven't used the old abrasive since even abused it with lot bigger stuff than it is suppose to cut so I politely suggest the wrong technique ( hint think like a machinist not a boiler maker) or most likely probably chinesium blade.
@@marsterofnotrades As you pointed out, it was the blade (most likely). I do wonder if some "cold saws" are actually warmed over chop saws for wood. Same thing with the blades and carbide teeth. The speed of the carbide tooth is drastically different between a wood saw and a cold (metal/steel) saw. They look the same (saws and blades) but they very much are not the same.
Only thing I'd add would be to check part length now and then to see if you are slowly knocking the stop block further out.
Your tips on safety will save many viewers visiting hospitals.
I love these workshop videos keep them coming
One on welding would get a lot of attention
Another Great safety talk can never have to many , got a chuckle when you said that bit about working outside because it was to hot in the shop and here in canada where i am looking out the window it's a blizzard
Mind opened. Thanks fella.
I also have been doing a lot of Fab here lately. I bought an Evolution EVO380 cold cut saw 6 yrs ago and boy is that thing awesome and fast. Almost as fast as a mitre saw for wood...not quite the cut speed but close. Way faster then any band saw and you don't have to worry about the saw band going off course, it cuts straight. I still have a 4x6 band saw on a stand that I use occasionally but the cold cut saw is miles ahead of that band saw for speed and accuracy. It's probably more than most guys could afford, but if you find yourself doing lots of fabrication, they're around $500 US dollars, well worth the money. I still have the same blade on mine from 2018, it has one or 2 teeth missing and still cuts just fine on mild steel. It is loud though. I still use the band saw for anything harder than mild steel as the blades are around $100 US dollars, but still well worth the money in time savings alone.
Watching this was very enjoyable, thank you.
My pleasure - thank you for watching.
brilliant and topical video.
I may suggest that common problem with using the stop block that will vary the cut length is the presence of any burs or debris at the end of the section being cut that is placed against the stop block. So a check that the ends are clear helps.
Its just smart thinking.
Good job dude
Great work as usual John regarding repetative work, stop blocks and jigs. Grinding saws noisy and cheap, bandsaws pretty good, however, the one i have and love, the best is Cold Saw. Cold saws are the best 👍🏻 so accurate, clean, neat and quiet.
Cold saws are awesome - if the boss is buying...
A bit late to the party but thanks John, I'm really enjoying this content.
I like your T shirt John. 😄
GHS would disagree.
I like anything with a snatch.
This particular content is something that i tried over the years to remain vigilant with. Many years ago, as a much younger employee, my employers son-in-law was killed when he was using an angle grinder in his shed.
He used an old cut-off wheel that was worn down and fitted it to a 9-inch grinder to cut some props.
His wife found him in his shed. The wheel exploded and killed him, severing his spinal cord, and several pieces had punctured many interal organs. That incident has always remained in front of the mind when working high potential equipment.
On point John, good advice.
New cutting tool... make your stop with a flip up stop/lever that drops out of the way with gravity
Great vid, John! As to angle grinders and their inclination to occasionally disintegrate at 3,000 RPM, I feel a bit more protected wearing an "impact resistant" full face shield.
I also wear a face shield when cutting with the angle grinder - I got some great ones that scoop down low so I don't set fire to my beard when I get the rotation direction wrong.
Armadillo
@@jackd1582 Yep - Armadillo. Excellent pro.
Ahh JC, the production project guru👌
Recreational me...
Spot on with a reference stop AND not using an angle grinder to cut structural steel. For a few more bucks an Evolution cold saw would be the best investment though. You simply can’t beat the speed and accuracy. Perfect miters are a snap. However they do not come with a reference stop. I made one for mine and use a 1 inch diameter piece of short tubing for the fall off spacing. Very important fact to have that otherwise your material can jamb up and make a real problem for sure. Helpful video , and God knows way too many “fabricators “ on here need help. 😂
I’m not a fitter but I did stay at a Holiday Inn Express, so let’s get er done !
Just found your channel. Recently purchased 123 blocks. I'm a woodworker but definitely can your info your presentation ideas on my Miter Station. Subscribed. 👍
Great advice for the modern generation, us old school generation like a little risk to keep it exciting.
Great content either way as usual.
Great teacher, great vid, thanks John 🙂
Fantastic video thank u .Wayne from sunny South Africa.
Plus u have a great sense of humor. Ps love your t shirt
Awesome matey
Thank you.
Angle grinders are fantastic as a fire starter. Better than a EV
wonderful information on cutting.......cheers from the other 'Sunshine State' Florida, US...Paul
Great Video! Love the Shirt!! 🙂
Really informative. Learned a lot. Thanks!
Thanks!
quite the aussie shirt! and not shabby at all. Love your vids!
John, I noticed that you are running the saw without the plastic wheel covers on. Is that because you want to make it easier for the metal dust to fall out and not accumulate around the two wheels?
You’ve convinced me! Im just not sure if I’m first going to invest in one of those bandsaws or one of those t-shirts! 😂👍
Great tips.
Thanks, dude.
Noted that the very amusing and informative German engineer Christian Muth of YT Channel "LR Time" (made by himself and wife Vera) uses a Vevor bandsaw (amongst a bewildering array of equipment). That's a double endorsement.
Bandsaws are awesome for metalwork.
Nice video..I thought it was interesting that you referred to your measurements in mm yet still referred to your blocks as 1,2,3 blocks. I'm from the USA so we use inches so yes we call them 1,2,3 blocks also...1in,2in,and 3in. Just thought it was interesting. Thanks for the tips. Cheers
I’m a machinist, and I approve of this message.
Thank you, Paul.
Too right, this would make life easier thats for sure.
