Hi Guys - I wasn't sure where to put this, but since it in reference to my milling chain, figured I'd put it here. If Mods want to move, ok with me. Anyways, I've been running a a home-made ripping chain (made from c83 Husvarna x-cut chain). I'm pretty disgusted on how long the chain stays sharp. I get one good past thru ok, the second pass is marginal and by the third pass its complete crap. The wood isn't dirty (no rocks or anything). I've been using my super jolly to sharpen with CBN disks. I'm wondering if I am too aggressive with my pressure and am heating the temper out of the cutters. The chain I'm using is nearing the end of its life, so I'm trying a different cutting angles. I was running 15° on my scoring cutters and 5° on my clearing cutters. On my last sharpening, I put everything at 10°. I didn't get to try it out as it started raining yesterday just as I was finishing up. Stupid rain. Is the performance that I'm getting out of my chain typical with a chain mill or am I cooking my chain teeth? EDIT: LOL, title was supposed to be CHAIN TOOTH TEMPER, no tool. Mondays..
Depends on the size of your cuts. If that’s a huge 10’ long 40” wide oak, then not so bad. Can you share a pic or 2 of the chain? Have you considered trying a loop of full skip full chisel for comparison? I’ve milled a lot and I’ve never used a dedicated ripping chain. Just adjusted the angles for milling. Top plate is about 10-15.
I got a couple of the plated wheels, I do a lot of sharpening, wore them out in a weekend. These particular wheels gave a decent grind although not as smooth as the stones. Got about 100 chains on each width wheel, so it cost $1.00/chain in wheel life. Started raising a huge burr in the top plate, so had to go back with a stone to polish it off - not cost effective in my book. I use a lot of plated and matrix diamond, wheels in my shop for many other things. About the same experience I had with diamond chain saw wheels when first introduced some 20+ years ago- was hoping for better. So it is possible that the fancy wheels may be part of your problem. You might have to play around with angles depending on the wood being cut.
I haven't tried full skip/chisel yet. I'm not cutting a 40" board, but its all of 20" oak. Maybe I'm just expecting more than the chain can do. I don't have any pictures of the full chain, but its modeled after the granberg chain. Two clearing cutters followed by two scoring cutters. I basically just cut half of the tooth off with a grinding wheel and re-angled the top plate. I'll have to see if I can get a picture of the chain. What advantage does the full skip provide over a full chain?
Were they CBN or diamond wheels? CBN is for sharpening regular chain and diamond is for sharpening carbide chains. Your results aren’t normal. I don’t believe I’ve heard of anyone wearing one out
I'd say give regular chisel chain a try. You may be surprised. Skip benefit is just like intended for felling/bucking. For really wide wood it helps give a place to carry out the powder/chip. That last oak I milled, I started with my long bar w/ skip, then switched to a 28" w/ full comp. My cuts were much faster w/ full comp. Reading back over the thread ( Oak is no joke! ) I believe I got about 4 cuts per loop before swapping them out. One thing though, I am very particular with cutting/sharpness of my chains. Being that I [used to] hand square file, any little drop off in performance and I'd change chain so it would only take one or two swipes with a file to get back to 100%. I could have gone longer and will now that I have a grinder.
Since the main topic intended for this thread is about temper, I'd like to learn as well. I've recently got my first grinder. I had 2 16" loops that had a wild round grind on them. Decided to grind it out to full square. There was very little metal at the cutting edge and some of them over heated rather quickly. I've never dealt with extremely hard cutters till recently. I had a couple friends square grind some loops before I got my own. While resharpening, I hit a couple cutters so hard the file just skated. To me, it meant the metal became fully tempered. This is how knife makers check for a good heat treat. So @ what point is the temper lost or made "better"? I'd love to know...
The only thing that makes sense to me is that when you grind too hard and overheat the cutters, they become hard and brittle from cooling off too quickly. And then the edge chips, rather than round over and become dull like normal. Otherwise we would always try and burn the cutters to harden them
Thanks Kevin. That does make sense. I'll watch those 2 loops carefully when I get around to using them.
Yep, don't overheat the cutters Jason. I've gotten too aggressive on my chains & made the teeth brittle. They won't stay sharp for long & it really takes life out of the chain. I assume the same is true for milling chain. I think the factory hardness is about optimal.
I forgot you still have your printer’s loupes. Ought to be able to get a closeup of an intentionally hardened cutter before and after some use and see what actually happens . It’s all just theory on my end. Maybe they actually stay sharp longer. Who knows
Exactly what I planned to do. If any chipping occurs, I’ll share pics. With this grind, it was almost impossible to do. I did go slow and w/ patience, but it happened more than I wanted. On my square filed chains I had no problem keeping them from getting too hot. I think too much metal was removed. Curious, those overheated brittle chains.. we’re they very hard/near impossible to hand file? When I hit those few cutters, I used a dremel w/ a round stone to grind off that hardened part, then I was able to proceed.
I think I may try to rig up a air line next to the grinder and direct compressed air at low pressure to see if that helps. I try to go really slow with the grinder (just bumping it) but man there is so little metal there for a heat sink, I don't know how you could keep the tooth from over heating. I've got a dedicated ripping chain from JB and some standard Oregon chain that I'll just put new angles on (won't make any scoring cutters). I'll have to see if I can find some full chisel/skip chain and try some of that. Let's burn wood my wife said. It'll save us money she said... LOL
Any idea if those cutters are brittle, like mentioned above? I have a decent array of magnifiers to look at edges very closely. If you could clean a couple cutters up and zoom in real good with a decent camera or grab something to magnify, you might be able to see if the lack of durability is from overheating. Are you cutting through dirty bark? That could contribute as well.
I've got a pretty good camera on the phone. I've got a fresh grind on the chain, so I'll see if I can get zoomed in far enough to get some pics of the teeth to see if I have any discoloration going on. No bark on these sticks that I am currently working on, but the first 2 inches are pretty punky, so I would imagine there is some crud in there.
The chains I've overheated, a file won't touch. Did the same thing with a dremel & round stone to remove the heated area. I looked at one under a lab type magnifier after about 3 cuts in an Oak log i.e. "normal" bucking for me & the leading edge was literally chipping away. The chain only cut good for 10 minutes or so. I'm no sharpening expert by a long shot, but I learned what not to do real fast, at least for my purposes.
Thanks for the insight. Sounds like I'm headed down the same rabbit hole, at least with those two loops. Chalk it up to good experience.
