Getting serious about lo-pro

[Rooshooter]

That seems to be in dispute. I don't claim to know for sure except, as someone pointed out, there are 1640 links in a 100 foot roll for both types of chain. That's roughly 0.365" pitch.

Thanks for the comments mtngun.
It may be a point of dispute, However the Oregon importer also told me 3/8LP is actually .365"
For those that doubt it hang several feet of both 3/8LP & a 3/8 std chain both on the same nail and see which chain is longer for the same amount of drive links - not much in it but the 3/8 std is longer.
In Carlton chain both 3/8 LP & 3/8 std are 1632 links per 100' roll.

Laurie

 

[mtngun]

The five minute fix ? ? ?

Ground 3 teeth on my see-through nose sprocket. The teeth were simply ground flush with the nose. I left the remaining teeth as-is for comparison and for future experiments.

Now the drive links are supported fairly well. :rockn: :rockn: :rockn: :rockn: :rockn: Perfect ? No, but bear in mind this is a well worn sprocket. At least now the sprocket tooth is not trying to wedge the links apart like the OEM tooth.

View from the other side.

The grinding process leaves burrs on the teeth, and there is no way to deburr them, so the burrs cause the sprocket to bind at first. The burrs will wear off quickly, though.

I'm feeling pretty good about this mod , but will reserve judgment until it has been field tested.

 

[mtngun]

Back to the pitch dispute........

I'm not sure that it matters -- yes, the pitch needs to be compatible with the sprockets -- but sprocket fit is also effected by the height of the side lengths and the shape of the drive lengths. And, the effective pitch will change over the life of a chain, as the chain stretches.

Nonetheless, I used a digital caliper to measure chain pitch. I measured center-of-rivit to center-of-rivit across 16 links, because that's as far as my 6" calipers would span.

A new Oregon lo-pro was 0.366", as best I could measure.

A new Carlton "regular" 3/8 was 0.367", as best I could measure.

 

[Rooshooter]

Back to the pitch dispute........

I'm not sure that it matters

Thanks mtngun, I'm not really worried whether it matters, I am merely pointing out facts. I've had my input on this discussion and that's abt all I have to say.

:deadhorse:

 

[Andrew96]

The five minute fix

Well you had me thinking about the pitch vs. sprocket issue in the shop all day (remembering your photos). Through various drive systems that I've worked on, a pitch that close for an idler (that's all the nose sprocket is anyway) is close enough. The side plates however are an issue. As you know..you cannot have the chain riding up on that side plate like your earlier photos (low pro on standard nose sprocket) as the whole load will be point loaded on the side plate and will wear wrong and I bet...weaken it over time and cause a failure. The only thing I could think of was to mill the sprocket down to fit the low side plates. You'd have a dedicated low pro bar though.
Today...I see you've already done that...although with a burr...which I feel (as you) will wear off in a 2 minute warm up.
I think your setup is a safe go....good for you for sorting it out. I'm excited to hear about the performance. I'm going to try to figure out how to send you one of those reward thingys.

 

[mtngun]

You'd have a dedicated low pro bar though.

My new 0.050" bar will be dedicated to lo-pro. However, I can't think of any reason the modded sprocket wouldn't work with regular 3/8.

I am not aware of any lo-pro nose sprockets for milling bars other than the few that Rooshooter has for GB bars. However, I did not do an exhaustive search. My goal was to use economical, readily available components.

I assume Stihl picco nose sprockets would not fit Oregon/Carlton lo-pro, but don't know that for a fact ?

I'd like to run out and field test lo-pro today, but it may be weeks before everything is assembled and then I'll have to wait for a break in the weather.

 

[huskyhank]

How about a roller nose instead of a sprocket?

 

[DRB]

How about a roller nose instead of a sprocket?

Ya I was wondering about that to. Have not had time to look into it though.

 

[mtngun]

How about a roller nose instead of a sprocket?

Like the one in Rooshooter's pic.

Not too common in the states, though.

 

[Philbert]

Did not know what the inside of a roller nose bar looked like.

So there are 2 discs that support/rotate the links without engaging the drive link tangs like a sprocket?

I get that this would work with any pitch chain. Does this extra thickness at the nose get hung up in the cut?

