Alright so I have decided to build my own thumb for my micro ex. Been scouring scrapmetal places for suitable steel and and now need to think of the construction side of things. All the welding I have done has been with GP rods or hard facing rods but apparently 7018 rods are the go for this type of job, however I have heard that they are a pain to get started and if they stick they are very hard to un-stick. There is a newer version of the 7018 called the 7018ac which is apparently a lot better to work with but are fairly rare. Should a amateur welder go with 7018 or try and find 7018ac rods? Or can I get away with GP rods? Another thing I cam e across whilst finding out info about rods is that there are cutting rods out there, what is the go with them? Do you need a special welder or will a little welder work with them? I have a full size angle grinder that is hanging out to do some serious work but if there is an easier way to slice through steel I am all for it. Anyway if there are any people who like to dress in heavy leathers out there I would be most grateful in some tips on how to make the project work.
Try the 7018 rod, you will like it. That is the rod I used when I first learnt how to weld.
I'd go with the 7018. I'm not aware of a newer 7018ac, doesn't mean there not out there though. The 7018 low hydrogen rod is ideal for strong structural welding applications, like your thumb build. Yes, the rods do stick, probably more than the 6013 or 7014. But the more you work with the 7018, you'll get the knack of working with them. The best advice I can give you on the 7018 is getting the rod ready for start up. A fresh rod isn't too bad as the end is clean and the flux on the tip is tapered. You can start it up by quickly "dragging" the rod across the steel. Try doing this on some scrap metal to get the feel. Eventually, you'll be able to start up without dragging. But once you've burned some of the rod, and stop, the flux on the end of the rod is insulating the core of the rod making start up difficult, that's where people experience the "sticking", because they peck peck peck at the end of the rod until...stick! The best way to deal with this is give the end of a burned 7018 a quick smack right on the end of the rod on the piece of steel being worked on. This smack knocks away the flux right at the tip of the rod exposing the core. Now your ready to start up using the dragging method, or by just sticking it in as you become more experienced with the 7018. As for cutting steel, the old cutting torch is probably still the quickest way if you don't have a plasma cutter. Had to edit and add one more thing. Even an experienced welder will occasionally "stick" a 7018. Don't panic! Don't try going back and forth trying to get the rod loose! Just unclamp the stuck rod from the rod holder. Then reach down and, with gloves on, grab the rod and dislodge it. Put it back in the stinger and give it another go.
I've never been able to confirm this but some old geezer who hangs around my shop all the time claims that the 7018AC is designed for AC Welding. They can be hard to find and do seem a do a little better on AC machines. I absolutely love 7018's, been using them so long I probably couldn't weld with anything else
A friend of mine built his own thumb, he made a model out of cardboard first to try the hinge points as I remember they bent the ram some way and had to get another. Good luck, 7018 is good to work with, it does'nt splatter. I like 1/8"
Another thing we forgot to mention here; the 7018 is designed to be a DC reverse polarity rod.
Sounds like a good project Hendrik.I would use 3/4 inch thick steel for the thumb on the mini- ex.I do allmost all my welding on DC current.The 7018 is a good rod,tap it smartly on the steel to start the arc,then keep it close to the weld pool when running the bead.The 6010 or 6011 also work good,They have good penetrating qualitys and good strength.Most pipe line's use 6010's & 6011's.I would use a standard cutting torch or plasma cutter to cut the steel to shape.Use the grinder clean up and bevel the edges.I built a thumb for my excavator years ago,I'll send some pictures if it will help.
Cheers guys, I'll give the low hydrogen rods a go. Yes the 7018ac is designed for ac operation http://www.tractorsupply.com/webapp...19|61720|53252?listingPage=true&Special=false My info on the hard start 7018 came from here http://www.steamengine.com.au/misc/welding/index.html This has a few good tips http://www.weldingtipsandtricks.com/stick-welding.html I like that idea of the file as I have had the flux break off the rod when using the tap tap method This is what I was referring to in regards to a cutting rod http://www.welding.com.au/df163-58/austarc-cg/ This is going to be just a very basic set up, no hydraulic ram. However most manual thumbs have two working positions, one at 90 degrees and another at ~110/120 degrees. Is there any real advantage to having this as I was planning on 90 degrees but would be able to get more with a longer supporting arm. Also given the size I will be making it so that it is taken off the machine when not in use rather than having a stored position on the arm. Ooooh yeah BTW, did you know that Kobelco make welding rods, might the thing to use on a Kobelco ex http://www.nationalwelding.com.au/electrodes1.htm
If you want to file the rods, that's up to you. After burning tons of 50 pound boxes of rods hanging stuctural iron I'm just used to smacking the end of the rod to prep for re-start. Didn't have time for a file. The cutting rod you refer to looks like a typical carbon rod or "gouger". It's typically used for removing welds. It can be used for cutting, but it's not nearly as efficient as the old acetylene/oxy torch for cutting steel in a precise line.
