Best Bearing Installation Alignment Methods?

[Cantdog]

I don't know how everyone else does this but this how I do them. First I don't bother trying to freeze the bearings, it would make a difference if you used dry ice but a conventional freezer does not have the temp differential to be of much help IMHO... I have an old used electric toaster oven in the shop that I use to heat whatever parts I'm dealing with...so far this has accepted cases up through saws in the 70E Jonsereds size. The main bearings I put on the crank first....put a bearing in the oven, 200-210 degrees for 10 mins...grab with a welding glove and drop right onto the crank held vertically in a vice....by the time the second bearing is ready the first has cooled plenty so I flip the crank end for end and do the same thing...no beating, tapping etc. required, they just fall right into place. That done it's time for a case half..in the oven it goes..usually 160-180 for ten mins..pull it out and place the crank and main bearing in it...you have to not waste time as a mag case will dissapate heat rather quickly. Anyway it goes all the way in.....heat the other case half the same amount of time and when everything is ready (gasket in place and 3 screws and T handle ready) put them right together and quickly snug the screws up...now comes the beauty....the second case half will nearly always dissapate enough heat to the other side enough to allow both outer bearing races to move and you to shift the crankshaft to the center with hardly any effort. The only thing is you have to do is move swiftly and accurately...no beating, striking,pressing or tapping required and there is enough time to get the bearings centered and free spinning....this has always worked super for me......just one of many ways I'm sure..

 

[PogoInTheWoods]

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.

How to get em started 'true' was my main question in the first place. Still no answer there, but plenty of "freeze their asses off and bake the case and they'll drop right in" responses.

Gettin' ready to try that approach on the flywheel side here in a minute...

 

[Simonizer]

I don't know how everyone else does this but this how I do them. First I don't bother trying to freeze the bearings, it would make a difference if you used dry ice but a conventional freezer does not have the temp differential to be of much help IMHO... I have an old used electric toaster oven in the shop that I use to heat whatever parts I'm dealing with...so far this has accepted cases up through saws in the 70E Jonsereds size. The main bearings I put on the crank first....put a bearing in the oven, 200-210 degrees for 10 mins...grab with a welding glove and drop right onto the crank held vertically in a vice....by the time the second bearing is ready the first has cooled plenty so I flip the crank end for end and do the same thing...no beating, tapping etc. required, they just fall right into place. That done it's time for a case half..in the oven it goes..usually 160-180 for ten mins..pull it out and place the crank and main bearing in it...you have to not waste time as a mag case will dissapate heat rather quickly. Anyway it goes all the way in.....heat the other case half the same amount of time and when everything is ready (gasket in place and 3 screws and T handle ready) put them right together and quickly snug the screws up...now comes the beauty....the second case half will nearly always dissapate enough heat to the other side enough to allow both outer bearing races to move and you to shift the crankshaft to the center with hardly any effort. The only thing is you have to do is move swiftly and accurately...no beating, striking,pressing or tapping required and there is enough time to get the bearings centered and free spinning....this has always worked super for me......just one of many ways I'm sure..

You know what you are doing, nice to see. You understand how the coefficient of linear expansion works as well, bravo. Excellent post bro.

 

[ndlawrence]

How to get em started 'true' was my main question in the first place. Still no answer there, but plenty of "freeze their asses off and bake the case and they'll drop right in" responses.

Gettin' ready to try that approach on the flywheel side here in a minute...

Keep us posted!

 

[Cantdog]

How to get em started 'true' was my main question in the first place. Still no answer there, but plenty of "freeze their asses off and bake the case and they'll drop right in" responses.

Gettin' ready to try that approach on the flywheel side here in a minute...

Pogo when the bearings are on the crank and the case is heated they will slide right in...there is no reason nor room for them to be crooked..you are only generating maybe a couple thousanths clearence. If you don't have to force them and allow them slide right in "true" is pretty much a builtin feature.

 

[Cantdog]

You know what you are doing, nice to see. You understand how the coefficient of linear expansion works as well, bravo. Excellent post bro.

Why...Thank you Simon..and a tip of the hat to you as well..LOL!!

 

[TonyRumore]

I don't know how everyone else does this but this how I do them. First I don't bother trying to freeze the bearings, it would make a difference if you used dry ice but a conventional freezer does not have the temp differential to be of much help IMHO... I have an old used electric toaster oven in the shop that I use to heat whatever parts I'm dealing with...so far this has accepted cases up through saws in the 70E Jonsereds size. The main bearings I put on the crank first....put a bearing in the oven, 200-210 degrees for 10 mins...grab with a welding glove and drop right onto the crank held vertically in a vice....by the time the second bearing is ready the first has cooled plenty so I flip the crank end for end and do the same thing...no beating, tapping etc. required, they just fall right into place. That done it's time for a case half..in the oven it goes..usually 160-180 for ten mins..pull it out and place the crank and main bearing in it...you have to not waste time as a mag case will dissapate heat rather quickly. Anyway it goes all the way in.....heat the other case half the same amount of time and when everything is ready (gasket in place and 3 screws and T handle ready) put them right together and quickly snug the screws up...now comes the beauty....the second case half will nearly always dissapate enough heat to the other side enough to allow both outer bearing races to move and you to shift the crankshaft to the center with hardly any effort. The only thing is you have to do is move swiftly and accurately...no beating, striking,pressing or tapping required and there is enough time to get the bearings centered and free spinning....this has always worked super for me......just one of many ways I'm sure..

+1 That is Exactly how I do it as well. Never had a problem. Stole the process from Pioneer Guy, but he puts one bearing on the crank, then puts it in the case, then puts the other bearing on the crank, then the other case half. I'm sure that works fine as well, but for some reason it just seemed easier to do it this way.

