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what is this knob on my chainsaw?

paulmars

paulmars

New Member
Joined
Jan 29, 2009
Messages
4
Location
st pete FL
I found this old craftsman electric chainsaw in a garbage can. Chain was beyond dull. Got new chain and except for oil leak while sitting on shelf, it works great. However, there is this knob (red arrow) and I don't know what it does. I asked sears and they don't know and don't have the user manual and I cant find it online. It's not for chain tightness adjustment. Im sure you all already know that based on where it is, but I need to say that now to save me from having to respond to someone who might suggest that.

It can be turned in either direction as many times as you want. It never stops or gets tighter. It's got mild resistance which never changes when turning it. It is attached with set screw. I removed the set screw and knob and you can see the retaining clip below that.

I can't see any thing related to that knob by looking into the oil filler when its cap is removed. Even when looking at angle w/flashlight to try and see below the knob.

Black arrow is a spring loaded push button, below the oil filler cap. What is that for? Someone suggested it's to prime the chain after it's filled, if it ran out of oil. I doubt that.

power-sharp
model number 315.34170
sears roebuck and co
simpson-sears LTD.
 

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HarleyT

HarleyT

Tree Freak
Joined
Dec 6, 2014
Messages
17,684
I found this old craftsman electric chainsaw in a garbage can. Chain was beyond dull. Got new chain and except for oil leak while sitting on shelf, it works great. However, there is this knob (red arrow) and I don't know what it does. I asked sears and they don't know and don't have the user manual and I cant find it online. It's not for chain tightness adjustment. Im sure you all already know that based on where it is, but I need to say that now to save me from having to respond to someone who might suggest that.

It can be turned in either direction as many times as you want. It never stops or gets tighter. It's got mild resistance which never changes when turning it. It is attached with set screw. I removed the set screw and knob and you can see the retaining clip below that.

I can't see any thing related to that knob by looking into the oil filler when its cap is removed. Even when looking at angle w/flashlight to try and see below the knob.

Black arrow is a spring loaded push button, below the oil filler cap. What is that for? Someone suggested it's to prime the chain after it's filled, if it ran out of oil. I doubt that.

power-sharp
model number 315.34170
sears roebuck and co
simpson-sears LTD.
Likely just the knob/plunger to sharpen the chain.
 
CausticUC

CausticUC

Need to fix that pull!
Joined
Mar 12, 2019
Messages
441
Location
CA
Chain sharpener and lockout button.
 
Philbert

Philbert

Chainsaw Enthusiast
Joined
Nov 25, 2006
Messages
17,296
Location
Minnesota
Power Sharp. It jammed a lipstick-sized grinding stone into special cutters to sharpen them on the saw, while running. Top bevel grind.

IMG_5959.jpg
IMG_5960.jpg

Old style PowerSharp. A.k.a ‘Barracuda chain’! As @HarleyT stated (as much as I hate to admit that he is right), different, and not compatible with current PowerSharp chain. Same concept, but totally different geometries.

Philbert
 
Bob Hedgecutter

Bob Hedgecutter

Addicted to ArboristSite
Joined
Jul 18, 2019
Messages
1,289
Location
Small Town, way down South- New Zealand.
That is the get out of jail button.
If you are cutting with the saw and things go real tits up and you get into a dangerous situation that is going to hurt you or really damage the saw- you hit that button and it jumps you back in time 5 minutes, but you retain full memory of the incident, thus you do not make the mistake again.
Be warned though- you can only use the device once- so choose wisely! :innocent::ices_rofl:
 
Brad Krause

Brad Krause

That chain is SHARP!
Joined
May 12, 2014
Messages
75
Location
Milwaukee, Wisconsin
I believe the red arrow points to the oiler pump button, push once every 30 seconds. It should cause oil to enter the bar lubrication chamber in the normal location. Take the bar off and clean that area (they're known to clog), then try pumping--something like 10 pumps to prime. The oil tank has to be drained after use or the saw, like many, will gravity - feed until empty.

Use cheap bar oil from a big-box store. Do NOT use really sticky (do not use high-quality) bar oil, the chain speed isn't high enough to throw the chips and it'll clog.

The black arrow I don't know.
 
Old2stroke

Old2stroke

Never too many toys
Joined
Jan 24, 2016
Messages
738
Location
Ottawa, Canada
Button is in the wrong place to operate the sharpening stone of a power sharp, the saw has likely been converted (like most of them) to run a normal chain that actually cuts rather than scrapes. The button should be there for some sort of manual oiler, what happens when you press it down? The weird pin under the filler cap might be some strange vent for the oil tank????
 
paulmars

paulmars

New Member
Joined
Jan 29, 2009
Messages
4
Location
st pete FL
tks all. its automatic oiler, but push for extra oil in HD use. Black pin to hold missing sharpener button in position. missing the two buttons for the sharpener, which i dont need. This tool is more powerful then my other nevver ele chainsaw.
 
Old2stroke

Old2stroke

Never too many toys
Joined
Jan 24, 2016
Messages
738
Location
Ottawa, Canada
Thanks for clearing up the mystery, if you had ever used one of the barracuda chains (auto sharpening scrapers) you would know why they all get converted to normal chains and were given up by the industry as a bad idea.
 
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