Problem is I only have little 240v but from what I understand the 7018 will work with both ac and dcrp, as stated in the old school welding link I posted earlier. The 8 in the electrode code refers to the type of current the rod will accept. The thing is that I am trying to keep the weight down as much as possible and only have a small space (about 75mm across the arm) to work in. I would ideally like to get some plate and then weld the lugs to it and then weld the whole assembly to the arm which would give more strength but add weight. Problem being I can't weld across the arm, so have to rely on welds down the side, to this end I would want to use the best rod I can and the 7018 is stronger than the 6011. I have 6013 rods which are classified as GP rods and thumb manufacturers stipulate that 7018 must be used when attaching their thumb to a machine. However I will get out tomorrow and look for more material and if I can source a good quality small I beam I will be able to cut it to suit. This was my original plan, take an I beam and cut it in half and then cut the sides to fit on the machine and then cut two holes for the thumb and support link. Here is another good tip for storing rods http://www.woodworkforums.com/archive/index.php/t-34235.html
I use a carbon rod in my "air arc" .I agree with Atcoequip,the air arc carbon rod works great for removing welds & undercutting for a new weld.Use a oxy-acetylene torch for cutting.I have never herd of "filing" a welding rod.Give that 7018 a good smack to start it,and keep the arc short.Or use a 6010 or 6011 rod.They start better and you can run a longer arc.
Every tool has it's purpose, and the sorriest job in the world is the home handyman, he needs every tool in the store. The welder is the luckiest. There are a few basics, welder, torch, grinder, a few hand tools and you are ALMOST in business. Away from the shop, a pipefitters tri-legged stand with chain vise is really handy. Right on the 7018. No rust though, and keep it tight into the weld. Also no moisture on the rod. If the can is open for long, heat at 300 degrees for an hour, minimum. Rod oven is necessary for shop use. Serious work, 7018 DC, 7018AC will be fine. 6010 is DC, 6011 is AC. For best weld run the rod as hot as you can handle it. Penetration and good weld chemistry is the result. 7018 is better because it is just tougher. 6010 and 6011 cracks easily unless done well. (30 year Boilermaker)
I agree that a gas axe is the way to go but I don't have one due to the cost of bottle rental. I also agree that with experience the tap method is the most efficient for 're-setting' a rod but it does take a bit of skill.
My main concern is the welds on the ex arm, as they may well take some shock loads. Thanks for the tips, I'll be doing some practice runs with a 7018 before going into the serious stuff.
If the 6010 and 6011 crack easily,We would not use them on pipe lines or boilers.They are the favord rod for this type of work.I use 6010 and 6011 on DC and get good results.
From my limited understanding the 7018 is better at absorbing shock loads, which is an issue on an ex, particularly low down on the arm. This is not an issue on a pipe, unless you back the D10 into it Sure I would love to use 6011 rods but I have to use the best rod for the job but still be able to use it with my limited skills andequipment.
I made that comment because pipe and boiler tubing are not the same thing as welding on heavy stuff. Try using 7018 and 6010 on dogs, weld on one side only then knock them off with a hammer and see the difference. Also for tacking, the 7018 is "tougher". Cert's on ASTM Boiler and Pressure Vessel Code #9, Navy, Coast Guard, Pipe G6, forgot others.
Way back before we had a torch I bought some cutting rods. They were not what are sold for gouging today. They worked but pretty rough cut and smoky. Actually you can take any rod and run it at 50% or so higher amperage than spec. and it will cut about as well as the purpose made ones. But they will up burn at an amazing rate and get very hot. The cutting rods lasted a little longer. Still, if you have some old or free rod it will work.