 

[Fish]

I never even hinted that the freeze/heat thing wasn't the way to go, just said that I never saw the need to do it!!!

 

[PogoInTheWoods]

Pogo when the bearings are on the crank and the case is heated they will slide right in...there is no reason nor room for them to be crooked..you are only generating maybe a couple thousanths clearence. If you don't have to force them and allow them slide right in "true" is pretty much a builtin feature.

I hear ya and understand what ur sayin', mang. Makes all the sense in the world and I 'preciate the input. Just goin' with the "bearings in the case first" approach for the maiden voyage on doin' this.

Cases are in the oven...

 

[Fish]

I don't know how everyone else does this but this how I do them. First I don't bother trying to freeze the bearings, it would make a difference if you used dry ice but a conventional freezer does not have the temp differential to be of much help IMHO... I have an old used electric toaster oven in the shop that I use to heat whatever parts I'm dealing with...so far this has accepted cases up through saws in the 70E Jonsereds size. The main bearings I put on the crank first....put a bearing in the oven, 200-210 degrees for 10 mins...grab with a welding glove and drop right onto the crank held vertically in a vice....by the time the second bearing is ready the first has cooled plenty so I flip the crank end for end and do the same thing...no beating, tapping etc. required, they just fall right into place. That done it's time for a case half..in the oven it goes..usually 160-180 for ten mins..pull it out and place the crank and main bearing in it...you have to not waste time as a mag case will dissapate heat rather quickly. Anyway it goes all the way in.....heat the other case half the same amount of time and when everything is ready (gasket in place and 3 screws and T handle ready) put them right together and quickly snug the screws up...now comes the beauty....the second case half will nearly always dissapate enough heat to the other side enough to allow both outer bearing races to move and you to shift the crankshaft to the center with hardly any effort. The only thing is you have to do is move swiftly and accurately...no beating, striking,pressing or tapping required and there is enough time to get the bearings centered and free spinning....this has always worked super for me......just one of many ways I'm sure..

Does this same post apply to bearing/seals with rubber parts?

 

[Cantdog]

Does this same post apply to bearing/seals with rubber parts?

I have never used any of those but I would expect any seal/shield to be able to handle 200 F with no problem. If the case paint can take it I would expect the nitrile to as well. Sometimes saws get that hot too..

 

[Fish]

Very true.

I am not saying anything against the heat/cold approach, as it works very well. No denying physics here....

I just never found the need to try it myself.......

That is all.......

 

[angelo c]

Just taggin in.

 

[Fish]

But some of the guys here might go to the extreme....................................................................

Their thermometers might only read Kelvin...................................

 

[PogoInTheWoods]

Got em in. 150F didn't get close. 275F (a little hotter than the 120C spec'd by Stihl) did the trick.

They dropped right in -- as in "dropped right in". Once everything cooled down, everything seems nice and tight, tho the clutch side may need a whack or two with a deadblow to center up on the crank.

So do ya put a lot of stock in the oilpump being the alignment stop on the clutch side for seating the bearing on these 1125 cases?

Seems like a pretty flimsy approach to me.

Thanks for all your input, gang. May try bearings already on the crank for the next one and see how that goes as a comparison.

Poge

 

[PogoInTheWoods]

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

I did put the bearings in a bag for that reason. And as mentioned, I ended up at 250+ F per the Stihl recommendation of 120 C. Not much luck at 150 F for me with these particular case halves and bearings.

As for removing good bearings from a damaged case, I can only imagine that heating would expand both the bearing and the case, though maybe the magnesium at a greater rate? I used a press and an exact sized socket for removing the bearings on this project (with no heat). Took some pressure and there wasn't any gently tapping going to get them out otherwise! The socket with a same-sized washer should distribute the stress across both sides of the race to minimize any distortion if done carefully, though the old bearings in this saw were already shot, so my only concern was not screwing up the seats. Maybe someone else will chime in on their removal method. I've read not to reuse a bearing once it has already been installed due to the removal process distorting the races. Doesn't seem like careful removal would distort em any worse than freezin' em and droppin' em into a 250 degree case! Seems like a waste and I'll take a SWAG that guys reuse em all the time -- at least on a basic saw rebuild. I can see being more discriminating on higher end saw projects and bikes and sleds and such, but would think reusing a "good" OEM bearing would usually be better than using a cheap new aftermarket bearing any day.

Comments/opinions?

Poge

 

[nmurph]

The spec from the 034 SM is 120°C (248°F) for the case. It also says to place the bearings in the case first and then the crank into the bearings.

 

[Jacob J.]

The spec from the 034 SM is 120°C (248°F) for the case. It also says to place the bearings in the case first and then the crank into the bearings.

That's how I do it. The reason I use 150f is that I can still handle the case and I have the Stihl bearing installation tools. So the case isn't very hot and the
installation tool easily seats the bearing with a couple taps. That's how they're made to be used.

 

[nmurph]

I heat the cases to 220°F. I can still handle them without gloves at this temp. I pull them out of the oven wrap them in a towel. It takes me about 1 minute from the time I pull them out until I am at the bench. I already have everything ready in the shop when I land with the cases. The bearings pretty much drop in. Sometimes they require a light tap to seat them.

 

[watsonr]

That's how I do it. The reason I use 150f is that I can still handle the case and I have the Stihl bearing installation tools. So the case isn't very hot and the
installation tool easily seats the bearing with a couple taps. That's how they're made to be used.

Have any video of how to put the bearings, crank and case back together using the Stihl tools? I'm going to attempt it in a few weeks, would have been tonight if I wasn't leaving for business.