Philbert

 

[mtngun]

Does this extra thickness at the nose get hung up in the cut?

That would be my guess as to why the roller nose fell out of favor. Wouldn't be an issue for an Alaskan mill, though.

 

[BobL]

I use a GB roller on my 60" GB bar.
I also use a GB roller nose on my 404 60" Stihl bar with my home made adapter plate.
Adapter made from Hardened steel plate from a circular saw on left, mild steel prototype on right.

 

[Philbert]

So, aside from the exposed fasteners you used, would/does the roller end part ever get hung up in a kerf?

Philbert

 

[BobL]

S, aside from the exposed fasteners you used, would/does the roller end part ever get hung up in a kerf?

Philbert

While the raised roller part does look significantly thicker than the bar part, the roller nose thickness away from the raised roller itself is 6.05 mm while on the raised roller section is 6.35 mm so about 0.3 mm or 0.012"

I have not used a roller nose bar on a conventional saw but I believe they are fine with 404 chain. For 3/8 they are also OK when the chain is new and it's only once the cutters are more than about 1/2 gone that it can become a slight issue.

 

[mtngun]

Carlin's statement

Finally heard back from Carlin. Remember as you read this that Carlin sells lo-pro ripping chain.

I contacted our engineering dept and they advised against running 3/8 LP on a 3/8 sprocket. 3/8 LP is actually .365 while the 3/8 is .375 so there is a dimensional difference which could cause the chain to fail prematurely causing injury or death to the operator.

20 years from now, AS members will still be debating whether 3/8 is 0.375 or 0.365. :monkey:

I replied to Carlin with pictures showing how lo-pro fits on a rim sprocket and on my modified sprocket. I don't expect them to change their tune, though. Their statements are obviously being vetted by lawyers.

I expect to have my lo-pro bar running later this week.

 

[mtngun]

Virgin Stihl 0.050" 36" bar, sprocket teeth ground down, shown with Woodland Pro Lo-Pro milling chain.

I tried to measure the kerf width of the lo-pro milling chain, but it's easier said than done. Here are my measurements, but remember the kerf measurement is not very accurate:

Woodland Pro lo-pro milling chain -- 0.253" kerf

Woodland Pro 0.063" 3/8 milling chain -- 0.312" kerf

Stihl 36" x 0.050" ES bar -- 0.190" thick

The lo-pro kerf is approximately 20% thinner than regular 3/8 chain.

The lo-pro kerf is wide enough to provide clearance for the Stihl bar, but there isn't a lot of wiggle room.

That's as far as I got tonight.

 

[DRB]

Mtngun keep up the good research

I want to setup my 356 husky with some sort of thinner kerf set up for ripping boards from cants.

 

[Kicker_92]

Do you predict that a 20% smaller kerf will correlate to a 20% decrease in cut time?

What is the angle on the milling chains? Also, do you have a way of measuring the width of the cutters? (for what they would cut at near a 0° file angle)

 

[mtngun]

Do you predict that a 20% smaller kerf will correlate to a 20% decrease in cut time ?

I hope to do some timed cuts on a cant later this week, comparing the speed to 3/8". Meanwhile, didn't someone else post lo-pro speed tests a long time ago -- it might have been Aggiewoodbutcher ?

What is the angle on the milling chains?

10 degrees

Also, do you have a way of measuring the width of the cutters? (for what they would cut at near a 0° file angle)

I'm not sure what you mean by "width of cutter" as opposed to width of kerf, but I'll try to post a close-up pic of the cutter tonight.

It is a dainty chain, no doubt about it. I wouldn't recommend it on your 880. It remains to be seen if it'll hold up on my 066.

 

[Kicker_92]

I'm not sure what you mean by "width of cutter" as opposed to width of kerf, but I'll try to post a close-up pic of the cutter tonight.

It is a dainty chain, no doubt about it. I wouldn't recommend it on your 880. It remains to be seen if it'll hold up on my 066.

I'm thinking more for the 385xp. I will be switching my Poulan 56cc to lo-pro soon, but still debating on the 385xp if it's too much grunt.

By width I meant the distance to the edge of the cutter from the centerline of the chain. So in theory, if the cutter was filed near 0°, it would make a cut that is the width of the chain.