Raker shape?

[noyb72]

Just wondering if it as important to keep the rakers the same shape as factory as it is to maintain the fatory angles on the cutters? I seem to make my rakers a little "longer" on the top every time I take them down. My chains cut fine, I'm just wondering if I can improve things by doing something diffrent with the rakers.

Thanks
Ron

 

[redprospector]

On a work chain if the top of the raker get's too flat I'll round off the front a little.
This is what I do to the raker's on my competition chain's.

Andy

 

[noyb72]

I just purchased an "aggressive" work saw chain and it's rakers are about as wide as yours but they come to more of a point at the top. The standard chain I have has much wider rakers, I'm guessing it's more like safety chain. I've ground them down quite a bit and that has taken the radius out of the front of the raker.

Thanks, the pick is always worth a thousand words.

Ron

 

[ShoerFast]

Noyb72

Welcome to the site!

Don't ever loose any sleep over it, but if you spend a little time trying to maintain the same shape as the factory racker 'depth gauge' and tweak the depth to match you saw,,,,,keeping the same radius, your in hog heaven!

Remember that the cutter dose a lot of rocking into and out of the cut each time around, the factory profile is as smooth as your going to get.

 

[ents]

I always round mine out a bit, not "factory" look alike, just a little relief. Seems to take the chatter out of the cut.

 

[noyb72]

Thanks guys, the wind is howling today, I'm sure I'll be making next years firewood tomorrow. I'll give the "rounding a try!"

Thanks again

Ron

 

[Adkpk]

keeping the same radius

Can you give a little more on this? The radius is that inside curve?

 

[joesawer]

Can you give a little more on this? The radius is that inside curve?

The raduis he is refering to is the top, outside profile if the depth guage. the "raker" acts like a wheelie bar on a drag car, so a flat top changes the length and angle the cutter can run at as the tooth tilts back. A radius in the top keeps the tip of the raker against the bottom of the kerf instead of moving the contact point forward as the cutter tilts back. This allows a slightly more agressive depth.

 

[ShoerFast]

Had this pic for awhile now,,,forgot why?

Joe covered it real well, just a point I would like to make refrancing a picture, for all most any work chain, maintaining the angles, depth, coutures and profiles is all you really need to run a chain right down to nubs.

 

[PA Plumber]

I've wondered about this but haven't done the "search" yet. I have been leaving "flat tops" on the rakers, but take them down an extra couple of thousandths. Did noticed a slight improvement when I've taken the time to round off the fronts of the rakers.

 

[Adkpk]

I try to keep them in the same shape as original. But I don't get fanatic about it. Just hit them with a small grinder on the top and then the backside. It's ripping chain I usually try to get cutting really perfectly. So I will often fine tune the depth gauges as I cut. Especially pine is a pain. Very informative posting on this thread. Good work guys. Great pics.

 

[noyb72]

I really appreciate all the info. So, for now I will try to keep the flat area to a minimum by radiusing the top, it seems to me this will make the rakers disappear faster, but if it makes a more aggressive cut, then that's what I'm after.

Thanks again

Ron

 

[PA Plumber]

I went through and rounded off all the rakers on my .325 chains for the 026 today. Definitely cut better than "flat tops."

 

[noyb72]

I never realized the cutters "rocked" through the cut. Come to think of it it makes sense. I guess that's a reason why chain tension is so critical? It always seemed to me that you should run the chain as tight as you could without bogging down the saw, but if the chain actually moves around during the cut it would have to be a little looser.

As always;

THANKS

Ron

 

[Crofter]

I never realized the cutters "rocked" through the cut. Come to think of it it makes sense. I guess that's a reason why chain tension is so critical? It always seemed to me that you should run the chain as tight as you could without bogging down the saw, but if the chain actually moves around during the cut it would have to be a little looser.

Ron

Here is a picture showing the interrupted or bobbling cut action. Same square filed chain, same wood, with only some minor changes that affects the cutters way of going in the wood. Raker clearance and chain tension do have some affect on a chains sweet spot.

 

[raccerx67]

Frank that is very very interesting to me. I am not a comp cutter by any meens but those pics you posted of the "chain action" being so much different.... that is just amazing. I am curious as to which cut was faster and what the slight changes you made on the sharpening were? In particular was it rounding the depth gauges compared to having a somewhat flat top to them? I know its a very old post but I have been wearing out the search feature on here to try to improve my habits and skills with a saw and chain. Thank You for your response if you see this!

 

[Crofter]

That is with square filed chisel chain. The biggest difference would be the amount of raker clearance and a bit of work on the outside of the side cutter and a bit sharper angles. More related to competition chains than work chains. The amount of raker clearance controls the chip thickness and also how rapidly the cutters bobbles in the cut. Lower rakers makes the chain dig deeper down as well as spread out to cut a wider kerf. It takes a bit of playing to find out what cuts the fastest for you and your saw.

Shaping the nose of the rakers something like the factory profile instead of just topping them makes a bigger difference in bore cutting performance than straight blocking cuts so it depends on what you are doing to decide if it is worth the extra time.

 

[raccerx67]

That deff answered my questions. Thank you for the info. I do very little bore cuts if any. What i have done in the past is set the depth gauges to the .25 and every other time that I have to take them down I add the curve back to the leading edge of it. They seem to cut well and smooth and the chip size is what i would consider normal.

Thanks again!

 

[wvlogger]

i have found that if the rackers are flat on top the chain wants to kickback more. found this out in a bore cut. that was a fun day i quite after that, and it was only 8 am.

 

[BobL]

Most folk don't realize that the rakers actually are pulled a small distance into the wood by the cutter. Flat rakers won't penetrate much and pointed rakers penetrate too far and can bog the saw.

Whatever you do there maximizing cutting speed requires a balance between raker depth and degree of roundness of the raker. Less raker rounding will need greater raker depth and VV.

One guy I know who mills aussie hardwood, files his rakers almost to a point at an angle of ~45º , and he uses around .030" raker depths. He also nips the sides of the rakers so they are narrower so they bite a little more.