Chainsaw noob needs help i.d.'ing file size for "Homelite 38" chain on a 150 Auto

[JFenn]

I've got one saw, a Homelite 150 Auto I bought at a church yard sale in 1993. I use it a little every year for some yard cleanup and cutting a little firewood, and it's always been ready to go on the sixth or seventh pull when cold, and after that the first or second pull. But the chain needs sharpening and I fear I may have been using the wrong file size -a 7/32" - and possibly making things worse. The chain has the Homelite logo stamped on the links and the number 38 stamped on the drive links. A spec page I found here - Model Profile: 150 AUTO - says this saw uses an Oregon 72 chain type. As best I can determine, Oregon 72 chains all require a 7/32" file, but that file seems like it may be too large for the "Homelite 38" that is presently on the saw. I'd like to know for certain what file size is required for this chain, and then acquire one of those field sharpening kits and learn how to use it. So if any of you chainsaw top guns know which file size I need, please reply. Thank you.

 

[Fifelaker]

Chain Saw Chain If this is the chain the 7/32 should be correct.

 

[JFenn]

Case closed.

Chain Saw Chain If this is the chain the 7/32 should be correct.

It's not that one. Actually, that webpage says that chain is for an electric saw.

Nevertheless, some further online sleuthing has produced the answer. The chain that is presently on my saw is a low profile chain that requires a 5/32" file. I have been using the wrong file all along. I could not identify it simply because I'm a noob who has not seen enough chains to distinguish it from a regular chain. I found a photo on another website that showed a regular and a low profile side by side; that set me straight. I was thrown off by both the data on the website I previously referred to, which stated "Oregon 72" was the correct chain, and also by a post by one of the moderators of a Homelite forum, who had opined that it was highly unlikely that a Homelite 150 Auto would be equipped with a low profile chain. Actually, low profile chains are apparently common on consumer grade 16" saws under 50cc like the 150 Auto.

So, case closed. I have a 5/32" field sharpening kit on the way, and if I haven't ruined the chain already, I should be throwing chips again in a few days.

 

[galde]

The 150 was equipped with standard 3/8 pitch chain. If the stock bar was equipped with a nose sprocket for 3/8 pitch chain, then the lo-pro chain would rub on the rails on the nose since its drive links are shorter. The lo-pro chain also would not properly match the teeth on the drive sprocket, which would produce rapid wear on both sprocket and chain.
EDIT: Regarding file size, 7/32 file dia is correct for the 3/8 chain until the tooth is about half gone -- the 13/64 file works better for the rest of the chain's life since the proper hook can be made without cutting down into the drive links.

 

[JFenn]

I was wrong again!

The 150 was equipped with standard 3/8 pitch chain. If the stock bar was equipped with a nose sprocket for 3/8 pitch chain, then the lo-pro chain would rub on the rails on the nose since its drive links are shorter. The lo-pro chain also would not properly match the teeth on the drive sprocket, which would produce rapid wear on both sprocket and chain.
EDIT: Regarding file size, 7/32 file dia is correct for the 3/8 chain until the tooth is about half gone -- the 13/64 file works better for the rest of the chain's life since the proper hook can be made without cutting down into the drive links.

Thank you for posting. Upon closer inspection, I believe the chain is a standard 3/8 pitch chain. So much material has worn off or been filed off the teeth of the chain, that it appeared to my untrained eye to be a low profile chain. When I was filing with the 7/32 file, the file was cutting into the drive links, so I thought I was using the wrong file. The sprocket shows only normal wear, and the rails on the end of the bar look fine.