Talk nerdy angles to me, baby

[Backstage]

Finally got a decent chain grinder (tecomec evo). I’m pretty decent with a hand file, but wanted this for mainly for restoring rocked and nailed chains. Also have a few guys who refuse to sharpen in our group and I end up with their perfectly good chains when they just buy new ones.


For reference, I’m mostly cutting dry ash, and green oak/maple/beech/hornbeam.


What’s this down angle thing? With the hand file, I just try to keep levelish. Why would I go down or level?
I also have a tilt angle between 90-50º. 55-60 is recommended in the manual, but should I go lower that for the harder woods I‘m working with? I don’t mind working a bit harder for the occasional 6” pine if it means cutters last longer in the hard stuff.

A guidance decoding this is appreciated.

 

[hwrdpromac7900]

60/30/0

 

[user 122190]

60/30/0

Worked for me. The last 10, I tried and it made no difference.

 

[link]

Finally got a decent chain grinder (tecomec evo). I’m pretty decent with a hand file, but wanted this for mainly for restoring rocked and nailed chains. Also have a few guys who refuse to sharpen in our group and I end up with their perfectly good chains when they just buy new ones.


For reference, I’m mostly cutting dry ash, and green oak/maple/beech/hornbeam.


What’s this down angle thing? With the hand file, I just try to keep levelish. Why would I go down or level?
I also have a tilt angle between 90-50º. 55-60 is recommended in the manual, but should I go lower that for the harder woods I‘m working with? I don’t mind working a bit harder for the occasional 6” pine if it means cutters last longer in the hard stuff.

A guidance decoding this is appreciated.

The down angle thing, if its about tilting the vice... does one of two things;
One thing it can do if I'm not mistaking - is to make a sharper angle on the outer tip of the top plate, so you have one side of the top plate that is attached to the vertical part of the tooth, and one side that is kinda hanging free. In aerodynamics its called a "washout" - the root and the tip of the wing have slightly different angles of attack, the root have a higher angle of attack and a higher work load than the tip.
The other thing it can do is to adjust for a smaller / worn grinder wheel to be properly centered at the tooth when the wheel is lowered, seen from the front of the chain (as if the guide bar is pointing directly towards you).

 

[sean donato]

The down angle thing, if its about tilting the vice... does one of two things;
One thing it can do if I'm not mistaking that is - is to make a sharper edge on the outer tip of the top plate, so you have one side of the top plate that is attached to the vertical part of the tooth, and one side that is kinda hanging free. In aerodynamics its called a "washout" - the root and the tip of the wing have slightly different angles of attack.
The other thing it can do is to adjust for a smaller / worn grinder wheel to be properly centered at the tooth when the wheel is lowered.

You should be sliding your vice to accommodate for wheel wear, not using the 10* down angle.
The 10*down angle is an oregon chain thing, I've never noticed a major difference when doing it or not.
I set my grinder to 55-30-0 doubt there is much of a difference with the 60* top angle in moat woods.

 

[Dennisthemenace]

My Tecomec is at 60 /28/0 for semi in dry or dirty hardwood or 55/30/0 for full chisel in clean and green timber. CBN wheel

 

[Backstage]

Thanks for the good recommendations. I think I get the 55/60 angle. It creates more "gullet" the lower you make the angle. lower angle="sharper"=dulls faster.

I'm really curious what the 10º and 55/60º are actually doing in the wood though.
Probably going to standardize on 55/30/0.

 

[huskihl]

The 10° slide/tilt, depending on which model you have, replicates lowering the file handle and filing up through the tooth. It leaves a more blunt working corner since the file is higher in that area, and a sharper trailing edge since the file is lower there. Same thing happens with the grinding wheel if you only sharpen with the radiused portion of the wheel. My grinder has the slide option, but I don’t mess with it. It’s one more thing that needs to be changed every time you grind a different side

 

[Patrick62]

Having sharpened hundreds of chains, I think I have a theory here.
However, we are cutting softer stuff out here...

The 10 degree tilt (in theory) makes a sharper point on the cutter. I tend to use it on .375 and the .325 chains.
On the low profile and small stuff, I just leave it at zero. My theory is the cutter is narrow enough that it don't make much diff.

It's a compromise on the 55 degree, verses the recommended 60 deg. You will get a sharper chain with the 55 deg, but it will not hold it's sharp as long. Kind of like the difference between using a 7/32 vs 13/64 file.

One thought... A recent observation of mine. Take a chain that you have hand filed, and it is cutting to your satisfaction.
Haul it into the shop, and check the angles with the grinder to approximate what you did with the file.

One thing I tell the guys I sharpen for, a grinder can sharpen a chain in a few minutes.
It can also destroy a chain in the same time frame.

consider rigging up a switch to reverse the motor for the right side cutters. Keeps the chrome edge cleaner that-a-way.

KEEP the wheel CLEAN. Do not over heat the cutter..... you will regret the results.

 

[link]

consider rigging up a switch to reverse the motor for the right side cutters

It shouldn't be necessary, I use a cloth saturated with water that I apply on to the tooth every second. I usually don't get raw edges from the grinding, they just brake off leaving the cutting edge clean.
This is a harvester chain - about twice the thickness of a regular chainsaw chain...
Besides - you'll get all the dust and fragments in your face (eyes).

Much better with a diamond wheel, but you cant shape it to adjust the rakers.

 

[Patrick62]

There ain't nothing "safe" in this world.
Yes, the grinder shoots sparks at me on reverse. Sit off to the side. works fine.
I actually like my OLD foley Belsaw which is reversible by design.

I reversed the Stihl USG, and also know how to reverse the other tecomec style.

To each his own...