Project Lay out/Marking the Metal

[ThorsHammer82]

I looked for a Project layout sub forum and didn't see anything (probably just blind and not looking hard enough).

Anyway, I'm wondering what you guys use to mark you metal that will last through the heating process. For example. If I wanted to make a bend at 4" up the piece, and again 2" up from that. How do I mark the work piece so that I don't have to measure after the heat so that I'm not wasting heat, but I'm still getting an accurate location on my bend?

[Quarry Dog]

  A center punch mark works well if you have the eyes for it, and doesn't go away unless you really want it to, or if you burn it off, in which case you have bigger problems.  One way to get it to go awaywithout filing/grinding it out is to take a ball pein and just lighty pein all around it for a bit, or you could just leave it.

  Soapstone holds up untl just about orange. I hear white-out holds up about the same, but shows up better.  Silver pencil works pretty well too.

[DSW]

Quarrydog covered the ones I usually use. Depending on what you need to do, some times you can mark the anvil and use that as your guide. I'll often do this if I need to step down material on the near face of the anvil. I'll mark the anvil face say 1" from the edge, then use that mark to set the end of my stock and start forging. On the other edge, I'll often use a steel ruler to measure out how far I need to hold the stock, or use a pair of dividers already set for the measurement I want. I'll use the dividers to also help set things for punching or slitting. Just use the dividers to tell me how far from the end I need and set the punch there, double checking my light punch mark with the dividers before I got at it for real.

[ThorsHammer82]

Would a scribed line be visible? I'm not worried about the mark being left on this project. I just want it accurate.

[DSW]

Maybe, depends on the project and how deep you scribe it. Scribe marks would disappear with any scale or high heat though.  I've used a light saw mark in the past to show where I wanted to do something. I make it deep enough to feel, but not deep enough to cause issues. I'll occasionally do the same thing with a cold chisel.

 

 

One thing to be careful of with scribe marks. Don't use them on thin sheet metal unless you plan to cut there. They create a stress riser that can cause the sheet to break on that scribe line.

[1forgeur]

I use a square center punch instead of a round one. Read about it somewhere,prolly on this site. I can see it way better than a round punch mark.

[Rashelle]

A round one works but you can try triangular, diamond, or square center punch. Placing the center punch mark on the edge of the piece making a frogs eye dimple on the side all work. Prior to scaling heat silver pen, silver pencil, soapstone, and chalk all work, same for the already mentioned white out, artists chalk pencils, etc. Making a line with the punch marks, scribing a line, or cold chiseling a line for a cut. Bends I normally use one of the center marks. You can also mark a place on your work that will be out of the heat but can line up with for example the nearside edge of your anvil, then use the anvil as an instant reference. Same as for using the face and sides of the anvil mark what you need with a form of above marker then reference the piece to it. It it's long ways reference the piece then place the edge of your hammer to it, move to where you are bending, then remove the hammer.

[Judson Yaggy]

Covered before but...

Presto brand white out/correction fluid.  Best brand available here in the USA for off label applications!  Visible up to a few thousand degrees, also works great for torch and plasma cutting. Put it on cold or it just boils in the tip of the pen and doesn't stick to the work.

If you can't see a center punch mark (round or square) punch the very edge of the bar so the punch makes the profile bulge out.  Easy to see a bulge in an otherwise straight line. 

Edited July 29, 2015 by Judson Yaggy

[Quarry Dog]

Forbidden Kingdom.  Good Jackie Chan movie, Jet Li's in it too...Oh wait, how'd I get on the credits?

Well that didn't work.

Admin can delete that last one...I wouldn't mind one bit.

  DSW:  That reminds me.  A lot of times I'll draw rough sketches of smaller stuff on the face up next to the shelf or a life size sketch along the far edge.  I'll often mark measurements that I have in mind on the edge too.  Or I'll mark progress like that.

I had more but I'm semi-forbidden.

[ThomasPowers]

Mark the dimensions on your hook rule.  Don't have a hook rule?  Buy an old carpenter's square at a garage sale for a dollar and shear off one end so that you do have a hook rule!

[Rashelle]

Oops more ways popped into my mind. Someone earlier mentioned a compass set at the right length. Another was is using a metal square set at the correct measurement, or sometimes I mark with one of the earlier markings on a metal ruler or scrap the depth to stop at and hold it to it then hit it.

[Alan Evans]

I think I have used all of the above at one time or another. 

A variation that I did not see listed...I have a small cross pein hammer that I have ground to about a Ø5mm (Ø3/16") and I use that as a fine fuller and thump it at 45 degrees into the arras or corner of the bar.  Combined with a chalk mark squiggle to identify which corner, you can then either slide a tool along or slide that corner of the bar over the corner of the anvil until you feel the notch.  

I like to see the making marks and so often will chose the system appropriate for its effect upon the end product rather than purely the process in hand.

