Best Bearing Installation Alignment Methods?

[PogoInTheWoods]

What's the most common/best practice for aligning crank bearings during installation in case halves so they don't get cocked in the seat?

Is there a better/different method when doing it by hand with a heated case and frozen bearings vs. just using a press in the first place?

This will be my first shot at it using the heated case/frozen bearing approach -- basically by hand hoping they "just slip right in" for me like it seems to work for everyone else. I do also have a press to go that route if more precision can be obtained just forcing it into the seat.

It'll be my first shot either way and I'd sure like to have it work out a little better than my "first shot" at doing the flywheel side crank seal on an 026.:msp_tongue:

TIA as usual for any input/responses. I'm sure this has been covered and buried in the search somewhere, but it drives me nuts drilling down through all the damned clutter.



Poge

 

[sefh3]

I usually heat/freeze and drop them in. I have also used a press and have had no problems.

 

[jus2fat]

I'm confused..!!

I understand the freeze the bearing to reduce it's size..

Why would one heat the case...only would expand it..I would think..??

J2F

 

[Fish]

Yes, it expands it, and the diameter enlarges.

I have never bothered anyway, just tap the buggers in...

 

[PogoInTheWoods]

I usually heat/freeze and drop them in. I have also used a press and have had no problems.

So the contraction of the cold bearing and the expansion of the case is actually enough dimensional alteration of each to literally just drop the bearing into the seat without any pressure or anything else needed to press it home?

 

[PLAYINWOOD]

Yes, generally they fall in.

 

[jbighump]

i have always froze the bearings and heated the case works for me:hmm3grin2orange:

 

[PogoInTheWoods]

Yes, it expands it, and the diameter enlarges.

I have never bothered anyway, just tap the buggers in...

Tried the 'tap it in' approach for starters on the first one and immediately got it cocked in the seat, hence the alignment question. Popped it back out before trying to force it any further and screwing somethin' up.

This is that 036 I ended up with from the trashed clutch/oil line eBay deal gone bad saga of a few weeks ago. And yeah, the bearings were shot, too.

New bearings are in the freezer and the cases will be headed for the oven a little later. I sure hope it's as easy as everyone claims. I could use something going right on one of these projects for a change!

 

[nmurph]

Using this procedure, some bearings slip right in, some require a little tapping.

 

[Fish]

Maybe a dinner and a movie.....

 

[Jacob J.]

If you're using a conventional oven, you don't need to set the heat any higher than 150 degrees f. Ten minutes ought to do it.

The best alignment tool is a steady hand and a sharp eye. Putting saws together isn't rocket science but it does require some measure of finesse.

 

[PogoInTheWoods]

Maybe a dinner and a movie.....

That's pretty much what it's gonna take for me to get access to the oven for the YF to let me put chainsaw parts in it!

 

[PogoInTheWoods]

If you're using a conventional oven, you don't need to set the heat any higher than 150 degrees f. Ten minutes ought to do it.

The best alignment tool is a steady hand and a sharp eye. Putting saws together isn't rocket science but it does require some measure of finesse.

I read 120C in a Stihl shop manual recently. Does seem a bit excessive, tho.

And I'm workin' with one eye and the shakes, so throw finesse out the window for this rocket scientist!:hmm3grin2orange:

This is just my first complete teardown/rebuild -- of two saws simultaneously -- and I'm into both projects for more $$$ than really makes any sense except for the experience aspect. Just don't want to be dumping more caish into em 'cause I didn't take my time, ask the right questions, and heed good advice.

The input from everyone is appreciated as always.

Poge

 

[kevin j]

old style hairdryer that blows hotter air than the newer ones.
Just put new bearings in my metal cutting bandsaw electric motor this weekend. die cast end bells, not want to risk press and I don't like pounding on the shaft as that passes forces through the balls and can damage the races.

k

 

[Old Crosscut]

Poge,
I started the below thread a short while back. It's fairly short, but substantive. Hope it will help you--sure enough solved my problem!

http://www.arboristsite.com/chainsaw/191856.htm

 

[PogoInTheWoods]

Poge,
I started the below thread a short while back. It's fairly short, but substantive. Hope it will help you--sure enough solved my problem!

http://www.arboristsite.com/chainsaw/191856.htm

I read it with interest and even posted to it. Thanks.

 

[fastLeo151]

whats the correct procedure for the clamshell homeowner stihl saws?

Btw Good thread Poge!

 

[PogoInTheWoods]

whats the correct procedure for the clamshell homeowner stihl saws?

It's my understanding that you actually heat the bearings and freeze the crank -- but the bearings should only be heated to around 120 degrees F. to minimize race distortion. Slide em onto the crank till they bottom out. Let everything expand. Done.

Have a coupla clamshell disasters sitting here myself waiting to find out if it's really that easy.

 

[Fish]

I always got the tricky jobs, one of my bosses used to say, "give it to Fish, he is our best piddlephacker".....

So I was always given the jobs that someone else already boogered up.........

The bearing fitment issue trouble was almost always due to the tech getting too excited, and not willing to make sure it got started true.

I also was given all of the boogered thread problems too.

 

[Philbert]

You guys put the bearings in a plastic bag before freezing to keep them from frosting up?

120 C is around 250 F. Jacob J says 150 F. Any other opinions or experience on the heat?

How about removing bearings that you want to salvage from a damaged case? Heat them both up, or just tap gently?

Thanks.

Philbert