Tips For Turning A36 Hot Rolled Steel

[T Bredehoft]

if you have a relationship with a tool supplier

Unfortunately, I don't, never worked under my own name, I could always talk the boss into what ever was needed.
Now my needs are one or two at a time, anyway.

 

[Tony Wells]

You could look at one of the mfg catalogs, then find a distributor. It's not uncommon to have small orders, so I doubt you'd have trouble getting them to sell to you.

https://www.carrlane.com/catalog/in...D020609090C0015480013180B041D1E173C1B08535246

Or order direct:
http://www.drill-bushings.com/

 

[mrjbinok]

I guess I didn't explain exactly what I was making with my jigs and is causing some confusion. I am making jigs that will slip inside a newly installed bushing, which require a dowel pin to keep the bushing from twisting in a aluminum housing. A hole is drilled through the bushing shoulder at a specific distance from center and needs to be perpendicular to the shoulder. My jig allows you to line up the drill at the proper bushing radius and guide the drill bit straight in. With a drill stop set to the proper length on the drill bit, you end up with a straight hole that is the proper depth which will then accept a dowel pin to be pressed in.

I plan to sell these at a low cost to the end user, in various sizes for a specific application. Adding a drill bushing would increase both cost and the time required to make the jig. In most cases the end user won't be using the jigs for high volume production, so I believe that heat treating will be all that is needed and allow me to sell at an affordable price.

 

[mrjbinok]

Use a deep enough first cut to get under the scale, then turn up the speed until you get yellow to blue chips and you will get a better finish.

How much of a cut would be considered typical for a "deep cut" to try in situations like this? I am waiting till my TGP order gets here to continue with my project, but since I have the hot rolled, eventually I will probably want to use it up.

 

[JimDawson]

How much of a cut would be considered typical for a "deep cut" to try in situations like this? I am waiting till my TGP order gets here to continue with my project, but since I have the hot rolled, eventually I will probably want to use it up.

Given the size of your lathe, I might try 0.020 and see if it is happy there, maybe a bit more or less. You are somewhat limited by power and rigidity, so you just have to figure out what works best for you and your machine. Experiment a bit. Maybe you can take 0.100 per pass, but slowly work up to that!

 

[Bob Korves]

How much of a cut would be considered typical for a "deep cut" to try in situations like this? I am waiting till my TGP order gets here to continue with my project, but since I have the hot rolled, eventually I will probably want to use it up.

It depends on how much scale is on the metal, but I agree with Jim Dawson on perhaps starting at about .020" with your lathe. The feed depth also comes into the equation, you would really like to keep both pretty deep. The idea is to expose the sharp cutting edges to as little of the scale as possible, which will tear them up.

 

[mrjbinok]

Thanks for the suggestions. I should have my new QCTP ready to install tomorrow and maybe I can do some experimenting. Today is a different story..... weather is beautiful outside and a perfect day to get out and ride!! Haven't been able to do this in a while so I'm going to enjoy the breeze in my face.

 

[intjonmiller]

I have hundreds of pounds of A36, as a shop where I worked threw out substantial scraps like lawn clippings. As far as I understand it, the main difference between A36 and 1018-ish is that 1018 has a clearly defined standard composition, whereas A36 is more like pot/mystery metal. Lots of recycled content of unknown composition, with different sections of the same piece behaving differently (some hard, some soft; some machining easily while most is gummy). As has been mentioned, it is better suited to welding up machine stands and shelf brackets and so forth than it is to machining. That said...

I have turned a bit of it, as I wanted something I didn't mind using up for the first while on my first lathe. I hate using good material for practice, even though it means imperfect practice, but I just keep in mind that I'm practicing using the controls of the lathe, turning to a certain diameter, etc., not practicing getting ideal finish.

And then there were a couple things where what I was doing worked well enough that I wanted to make it look good. I found that a vertical sheer bit (HSS ground very differently from other types; search on here and YouTube for plenty of examples, including how to grind it) cleans it up rather well. But you're only going to take off up to ~0.001" at a time with that tool, and it is impractical to use it right up to a shoulder. But it is a useful option to keep in mind.

 

[Doubleeboy]

Flood coolant, use negative rake carbide tooling meant for steel with a large nose radius and as mentioned above use a large depth of cut and spin as fast as you are comfortable with.

Cutting oil is not coolant as it doesn't remove the heat. Above all try not to use hot rolled bars whenever possible, also take note that 12L14 is mostly un-weldable due to the lead content, it was developed for automatic screw machine products but has been largely replaced by 1215 due to the toxicity of lead.

For decades I heard this about 12L14 and repeated it cause I had heard it. Then a 75 year old, life long machinist called BS when he heard me repeat it. Drug me over to his shop welded up 2 pieces of 12L14 flat stock, took them over to the press, 50T and the weld started to give about the same time as material. Its not allowed for certain jobs that need to be welded, but it can certainly be welded even by a hack like me.

cheers
michael

 

[intjonmiller]

For decades I heard this about 12L14 and repeated it cause I had heard it. Then a 75 year old, life long machinist called BS when he heard me repeat it. Drug me over to his shop welded up 2 pieces of 12L14 flat stock, took them over to the press, 50T and the weld started to give about the same time as material. Its not allowed for certain jobs that need to be welded, but it can certainly be welded even by a hack like me.

cheers
michael

Welded with what process and filler?