Help w/ Chain Saw Chains Please

[quercus_kelloggii]

I have a McCulloch Timber Bear.

I "believe" it to be a 20" bar, but I'm not 100%. I measure the cutting length and get 19 and a bit more inches depending on where exactly the tape measure starts/stops. See Photos!

I have three chains for it, an Oregon 72, and Oregon 76 and one marked 370, which I believe is the original McCulloch PM370G chain mentioned in the manual. (3/8" pitch, .050 chain gauge)

The manual mentions a 7/32 file for the PMG370G, I want to buy some files to sharpen the chains myself (I have an Oregon sharpener deallie that clamps on the bar. I used it ages ago and it worked good. There is no file with it currently so I'm not sure what size to get.

Also, is this a 20" bar? Can that be determined from the chains? Also, what are the different numbers? I thought it was drive teeth but if that was the case, shouldn't they all be the same.

And finally, how do I determine if they are safety chains? I imagine they are.

Thanks

P.S. I know it's not a high end saw but it hasn't failed me in a lot of cutting of black oak, ponderosa pine, incense-cedar and douglas-fir over the years. And it was my dad's saw initially, he gave me this 55cc beast.

 

[smokinj]

7/32 file Thats the file you want.

 

[Battenkiller]

Those raised humps on the tie straps between the cutters are found on safety chain. I have an old Sears gear drive saw that has a 19" bar. Yours looks like a 19" to me.

 

[wendell]

And you buy chain by the number of drive links. Some bars can be the same length and take a different number of drivers.

 

[Battenkiller]

I have three chains for it, an Oregon 72, and Oregon 76 and one marked 370, which I believe is the original McCulloch PM370G chain mentioned in the manual. (3/8" pitch, .050 chain gauge)

What do you mean by Oregon 72 and Oregon 76? These numbers should correspond to the drive link gauge. Are these numbers stamped into the bottom of the drive links? The first two numbers on Oregon chain indicate the pitch and gauge of the chain. 72=3/8 pitch,.050"ga, 73=3/8 pitch,.058"ga, 75=3/8 pitch,.063"ga. I don't know about that 76, it's not in the Oregon catalog. Anyway, if your original bar has a .050" groove (as is specified in the manual), you need to stick with the Oregon 72 type chain.

All of this information is found on pages 71-73 in the Oregon product catalog:

http://www.oregonchain.com/pro/2011Catalog.htm

 

[midwestcoast]

You did check the bar for engraved info right? It may say something like "72 DL" = 72 drive link chain which is commonly called 20", but as wendell said you buy by the # of drive links.
If no markings on the bar you'll be counting drivelinks & going cross-eyed

 

[quercus_kelloggii]

7/32 file Thats the file you want.

THank you, I bought some Oregon brand 7/32" files that I'll put to use with the 'Sure Sharp' soon.

Those raised humps on the tie straps between the cutters are found on safety chain. I have an old Sears gear drive saw that has a 19" bar. Yours looks like a 19" to me.

Thanks Battenkiller - looks like all my chains are safety chains then, hence I still have my legs and arms...

And you buy chain by the number of drive links. Some bars can be the same length and take a different number of drivers.

Wendell - all the chains I have have 70 drive links it appears. (I counted them )

...What do you mean by Oregon 72 and Oregon 76? These numbers should correspond to the drive link gauge. Are these numbers stamped into the bottom of the drive links? The first two numbers on Oregon chain indicate the pitch and gauge of the chain. 72=3/8 pitch,.050"ga, 73=3/8 pitch,.058"ga, 75=3/8 pitch,.063"ga. I don't know about that 76, it's not in the Oregon catalog. Anyway, if your original bar has a .050" groove (as is specified in the manual), you need to stick with the Oregon 72 type chain...

Well, I've attached a picture of the three chains. Yeah, stamped with a 76 and says Oregon on it. [del]So I'm confused a bit.[/del]

You did check the bar for engraved info right? It may say something like "72 DL" = 72 drive link chain which is commonly called 20", but as wendell said you buy by the # of drive links.
If no markings on the bar you'll be counting drivelinks & going cross-eyed

midwestcoast - I just cleaned off the bar and can't find anything engraved/stamped on it. It measures 22 1/2 inches in total length... I countd the drive links on all the chains I have and they each have 70, [del]so maybe that means 18" bar[/del], ETA: from what I see on Oregon's website, if I choose my saw with 18" bar, it gives me 66 drive links, if I choose 20" bar, it gives me 70 drive link chains - so this must mean it is a 20" bar (?)



Thanks everyone for their responses! Greatly appreciated.