Marking out on mild steel with mill scale- good markers?

[phaxtris]

Uh, not exactly. You can put a mark exactly where the cut needs to be made (at least to visible accuracy) and then align the blade to the mark. Trying to measure from the blade on anything handheld or where the blade moves (chop saw, horizontal bandsaw, etc.) you cannot accurately measure off the blade anyway. About the only thing you can measure from blade is where the blade is fixed and you measure to a fence. At best, saw cuts aren't going to get beyond say 1/32nd of an inch accuracy anyway. If you need more accurate than that, you're doing a rough cut and then setting it up on the milling machine or lathe or whatever.

How many guys here are cutting mild steel with a skill saw? And even with a metal cutting skill saw you would normally set up some kind of fence...and you should know the offset of the blade to the fence on the saw...

As for a chop saw if you don't know how to pull the tape off the end of your piece and lower the blade down there really is no helping you, same thing with a bandsaw

With 18 years of being paid to fab/errect/install steel I may have a slight idea of how to cut a piece of steel quickly and with accuracy

 

[SomeGuy]

How many guys here are cutting mild steel with a skill saw? And even with a metal cutting skill saw you would normally set up some kind of fence...and you should know the offset of the blade to the fence on the saw...

As for a chop saw if you don't know how to pull the tape off the end of your piece and lower the blade down there really is no helping you, same thing with a bandsaw

With 18 years of being paid to fab/errect/install steel I may have a slight idea of how to cut a piece of steel quickly and with accuracy

Uh I said as much for a fence...

I use a dry cut saw, I don't measure stock to blade, I mark the stock and align blade to mark, I am accurate and fast. This goes for most mild steel tube work, dry cut/cold cut are the most common tools by far.

Just going through the list of tools though, abrasive/dry/cold chop saws what I said applies. Horizontal bandsaw, same deal. Portaband, same deal. O/A torch or Plasma, mostly same deal but you'd probably align your guide to a mark, hack saw, jig saw, sawzall you'd cut to a mark...honestly the only thing I can think of where you'd measure blade to fence is a large vertical bandsaw.

So what do you use exactly?

 

[Dan Dubeau]

I don't have hard rules for how I measure, mark and cut stuff. Each job, and task requires a different or similar process. Choose accordingly. Sometime I measure directly to the blade, sometimes I measure to a sharpie line, and others a scribe line, etc. Others I use another piece I directly "measure" too, no units involved. Depends on the job, which shop I'm in, what tools I'm using, and what I have available to me.

 

[phaxtris]

Just going through the list of tools though, abrasive/dry/cold chop saws what I said applies. Horizontal bandsaw, same deal. Portaband, same deal. O/A torch or Plasma, mostly same deal but you'd probably align your guide to a mark, hack saw, jig saw, sawzall you'd cut to a mark...honestly the only thing I can think of where you'd measure blade to fence is a large vertical bandsaw.

So what do you use exactly?

the only time i cut on a line is with a zip cut/torch/plasma/portaband, or i have 0 shits about the actual length

if i want something to be 512mm or 5-7/16", or some other specific measurement and i am using a saw i will chuck it up in what ever saw i am using (cold cut, chop saw, band saw), measure to the blade, clamp, check it again, cut, .5-1mm accuracy, under 20 seconds (excluding cutting time obv), 1 place for error, i read the tape wrong, that it, vs 3-4 by marking/lining up

do notice i specifically noted "saw cutting/chop sawing/shearing"

Bandsaw (horizontal or vertical), measure to the blade. Chop saw measure to the blade. Slow or fast cold saw, measure to the blade. Metal cutting saw, measure to what ever guide/fence you are using, minus the blade off set. Shear without an electronic backstop, from the lower blade. If using a guide for the plasma/torch, i measure to the guide minus/plus the offset of the tip to your guide.

i use all of the above on a regular basis *Edit other than a vertical saw

even if i am cutting a piece roughly on a saw, i will normally just measure to the blade, less steps, i just don't fiddle with getting the piece exactly right "278, close enough (to 275)"

 

[YotaBota]

The red & silver streak pencils can also be bought at KMS tool.

