Dolmar throwing chains

[Franny K]

It’s a spur sprocket and I’m not in the mood to trying a rim. I am curious if it’s possible to run something other than a LP chain in the saw.

Look at the parts sheet. You have pulled the crank out of these and make all these posts and can not .......

 

[Franny K]

What about the drive method…drum clutch or rim sprocket? My preference learned about ten years ago is a rim sprocket. This year I became curious about the mechanical reason about a 6, 7 or 8-slot sprocket. I got sidetracked before I could complete the research. The logic is that certain chain sizes deserve specific slot sizes. Somebody out there help me describe this meaning and the differences. Thanks!

6 would only be in 3/8lp spur. The drive links kind of wedge in a spur similar to a nose sprocket, and/or are held out by the points of the spur at the mid point of the tie straps.. For the rim the bottom of the tie straps hold the tension and the pockets provide the drive. Unless the chain is 0.063 drivers I doubt the chain will be held in a plane very much.

 

[redhawk23]

The Husqvarna battery chainsaw and pole saw are essentially set up this way. My help was able to make the clip and washer disssapear. I run it in favor of chip clearing, no washer either a c clip for the thickness or a Makita sprocket that needs thinned a bit near the shaft. If chain throwing was much issue could buy more washer things from Husqvarna.

 

[redhawk23]

I have no reason to think the sprocket has anything to do with chains coming off. I don’t know the reason why some saws have this sprocket-washer combination and I doubt Makita engineers are available to answer questions either. One day I would like to try a rim sprocket as they are cheap to replace and don’t beat up thrown chains.

As I have mentioned above, I am a bit intrigued that LP chains have shallower drive links which allows them to be pried out of the bar more easily, I’d Iike to know about using a regular chain on this saw.
If anyone rarely throws chains, try using a small saw with a LP chain on brush (Amur honeysuckle is a good one) or dismantling recently downed green trees. Slice through a bunch of the stems on something like a honeysuckle or shove the saw in a tree top with a bunch of small branches. You might start throwing chains.

I had the saw inspected the other day and the guy couldn’t find anything wrong. I don’t think I’ve found a defect in the saw but I am wondering about some chains being more likely to be pried out of the bar: the LPs with the shallower drive links.

 

[tomalophicon]

I have no reason to think the sprocket has anything to do with chains coming off. I don’t know the reason why some saws have this sprocket-washer combination and I doubt Makita engineers are available to answer questions either. One day I would like to try a rim sprocket as they are cheap to replace and don’t beat up thrown chains.

As I have mentioned above, I am a bit intrigued that LP chains have shallower drive links which allows them to be pried out of the bar more easily, I’d Iike to know about using a regular chain on this saw.
If anyone rarely throws chains, try using a small saw with a LP chain on brush (Amur honeysuckle is a good one) or dismantling recently downed green trees. Slice through a bunch of the stems on something like a honeysuckle or shove the saw in a tree top with a bunch of small branches. You might start throwing chains.

I had the saw inspected the other day and the guy couldn’t find anything wrong. I don’t think I’ve found a defect in the saw but I am wondering about some chains being more likely to be pried out of the bar: the LPs with the shallower drive links.

All I know is mine did exactly the same thing till I changed for a modified sprocket and it never did it again

 

[Brufab]

3/8, it’s the original bar and chain the saw came with

Shouldn't the bar say LP on it? My oregon bars do that take the 91 series chain for my 40cc echos

 

[Philbert]

Shouldn't the bar say LP on it? My oregon bars do that take the 91 series chain for my 40cc echos

The gauge of the bar groove may be the same. But 3/8 low profile chain, and standard 3/8 chain, use different sprockets, due to the different shape of the drive links. So the nose sprocket would be different on the guide bar.

It should be marked, some way, but not all are.

