Changing to a larger bar and chain

[Al Slitter]

I purchased a Chinese chain saw it came with a 11.5" bar and chain and it works well. Because I want to run this saw for milling of wood I want to increase

the bar and chain length to 18" or 20".

I purchased on line a 20" bar ( .325 058 gauge 76DL chain) and a chain to match. When I tried to set it up and started to tighten up the chain the chain locks up.

I then purchased a 18" bar and chain (0.325" .058" Gauge 72DL) and the chain locked up as well.

I am now starting to believe that the movable sprocket might be the issue. The specifications for the 11.5" bar and chain is 3/8" .050 43DL .

I am hoping the some might have a inexpensive solution as I have been purchasing things but am no longer ahead.

[Steve Bullman]

Yes you need the right size sprocket at least. Unlikely that saw is going to run an 18” bar too well if it came with an 11.5 as standard...as for milking with it, I expect you’ll be on a hiding to nothing 

[outonalimb]

"as for milking with it, I expect you’ll be on a hiding to nothing "

Totally agree with the above statement.

 

Milking with a chainsaw is NOT recommended.

 

[bmp01]

Err ...chain pitch. ... 

Just because life is what it is and not simple or straight forward there are several pitches of chain. The common ones: 3/8 Low profile, 0.325 and 3/8 std. There are others: 1/4 and 0.404  The pitch is the distance between rivets, measured in inches.

 So you originally had 3/8" (probably low profile) and you've bought 0.325" bar and chain. The drive socket, bar sprocket (if there is one) and the chain all need to be the same pitch. 

Typically, one would buy the approprite bar and chain to suit the drive sprocket and save the hassle of swapping sprockets. 

Also worth considering,  a 0.325 chain will be bigger than a 3/8 low profile chain - taller, wider cutting teeth which require more torque and power from the engine. The length of bar is a consideration too but if you are milling you will not be using the full length of the bar so maybe ok in a hobby milling type application. ..but don't expect rapid progress.

 

 

 

 

[Silverhooker]

I don't mill much, but what is the cc or power out put of the saw ? As an11. 5" bar will only be good for milling kindling ! I alway thought that big high torque saws with big bars was what was needed to mill.

[topchippyles]

3 hours ago, Steve Bullman said:

Yes you need the right size sprocket at least. Unlikely that saw is going to run an 18” bar too well if it came with an 11.5 as standard...as for milking with it, I expect you’ll be on a hiding to nothing 

I think you do it on purpose sometime steven ?

[Rough Hewn]

I would strongly advise getting a proper chainsaw for milling.
A Chinese saw will not last long.
Especially if you put a bigger bar on it.
You could get a large second hand saw off eBay or ask on here?
[emoji106]

[Wonky]

As saw that has and 11.5 inch bar and chain is probably about 35cc 

 

if you want to run a 18 or 20 inch bar and chain you'd be looking at a 50 or 60cc saw

and thats for cross cutting wood. Milling is a lot harder on a saw and a lot slower.

depending on what you plan to do will dictate what saw  you need.

 

now I’ve not said anything about chain pitch  etc.  I will say like others you can’t mix them thou. 
Either you need to ask a lot of questions or you need to do a lot of reading.

also knowing how to file properly the chain really helps.

 

I wish you the best, if you succeed it will be an awesome feeling

??

 

[Stubby]

4 hours ago, Silverhooker said:

I don't mill much, but what is the cc or power out put of the saw ? As an11. 5" bar will only be good for milling kindling ! I alway thought that big high torque saws with big bars was what was needed to mill.

Google the specs for the saw if you can but , as others have said its probably a " home owner " small capacity saw . Rule of thumb .. Take the cc of the saw and divide by 3 gives you max bar length in inches .   E.G. 60cc saw can use a 20" bar max .   20 X 3 = 60 .

[Al Slitter]

First off I want to thank everyone who took the time to respond.

OK what you do not know and fail to understand is that I am retired and live in Thailand. Here the government has draconian laws about blade length and HP rating. The government will not allow any saw to be imported that has a bar length of more than 11.5" regarding the motor the HP output must be below .9 of a HP.

Well how dos this work? First off a chain saw of let us say 50cc's would normally come from outside the country and the manufacture or consolidator wouds swap out the 18" or 20" bar for a 11.5" to meet import requirements. The second is is the HP rating which has to be below .9 HP. This is done by the consolidator adding into the saw a re-stricter devise into the air flow thus lowering its performance to below the .9HP maximum rating. Once the model is approved and is imported many resellers her simple remove the re stricter and the HP then reaches the level it was intended to achieve. With the blade length All saw are sold with a blade length of 11.5" As an owner failure to operate or own a saw with a longer blade is punishable by a jail term. The police are not set up to check the HP rating so the risk comes with travelling with a saw with a bar of more that 11.5"

The irony here is that longer blades are readily available for purchase but the risk is on the owner not the store.

 

OK about my saw is is a 50cc saw, producing 2Kw of power which equates to 2.7HP, when I bought this sa the seller lied to me and stated that the saw produces 3.5HP. The model number of the saw is DD-5880 which leaves one with the impression that the saw is 58cc and at this mark would yield an out put of near 3.5HP. Getting back to my issue and my options as I have in my shop new 20" bar and 3- 20"0.325" Pitch 0.058" Gauge 76 DL (Peco Style or Low Profile).

The cheapest option is changing out the sprocket and once that works looking at an option to see if the existing 11.5 chain and bar can function with the larger sprocket. If not I will then have to acquire a new bar and chain.

One last point I will be doing an extensive muffler modification which should yield an approximate 25% increase in horse power. In addition I will then be looking at doing a conservative engine porting job which should add additional HP. If I had a choice I would simply purchase a new 70 to 80cc chain saw but due to government rules the saw would not be allowed into the country.  Sad Sad Sad!