Are you saying that you do not have a DC welder? If so, you may need the 7018ac, if the ac means that they are made for AC welding. If you want to make life easier, go and buy a DC welder. I doubt that you will ever regret spending a little more for a decent welder. One of the first things my welding instructor told the class many years ago was to never buy a welder that only welds on AC. I took his advice. Buy a DC welder (it also can weld AC if one ever wants to) and forget about AC. Most of the cheap welders (300 or 400 dollars) are AC only. You can buy a good basic Miller or other name brand DC welder for well under one thousand dollars and have something that will allow you to do good work. Another piece of advice, if you can afford it buy a good welding helmet - something like an Optrel self darkening helmet. Again, you get what you pay for. A good helmet is especially important for MIG welding where the weld is not as bright and the work often is of a finer nature. A good helmet lets you see what you are doing and will make a world of difference.
Get a good pair of gloves,and just before you go to strike your arc, reach down(with gloved hand) and break the flux off the end. I learned that from my godfather who Retired,but still welds everyday. This is really helpful when you are tacking things together. When you think you are ready,tack everything together and dry fit. Also don't weld on one side at a time. Spread your heat around so that it don't pull or warp. Some of the more experienced hands can elaborate more on whats the best way to go about it. I just know that I have seen alot of people spend alot of money getting things straightened out because of this. Good luck and don't forget to post the pics
If you don't have a gas torch and are considering cutting the metal with a carbon arc rod, keep this in mind; the carbon arc requires a fairly substantial welder, they put a pretty good load on a welder. Also, they required a fairly large compressor to supply air. I can't remember the amount of CFM of air they require, but I can say a small compressor can't produce enough CFM. When you don't have enough air to remove the molten steel, you will carburize the steel. You'll know this has happened when the gouger rod stops removing the steel at the spot your working.
Hey flyboy912,I forgot my manners.Welcome to the forum.The 7018 rod is good for strength,the 6010&6011 are good for strength,penetration,galvanized metel & rusty surfaces.The 7018 rod does not like an impure surface to weld on.I start my weld beads with a 6011 ,then build up with a 7018 .Look forward to posting with you.
Hendrik, Hello, I recently built a grappler for my mini-ex. I used zip disc's to cut some of the pieces. Zip disc's are thin grinding wheels for a 4-1/2" grinder. There only .045" thick so you can't put a lot of down pressure on them, but, they work great! I mig welded mine together with .035 flux core/inner shield. Techincally, it's still considered arc welding though. If you only have a ac arc welder, you probably should use 7018. To tell you the truth, I used 6013-E on lots of stuff and never had any problems. It's a all purpose, all position rod, that's easy to work with! A lot of it's preference and an old on going arguement that 7018's the only way to go! Good Luck! Jeff S
Interesting link, this. in my limited (32 years) welding experience 7018's are better on DC reverse, provided you are on clean metal. On slightly less clean, (sanded - off rust) AC will give better results, providing the OCV is 60 - 65 volts. Any less and you can forget it, and generally that means an oil-cooled unit with changeable voltage connections, like the old Cytringans. Another factor is the manufacturer. I prefer Esab, Bohler or Murex for anything other than GP and they are a bit forgiving of either the plant or the welder. Someone nailed it with the comment about moisture - 7018's are a hydrogen-controlled rod, and any moisture undoes the benefits of using 7018's as you go back to hydrogen inclusion which causes embrittlement. Whoever said a 6010 or 6011 is as good as a 7018 needs to have a look at the code - the first two digits refer to ultimate tensile strength and if the electrodes are stored and used correctly the weld from a 7018 is stronger. Most failures of a 7018 weld are down to the increased skill required to deposit a good weld, or poor preparation. On the downside it's a rare welder who can make a really pretty weld with a 7018.
