3/8 lo pro and 3/8 sprocket differences?
- Thread starter B_Turner
- Start date
Help Support Arborist Forum:
B_Turner
Addicted to ArboristSite
Granted. Mostly I wanted to better understand the issues and thanks to all the good info in this thread I think I do more than before.
But I've added a number of small saws lately including a couple small redmaxes that are designed only to do 3/8 lo pro (only sprocket size redmax sells for them). ALthough I'll probably switch them out at least some of the time to 1/4 (aftermarket source for 1/4 drum sprockets), I was thinking of comparing them and my 339 for time with the same lo pro chain and bar.
Kind of would like to esp be able to compare gz4000 and 339 under same conditions. 40cc vs 40cc shootout.
Matt Thompson
ArboristSite Lurker
0.375" is simply the fractional equivalent of 3/8" (3÷8=0.375) and it should never be thought of as an indicator of the profile of the chain. Make sure the new chain IS or IS NOT low-profile. If you're not sure, ASK.
I'm looking at a Poulan Pro PR5030 for a third saw to have around so the girls can help with thinning the back yard out, and they list their chain in the manual as 3/8". If that sounds strange for a cheaper saw, that's what I thought. But I just asked Poulan and Jonathan T. replied back that it is, indeed, a full 3/8"×0.050"×70.
Never guess on this stuff, and if you plan on using the trial-and-error method then keep in mind that errors can be fatal. I'm overly-cautious, and I'm not a professional, but I've seen enough accidents and know enough people who are scared to death of chainsaws so I help them out whenever I can. I don't want my neighbor's kids see me, or anyone else, get hit in the face with a busted chain.
I'm looking at a Poulan Pro PR5030 for a third saw to have around so the girls can help with thinning the back yard out, and they list their chain in the manual as 3/8". If that sounds strange for a cheaper saw, that's what I thought. But I just asked Poulan and Jonathan T. replied back that it is, indeed, a full 3/8"×0.050"×70.
Never guess on this stuff, and if you plan on using the trial-and-error method then keep in mind that errors can be fatal. I'm overly-cautious, and I'm not a professional, but I've seen enough accidents and know enough people who are scared to death of chainsaws so I help them out whenever I can. I don't want my neighbor's kids see me, or anyone else, get hit in the face with a busted chain.
Brent Nowell
Addicted to ArboristSite
Holy moly... this makes things confusing, before I read this thread I had no idea there even was .365No, there just are some that call it that, to differentiate it from regular 3/8", that they call .375.
In reality the pitch of all chain called 3/8", .375 or .365
is .367.
Now I just learned that all 3/8 pitch chain is actually .367
So really we should be calling all 3/8 chains
367/1000 chains to be correct
Lol
Brent Nowell
Addicted to ArboristSite
Here’s a question, how are the bars and sprockets marked for low profile if they are both called 3/8
Call it 3/8 not .375. use 1640 drive links per hundred feet in any calculation.
I can tell by looking at a spur or nose sprocket. Stihl rim drive sprockets are marked picco if for that.
SawTroll
Information Collector
.367 (or maybe .366) would be most correct for new chain - but calling it 3/8" isn't that bad as "just a name" provided nobody is "translating" it to .375 (or calling the lo-pro variant .365, no doubt as they thought it was a "smart" way to tell that it is different - which it isn't when the pitch is about the only thing that is the same).
That train left the station long ago though, due to assorted marketing people. As usual, the marketing people knew too little about the products, and created a mess.
SawTroll
Information Collector
Picco, or just P - I have seen both (note "P-7 and "P-8 on the Picco rims to the right in the picture below).
Also note that Picco rims are larger than regular 3/8" (to the left), they have to be to compensate for the lower chassis of Picco/lo-pro chain.
Brent Nowell
Addicted to ArboristSite
Excellent thanks for the clarification, but what about husky standard spur sprockets, how do you know if one is low pro or standard 3/8? Again is the diameter larger on the low pro 3/8?