Alan

[ThorsHammer82]

to give an idea of the particular project that brought this to mind. I plan on making a pivoting recovery shackle for my ATV. The plan is to bend 2"x3/8" (you'll see that size as a common theme for me for a while as I was given 8 full sticks and then some so it's on hand and free) into a U shape and that will be pinned through a hitch bar  (1.25") that will go into my ATV's receiver. The Pin will be the 1/2" Receiver pins that match the 1.25" hitch systems. I want to bend the flat bar with my post vise to keep the bend square and hopefully sharp. I will be welding in a half circle of pipe on the inside of the U to reduce stress on the strap.

a Center Punch mark seems to be the simplest, yet most effective way to get the mark I'm looking for. I'll lay out and scribe my marks and then Center punch the bend lines so that I can line them up in the vise easily before bending.

Edited July 29, 2015 by ThorsHammer82

[DSW]

If you are looking to keep the bends square and sharp, a torch would be the best method most likely to limit heating areas you don't want to bend. If you use that, measuring and loading it in the vise in the correct spot should be easier.

 

I'm not sure I see the point to welding on the pipe though.  I'd just heat and round the edges of the flat bar since you want to make this a forging project. If that thins your material too much, upset the center 1st to thicken the material, then reshape the stock. For that I'd use the coal forge and maybe quench the areas on each side to isolate the area to be upset.

[Alan Evans]

I am not quite sure what you are doing.  A sketch would remove the lost in translation bits.

You will be introducing a bit of stress in the HAZ when you weld in the tube.

Why do you not bend the strap into a soft U to start with. Why make sharp corners and then fill up the inside with tube, or have I totally misunderstood?

Alan

[ThorsHammer82]

If I keep the bottom of the U flat and square it won't tend to cause the strap to bunch up in the bottom of the U. Adding the section of pipe into that will keep the eye of the strap open (like an insert/thimble on a rope eye, or wire rope eye). Both of these reduce the stress on the strap adding to longer strap life. The amount of load that this might see means that the haze will not have any affect on the finished product.

Yes I know I could just buy a large shackle and get the same thing essentially. but I'm cheap, and I like projects.

[Alan Evans]

Ah misunderstanding number one....you were referring to a fabric sling when you said strap...I was thinking the bit of 2" x 3/8" was the strap....

So if I have now got this right your bit of tube would ideally be shaped a bit like a Pringle (if you have those double curved reconstituted potato crisps in a cardboard tube) a section from a torus, which would reproduce the inside face of a bow shackle keeping the strap eye open and allowing the pull to come from up and down as well as side to side...?

How about fuller in along the length of the centre section of your bit of flat and then bending that into a soft U in order to reproduce the contact surfaces of a bow shackle...if you want a blacksmithing project....

Alan

[ThorsHammer82]

not so much a blacksmith project. Just using the forge to get the metal up to bending temp.

I want the sling to stay flat. So I don't plan on pringling the pipe at all. The weld will radius the top and bottom of the pipe slightly, but in reality not enough to really make the pipe pringle shape.

I trust my welding skills much more than my smithing skills at this point. Not enough time on the anvil yet, and a lot fewer Blacksmithing tools than welding tools at this point. I'm slowly but surely getting there. but for this, I'd rather just get it done, than try to improve my minimal forging skills. I have several Smithing projects in the line up for practicing that in the next dozen or so projects on the ever growing list.

[Frosty]

Seeing as I've been Forbidden and didn't take the precaution of saving my reply I'm not going to tell you how to do this jr. high metal shop 1 side job. No fooling my metal shop teacher wouldn't even reply if I'd asked how to do this.

Frosty The Lucky.

[ThorsHammer82]

Well someone is grumpy this morning...  I can only assume it's because you're other post was much longer and for some reason the sight still isn't running at full steam.

I know how to do it, and just was wondering what everyone uses to mark the metal prior to heating it.

[Alan Evans]

In that case if your welding is better than you blacksmithing, I would not bother with heat at all. Just part cut through where you want your bends with an angle grinder, bend on the cut, then fill up the corner with weld fillets and then weld in your pipe bit.

I know you want the strap eye to stay flat, but can you guarantee that the anchor point will always be at the same level as your hitch?  Without the torus shape your strain will always be on one edge or other of the strap eye....Or is there another articulation to allow for that in the system?

Alan

[ThorsHammer82]

Yes. The hitch in question will be part of a 3 axis hitch that will also be used on my ATV trailer. the U will pin into the center section of the 3 axis hitch. Behind the horizontal pivot. The vertical pivot and rotational Pivot will be removed for use as a recovery hitch.

[gote]

If I want to have a bend in a precise place, I usually do not mark at all. I put a fixed stop onto/below the vise. C-clamps are useful. I then drop the piece through the vice until it rests on the stop, close the vise and bend. Unfortunately this is not always possible. But when it is, it is obviously a very quick method and saves on the heat. It is accurate and repeatable.

Göte