You can bust a crank too...
I just did one that needed a breaker bar....the impact wouldn't do it. ...it came eventually
I just did one that needed a breaker bar....the impact wouldn't do it. ...it came eventually
How in the world am I supposed to get this off?
- Thread starter mtcowboy77
- Start date
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TreeTangler
ArboristSite Guru
You can. Either way can destroy a crank. I've just seen the impact result in failures more times than a bar with strong, steady, and even pressure.
There is impact, and there is impact...
Don't use the kind of impact wrench you loosen/lighten your car's wheel nuts with.
A regular electric impact driver with variable torque control (trigger action) will work best.
[edit] should have been "impact driver"...
Don't use the kind of impact wrench you loosen/lighten your car's wheel nuts with.
A regular electric impact driver with variable torque control (trigger action) will work best.
[edit] should have been "impact driver"...
TreeTangler
ArboristSite Guru
And there in is the problem. One person sees this post and uses his 3/8 Craftsman impact and another fires up his 80 gallon compressor at 175 psi and breaks out his Nascar approved thunder gun!
KenJax Tree
Terraphobic
I would love to have a nitro charged NASCAR impact that puts out 1,000 lbs of torque at 15,000 rpm
unfortunately they are only sold to race teams for $1500
unfortunately they are only sold to race teams for $1500
mtcowboy77
ArboristSite Member
Will direct applied heat damage the crank at all?
Depends on the "heat" source
Heat gun...no
Oxy/act torch...maybe.
Kroil works well for rusted stuff. Equal parts diesel/atf/acetone works great too. I've had good luck with dewalt Impact battery operated 18v guns . Never used rope. Your mileage may vary.
I use a cheap (Chinese) electric heat gun - first at 180 degrees C, and if that is not enough at 300 degrees C. Only the center portion of the clutch (the part threaded onto the crank shaft) needs to be heated - repeated expansion/contraction will eventually loosen the threads.
Anything hotter might damage non-metal parts behind the clutch (drum)...
RBurtcher
ArboristSite Operative
fearofpavement advised a 3/8" butterfly style impact. There is a very specific reason for this. Lots and lots of little impacts vs heavy torquing or major impacts that can cause irreversible damage. The 3/8" Butter fly impact is special in that forward and revers are instantaneous. If a 3/8 butterfly impact is to break a crank, skirt or maul bearings they were doomed from the start.
The nut is seized and rocking it back and forth breaks it free in tiny increments. Breaking it free back and forth allows all the stuck rust, corrosion or bonded particles some place to go besides one direction usually causing further resistance. Penetrating oil and (some) heat can help this process as well. It also allows any lubricant to work its way into the threads.
The nut is seized and rocking it back and forth breaks it free in tiny increments. Breaking it free back and forth allows all the stuck rust, corrosion or bonded particles some place to go besides one direction usually causing further resistance. Penetrating oil and (some) heat can help this process as well. It also allows any lubricant to work its way into the threads.
drf255
BAD CAD
I've always used my 1/2" impact gun with no issues. No stop though, just use compression.
Please explain how this will break piston skirts.
Please explain how this will break piston skirts.
TreeTangler
ArboristSite Guru
Rocking back and forth quickly like that is exactly what will damage a piston skirt.
TreeTangler
ArboristSite Guru
I'm hoping my point wasn't lost in my gross over exaggeration...I would love to have a nitro charged NASCAR impact that puts out 1,000 lbs of torque at 15,000 rpm
XSKIER
Addicted to ArboristSite
Better not piss rev your saws when you get them back together. The piston will rock back and forth too quickly.
drf255
BAD CAD
And the other side speaks of all the damage that can occur from a rope piston stop and heavy torquing.
So what is correct?
So what is correct?
TreeTangler
ArboristSite Guru
Not even close to the same movement.
TreeTangler
ArboristSite Guru
The best way to make sure that you are doing it correctly, is to follow that particular saws service manual.
mtcowboy77
ArboristSite Member
TT, I guess I'm kinda confused too. Not to discount your experience or information, but I don't really understand what movement from using an impact on the clutch would cause piston skirts to break. I know you're saying that it's the rocking back and forth that would do it, but if the piston is held secure in the cylinder, and you're only moving the crank a small amount with the torquing, then how would the skirts get damaged?
i imagine he is referring to the piston stop acting eccentrically on the top of the piston, putting more force fore or aft of the piston pin...therefore putting more force at the bottom of the fore or aft skirt
If your clutch bearing goes bad just put that puppy in the mail to me and don't take the chance of ruining the whole saw with that nasty impact driver. I will properly dispose of that oil leaking, environment destroying machine for you. 
TreeTangler
ArboristSite Guru
First off, if you do insist on using an impact tool on clutch removal, please forego the piston stop.