I have heard that the problem with the thin dics is that they can break and send pieces flying, however I have used them in my small grinder but have been very careful. I would be reluctant to use them in my big grinder. I went out yesterday and got a few more bits for the project (including some paint to finish it off) and got a box of 3.2mm 7018 from a specializes welding shop (WESS on Cormack road WIngfield), whilst they had Kobe 7016 on special I stuck with the manufacturers recommendation of 7018. I made up a PVC rod storage thingy, to keep the 7018 and other rods dry (gotta keep your powder dry ) Come monday it's time to get busy. The plan is coming together nicely but it's the lower pivot that is still giving me grief, as far as designing it goes. This is the one that will have to withstand the twisting forces as I load up one side of the thumb (which is 20 cm wide), the lug on the actual thumb and further up the ex arm won't matter so much as they will be getting directional up and down force only. Further I am planning on making an special 'thumb' for my 600mm wide final trim/mud bucket. This will basivally consist of a steel plate to 'shut' the bucket so I can grab stuff and the lock it in the bucket. If not used carefully this plate will have the ability to twist the bottom pivot off the arm in a flash. I have also decided to rip the tiger teeth off my 200mm trenching bucket and put them on my 300mm GP bucket, as the original teeth on it are a bit worn and the trenching bucket is a bit longer than the GP and hence has limited ability to dig, due to bucket turn radius. Not having teeth on the trenching bucket will allow me to make up a thumb that fits nicely onto the bucket but there again, picking stuff up on one side only will put a lot of twisting force on the pivot. Anyway I am leaning towards getting a pro welder to weld the bottom pivot onto the arm, as this is the most critical weld and must be gotten right the first time. But back to the design of the bottom pivot, originally I was planning on a thick plate with ears on the thumb but now I am thinking of having 2 smaller plates near the edge of the ex arm and then having the ears on the thumb on the outside of these plates to spread the twisting force as much as possible, plus this will allow me weld a bit of pipe between the plates of the bottom pivot to give more strength. However I have to get the ex in the shed first and make sure it can work like that. Okay now we are all really
Hendrik, A thumb is definitely handy. I kind of wish I would've made a thumb instead. By having a grappler, you have to take the bucket off and on. It's not hard but as soon as you put one or the other back on, you seem to need the oppisite to finish the job! LoL. My grappler and steel pipe don't seem to get along. Pipe seems to bend one of the fingers every now an again! Other steel pieces: plate,channel, box tubing, etc. don't seem to bother it! It's the best for grabbing logs or pulling out brush or pinching the neighbors cat. (Not really,JUST KIDDING ABOUT THE CAT) Are you going with a manual or hydraulic thumb? Hydraulic's not much more work. Not sure there much of a benefit to though! Well good luck! Jeff S
I am going manual because of the size of the machine and having extra hoses running along the boom would be a problem. Also the aux hyd outlets are in a exposed position and would more than likely be damaged. I'll post some pics when I get a chance to show you what I mean. I could re-route the aux hydraulics but right now a manual thumb will do me. Hydraulics have the benefit of being able to get the thumb out of the way quickly but are more expensive. I would say a hyd thumb would be applicable to machines 3 tonne and up but would depend on the individual application, especially if you are in the situation of switching often between using a thumb and not.
I'll agree with you Hendrik. Hyd thumbs are very handy, can't argue that. But as you said, with a small machine the manual thumb will work just fine. You haven't said if you've considered this, but what you should do is put a little thought into your design and make your thumb in such a way that you can stow it back on the arm when you don't need the thumb. You leave the stiff leg pinned to the thumb, pull the pin that attaches the stiff leg to the arm of the excavator, then fold the thumb back against the arm, then put the removed pin into a retainer on the arm that holds thumb and stiff leg in this stowed position.
I have thought about making it stow able but my two main concerns are noise (others have indicated that a stowed thumb rattles unless really well designed) and the other prob is space. On my ex there is not a lot of room to work with and to make it in such a way that it can be folded out of the way would mean I have to make it smaller and less strong. The way I intend to design the thumb would mean I have to pull two pins and the thumb is off, it won't weigh much and I have to get off my behind to change the position of the thumb anyway.
Hendrik, Thought I'd post these pix of my Frankinstein "grappler" for you. I'm a little embaressed cuz I never got to finish it 100 percent before using it!
Looks alright to me. Although I am a little concerned about the geometry of the support strut.
Do you mean busting the boom? I don't go crazy with it, but, I don't pamper it either and so far so good- Way things have been going though it wouldn't surprize me at all if it snap's. Please give me your imput though! I honestly, questioned this same thing back when I was trying to lay everything out! Thanks Jeff
I am no engineer but it seems that support strut/link could have been attached a bit further down on the rear grapple. I am thinking if you use the rear grapple to push stuff it would place a big load on the support and may break the top bracket that is welded to the arm.
