Are All Stihl 3/8" .050 Chains Interchangeable?

[Franny K]

3/8" = 0.375
3/8"LP= 0.365
Simple math.
;-)

No they both have 1640 drive links per 100 foot roll. I think it is 0.366 or 0.367 if you work it out. The lp does have smaller drive links. The real reason they don't interchange well at the sprocket is that the center of the rivet to the sliding surface is different making a Stihl picco 3/8 sprocket larger in diameter. I would expect the nose sprocket problem to be mostly due to the different sized drive links.

 

[Franny K]

Just curious as I have no idea. Is the purpose to save wood, is the 3/8 LP a more narrow kerf ? Or, is it less load on the saw. There again, I don't mill or know anything about it.

I don't suppose I want to know to the point of making some search for threads on it. So, if it is overly deep we can skip on to how much oil to use or something.

Not on the milling aspect, I believe there could be obtained 10 degree cutters of the 63 class picco. Stihl is harder to see a max cc recommendation for their chains.

3/8 lp or Picco in Stihl (they are being legal in not stepping on someone else's trademarked term) is a much lighter chain. I think in Oregon it is for 42cc and down where regular 3/8 is good for up to 100cc. For splicing the 0.043 3/8lp uses a smaller punch for the breaker. The 3/8lp and normal 3/8 both use the same "normal punch, well according to the instructions. 1/4 like carving chain 3/8 lp and .325 use the smaller spinner anvil where 3/8 and .404 use the larger spinner anvil. Again according to the instructions.

I believe someone years ago made a chain with the 3/8 spacing but using essentially the 1/4 cutters. Now it is very common and when one says 1/4 inch chain on here many think of the mini 1/4 inch pitch 0.043 drive link 71 class stuff not the original like 13 rm or Oregon 25ap.

 

[Mad Professor]

Not on the milling aspect, I believe there could be obtained 10 degree cutters of the 63 class picco. Stihl is harder to see a max cc recommendation for their chains.

3/8 lp or Picco in Stihl (they are being legal in not stepping on someone else's trademarked term) is a much lighter chain. I think in Oregon it is for 42cc and down where regular 3/8 is good for up to 100cc. For splicing the 0.043 3/8lp uses a smaller punch for the breaker. The 3/8lp and normal 3/8 both use the same "normal punch, well according to the instructions. 1/4 like carving chain 3/8 lp and .325 use the smaller spinner anvil where 3/8 and .404 use the larger spinner anvil. Again according to the instructions.

I believe someone years ago made a chain with the 3/8 spacing but using essentially the 1/4 cutters. Now it is very common and when one says 1/4 inch chain on here many think of the mini 1/4 inch pitch 0.043 drive link 71 class stuff not the original like 13 rm or Oregon 25ap.

The Stihl picco milling chain is 63PMX, it is 63PM chain with top plate ground at 10 o like you mentioned. There seems to be a monopoly on it in the USA as Stihl dealers cannot get it.

This Stihl 63PMX chain is used on 066/660 with 36" bars milling without a problem. I don't run bars that long on my 066 as my Logosol mill won't take logs that diameter.

I do use 25" bars, and use the chains until the cutter teeth are worn out/start snapping off. Never snapped a chain.

 

[Hundred Acre Wood]

No they both have 1640 drive links per 100 foot roll. I think it is 0.366 or 0.367 if you work it out. The lp does have smaller drive links. The real reason they don't interchange well at the sprocket is that the center of the rivet to the sliding surface is different making a Stihl picco 3/8 sprocket larger in diameter. I would expect the nose sprocket problem to be mostly due to the different sized drive links.

Right. The pitch is identical. The difference in drive link depth is the source of the interoperability problem. The post I previously linked to shows this clearly.

Here are the three photos (not mine) that they included in that post to demonstrate this.

Driver link depth difference (3/8" LP on bottom left, 3/8" on bottom right)



3/8" on 3/8 LP Nose Sprocket (too deep drive link depth doesn't fit)



3/8" LP on a 3/8" Nose Sprocket (too shallow drive link depth causes sprocket teeth to hit tie straps)

 

[Mad Professor]

Right. The pitch is identical. The difference in drive link depth is the source of the interoperability problem. The post I previously linked to shows this clearly.

Here are the three photos (not mine) that they included in that post to demonstrate this.

Driver link depth difference (3/8" LP on bottom left, 3/8" on bottom right)

View attachment 1049515

3/8" on 3/8 LP Nose Sprocket (too deep drive link depth doesn't fit)

View attachment 1049516

3/8" LP on a 3/8" Nose Sprocket (too shallow drive link depth causes sprocket teeth to hit tie straps)

View attachment 1049517

Excellent illustrations!!!

Pictures of the mismatch on the drive sprockets prove the points too.

 

[Franny K]

This is the smaller chain on the two types of drive sprocket. In this case the small drive links fit into the larger holes of the upper one. I ran the mis matched set up on my 338xpt for a while. 1.7 kw 2.2 hp it worked ok kind of catchy pushing the chain back and forth, cut hazard with no gloves.