Est. 1998 — 27 years of woodworking knowledge
Metal Experts?
Ron in Drums PA
>I used to know this.
What is the difference between cold rolled steel, hot rolled steel and weld rod. I went to a big box store and found I could get 5/8" rod of each.
I picked cold rolled for a tool that I will be making with a cutter attached. Did I make the right decision?
Useful metals link *LINK*
Fred in NC
>
Metal terminology
Re: You chose wisely
DaveZ
>Not that there are anything resembling experts on this end, but that's what I would have picked too ;-)
Re: Metal Experts?
John Lucas
>Ron
Without doing some research I'm not exactly sure what the difference is in terms of usage. What are you going to do with the metal and maybe I can make some suggestions.
Re: Metal Experts?
Bob Hackett
>The biggest difference between hot and cold rolled steel is that the cold rolled doesn`t have a layer of mill scale on it so it`s cleaner to work with and you don`t have to grind it to weld or braze it.
The steel is probably the same grade,only the way it has been worked is different.
Hot rolled will bend alittle more easily(think re-bar)than cold rolled.If you want a tool that resists bending then you will have to size the steel appropriately or go to drill rod(O1) and heat treat it.
Mainely,Bob
Re: Metal Experts?
Russ
>Hot and coll rolled are exactly what their name implies.
Hot rolled is formed into a rod by passing it between rollers while the steel is is still bright orange hot from the ingot. Hot rolled can be any specification that is required of a piece of steel. It has a rough black mill-scale finish. In its common form, the only difference between this rod and channels or angles is their shape.
Cold rolled is formed into the rod by rolling the steel while it is at room temperature. It will have a smooth and clean surface that can be used "as is". Dimensional tolerances are in the order of plus or minus 0.005". The cold working will generally make a small improvment in the properties of the steel and increases the surface hardness of the rod. The cold forming requires that it be a low carbon steel, and this low carbon content makes it unsuitable for any heat treatment. What you see is what you get.
Welding rod is a grade of steel with a specification for use as a filler material when welding to fill and join steels. I would be surprised to find it in diameters as large as 5/8" on the general market because it would take a lot of heat to melt a rod that size into a puddle of molten steel.
Drill rod is a specification grade of high carbon tool grade steel whose purpose is the making of cutting tools. It is made by either drawing or centerless grinding to a dimensional tolerance of something like +0.000"/-0.0015. It is available in several designations based on the method for hardening and tempering (air, oil, or water) and its carbon content and alloying metals. This is what we would use for making a carbon steel turning tool. The name "drill rod" comes from the fact that it is a tool classification of steel and it is available in twist drill diameters and tolerances.
If you are going to drill a hole in the rod for inserting a piece of HSS tool steel for use as a hollowing tool, then you have chosen correctly. That is the same steel that all of the fabricated hollowing tools on the market are using.
If you are planning to use the rod itself as a cutting tool, then you have chosen the wrong one. Cold rolled is too soft for a cutting tool and there is nothing that can be done to improve it. In that case you should be buying a specified Drill Rod, and from a steel supplier and not something you will find in the rack at a "big box" store.
Re: Metal Experts?
Ron in Drums PA
>I'm using the Sorby's goose neck Hollow Master (yuck) and need a straight tool to better get into the bottom of a hollow form. I was planning on attaching the cutters from the Sorby tool on a 5/8" rod (with a handle) to do this.
What do you thnk?
Depends
Bob Hackett
>How big a catch do you plan to have.;^)
5/8 should be all that you need to work the bottom of small/medium hollow forms.If you bend that size cold rolled scraping the bottom of your work the diameter of the tool is the least of your worries.
For larger/deeper work you may want to think about making a short bit holder out of that 5/8 and putting it in a heavy boring bar type setup.
Mainely,Bob
Re: Metal Experts?
John Lucas
>Ron
I my loosely controlled experiments 1/2" rod would only let me hollow about 6" deep and even then it starts chattering. I went to 3/4" bar and can hollow 12" or around that before chatter gets bad. I would have to assume 5/8" would be somewhere near the middle. I use the rod from Lowes which appears to be cold roll but it doesn't say on the box.
Thanks Bobo and John
Ron in Drums PA
>The hollow form is about 6" deep and might finish out to about 7" deep.
The reason I picked 5/8" rod was that is the thickest they had when I was there.
What I really need to do is break loose for a good hollowing system. The only reason I hesitate is that I plan on moving up to a bigger lathe and I'm not sure if and what will be interchangeable.
Talk about Typo's
Ron in Drums PA
>Sorry Bob
Re: Talk about Typo's
Bob Hackett
>Least you didn`t call me Todd O.
Don`t want the boss to think I`m impersonating him.;^)
Mainely,Bob