Full Chisel Sharpening

When sharpening full chisel chain, do you all tilt the recommended
10 degrees? Just curious. If not, why not?
Fish

Howdy,

Oregon really confused the market when they went with a recommendation for a straight-level filing at some 20 degrees hook and with a 22 degree topplate. I felt that they made a major mistake with that recommendation. I understand that they are in the process of going back to the 30 degree topplate and 15 degree hook recommendation. Their filing and maintainence manual is still the one with the straight across at 22 degree recommendation, but I understand a new book is in the works.

With Stihl RS, you are almost stuck with a straight across filing if you try to use a 7/32 file, due to hitting the tiestrap on the opposite side. With a 5mm file (13/64) as recomended by Stihl, the filing can be down-angle quite successfully , though still not a good as the factory sharpening. Their original down-angle is almost 45 degrees!

Personally, I file round filed chisel chain with every bit of 10 degree down angle at the file handle, and probably plus a bit, even though this gives a slight curve to the topplate cutting edge due to the radius of the file. I have been known to cheat around underneith a bit at the last stroke to straighten this out, and even thin the topplate a hair more. (You also touch up sideplate gullet at the same time. This is called "racehorse" filing). I kind of pretend that the damage to the tiestrap opposite, didn't happen. "You didn't see that, boss"!

I hold the 30 degree topplate filing angle except if the chain is to be used in frozen wood, and then I go to 25 degree or so with minimum sideplate hook.

For my own saw, I like to chisel bit file just for the fun of it, but would not recommend this filing to anyone unless they seriously want to commit the time and effort to the practice necessary. You generally completely destroy one loop of chain in learning and invest a lot of time. It's lots of fun to watch someones reaction to the size of ribbons being pulled for chips by my piece of junk chainsaw, however. Some guys don't take to well to having their $600 chainsaw out cut by a $75 junkshop saw! (You do get their attention however).

Regards,
Walt Galer

Wow! So is that a yes or no?
Fish

Like Walt said, I have a hard time getting the 10 degree down angle in without hitting the tiestrap. On a new chain it is easy but you have to switch to a smaller size file than is reccommended when about half the cutter is gone to maintain the 10 degrees. So, Walt, which is better:
Getting the 10 degree down angle and switching to a smaller file or using the proper size file the manufacturer calls for and filing at a right angle?

Howdy,

As I said, I just go ahead and rather clobber the opposite tiestrap with the file. You had best not do this with someone else's chain however without permission!

As I review Fish's posts, I believe he might have been refering to grinding rather than filing. In that case; Yes, you definitly Tilt or offset the vise. This allows the radius of the wheel diameter and the offcenter positioning to do the down angle sharpening. In addition, you should tilt the head on over to 45 or 50 degrees. (Yes, I know the instructions say 60, but that is plain foolishness). On a new chain, you may not have clearance behind the depthgauge, and you dare not hit the depthgauge, so you either have to relieve the backside of the wheel with the dressing brick, or you have to accept the more blunt topplate of having the head at 55 or 60 degrees for that loop only. (I assume that this problem is why the 60 degree thing is still around in grinder instructions).

Regards,
Walt Galer

I was just wondering, I am the only one around here that does
the tilt, and I have a good following. Even a few woodcutters
bring them to me to true them up from time to time, but the
guys that cut wood around here are a stubborn and ornery
breed, nothing like you guys.
The guy at our county's Stihl dealership has a metal wheel
that is diamond coated or something, he says he likes it.
He doesn't sharpen very well, but the edges he was making
looked clean and sharp. Have you seen on of these?
Fish

Howdy Fish,

What you are referencing is a Borazon wheel (or other carbide particle wheel). These are often called "Diamond wheels", but they are not diamond.

They now are about standard at the factories, but remember - that is grinding under coolant and with the cutter absolutely rigidly clamped in a fixture. Many dealers have been sold these wheels, at about $250 each.

They do a good job only if the grinder vise holds the cutter securely. (Most can not due to the looseness in the assembly of the chain). If the cutter vibrates, it picks the particles out of the wheel, greatly shortening it's life. Some dealers claim to be able to do 300 chains on one of these wheels. (Still figures to cost almost $1 per chain, which is about 3 to 4 times what the normal abrasive cost would be. (I usually figure about 25 cents, as I like to claim 40 chains on a wheel and a cost of $10 per wheel. I may be a little optimistic since I like to grind aggressively and fast, breaking down the wheel to prevent overheating the cutter).

Another disadvantage is the fact that the cutters are usually overheated with these carbide wheels due to the dry grind. The cutter is too hot if you can't lay your finger on it immediately after sharpening. Too hot means that the chrome plate has been softend, and that means the staysharp ability of the chain has been destroyed. (This happens long before the steel discolors!) Chrome begins to soften at 350 degrees F. - Steel goes straw color at 750 - 800, and blue at 900F (Blacksmith's draw colors).