Philbert

 

[redhawk23]

All I know is mine did exactly the same thing till I changed for a modified sprocket and it never did it again

If the sprocket is the cause A rim sprocket might to the trick as well. I’ll look at what the suggestions were

All I know is mine did exactly the same thing till I changed for a modified sprocket and it never did it again

I am not a machinist but I’ll look at the suggestions made for modifying the sprocket with washer, maybe I’ll show it it to someone

 

[redhawk23]

Can someone remind me how I’m supposed to do the washer thing?

 

[Abbeville TSI]

Its the bigger stronger bars, you could stick the stock bar in a cut or vise and twist the saw around with ease if you wanted to.
The drivers are the same size on full sized 3/8 and 3/8lp so big chain on its own wont help.
IMO the light 16 inch bars are on there for advertising as people think the saw will cut bigger wood with the longer bar but the small saws work better with 12-14 inch bars.

The Echo CS-400 I got my grandson is listed in the Echo catalogue with only the18" B&C. IMO, that is too long for a 40cc saw. However, he is tall so won't have to bend over so far when bucking.

 

[TRTermite]

is it my imagination or do smaller saws throw chains more than bigger saws; for instance, I see folks with chains hanging off 60cc saws and they’re not losing chains.

My neighboring sawmill and mine had a Logger That Ran a chain so loose there would be AT LEAST 1" of daylight on a 28" bar. Larry would start with a snug chain but seldom stopped to retension it (LAZEE) and some times the stretched chain needed shortened. He cut Cottonwood and other pallet logs for me and walnut and grade logs for the neighbor. He got started logging when ground for the Milford Kansas Damn was being cleared. A lot of lumber had to be left. He started with a hard nose bar in the 50s' .. When cutting walnut there is a lot of Bore cutting and he still had a loose chain, not many twigs (branches) but a sh#t load of buck brush to clear before the cut. Before he laid the saw sideways the chain was moving . My neighbor (and Me) still mention this every once in a while. He would use J 2095/5 or 2188 or Stihl 051, 56, 084 when I would see him logging Sometimes he used a 48" bar same slack. He seldom threw a chain. Side note he was 5ft. 6or so inches and less than 140 lbs. He logged here locally from 1969 or 1970 to 2002?(guessing from memory) My long winded comment is attempting to acknowledge "TECHNIQUE" and "EXPERIENCE" Has a place when using a chainsaw and you may not realize it but you are certainly acquiring it and yes I have read every post on this thread so far and I am still gleaning information. Thanks for starting it.

 

[Brufab]

The Echo CS-400 I got my grandson is listed in the Echo catalogue with only the18" B&C. IMO, that is too long for a 40cc saw. However, he is tall so won't have to bend over so far when bucking.

I run 14" oregon bar and have the 18" it came with. It runs both bars pretty good but I never used a pro saw before. Just old remimgtons and newer echos cs 400 590. 590 pulls a 24" bar pretty good I thought. The 400 power surprised me

 

[redhawk23]

My neighboring sawmill and mine had a Logger That Ran a chain so loose there would be AT LEAST 1" of daylight on a 28" bar. Larry would start with a snug chain but seldom stopped to retension it (LAZEE) and some times the stretched chain needed shortened. He cut Cottonwood and other pallet logs for me and walnut and grade logs for the neighbor. He got started logging when ground for the Milford Kansas Damn was being cleared. A lot of lumber had to be left. He started with a hard nose bar in the 50s' .. When cutting walnut there is a lot of Bore cutting and he still had a loose chain, not many twigs (branches) but a sh#t load of buck brush to clear before the cut. Before he laid the saw sideways the chain was moving . My neighbor (and Me) still mention this every once in a while. He would use J 2095/5 or 2188 or Stihl 051, 56, 084 when I would see him logging Sometimes he used a 48" bar same slack. He seldom threw a chain. Side not he was 5ft. 6or so inches and less than 140 lbs. He logged here locally from 1969 or 1970 to 2002?(guessing from memory) My long winded comment is attempting to acknowledge "TECHNIQUE" and "EXPERIENCE" Has a place when using a chainsaw and you may not realize it but you are certainly acquiring it and yes I have read every post on this thread so far and I am still gleaning information. Thanks for starting it.