This is very similar to all the different Cali era for rifles, for example 5.56mm rounds and .223 rounds are virtually the same but case dimensions are slightly different. Both will work in a rifle chambered in .223 but due to case pressures on 5.56 should not be used in a .223 rifle. The opposite is true for 7.62mm and .308
SawTroll
Information Collector
I know of those rifle caliber differences, and the result surely is somewhat similar to the Picco/lo-pro vs. regular 3/8" issue. With the chain it sort of works using Picco chain on a "regular" drive sprocket (the chain runs erratic/sloppy around the rim though), while the other way around isn't really doable at all (at least not with fairly new sprockets and chain, that are within normal production tolerances) - with a badly worn or undersize sprocket and/or a badly stretched chain it may be doable though.
Regarding the Husky spur sprocket I don't know, except that the lo-pro spur should have a larger diameter, just like the rims. I have never used a Husky with a spur on it.
Grande Dog
ArboristSite.com Sponsor
Howdy,
All Lo Pro spur sprockets that I'm aware of are 6 tooth. If you need a Lo Pro rim with a standard spline http://leftcoastsupplies.com/product/rim-3-8lp-x7-standard-spline-gbf-gbr7l7/
Regards
Gregg
All Lo Pro spur sprockets that I'm aware of are 6 tooth. If you need a Lo Pro rim with a standard spline http://leftcoastsupplies.com/product/rim-3-8lp-x7-standard-spline-gbf-gbr7l7/
Regards
Gregg
Can't help but give this thread a thumbs up for longevity if nothing else. And while I'm at it, here's an FOP for Carlton's LP chain back in the day. Evidently .365 was close enough for them to label it as such..., most likely to simply differentiate between the FOP model numbers and obviously the two 3/8's chain types. ('N' designates LP and 'A' designates normal 3/8's)
Ok, here are the rims side by side to show the differences
SawTroll
Information Collector
Standard spline GB Picco rims have been available for some time (in the UK), but this is the first time I see them for sale in the US - and the first time I see them not carrying a "premium" price tag!
What have been totally absent in the market (as far as I have looked) are small spline Picco rims (for Husky saws etc. etc.). The Stihl rims a mini spline, and as far as I know only compatible with Stihl saws (as they come, it should be possible, although not easy, to make them fit small spline drums).
I believe Danzco made some pin type small spline ones some years ago, as I have been told so - but I have never seen them listed for sale anywhere.
SawTroll
Information Collector
Yes, I believe Carlton has to carry most of the blame for starting the very unfortunate .375 vs. .365 mess. This is just an impression I have though, I obviously don't know everything....
I see the subtle differences in the size of the drive design but they look to be the same diameter by the way you have them held in the pic.
And out of curiosity, what are those?
The lo pro is slightly larger diam. If you look at a lo pro bar you will see the blunter points on the wheel where the regular 3/8 wheel has pointy points.
It's been a while since I took those picks but think they were for an 026.
I picked the 026 in trade, it had a 3/8 bar & chain on it but the chain ran very rough no matter what I did, I finally figured out the 3/8p on the drive rim meant 3/8 picco which is Stihls term for lopro, changing to a regular 3/8 rim cured it.
I have run lo pro on reg 3/8 drive & bars, it will work but it ain't right, the other way around however does not work.
It's been a while since I took those picks but think they were for an 026.
I picked the 026 in trade, it had a 3/8 bar & chain on it but the chain ran very rough no matter what I did, I finally figured out the 3/8p on the drive rim meant 3/8 picco which is Stihls term for lopro, changing to a regular 3/8 rim cured it.
I have run lo pro on reg 3/8 drive & bars, it will work but it ain't right, the other way around however does not work.
Good examples. That’ll help him.Difference between both chains (I'm sure most are aware of this)...
3/8"LP on a standard 3/8" nose sprocket (ie: BAD!)...
Standard 3/8" on a 3/8"LP nose sprocket (ie: BAD!)...
A standard 3/8" rim sprocket will drive a 3/8"LP chain (not sure about spur sprockets though), but best to get the bar for the job. I don't think the standard 3/8" tang will fit a LP sprocket but not sure - bit too deep I think?
