The ultimate milling saw?

[mtngun]

currently I use a dremel with a oregon 7/32 stone to sharpen the chain on my 076 . What is the best way to use this tool to sharpen the saw. I am doing something wrong . I am not sure what it is. I think my angle on the cutters is 10 deg. Would changing it to 6deg make a big difference?

Post a closeup or three of your chain and perhaps our resident filing expert will be able to give you some pointers.

The angle BobL was talking about is the angle between the cutter and the raker. As per his excellent pic:

 

[BobL]

currently I use a dremel with a oregon 7/32 stone to sharpen the chain on my 076 . What is the best way to use this tool to sharpen the saw. I am doing something wrong . I am not sure what it is. I think my angle on the cutters is 10 deg. Would changing it to 6deg make a big difference?

I don't think you are doing anything wrong to the cutters but I do think we still have our angles crossed.

This is the angle you are referring to - it's called the top plate filing angle.

Whereas the cutting angle I am referring to is that between the wood, the cutter tip and the raker and it is determined by the raker depth and the width of the gullet.

This (together with the cutter hook) determines how big a chip a cutter will generate and this has a substantial effect on cutting speed.

On new 3/8 chain, with a raker depth of 0.025" and a gullet width of 0.25", this corresponds to a cutting angle of 5.7º. Every time the chain is sharpened the gullet gets wider so the cutting angle decreases. By the time the gullet is 0.5" wide the cutting angle is only 3º so the cutter grabs half as much wood.

In addition to this, for optimum cutting speeds, the cutting angle may be different for different cutting situations so superior cutting speeds can be obtained by using different angles.

Very few people know or care about the cutting angle.
They either use;
- a constant raker depth gauge, which results in a decreasing cutting angle every time the chain is sharpened. This just creates more dust and slower cutting speeds.
- a Carlton File-o-plate (FOP) or similar. These are much better than a constant depth raker gauge, but they also slightly reduce the cutting angle as the cutter wears but not as much as using a constant raker height.

I have seen a raker depth gauge like this one that can be used to generate a more or less constant cutting angle.

The way to use this gauge is as follows.

To generate a ~6º cutting angle the gullet width is measured and the you divide that by 10 and that is the raker depth gauge to use.

So
if the gullet is 0.25" use the 0.025" raker depth setting.
if the gullet is 0.30" use the 0.030" raker depth setting.
if the gullet is 0.35" use the 0.035" raker depth setting.
if the gullet is 0.40" use the 0.040" raker depth setting.

Then there are variations to this to suit saw power, width of cut and type of wood.
In soft wood consider using a half to one step greater raker depth.
In very wide wood use a half to one smaller raker depth
In very hard wood use a half to one smaller raker depth
For a very powerful saw use a half to one step greater raker depth.

The above recommendations are just a guide, there is also no need to microanalyse it to this extent. In practice I experiment and keep dropping the rakers until the saw bogs, then I take a bit more off the cutters and measure the cutting angle with a digital angle finder and stick to that.
For my muffler modded 880 it works out to 7.5º in narrow aussie hardwood and 6º in big Aussie hardwood. Lower angles still work but make more dust and cut slower.

Unless I am going to mill a lot of a particular type of wood with a particular powerhead I tend to use the lower cutting angle for that combination.

In the field, depending on how its cutting, I always start out with the cutting angles that are slightly on the high side and just give the rakers a swipe or two or three after every 2-3 touch ups.

If this sounds all too technical just use an FOP.

 

[liftaddict]

here are some pics of the my chain: http://picasaweb.google.com/108717708067027922288/MillingChain#

it is a .404, .063 68 skip tooth chain

 

[mtngun]

Liftaddicts pics:

The angles look reasonable at first glance (I didn't actually measure). On the other hand, that raker doesn't look like it has ever been filed, while the cutter has been filed back quite a bit.

404 is not the ideal milling chain, but that's a whole 'nuther subject.

 

[huskyhank]

Looks like the cutters need more hook. Try using a file instead of the dremel.

 

[Chris Crouse]

BobL is very correct in saying that any saw can mill. You just need to decide how big of a saw do you need for what you will for milling.

My mill is running an industrial 134cc 2-stroke motor. It's the same motor that came on some of the old Mongomery WARDS saw. There were other manufactures that used this motor. It is a 820 PowerBee motor. these motors went into production in the early 1960's and every part including electric ignitions are available today.

Here is a link to pictures of the mill. I'm running a 2" exhaust pipe and a 1" intake/carb. I have just installed a 8 x .404 drive rime which BobL figured out for me that I will be driving the chain 14 percent faster. Chain speed a torque will mill big hardwood (oak etc.) with ease.

http://www.arboristsite.com/showthread.php?t=118268

Haven't been doing any mill as I pinched my sciatic nerve in my right leg building a wheelchair ramp for my Dad's house. It's getting better, but I'm not going to push it. The trees will be there waiting for me.

jerry-

The video of your mill in action in that link is no longer working. Could you provide a new link? I would like to hear that motor working.

