Case Bearing Installation

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is this a flat rate type job? 150 seems cheap for the amount of time spent...I gotta assume this takes a min of 2 to 2-1/2 hrs. cool thread, thanks for sharing

You are welcome to pay more. :)

It's only worth so much to revive an old saw.....

We do very few that are that ugly, but we split several a week for rebuilds.

Flat rate in a way... this type of work is probably "cored and used or charged accordingly".

I bet Mastermind and his Guy(Randy and his Son In Law, but I wont pretend like I know them... "Randy" just gets thrown around lots on this site) can hammer a pro saw apart and back together in record times.

$150 price might seem cheap to us but I cant imagine it being all that difficult OR time consuming if you know what you're doing. Its all tricks of the trade. As an ex driveshaft builder and engine building apprentice, there are so many tips and tricks to be learned to make a job go FAST and PERFECT it'd make ones head spin.

It's threads like these though that spill the beans...Combined with what I already know mechanically, I am going to take what this thread has shown me and rebuild a pro saw.

It will take me many more hours than Randy and Jon can get it done, but with these tricks of the trade being handed out for free I should be able to get it done without grenading anything.

Thanks Mastermind!
 
While there certainly are a few true "craftsman/artisans" out there worth every penny while building amazing saws, nothing to do with a single cylinder two stroke on soft metal cases is rocket science. I'm just a hobby type as many who visit places like this. I do bearings for my saws and for my very small set of customers. ( Can't/Won't take on any more than I have ) Even so, seems like splitting cases and replacing bearings & seals is a weekly event any more.

It's a mix of heat differential and pressure. Less heat difference between bearings and cases means more pressure or trauma to put those bearings in. Or More heat difference is less pressure. Of course the "upper" limit on the heat has to do with the materials exposed to the heat. Simple as that. How you get that mix is dependent on the tools at your disposal. Did a video years ago using a wood stove, made fun of the "red neck" approach or extreme field conditions but made the point it's about physics.....many ways to skin this cat.

I use one of three things...a turkey roaster, a hot plate, or a heat gun. Key to for me is nylon vs steel, stuff still on the cases or bare cases, is it my hobby saw or customer saw, it's the mix of those factors defines approach and temperature 4 me.....SO beginning of this first video, or end of the second covers the "least traumatic approach" assuming bare cases and a higher temp.

I guess the only caveat for me is when installing nylon caged vs. steel cages. Not really "scientific" and I'm not even certain is matters, just what I do. But when installing the nylon's; I chill the nylon caged bearings and keep the case temps in the 275 plus a bit but under 300, then chill the assembly really quickly after installation where as with the steels, I leave the bearings room temp and heat the cases to somewhere in the 300 plus range. Temps don't bother them as much and having less "tapping" or pressure with the higher temps as shown in these video's is less stressful on everything involved. SO showed lower temps with a heat gun with a little tapping. Not optimal but not enough to hurt anything either, do this if all the chain brake stuff is still on, a quick and dirty approach. And also show the higher temps with steel caged where you literally can drop them in.

Done some derivative of this set of approaches since the 1970's with motorcycle cases as well, pretty much anything with a press fit or interference fit bearing in Aluminum or Magnesium.

For those who need visualization, While these video's are really about 372's and the many versions, they also covers replacing bearings. The first minute or so in the first video...then just ignore the rest and jump to minute 20 the second one and ignore the rest.



jump to minute 20 on this video
 
While there certainly are a few true "craftsman/artisans" out there worth every penny while building amazing saws, nothing to do with a single cylinder two stroke on soft metal cases is rocket science. I'm just a hobby type as many who visit places like this. I do bearings for my saws and for my very small set of customers. ( Can't/Won't take on any more than I have ) Even so, seems like splitting cases and replacing bearings & seals is a weekly event any more.

It's a mix of heat differential and pressure. Less heat difference between bearings and cases means more pressure or trauma to put those bearings in. Or More heat difference is less pressure. Of course the "upper" limit on the heat has to do with the materials exposed to the heat. Simple as that. How you get that mix is dependent on the tools at your disposal. Did a video years ago using a wood stove, made fun of the "red neck" approach or extreme field conditions but made the point it's about physics.....many ways to skin this cat.

You got it. I can think of at least a few ways ways to split and reassemble a bottom end without a specialized tool and probably a few more ways if custom tooling is an option. How many and what kind of tools you have available is going to be the deciding factor to get the job done.

At bare minimum I'm thinking all one needs to re/re a bottom end is a way to peel the bearings off the crank(if replacing), a 32oz ball peen hammer and an assortment of deep sockets and/or old races to use as drivers/supports and a brass hammer/drift. Using heat OR special pulls and presses is definitely the cleanest way to approach the job. Quickest could be argued. Depends what you're set up for.
 

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