Manufacturer's love grinders since they destroy chain and increase replacement sales. I have always told people that to grind chain, you have to know how to file. If you can't file, you might destroy a chain, but if you can't grind, you will destroy hundreds of feet. Please buy a grinder!

Regards,
Walt Galer

jokers is in the house!

I`ve got to jump into this fray. You have to have a 10 degree downangle on chisel chain or you have a blunt chain. It`s as simple as that. You don`t have to settle for filing into the straps though, and you have to switch to a smaller diameter file at some point or you aren`t going to have a sharp chain. This is almost like a throwback to a thread we had the other day. As the height of the tooth diminishes, the proper file diameter TO MAINTAIN THE SAME CUTTING ANGLES has to diminish. Everyone here must understand that the radius of a circle is half it`s diameter right. And you can break a circle into as many arcs as you want, but the number of arcs determines the joining angles of the arcs if they are thicker than a simple line drawing. So if you change the number of arcs between two circles of the same diameter, you change the joining angles. Or conversely, if you put what you can of a larger diameter circle within a smaller circle,you don`t get the same equal angles in the circumference of the small circle, ie: the sideplate and bottom of topplate angles effectively change giving a blunt angle on the bottom of the top plate. This is all probably clear as mud now, right? I`m going to show you a chunk of 73Lg that still cuts well after being filed with a 3/16 file due to the reduced tooth height. It will also show that there is a valid place for a grinder on depth guages, the leading angle on the front of the raker has been altered because the raker had been filed to the point where it`s shape was changed. The gullets have also been cleaned up with the grinder. Before anyone is so quick to point out, yeah I know that I got alot of hook, but I believe the angle is still about the 60 degrees that Oregon specs. Russ

Howdy Russ,

My comments would be that it looks like a durn good end-of-life filing. You sacrifice just a bit of performance for that smaller file size, but rather an academic amount.

I might comment, that your rim sprocket is getting a might worn, not real bad but deserves a look. That's what causes that little burr on the part bottom at the rear of the sprocket notch.

Your depthgauge configuration appears about perfect, but significantly lower on the left hand cutter than on the right. This is common if the depthgauges are done on a grinder. The chain tips away from the direction of wheel rotation plus it is highly unusual for the center position of the vise to actually be in center. If it is on a new wheel by some rare chance, it won't be with a worn wheel due to the wheel diameter difference and swing/arc of the grinder head stroke.

Regards,
Walt Galer

Hi Fish, I realize now your question was related to bench grinding.
I never tilt the vise because I use it only for evening up abraided cutters. I then do sideplate and gullet work with the hand file and finish off with a gentle tickle to the top plate.
John

Hi Walt, thanks for the positive feedback on my filing example. I should have used a different background material for the photo, the brown doesn`t show all the detail. I wanted to show what the underside of the top plate looks like with the 10 Degree angle. I believe that the rakers on both sides are very close to the same. The height of each raker is set with the Husky guide, specific to each tooth. I only ground the leading angle on the raker to ensure that the properly clearanced top of the raker is what actually determines cut depth. It`s also a virtually new 1/4" wheel, centered over the vice, since I only use it for this part of chain maintenance. I recognized the peening on the bottom of the chain, but I figured I wasn`t losing much chain life running that rim. I usually change the rims when they look like they are dished out about the thickness of a business card, about .015", I believe that this is a significant factor in chain stretch. Probably second only to dull cutters. Russ

Hi Fish, it is also ok to tilt the file up, 10- 20 degrees, or even use a raker file to get in under the top plate, kinda simulating at square ground tooth.
John

Lambert has become the "Witch Doctor" of AS. He is dancing
around the graveyard, trying to revive all of the dead posts. He
is afraid the quality of discussion here is dying, and he may be
right, so he is raising the ghosts of arboristsite past, to get
the new kids riled.
Good idea, maybe the ghost of Walt will make an appearance,
riding his pale grey Llama

Fish
What is your fetish with Llamas? Is it because they spit on you.

Walt? Is that you?

Hi Nelson, that comic reminds me of the other day. Driving on a country road, I came to an intersection and was turning the corner. At the same time a woman in a car, came around the corner towards me and unwound the window and yelled at me, " Pig!, Pig!". So I yelled back, "?????, ?????", then as I rounded the corner, I ran over a pig.
Go Figure.
John

I'll post this here as well. This has been useful to me.

Heres another link to the Oregon Manual with all the 3/8 angles



http://www.oregonchain.com/tech/ms_manual/ms_06.pdf

Heres the link for all their .325 chains


http://www.oregonchain.com/tech/ms_manual/ms_05.pdf

hope these help as well.

Later Rob.

My pic loads quicker.