high rakers vs. low rakers

[injun joe]

i was wondering the difference in cutting perfomance of a chain when the rakers are adjusted properly and when the rakers are taken way below the tooth. i ask this because i have a friend that has been cutting wood for a while and when he gets a new chain he cuts the rakers way down so is there any advantage/disadvantage to doing this.

 

[BobL]

i was wondering the difference in cutting perfomance of a chain when the rakers are adjusted properly and when the rakers are taken way below the tooth. i ask this because i have a friend that has been cutting wood for a while and when he gets a new chain he cuts the rakers way down so is there any advantage/disadvantage to doing this.

High rakers make dust and slow cutting, so operator starting pushing harder which makes bar and chain hotter which can damage the bar, chain and sprocket.

Rakers set to the right height make chips, little pushing needed by operator and bar, sprocket and chain life are optimised. The one benefit is you get a nice smooth finish using ripping chain while milling.

Rakers set too low can repeatedly bog down the saw, constant jerky operation can damage bar, sprocket and chain. When milling the washboard effect is increased.

The "right height" depends on things like, the type of saw, whether you are ripping or cross cutting, type of chain and type of wood, and probably even the operator will have their own preference.

If your friend mills softwood, has a powerful saw, a strong upper body, a clean stong chain, and doesn't care about the finish of the cut, then dropping the rakers probably gives him faster cutting.

Some people like a constant height raker. For my 076, milling Aussie hardwood, using 3/8 full comp ripping chain, I use 1/10th of the gullet width. For softwood milling I usually go to around 1/9th of gullet width.

 

[John Ellison]

Properly adjusted rakers and years of cutting= you will still have feeling in your hands.

 

[BobL]

Properly adjusted rakers and years of cutting= you will still have feeling in your hands.

Good point, I forgot about that one!

 

[Mad Professor]

Too low also = more kickback

Other things to consider big saw softwood or small saw hardwood?

 

[brages]

There is a post on the Injuries forum called "took a chainsaw to the face" involving a tree trimmer using a tophandle saw with the rakers filed down. Perhaps he still would have been injured with the "proper" depth gauge height..?

 

[thejdman04]

I have found w/a big sall small bar, hardwoods like oak etc, If you file the rakers way too low you will break teeth (cutting teeth). I have seen it happen. Somone I know would take the rakers all the way down and hed always break teeth, even when cutting limbs off oak trees (where there were no nails etc).

 

[THALL10326]

High rakers make dust and slow cutting, so operator starting pushing harder which makes bar and chain hotter which can damage the bar, chain and sprocket.

Rakers set to the right height make chips, little pushing needed by operator and bar, sprocket and chain life are optimised. The one benefit is you get a nice smooth finish using ripping chain while milling.

Rakers set too low can repeatedly bog down the saw, constant jerky operation can damage bar, sprocket and chain. When milling the washboard effect is increased.

The "right height" depends on things like, the type of saw, whether you are ripping or cross cutting, type of chain and type of wood, and probably even the operator will have their own preference.

If your friend mills softwood, has a powerful saw, a strong upper body, a clean stong chain, and doesn't care about the finish of the cut, then dropping the rakers probably gives him faster cutting.

Some people like a constant height raker. For my 076, milling Aussie hardwood, using 3/8 full comp ripping chain, I use 1/10th of the gullet width. For softwood milling I usually go to around 1/9th of gullet width.

Good post. Adding to it those low rakers that cause jerking and yanking in the cut is also very hard on the crank bearings. Its one of the common causes of bearing failure...

 

[056kid]

if you can accurately lower them to .035 or.040, it wont be that jumpy. It will want to kick back but it will also want to cut..

 

[MtnHermit]

This thread may be an answer to my saw:

I have a new Husqvarna 455 and when I do limb cuts it seems I have to apply an inordinate amount of pressure, much more so than my 32cc Poulan 2175. OTOH, when I do large blocks I find I can use the front tines/dogs to apply pressure and it cuts easy. I get nice chips from the cut, not sawdust.

I keep the chain sharp and out of the dirt and rocks. I sharpen the teeth every 2nd or 3rd tank of gas.

Any thoughts?

Thanks

 

[harrygrey382]

This thread may be an answer to my saw:

I have a new Husqvarna 455 and when I do limb cuts it seems I have to apply an inordinate amount of pressure, much more so than my 32cc Poulan 2175. OTOH, when I do large blocks I find I can use the front tines/dogs to apply pressure and it cuts easy. I get nice chips from the cut, not sawdust.

I keep the chain sharp and out of the dirt and rocks. I sharpen the teeth every 2nd or 3rd tank of gas.

Any thoughts?