I must have passed by them in my KMS search.
Thanks @Six O Two

 

[justin1]

It's no wonder I can't weld. The sphincter on my wallet is too tight......

Ye in the last 2 ish years my 1.5x1.5x.100 hss handrail has gone from 60$ for 24' to 105$ 24' stick same as everything else pretty much doubled aswell makes it hard to keep handrail under 30$ a foot material cost for a basic handrail.

What’s a good marker to use on steel with mill scale? For typical fabrication accuracy

I have a soapstone pen, but the lines rub off easily.
Sharpie pens are hard to see unless there’s lots of light.
Dykem layout fluid with a scribed line is hard to see when I add cutting oil. I do love the smell though.
The tips of White correction fluid pens doesn’t appreciate being dragged across mill scale.

I found these products:
Pica Water jet resistant deep hole marker
Markel Silver Streak Pro
Super Met-Al white paint pen

Another thing you could try is buying some 1/4 soft aluminum rod and sharpening it to a tip works like the silver streek pencils but lasts a lot longer not good for real dirt material but besides grease pen nothing works too good for the dirty shit.

If I'm not using soap stone for rough measurements I use just a normal lead pencil on cleaner metal or sharpie both work good. The pencil lead shows up good in mill scale but bad in ground surfaces. Both sharpie and pencils are safe for SS won't etch them.

Anything that precision matters I will use a center punch and scribe if doing layout for structural and sometimes pipe if not critical piping. I will center punch for saddle layout on pipe when torching to make re adding soap stone lines faster as I cut as it can be annoy to loose line after spending half hour doing layout because you burn off the paint.

That and half the time when doing structural you can do everything right and still end up just impacting a 3/4 reamer threw a connection cause they punch the holes off center half the time.

 

[StevSmar]

I use the Silver Streak welder pencil

Thanks for the recomendation!

I use a red sharpie, and also have one of the markal silver pens.

I didn’t think to try red…

@YYCHM , thanks for the princess auto link! I’ll have a look.

soapstone is the industry standard

I should have said when I’m using a Porta-band with oil. I did trying making a light cut “dry” until the metal was scored, and then adding oil. But if I get a better marker that won’t be necessary.

if I need more accuracy I usually use a carbide scribe.

I should add one of those to my (ever expanding…) shopping list! I seem to routinely break the tip off my HSS(?) scriber. Maybe I’m making it too sharp.

Another thing you could try is buying some 1/4 soft aluminum rod

That’s an interesting suggestion! I hadn’t thought of trying that.

Thanks everyone for the suggestions!

 

[Bandit]

Might want to make sure any aluminum is removed before welding, may/could cause weld problems. Even some grinding discs can make for bad welding voices.

 

[justin1]

Might want to make sure any aluminum is removed before welding, may/could cause weld problems. Even some grinding discs can make for bad welding voices.

You would have to put a lot of aluminum on it to make any noticable difference, we use backing bars made from aluminum/brass/copper for fixing holes or gaps then then grind some of the contaminated material out then fill up the other side of hole/gap to get a sound full pen weld. Even the contaminated weld is more a less at the surface level. For some applications we use ceramic backing but that's more for piping.

As far as the grinding discs go ye any of that grit can become imbedded in the weld if you just weld over it and will show up on x ray similar to slag inclusions and could help kick off cracking but I'm sure there is lots of welds out there full of dirt and all kinds of stuff (cough nuts and bolts for filler) that hold important infrastructure together as some joints you just can't clean out perfectly or the welder is just to lazy. But generally you wouldn't be able to tell with out x-ray or ultra Sonic's.

Best practice is to removed any mill scale before welding and keep everything as clean as possible. Specially if your mig welding with hardwire in short circuit as the welds can look good but not actually be stuck to anything.