Obviously, I'm no engineer either but my thought was this: If I place the grappler support strut down futher, it seems like it would put more pressure on the top bracket, where as up more would equal out the load. Pushing outward on the boom pin (attaching grappler)and inward on the support strut. As it shows the thing was made from srcap steel I had laying around. I think I have about fifty bucks in material, if that. As far as hours in it, I know friends that spend more time in bars/pubs then what I have in building that thing which also shows-lol. Thanks Jeff
The "Frankinstien Grappler" on the mini ex looks good Jeff S.The stick section is pretty tough on an excavator.Dont worry about pushing with the rear grapple,Excavators dont have near the power pushing as they do pulling.The force of the bucket cylinder is what will test the grapple.Good pictures.
25c, Thanks appreciate it! It might be the machines age showing threw but I squeezed a bare engine block till it started to pull the rpm's down. (as a weld test) No welds broke but a bolt (grade 8- 9/16) that holds the support strut broke in 2 places. I use it a lot. Almost seems like thats on more than the bucket these days! Thanks again! Jeff
It's the distance between pivot pins that's the worry. I was thinking that the boom pin would not move but if you use the bottom of the grapple to push stuff with it is going to put a lot of pressure on the strut and things may break. It's like you are levering a rock with a crow bar, you are not going to have the pivot up close to you but as close to the rock as possible to get the most purchase with the crow bar. Something to do with fulcrum forces or some such thing, however it is made and made well and would take a lot of engineering to change so leave it as is and worry about it if/when it breaks. Plus if you use a shear pin in the top support, it should not do any damage to the structure. Anyway I gotta get back to my thumb, although I am making progress it is slow due to interruptions. Funny thing about women, they tell you to get off your behind and do something and when you go off and potter in the shed building a thumb they keep asking why you haven't finished it yet. I was going to say something along the lines of "buy me a plasma cutter and good drill press and I'll be finished sooner" but I don't think she was in a humorous mood. Maybe I'll teach her how to weld and use an angle grinder and I'll get it done quicker. However I think drilling 1 inch holes with a hand drill is a little bit beyond her.
Lol- man you nailed it! (go do something) That's what my wife says usaully when i'm on a rant! You should let her drill them 1" holes, it'll give her an idea of what you go threw! Then you could tease her- "what still drill that first hole, man, what have you been doing all this time"? Well thanks for your imput! Jeff
speaking of plasma cutters hey, not trying to derail the thread, but I was wondering. Do you guys wear a hood or just tinted torch goggles with a plasma? I always wore a hood because it was an arc light. I found this really hard to do because there really isn't enough light to see. Then I read the warnings and it says you only need a shade of #6 my hood starts at #8 so I just wear goggles.
M.B. I'm not saying that it's right but I wear my sunglass's. My plasma cutter's a small Thermal Dynamic's cutmaster38. I've had it for roughly 3yrs. and haven't hurt my eyes yet. To me it's no different than cuttin with a torch as far as light goes! Again I'm not saying that it's right but it's what i do. I imagine I'll catch flack for saying all this. Jeff
I wear torch goggles when using the plasma cutter.I put my thumb on yesterday and took a few pictures.I built it out of 1x7 inch bar stock.I mig welded the thumb together in the shop.I installed the thumb on a job site so I used a portible welder to mount the brackets on the excavator stick.I used 6011's and 7018 rods to weld the brackets on.The strut arm is from a IH td 20 dozer blade.The pin bracket on the thumb also fits in the bracket on the stick when the thumb is in the stowed position.It has worked fine for 12 years now.
Just about got the thumb finished and got a few pictures to show, I did end up making it stow able.
A few more pictures
Before finishing it off I decided to give it a test, it passed with flying colours. In a couple of shots you can see it picking up a tree stump using just one side of the bucket and thumb, I guesstimate that the stump weighs between 80 and 100 kg. That lump of concrete is about 50-60kg.
Filling up the compost bin has never been so easy
The thumb looks great Hendrik.I know you will enjoy using it.They are handy.Good pictures.
That's sweet, I like it! :notworthy I can see it now, "honey, take out the trash!" (honey) "OK, I'm on it!"...and a Kobelco boom comes through the back door...:lmao
Hendrik, that came out awsome! I like how ya did the teeth. Nice looking welds too!
Cheers mate, although the one thing I would have done different is to make it so it could go lower with a longer support arm. I could still do that but would take a bit more engineering, as everything is pretty much fitting together like a jig saw puzzle. Guess I'll use it for a while and then see if it would be better to have two working positions. I can see how hydraulic thumbs are better but a mech thumb is better than no thumb. I am still planning on making one for my 600mm final trim bucket but that should not take much. Will post more pics when it is fully finished. If anyone has any specific question, please ask.
