Bar Height and Drive Lengths

[Fordiesel69]

I am very confused with the role bar height plays, in terms of operation and chain selection.

For example my Husky 555 ships with a Husky Branded 20IN Orgeon Canada 20IN 3/8 x 72 DL.

My Echo CS-590 ships with an Echo Branded Oregon USA 20IN 3/8 x 70 DL.

Very confused as to why. What is the advantage of tall vs short?

 

[RedneckChainsawRepair]

You just go by drive link counts. Always has been like that too.

Poulan did it also 20" was 70DL in 20" 3/8.

Nothing to get confused on.

 

[Franny K]

The height is determined by the diameter of the nose and the amount of curve the manufacturer selected. It looks like your picture is of a single rivet sprocket nose bar in 3/8lp 7 tooth.


Tall cuts straighter but will bind easier if the sharpening gets uneven right vs left. smaller nose less total weight, smaller nose sprocket will have smaller diameter ring of rollers, less rollers most likely to fail or develop play earlier everything else being equal. In .325 which you could run on the 555 if you change to a small spline clutch drum (I consider 9 tooth drive in .325 on the drum your saw comes with in the USA impractical) your choice will generally be 10 teeth in the NK kind of bars and 12 tooth in the heavier ones.

 

[heimannm]

The location of the bar studs to the drive sprocket vary from different manufacturers so the DL counts for chains will vary accordingly.

In the McCulloch 10 Series world there were two different bar patterns in 24", the narrow bar takes 84 DL and the wider bar takes 81 DL, has everything to do with the actual length of the bar as well as the location of the bar studs in relation to the drive sprocket.

When bar were primarily hardnose, a wider bar had a longer radius at the nose which helped reduce friction. Downside of a wide nose bar is the increased kick-back zone. As a result, most manufacturers are tending towards narrow bars and a small nose radius, particularly for non-professional users.

Mark

 

[Fordiesel69]

I just grabbed that photo from google. I meant what does someone notice during operation tall vs short?

 

[Franny K]

More curvature is less likely to throw the chain. A smaller nose generally should have less kick back potential. I think all my 3/8 bars that have sprocket noses are the same diameter so if the discussion is about what fits on the two saws in post 1 can't really comment. I would expect plunge cutting to be somewhat different. The larger the nose the less the chain bangs against the bar as it comes off the nose sprocket. I see 545 in your signature you should be able to experiment in 10 tooth vs 12 tooth .325 bars on that and see what you think. Call it tall vs short.

 

[WoodmanSr]

see 545 in your signature you should be able to experiment in 10 tooth vs 12 tooth .325 bars on that and see what you think.

Good points from Heimanmn & FrannyK. Lots of expertise there.

It's about "bar stud tail mount", last digits of bar part number. Husq Small Mount pattern K095 or Echo pattern D176.

The 'narrow kerf' short beam 10T sprocket tip bars do fine. My belief the taller beam 12T sprocket tip offer more durability.

FYI, see related in recent similar Husq 545xp & Echo 590 post. Note; are Echo D176 bars available in normal 72 drivelink length. Would be a bit longer bar.. by 2 links. If desire to share 3/8" .050 chain loops between your 555 & 590.

https://www.arboristsite.com/threads/opinions-on-dukes-and-woodland-pro.378774/#post-8398273

 

[Fordiesel69]

I am running a 3/8 x .050 x 72DL on my Echo CS-670 using the archer branded D176 mount bar from fleabay.