Thanks

may well do, how many times have you sharpened it? How much do you remove each time? Have you ever lowered the rakers? You have to keep them at the right depth - this means checking and lowering every few sharpens, depending how much you've removed since last time/how anal you are

 

[blsnelling]

Low rakers are not a good thing. They'll cause your saw to jump and jerk in the cut. A good way to knock out your crank bearings and maybe even break the crank itself.

 

[HolmenTree]

if you can accurately lower them to .035 or.040, it wont be that jumpy. It will want to kick back but it will also want to cut..

Depends how far back your cutters are filed to. Depth gauges at 35-40 thousands when the cutters are at the top plate witness mark is ok, but not when the cutter is new.

 

[yo2001]

Seems like I'll get a chatter with raker down to .035" every now and then. Been keeping the rakers at .030" and I can't tell the difference in speed but much smoother cut with less vibration.

 

[flatpikr]

Depends how far back your cutters are filed to. Depth gauges at 35-40 thousands when the cutters are at the top plate witness mark is ok, but not when the cutter is new.

This is a good thought which begs the question-- where are the depth gauges set on a new chain? I think it would be a good idea to measure the depth gauges before ever using the chain. I have guides for .025, .030, and .040. Here are a few of the thousand variables as I see it: saw power, age of chain, type of wood, experience of the operator, size of chips, etc etc. In my hands, if a particular chain, that is sharp, acts like it doesn't want to cut like I think it should, I'll probably reduce the d.g.s a little. There really are many many variables here. A noob should stick with the recommended depth (saw owners manual) until he establishes a middle of the road tactile sensation to a smooth running saw/chain combo.

 

[parrisw]

Too low rakers, can break and wear things allot faster, just not a good thing, you can also break a chain which also is Unsafe.

 

[HolmenTree]

Depends how far back your cutters are filed to. Depth gauges at 35-40 thousands when the cutters are at the top plate witness mark is ok, but not when the cutter is new.

My above quote left alot of questions unanswered. When Oregon first brought out the 72,73,75 LG chain in 1982, the depth gauges were set and marked 30[thousands] on the depth gauges. And the chain cut nice and aggressive but still smooth. About 6 mths later Oregon changed the setting back to the standard .025" because of safety and product durability concerns. What 056 Kid said early is not out of line,.035" set accurately would be fine in softwood even with a new chain. But .040 is pushing it. At .040 there is no room for error and for one guy he may get away with it but then the next guys cuts himself from a severe kickback because on the next filing he screwed up on the settings.
Chain companies designed their chains to cut at .025" depth gauge settings when new. The rule was to keep that setting throughout the life of the chain. About 35 years ago Carlton went one step further and developed the File-O-Plate. With the File-O-Plate as the cutters are filed back the depth gauge setting is increased coordinately. So like I said earlier when the cutters are filed back to their smallest usefull size the depth gauge setting should be .040" for the chain to cut as effectively as new.
Kickback is a serious issue especially when there is large 13 tooth sprocket nose bars out there.

 

[parrisw]

My above quote left alot of questions unanswered. When Oregon first brought out the 72,73,75 LG chain in 1982, the depth gauges were set and marked 30[thousands] on the depth gauges. And the chain cut nice and aggressive but still smooth. About 6 mths later Oregon changed the setting back to the standard .025" because of safety and product durability concerns. What 056 Kid said early is not out of line,.035" set accurately would be fine in softwood even with a new chain. But .040 is pushing it. At .040 there is no room for error and for one guy he may get away with it but then the next guys cuts himself from a severe kickback because on the next filing he screwed up on the settings.
Chain companies designed their chains to cut at .025" depth gauge settings when new. The rule was to keep that setting throughout the life of the chain. About 35 years ago Carlton went one step further and developed the File-O-Plate. With the File-O-Plate as the cutters are filed back the depth gauge setting is increased coordinately. So like I said earlier when the cutters are filed back to their smallest usefull size the depth gauge setting should be .040" for the chain to cut as effectively as new.
Kickback is a serious issue especially when there is large 13 tooth sprocket nose bars out there.

Good post.

When a chain gets filed back, it get smaller so it takes less of a bite, so to speak, so you lower the raker's more so it will cut the same as to when new. Does that make sense???

 

[HolmenTree]

Good post.

When a chain gets filed back, it get smaller so it takes less of a bite, so to speak, so you lower the raker's more so it will cut the same as to when new. Does that make sense???

Yes thats what Mr. Carlton and one of his favorite advisors Sven Johnson said too.

 

[parrisw]

Yes thats what Mr. Carlton and one of his favorite advisors Sven Johnson said too.

Ya, I think the Husky combi gauge is progressive raker gauge too. Thats what I use.