Best 60" Bar for milling

[DaltonPaull]

One thing they told me is that they use completely hardened material, as opposed to bars that are induction hardened only at the edge were the chain rides which I guess is the typical way of doing things. I'm not sure if that makes them stiffer or not.

 

[BobL]

One thing they told me is that they use completely hardened material, as opposed to bars that are induction hardened only at the edge were the chain rides which I guess is the typical way of doing things. I'm not sure if that makes them stiffer or not.

That will make a significant difference.

 

[mtngun]

One thing they told me is that they use completely hardened material, as opposed to bars that are induction hardened only at the edge were the chain rides which I guess is the typical way of doing things. I'm not sure if that makes them stiffer or not.

Modulus of elasticity, which is what determines "stiffness," is the same, hardened or not.

60" is a big bar. Post some pics when you get to milling those big trees.

 

[BobL]

Modulus of elasticity, which is what determines "stiffness," is the same, hardened or not.

I'm not sure what you mean. Modulus of elasticity is used to determine tensile strength and since there is a good correlation between tensile strength and hardness a harder material is usually much stiffer. So hardened bars will usually be stiffer than non hardened bars.

 

[mtngun]

I'm not sure what you mean. Modulus of elasticity is used to determine tensile strength and since there is a good correlation between tensile strength and hardness a harder material is usually much stiffer. So hardened bars will usually be stiffer than non hardened bars.

Hmmmm........ someone has been in management too long. Going to meetings, writing reports, making powerpoint presentations ....... that'll rot your brain. Good thing you have a stimulating hobby.

Modulus of elasticity is the slope of the stress/strain curve in the elastic region. Most carbon steels have roughly the same modulus of elasticity, heat treated or not.

Tensile strength, or yield strength, refers to the stress that would cause permanent deformation -- in other words, if you bent your chainsaw bar so much that it stayed bent and wouldn't spring back to shape.

A heat treated steel will have a higher tensile strength, and will better resist permanent deformation (and better resist wear), which is all well and good, but that's not what we are talking about. We are talking about the bar temporarily sagging when it is laid on its side -- that's elastic deformation, governed by the modulus of elasticity.

If you wanted to make the bar sag less, you would need either a higher modulus of elasticity (i.e., make the bar out of carbide rather than steel), or a higher area moment of inertia (i.e., a thicker bar).

wiki on bending stiffness for nuclear physicists who spend too much time going to meetings

wiki on modulus of elasticity

Are you back in Oz yet ? Done any milling lately ? It's still raining and snowing here, so I'll stay home and tweak my CSM.

 

[BobL]

Hmmmm........ someone has been in management too long. Going to meetings, writing reports, making powerpoint presentations ....... that'll rot your brain. Good thing you have a stimulating hobby.

Modulus of elasticity is the slope of the stress/strain curve in the elastic region. Most carbon steels have roughly the same modulus of elasticity, heat treated or not.

Tensile strength, or yield strength, refers to the stress that would cause permanent deformation -- in other words, if you bent your chainsaw bar so much that it stayed bent and wouldn't spring back to shape.

A heat treated steel will have a higher tensile strength, and will better resist permanent deformation (and better resist wear), which is all well and good, but that's not what we are talking about. We are talking about the bar temporarily sagging when it is laid on its side -- that's elastic deformation, governed by the modulus of elasticity.

If you wanted to make the bar sag less, you would need either a higher modulus of elasticity (i.e., make the bar out of carbide rather than steel), or a higher area moment of inertia (i.e., a thicker bar).

wiki on bending stiffness for nuclear physicists who spend too much time going to meetings

wiki on modulus of elasticity

Are you back in Oz yet ? Done any milling lately ? It's still raining and snowing here, so I'll stay home and tweak my CSM.

Yep, I agree, correct on all counts! Now its all coming back to me. In fact I even remember annealing some old files many years ago and and being surprised at how stiff they still were.

Yeah back in Oz, heaps more meetings, paperwork and bovine excrement to deal with.
We're leaving for PNW in a week so getting ready for all that at the same time is no fun.

Might sneak off to the milling yard today but its raining (at last) here too so can't see myself getting to much done.