iDRY Vacuum Kilns

Sponsors:

Hook angle and blade life

Started by coastlogger, May 15, 2013, 01:56:38 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

coastlogger

Recently I dicovered Id inadvertantly "adjusted" my sharpener so I get more like a 5 degree hook angle than the previous 10 degrees. Ive been cutting WRC and feed rates seem very good at this "new"angle.. However I broke a band quite prematurely for no good reason and that reminded me of some info I read somewhere about low hook angles tearing the blade at the gullet. I only have 13 hp and I seem to recall posts saying this is too low a power to run low hook angles.Can anyone add to this or refer me to the articles that spell out hook angle criteroia and pitfalls? I did a brief search but didnt get the satisfaction I was hoping for.
As far as I could see the band I broke was at the gullet and cracking had progressed in from both edges of band.Im running .042, 1.25 WM doublehard bands.
Also,I recently tried a 100 grit wheel on my sharpener(it uses a 1/8 chainsaw sharpener wheel)Prev I was using 60 grit. What are others using for grit?So far I think I like the 100 grit but havent done enough to decide for sure.Not using any lube.
clgr

ladylake

I think I remember reading about the hook angle  tearing blades apart also but it was the high hook angles that were hard on blades which makes sence.  I've been running 4 or 5°  for years and have really good blade life, if they start breaking check the v belts and guide roller adjustments first.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

dgdrls


ladylake

 It says that any blade with less than a 8° ( blades are sold with a 4° hook)  hook angle will tear itself apart.  After running a 4 to 5° for years I know better.  Seems like a high hook angle would be harder on the blade as it's trying to pull itself wood more stressing the gullets.  I can't remember where I read that a high hook was hard on blades, could have been in one of Cooks newsletters.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Tom L


Also,I recently tried a 100 grit wheel on my sharpener(it uses a 1/8 chainsaw sharpener wheel)Prev I was using 60 grit. What are others using for grit?So far I think I like the 100 grit but havent done enough to decide for sure.Not using any lube.
[/quote]

the finer the grit of a wheel the more heat it produces, the coarser the grit the less heat builds up in the cut. could the blades be getting too hot with no coolant on them?

tommone

There is also another factor in heat build-up in grit wheels, wheel hardness. This will be represented by a number on the wheel usually from F to V but varies from manufacturer to manufacturer. I am sure some members here will have experience in the difference in heat build-up of a hard WM grit wheel compared to a relatively soft pink Cooks wheel! Tom

coastlogger

The 60 grits I normally use are pink and seem quite soft. The 100 grit is a medium brown and does seem harder. I have not had a problem burning teeth probably because I am not removing a lot of material at one time I guess.Around 5 thou per sharpening,which seems about all my sharpener can do. Have wondered whether that is enough to remove gullet cracks.On the other hand I sharpen I think way more frequently than norm.due to dirty wood,low engine power and pers. preference to have straight cuts. One would think that would balance out the lesser amount removed per sharpening.I keep pretty good records of production per band and seem to be in the 1000 bf per band (total band life to breakage) and have been struggling to figure out why it is so low.All mill adjustments are fine tuned, boards are super straight, only complaint really is band life.
clgr

Dave Shepard

I've run 4° for a long time. If the 4s fail sooner, I'd be willing to bet that it's because I'm sawing black locust instead of white pine. :D
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

coastlogger

I fixed the loose part on sharpener so am now back to 10*.Not sure now whether 4* was better or not. Not a lot of difference I think.Might try to create a few 6* or so and try and do a bit of a study. Have never been that good at identifying miniscule changes in cutting speed etc,I tend not to push feed to max so one is left wondering how much "extra" feed speed was there not being used.
clgr

Thank You Sponsors!