 

[820wards]

The video of your mill in action in that link is no longer working. Could you provide a new link? I would like to hear that motor working.

Try this link, it should work. You will also see the 820 Wards saw I use for cutting firewood and a saw that Art Martin built from a Wards frame I found him a few years ago that he built into a race saw.

http://s450.photobucket.com/albums/qq222/820wards/

jerry-

 

[Chris Crouse]

Sounds neat. That's a pretty saw too. Thanks very much!

 

[liftaddict]

Ok here is what I think I should do. And thanks for all the input. Since my saw cuts great at first and gets progressively worse I have to assume I am doing something wrong. I know I consentrate on getting the top plate sharp ( cutting up toward the edge ), I have not been paying enough attention to the hook or the ( gully?) under the top plate. I can to that. What is this about the 404 chain being poo for milling?

 

[mtngun]

What is this about the 404 chain being poo for milling?

Wider kerf = slower cut

Narrower kerf = faster cut

I wouldn't run out and spend money on it right away, but it's something to think about down the road.

For 90cc saws, the fastest milling chain is lo-pro/picco.

For 100+ cc saws up to 40-something inch bar length, the fastest milling chain is 0.325.

For over 40-something inches bar length, use 3/8.

404 may have a place on the big slabbing mills with 4 stroke engines, but that's about it.

We have a few members who still swear by 404, but I think they are just being traditionalists.

 

[liftaddict]

I have to check my manual for the smallest sprocket size for the 076 thanks. I will take the smaller chain info under advisement.

 

[huskyhank]

You'll want to sharpen often to keep the chain cutting well.
On a 24" log I touch up every other cut. On bigger wood I sharpen every cut. Don't worry about a new chain just yet. Figure out how to make this one cut.

Ok here is what I think I should do. And thanks for all the input. Since my saw cuts great at first and gets progressively worse I have to assume I am doing something wrong. I know I consentrate on getting the top plate sharp ( cutting up toward the edge ), I have not been paying enough attention to the hook or the ( gully?) under the top plate. I can to that. What is this about the 404 chain being poo for milling?

 

[BobL]

OK - your cutter profile and raker depth say it all.

The height of the red bar (that's the raker depth) is 1/13 of the length of the red bar (I call that the gullet width even though it isn't) so the resulting cutting angle is 4.3º.

Combined with what Huskyhank said of the cutters not having enough hook, what is happening is that you are (what is called) "cutting on the edge". This means the cutters grab some wood when they are initially sharp but as soon as the razor edge is gone the cutter cannot grab enough wood and so your cutting speeds will slow.

A cutting angle of 4.3º is not all that bad but the 076 should be able to cope with 7º in softwood. From the image the raker depth is 0.035" but based on the length of the red bar the raker should be 0.045" With an 076 you should be able to run even lower rakers when you are milling smallish wood.

When using the dremel are you using the chain saw guide? The gullet should also be completely clear so I would get rid of that little dimple in the gullet.

I'm not quite as negative as mtngun about 404 chain in softwood. The difference in kerf between it and 3/8 is around 10%, but I don't see it cutting 10% slower, in fact sometimes it cuts faster especially with a big saw in small wood. My theory is it's bigger cutters hold more sawdust than 3/8.

 

[gemniii]

You'll want to sharpen often to keep the chain cutting well.
On a 24" log I touch up every other cut. On bigger wood I sharpen every cut. Don't worry about a new chain just yet. Figure out how to make this one cut.

Nice point but how many square feet, what saw, chain and wood?
Do you cut a 2 foot wide long 15 foot long twice and sharpen up?

I'm trying to pin this down because I was "touching up" about every 25 square feet with my JD CS62 in red maple and BobL was touching up about every 32 square feet with his 880 on "Aussie Hardwood".

http://www.arboristsite.com/showthread.php?t=119564

Then in another thread RikBrooks writes

I've only gotten about 15' out of the saw. It doesn't need sharpening. I can feel the sharp side.

and he's cutting 18" wide hickory. which has a Janka of 1820 compared to my red maple of 950 and who knows what "Aussie Hardwood" , but probably as hard or harder than the hickory.

So I'm just attempting to pin down more numbers.

/edit - a Janka table http://www.sizes.com/units/janka.htm

 

[liftaddict]

Ok you guys are giving me some good leads. Btw the scale above the cutters in in inches ( the other numbers are 10ths of an inch ). My bar is a 21in 68 tooth bar. The bar usually only sticks out an inch or two in the thickest part of the tree. I do not think that our white oak and hickory is soft it is considered pretty dense ( but I am the rookie here ). When the shop sharpens the chain they probably put a good hook in. I focus more on the edge, and like you said with touchups remove the hook the edge gets dull and the fuel consumption goes up. So tomorrow I may get a chance to put in a hook and remove the dimple. I do not have any type of guide. I am still fuzzy about the rakers although they do not seem to be a big part of the problem. :deadhorse:

 

[huskyhank]

I usually cut 7-9 foot lengths because that's about all I can handle, carry and store.

