Bar oil usage compared to gas in your saw

I wish every saw I had except my earthquakes and 372xp oiled more

 

I have my oiler cranked to the max and use .75 tanks of oil per tank of fuel.

 

My '08 silverado used about 1/2 qt oil per tank or two of gas..... Oh my huskies use about a 1-1.5 ratio but I always fill both when fueling.

 

The blue you see is from the induction hardening process the manufacture uses to keep wear down. To turn steel blue it has to get to +- 600° F (They will get the bars to someplace north of 1000° F. before quenching, because it will change the molecular structure of the steel for optimum hardening). It depends on the carbon content of the steel they use, as to how hot it actually has to be before quenching. The carbon content also has a lot to do with how hard they will get after the process. That said I try to keep the bar oil to fuel ratio at 1:1 to keep wear of the bar and chain to a minimum. My ported 026 is a thirsty little saw so that is not quite possible but it still uses 3/4 oil to a tank of fuel.

 

If you look at the two blue lines they are very even. I have had this bar since new and I know it has never been hot enough that I couldn't grab it with a bare hand.

 

What brand of bar is on your saw that comes blue like that?

From playing around with my rivet forge, I learned a few things about heat treating and tempering. The steel would need around 1400 F or more to harden followed by a quench. The steel is then quite brittle, so that's where the tempering comes in.

If you wanted the part to be harder for less wear, wouldn't you keep the tempering temp lower? Blue is considered fairly soft for steel isn't it?

Is it only case hardened, or is it the same color inside the bar rails?

Dad was cutting roots in a trench, and got his own unique heat treating inside the bar rails.

 

It has been a couple of years since I took the metallurgy course and I haven't used any of it since I took it. It was a mandatory course for my degree in welding. If you look up a TTT curve it may explain stuff a bit better.

 

I have my oilers maxed out and I keep chains decently sharp...even with a brand new ground chain on a hot summer day I don't want to grab and hold the bars on my saws .

 

My Dolmar PS421 has about 1/3 left in the oil tank when the gas runs out. My Dolmar PS6400C is almost empty of oil when the gas runs out. I had a Stihl MS361 that was similar to the little Dolmar - about a third of a tank of oil remaining after the gas was gone.

In any event, it doesn't matter to me at all unless the oil runs out before the gas. I fill both tanks up every single time.

 

I think the TTT curve is going a bit off the path from where I'm sitting. All I'm saying is, that no matter the hardening temp, or the amount of carbon in the steel, the blue/brown/straw/gold color indicates a specific temperature that the metal has been subjected to. Obviously blue rebar would be softer than blue my truck leaf spring.

But my thinking of hardness is related to knife blades, not to chainsaw bars...maybe blue is soft for a blade, yet hard for a bar?

 

If memory serves to turn low carbon (.08%) steel blue it has to get to around 500° F. I cannot fathom a saw bar getting close to that, even milling. 200°-250° maybe but 500 is HOT. I was thinking carbon has an effect on the coloring temp but not much maybe 20°-50°. Unfortunately I sold that book when my class was done so I would have to use googlefoo. My main point was the blue on bar rails was from the induction hardening process not useage. Wikipedia turned this up.
If steel has been freshly ground, sanded, or polished, it will form an oxide layer on its surface when heated. As the temperature of the steel is increased, the thickness of the iron oxide will also increase. Although iron oxide is not normally transparent, such thin layers do allow light to pass through, reflecting off both the upper and lower surfaces of the layer. This causes a phenomenon called thin-film interference, which produces colors on the surface. As the thickness of this layer increases with temperature, it causes the colors to change from a very light yellow, to brown, then purple, then blue. These colors appear at very precise temperatures, and provide the blacksmith with a very accurate gauge for measuring the temperature. The various colors, their corresponding temperatures, and some of their uses are:

• Faint-yellow – 176 °C (349 °F) – engravers, razors, scrapers
• Light-straw – 205 °C (401 °F) – rock drills, reamers, metal-cutting saws
• Dark-straw – 226 °C (439 °F) – scribers, planer blades
• Brown – 260 °C (500 °F) – taps, dies, drill bits, hammers, cold chisels
• Purple – 282 °C (540 °F) – surgical tools, punches, stone carving tools
• Dark blue – 310 °C (590 °F) – screwdrivers, wrenches
• Light blue – 337 °C (639 °F) – springs, wood-cutting saws
• Grey-blue – 371 °C (700 °F) and higher – structural steel

 

Sometimes my attempts at wit and humor are lost, but it is funny to me non the less and that makes me happy.

The discoloring on bars I am referring to is extremely dull chains burning the bar from extended pizz revving attempt to punish the wood by dogging in said dull chain in a last ditch effort trying to get it to cut. At that point, no amount of oil is going to make a significant difference.

 

My Husky 555 will run out of fuel while there is still some oil in the tank. I fill both before I start so that I am never running the bar dry. My 026 is a little closer to equal amounts of run time on fuel and oil.