Definitely be subscribing to more of this, nice shop
This is awesome content - no slight intended but I get a lot more value out of this than watching some old guy complain about the fact that electric vehicles exist. 😄
T shirt is awesome 😊
I learned these lessons as a teenager working in a manufacturing environment and they have served me well over many years. Still. Great to see you putting this info out there as each generation needs to learn the basics and dont always have the opportunity or exposure to the journeyman brain trust. Plus the info learned here can be applied to ANY type of fab work where accurate repeatable material shaping is required.
I have a Harbor Freight horizontal hydraulic band saw and it has a stop that can be moved out of the way for shorter pieces. Since the saw is mounted on wheels I don't have any way to put a stop for longer pieces. And, yes when the cut is done it gets jerked but as the saw has an automatic cut off I am no where near it.
How many years did it take for planning approval to come through???
Agreed. The worst is the friction cutoff saw.
Poking that algo. Great channel. 🎉
Have you looked at the titomic cold spray? just wondering your thoughts and on additive manufacturing in general.
I love my band saw its cutting while I am doing something else
Well sir,
another excellent video, as per your usual. I noted your C.A.D., diagram, and was wondering where you got your paper…, it appears somewhat of a proprietary type. Is it available to us “Yanks”, or only in “Aus-land”…, hahaha..!
Thank you sir.
I see by your red bin that you live in my old shire.
Sorry to hear that. Funnel Web Shire Council...
Good video John
the issue I’ve had with these sorts of projects in the past is you take your measurements build whatever it is
shelving , privacy screen something based on a frame
and what you’ve done is perfect and as it turns out the house has not been built square…….
So now it doesn’t fit because the bloody house is out of plum and the only way to do it is to tack weld everything in situ
take it away and finalise it on the bench
and bring it back in a second time……
Sh1ts me to tears……..
Love the shirt John 😂 great video 👍🍻
Plasma cutter best tool I ever brought throw the oxy away 👍
what would happen if those sparks hit wood when someone is cutting metal ? would the wood get on fire?
Do you have a link to the magnetic sweeper you use please? It looks better than others I’ve seen with the release on the handle not down on the magnetic head
probably out of your scope but i'd love to see one on the table saw
A few years ago I invested in a bandsaw from Aldi for somewhere around a £100. One of the best buys ever made.
Bandsaws are excellent metalwork tools. I love them.
🌟Useful stuff...
...dude(😊).
Great tips, but jeasus. 3mm wall tube for a privacy screen?
Expecting thermo nuclear war to break out?
It's also a truss that spans 3.2m ... and corrision reisitance.
Plus, it's what they had.
Hi John,I noticed that your tungsten carbide blade saw retractable guard is only partial. I have a compound miter saw (tungsten carbide blade) with a fully retractable guard. Granted it's a pain to change the blade. There is a 75 mm hole (approximately) in the middle to access the bolt and a clip to release the guard.
man I love metal 🤟 🤣
Five Finger Death Punch and AC-DC for ever!
I Love metal too.
Risk management or a safe system of work is just like Swiss cheese. The more slices you have, the less likely the holes will line up and let the danger through.
Great shirt. Makes me hungry.. Cannot imagine why.
GREAT! Thanks!
what would happen if those sparks hit me when im cutting metal?
Do you have a link to the magnetic sweeper you use please? It looks better than others I’ve seen with the release on the handle not down on the magnetic head 13:27
Nice vid. Thanks from yanks.
Not directly related to metal fab but something to consider in your home workshop is the state of you air compressor tank. I could not find a standard for testing the tank in the manor that my SCUBA tanks are tested every 12 months but a compressor tank exploding will be a catastrophic event. I use an inspection camera every 12 months to check the state of my compressor tank for rust and any sign of wall weakness and replace my tank every five years. Perhaps it is overkill but I have seen one explode and it took a garage wall out. Is there an Australian standard for testing compressor tanks? If not what would be a safe working life?
Anyone made a table for that bandsaw so you can use it vertically, or had a look at the feasibility of it - is there room?
Good vid ... any advice about what maintenance you should do on cars when out of warranty? ... bearings, seals, fluids etc ... i have a Ranger so i know you suggested EGR cooler replacement
Also be careful the cut piece doesn't lean back onto the blade and jam, great way to stuff your blade, ask me how I know.
Great tips John thanks for sharing. Where did you get the mini weld fixture table? Perfect for a small workshop
I made it
I've used this for repeatability, never really thought about the safety benifits on the saw and leaving a gap.
How come you didn't prep your weld joints. Full penetration butt weld.
Nobody made a comment about his T-shirt logo? He does not eat it he just licks it.😉
Informative 👍 but what caught my eye was the inflatable spreader , what is that?
It's a bar clamp in reverse. They (nearly all) do that...
Bunnings Steel Demon blade and just cut it like timber.
About the welding distortion: most of the time it's gonna be there, and since you have a machinist approach when it comes to accuracy and tolerances, you can correct it before ot after welding. The tools or techniques to do it will make it a longer or easier job, but you can get long weld assemblies that are straight and flat.
Sadly this is something that the great majority of professional welders simply overlook, making them as a whole look like DIYers
I could probably just set the mitres up at 46 degrees each and jig @ 92 degrees, and wait for the sweet shrinkage.
I woul personally weld the first corner and check how much distortion there is after cooling down, probably heat to release stress before unclamping will mostly fix it.
I like this videos!
Yes - that would work also.
Ford falcon on top
I love snatch too, only know one unfortunately. Flip side is financially better off than knowing five.
It actually says "I kettlebell snatch". Try it - if you can snatch a 24kg kettlebell one-handed, you are a man.
I love snatch too.