In bigger wood (32-40") I can tell the chain goes off perfectly sharp --before-- I'm done with one length. The chips go from big chips to little chips and fine dust. In wood like walnut, cherry and especially poplar I can cut a second slab but its better to sharpen. The third big slab is real slow if I go that far, as I might if its the last one of the day.

 

[Fallguy1960]

Does anyone here have experience with Solo saws? I'm looking at the 694"s that Baileys has in their catalog. At 90cc I was thinking it would do what I need to do without breaking the bank.

 

[BobL]

Ok you guys are giving me some good leads. Btw the scale above the cutters in in inches ( the other numbers are 10ths of an inch ).

A scale is not necessary to work out the cutting angle (that's yet another reason its better to use cutting angle rather than the raker depth) I just open up the image in Photoshop, rotate the image until the line between two adjacent cutter tips is exactly horizontal, insert a box such that the diagonal is between the tip of the cutter and the leading edge of the raker and then use the Image infor box in Photoshop to tell me how many pixels wide and high the box is. A width to height ratio of 10:1 correspend to 5.7º - this is a nominal working value and is what new chain is sold as.

If I know what sort of chain it is being used, I can also use the fact that the distance between two adjacent leading or following rivets = chain gauge and can convert all pixel measurements into " from there.

My bar is a 21in 68 tooth bar. The bar usually only sticks out an inch or two in the thickest part of the tree. I do not think that our white oak and hickory is soft it is considered pretty dense ( but I am the rookie here ).

Those woods are only of average hardness compared to many other woods around the world. In that sort of wood with that short a bar and skip chain on an 076 I would even try running a 7º cutting angle. For your current cutter gullet that corresponds to a raker depth of 0.055"!

When the shop sharpens the chain they probably put a good hook in.

They might put a good hook in the chain but most shops have never heard about progressive raker height adjustment and on worn chains this will leave you to cut a lot of dust. They would probably have a pink fit if you told them some mad Aussie suggested you try 0.055" raker settings.

I focus more on the edge, and like you said with touchups remove the hook the edge gets dull and the fuel consumption goes up. So tomorrow I may get a chance to put in a hook and remove the dimple. I do not have any type of guide.

The edge is important but is quickly lost and then its up to cutter profile and raker setting to do the cutting. If they are not right - exactly what you say will happen, fuel consumption will increase and cutting will slow considerably.

Unless you have a lot of experience using a naked file, I recommend using a dremel guide, it will hold the file at the correct height and make a better hook. I have filed a lot of chains by hand but still usually use a file guide. You know when the hook is right because the saw should at least partially self feed and not need to be pushed to cut.

I am still fuzzy about the rakers although they do not seem to be a big part of the problem. :deadhorse:

At this stage the hook represents most of the problem and the rakers represent less of a problem but if the hook is fixed you will cut much faster if you drop the rakers using the progressive raker setting method.

 

[teatersroad]

Does anyone here have experience with Solo saws? I'm looking at the 694"s that Baileys has in their catalog. At 90cc I was thinking it would do what I need to do without breaking the bank.

No experience 'cept that it sure looked like a good deal and I'd buy at that on reputation alone. Too bad they seem to be sold out. Checked their website, nada.

 

[BobL]

Nice point but how many square feet, what saw, chain and wood?
Do you cut a 2 foot wide long 15 foot long twice and sharpen up?

I'm trying to pin this down because I was "touching up" about every 25 square feet with my JD CS62 in red maple and BobL was touching up about every 32 square feet with his 880 on "Aussie Hardwood".

There is no hard and fast rule because everyones setup is different and everything varies just about all the time.

The reason I say 32 sqft is because in stuff around the Janka 2000 (green) mark I try to tailor my chains for my 60" bars to last this long because it corresponds to an 8' x 4' slab and don't want to overload the saw and/or have to pull the mill out half way through the cut to touch up. This means, using semi chisel full comp chain (it takes longer to go blunt) and a touch less hook and a 6º cutting angle. In different woods the only variables I can mess with are hook (not much) and cutting angle - I don't have any skip or full chisel chain loops for this size bar. If I was going to cut up some big softwoods I might buy a loop of full chisel.

But what if the tree is say 30" by 10'.

Here I'll be using my 42" bar with the same type of chain as above and maybe increase the cutting angle in softer stuff like marri or even jarrah or even get out my loops of square ground skip. In practice I don't calculate the area to the exact sq footage - I'll get a feel for how its cutting towards the end of a cut and then I'll decide if I can get through the next cut without a touch up. I might make 3 cuts - touchup, then 2 cuts - touch up. and then single cuts and touch up even if its only 25 sqft.

Keep in mind that Janka hardness table you referred to in your last post is for 12% MC.