I don’t lose chains often on bigger saws either. I own a husky 555 and at my day job I use a Stihl 362. Wondering if the LP chains on small saws is the reason; shallow drivers.

 

[TRTermite]

Post 149 and 182 DEFINATELY have my attention. Visualize the spur propelling the chain and the Drive link as a blade on an Ice Skate now visualize the rim drive supporting the chain by the bottom of the tie straps.. I will leave you to ponder the concept . Thanks FRANNY K for a good explanation on spur vs. rim. Now I know why I favor rim drive.

 

[TRTermite]

I don’t lose chains often on bigger saws either. I own a husky 555 and at my day job I use a Stihl 362. Wondering if the LP chains on small saws is the reason; shallow drivers.

I run mostly 24" on my Stihl 051s' 056Mags (and Supers) the 460s' and I do the 63 ga . The Magnum 056 always seemed to stretch a 58 ga chain before wearing out the cutters. Yhat was more than 30 years ago. Ran 404 63 ga on the 051s' before going to rim 8T 3/8 chain. I like not having different gages to keep up with. need to avoid derailing this thread, I like the most of it.

 

[TRTermite]

Post 149 and 182 DEFINATELY have my attention. Visualize the spur propelling the chain and the Drive link as a blade on an Ice Skate now visualize the rim drive supporting the chain by the bottom of the tie straps.. I will leave you to ponder the concept . Thanks FRANNY K for a good explanation on spur vs. rim. Now I know why I favor rim drive.

Next QUESTION will be is a rim drive drum available for the OPs' saw???

 

[redhawk23]

Post 149 and 182 DEFINATELY have my attention. Visualize the spur propelling the chain and the Drive link as a blade on an Ice Skate now visualize the rim drive supporting the chain by the bottom of the tie straps.. I will leave you to ponder the concept . Thanks FRANNY K for a good explanation on spur vs. rim. Now I know why I favor rim drive.

Isn’t loosing a chain initiated at the nose? And isn’t the chain more likely to be derailed if the drivers are shallow (LP chain) and more readily come out of the bar?

 

[TRTermite]

Isn’t loosing a chain initiated at the nose? And isn’t the chain more likely to be derailed if the drivers are shallow (LP chain) and more readily come out of the bar?

Yes but You neeed to imaginate more. That lil' ole LP chain is still going to be top heavy on a spur (like a big beer bellied fella like me balancing on a skate blade). And let a chain enter the top of the bar with little or no support. A RIM will keep the chain standing straight with the Blade/Bar when it enters the top of the Bar.
Most car accidents start Behind the steering wheel not the front bumper. Your point needs to be acknowledged but it is only one factor of many. If that Drive link is a skate blade and the chain gets under torque(STRESS) to fast it may very well spin out and if the chain is tilted any the ripple affect comes into play. Picture pushing a cart sideways when it is at a stand still then when it is rolling a bit and crowding it sideways, Which Way is easies?. The twig at the nose is the trigger of the derail but the rim is like a 2 wheeled wheelie bar instead of a spur being like a 1 wheeled wheelie bar. AND a rim is a better investment in the long run..
Some previous post mentioned that LP chain is borderline rated on a 40 cc saw .. Then something has to happen - stretch ,, break ,, Stretch and derail ,, ??????

 

[NSEric]

Its 20-25 bucks for a shorter bar/chain with a bigger tip which will eliminate your issues. Been there done that on 4216 poulans with the exact same bar/chain and very similar spur sprocket as your dolmar.
The rim sprocket will help too but a short bar that doesnt let the chain derail is easier and cheaper.
There's 2 ways to fix this either one will get the job done.

 

[Fatherwheels]

All I know is mine did exactly the same thing till I changed for a modified sprocket and it never did it again

Any images of this modified sprocket or information on where to get it if it can be purchased.
I read somewhere such a sprocket was available for the 35 size Makita / Dolmar saws, and it
was an update Makita / Dolmar made themselves.