How to destroy a chainsaw

[gmax]

I bought a Oleo Mac 942 advertised as a wreck, It looks almost new until I removed the chain cover,:jawdrop:
The thread on the end of the crankshaft has been broken off, I'm guessing someone tried to remove the clutch counter clockwise with an impact gun.
An expensive mistake.

 

[Rookie1]

Thats too bad. Sometimes you have to wonder. I just fixed an 031 that somebody tried getting flywheel off and mushroomed the crank threads.
I would entertain the idea of drilling and tapping the crank to hold the clutch on.

 

[Norwegian Wood]

Are you able to get the rest of the screw out? I sometimes drill a smaller hole in the screw and put in a screw with Reich treads, when you're putting in the smaller screw the original will hopefully come out.

 

[gmax]

Are you able to get the rest of the screw out? I sometimes drill a smaller hole in the screw and put in a screw with Reich treads, when you're putting in the smaller screw the original will hopefully come out.

No screw, It's a thread on the end of the crankshaft.

 

[belgian]

No screw, It's a thread on the end of the crankshaft.

I have found a couple of nice collector saws where the thread was ruined or the shaft was broken off.... stupid wannabee techs...

Lakeside is a persistent preacher how to remove flywheels correctly, all too often he seems to be preaching in the desert...:deadhorse:

 

[gmax]

The goose who broke the thread off just lost $500, that's how much they cost
here, I have a Oleo Mac 946 with a scored piston and jug, I might be able to swap crankshafts. Big job, but its worth a try.

 

[Norwegian Wood]

Hard to explain but if you make some new treads inwards and make a bushing with treads on the outside, will that work? Can make you a drawing if my explanation is way off the line.

 

[Edge & Engine]

I've seen crankshafts break off right there just from stress from the clutch. Usually cheapo brands though.

 

[davefr]

Instead of trashing the saw could you weld on the clutch. At least the saw could be used indefinately.

Or could you drill a hole in the crack, tap it with a left hand pipe tap and secure it with a left hand bolt? However it would probably be difficult to line bore the end concentric to the shaft while on the saw.

 

[Nailgunner]

whatever you try the clutch will need to be concentric and completely normal to the crank axis. If not you'll get vibration from hell and it'll be awful.

Left hand thread remember, if you tap it. My guess is this is how it came off in the first place.

 

[Rookie1]

Thats kinda what I was thinking. Drill out end of crankshaft,tap left handed thread and use lefthanded bolt. Probably not very cost effective or practical but I would try it before I disassemble a good saw otherwise.

 

[belgian]

I've seen crankshafts break off right there just from stress from the clutch. Usually cheapo brands though.

That is the reason why I would be hesitating to weakening the shaft further by welding or further machining (thread insert, as suggested). I suppose the threaded part carries the clutch on this saw. Loosing a clutch at a few thousands of rpm could do some further damage to the saw imo...

Parting out the crank with a parts saw would be my preferred solution.

 

[jack-the-ripper]

http://www.youtube.com/watch?v=sH_v_SvAzSE

Here is another good way to destroy a chainsaw. That Homelite must have treated him very bad.

 

[pioneerguy600]

That is the reason why I would be hesitating to weakening the shaft further by welding or further machining (thread insert, as suggested). I suppose the threaded part carries the clutch on this saw. Loosing a clutch at a few thousands of rpm could do some further damage to the saw imo...

Parting out the crank with a parts saw would be my preferred solution.

Roland ;I have successfully drilled and tapped three broken crankshaft ends and not even had to remove them from the saw, left hand bolt and they are still in service. All the bolt does is hold the clutch on the shaft, all the weight was carried by the shaft and the bolt held the clutch back in place.
I have tried to break the ends off the cranks of two different crankshafts by turning them right hand with a 1/2 " Ingersol Rand impact gun with 150 lbs air pressure and all it did was strip the threads, these were ruined cranks to begin with but after reading on here that the way I remove the nuts/clutches on my saws was frowned upon by many I had to try and see how easy it was to do the dirty deed. I use a battery powered impact for all my clutch and flywheel removals and have so far never damaged a crank, I just hold the clutch or flywheel in my left hand and apply the impact driver to remove or replace the nuts or clutch carrier.

I would not weld one on the end of a crank as the cranks are hardened steel and would be prone to crystallization or even warping.
Its an easy fix most times to rethread a stripped crank end if you have or can get a slightly smaller threader in either Metric or Standard and cut new threads, I have always used fine thread for this job.
Pioneerguy600

 

[belgian]

Roland ;I have successfully drilled and tapped three broken crankshaft ends and not even had to remove them from the saw, left hand bolt and they are still in service. All the bolt does is hold the clutch on the shaft, all the weight was carried by the shaft and the bolt held the clutch back in place.
I have tried to break the ends off the cranks of two different crankshafts by turning them right hand with a 1/2 " Ingersol Rand impact gun with 150 lbs air pressure and all it did was strip the threads, these were ruined cranks to begin with but after reading on here that the way I remove the nuts/clutches on my saws was frowned upon by many I had to try and see how easy it was to do the dirty deed. I use a battery powered impact for all my clutch and flywheel removals and have so far never damaged a crank, I just hold the clutch or flywheel in my left hand and apply the impact driver to remove or replace the nuts or clutch carrier.

I would not weld one on the end of a crank as the cranks are hardened steel and would be prone to crystallization or even warping.
Its an easy fix most times to rethread a stripped crank end if you have or can get a slightly smaller threader in either Metric or Standard and cut new threads, I have always used fine thread for this job.
Pioneerguy600

Hi Jerry, I have noticed for a while you are a hands on guy who knows his stuff.

I of course agree with your method if the threaded part only carries a nut to hold the clutch drum, but not if it holds the clutch itself, which I thought to be the case here. it's difficult to judge from the pic.

 

[romeo]

I picked up a ventilation saw with less than an hour on it, broke off just like that. The fire dept. geniuses decided they could cut a Buick in half with it. You need to find a crankshaft, I wouldn't bother trying to drill and thread it.


Or you could just weld the clutch on and use it until the sprocket wears out then toss it.

 

[gmax]

Hi Jerry, I have noticed for a while you are a hands on guy who knows his stuff.

I of course agree with your method if the threaded part only carries a nut to hold the clutch drum, but not if it holds the clutch itself, which I thought to be the case here. it's difficult to judge from the pic.

The threaded part carries the clutch not a nut, tapping a thread wont work because it would have to be a smaller diameter than the thread on the clutch.
Swapping the crank is the way I will go

 

[lawnmowertech37]

http://www.youtube.com/watch?v=sH_v_SvAzSE

Here is another good way to destroy a chainsaw. That Homelite must have treated him very bad.

jack i seen that video before just to say that is not a Homelite that is a chinese plastic saw

 

[gmax]

Its all finished, I swapped the crankshaft today, runs like new again

Now I need a beer

 

[davefr]

Its all finished, I swapped the crankshaft today, runs like new again

Now I need a beer

Wow, you sure work fast!!