Well the plan is to teach her how to use it Although given the size of the machine I could drive it in the door, grab the rubbish and be on my way, it's width fully retracted is 600mm. Which leads me to a question I am yet to find an answer to, my SK005 is a series 1 and Kobelco have made series 2 and 3 SK005's but neither of those have retractable undercarriages. I am puzzled as to why they dropped that feature, as it would make the machine less stable. Perhaps I'll have to ask Kobelco in Japan?
Thank you, I ended up using 6013 rods as my little welder does not like 7018 rods and if you can't do half decent welds with 6013 it is best not to weld at all.
Nice one, very nice! :notworthy
I think you have missed your calling, Hendrik, you might do better going into engineering, rather than earthmoving. Nice job.:thumbsup Rn'R.
Nah, after doing that I am sick of metalwork (blowing black snot sucks). Although I'll drag myself into the shed to build a specialty thumb for the wide bucket and perhaps a ripper. However I have been toying with the idea of building an auger, using a two man post hole digger such as this http://www.tradingpost.com.au/Rural...ent/AdNumber=W1212741976464?BackToResult=true and making up a frame to attach it to the ex and run a long throttle cable and stop button. Should be cheaper than a proper hydraulic auger. Actually there are quite a few attachments floating around my head, scarifier, lawn mover, etc but they will have to wait.
Hendrik, Dam good idea!!!! Not to keep up with the "Jones" but i think i'm gonna make one too. I was going to rent one of those two man auger's for some gate/fence post at my property. Never even crossed my mind to make one! My machine has the aux. hydraulic set up and would be a piece of cake to do. I have some hydraulic drive motor's, just not sure if they'll fit the bill but i'll give em a try! 2marrow i'll get the material list together so i can get right after it! Thanks for the idea. Now i won't be able to sleep-lol
Piece of cake my ***! Not giving up but man, not easy at all!
Some pictures of the finished product, I made up a stow area for the support strut om the boom. The stow pins are just tack welded onto the boom, so as not to weaken the boom.
Here are some pics of the the 'standard' thumb with my trenching bucket (which used to have the tiger teeth on it) and with my final trim bucket. I was going to make a thumb especially for the trenching bucket that would fit it 100% and 'close' it but I don't think I'll need it and if I do I can make it at a later stage.
I made up a 'special thumb' for my final trim bucket. Unfortuantley I could not get the geometry right to allow it to be both a scooping thumb on the ground and a load increasing thumb up high, as I found that at height I could not get muvh in my bucket I decided to make it so it can increase the load when loading up high. The second picture shows it in the working position and the third shows the stow position and angle of the bucket at max height.
Final picture is of the machine ready to go to work.
Good job Hendrik! With the rock tooth ,general purpose,& wide ditching bucket's,and new thumb,you will be able to handle many jobs.
Thanks mate, I have a few jobs to catch up on and then might get started on a single tyne ripper for the really hard stuff. I see a lot of little ex's with rippers and I should have one too. Only thing I am wondering is what to put on the end of the ripper? Just hard face it, put on a tiger tooth or just do nothing?
I have welded "leaf springs" sections from trucks on excavator teeth .They are pretty hard and last a long time.Most of them are 3/8 to 1/2 inch thick.cut it a little longer than the old tooth and weld it on with a 7018 rod.
old thread i know, but. I figured while we were showing off hoe thumb's i would put up a picture of mine,......now if i can just explain to the wife why i am taking a picture of her hands I built this out of necessity for the 303.5 because I needed a thumb ASAP. that and CaT wanted $2k for one . Built out of an old (new) cutting edge and everything else is pretty self explanatory. Pj
Proper Job!
Except for the paint job.
if you have an ac/dc welding machine use the dc circut if you want to make small cuts with a welding rod such as 7018 crank the heat up about 45 amps higher than you would for welding but previous to this soak a few 7018 rods in water for about an hour.Say you want to cut a peice of flat bar 1/4" thick start at one edge and push your way through at the edge and keep digging on the edge of your cut if your not getting threw crank up your amps higher your cut will be probibbly be about 1/4" wide and not to pretty but it will severe the bar