Another victim of Cat Quality!

[yamamarc]

Looks like the 638 did its job. Did you drill the divots on a new axle shaft, or was that your preventative repair?
That axle looks like it's in good shape.

Val you should start making these shafts with a proper fit? I am betting it would become a full time job since all cat and yamaha have this issue

I am sure someone would donate a worn shaft to you for specs!!

 

[justinator]

Testing a shaft would be hard to do since the process would have to be recorded from start to finish to insure it was done fairly in the first place. Wouldnt be hard for some numb nuts to intentionally overheat the shaft far more than it has to be. I can go in my garage right now and weld 2 different beads on a piece of steel and make one have the weld pass and surrounding steel glow orange for a minute after and one barely burn the surrounding paint. This has different results on the base metal. I think your stuck with an image of some guy and a glowing orange shaft chucked up in his lathe and its not like that. Considering some of these repairs date back to 2013 -2014 maybe the crossed fingers and prayers is the big secret that was failed to be mentioned.

 

[Mainway Solutions]

That is my original shaft I drilled it as a preventive repair to give the compound something to grip too!
The 638 is a thicker compound works well imo!
I make sure both inner race and shaft was cleaned with alcohol , then coated the shaft , seated the bearing and left it alone till the next day to make sure it fully cured

Sounds good, I'm doing a bearing change with a friend this summer if this covid thing gives us a break. I'll definitely post a pic of what i am dealing with

 

[Turboflash]

Val you should start making these shafts with a proper fit? I am betting it would become a full time job since all cat and yamaha have this issue

I am sure someone would donate a worn shaft to you for specs!!

Question is what is "proper" fit? Seems like a big question for debate? Lots of opinions. IMO, from an engineering perspective, the application needs a press (interference) fit to ensure shaft won't/can't ever spin in bearing.
BUT, that would add complexity to assembly process/disassembly process both at factory and in field. IF there is no press fit, then how much clearance is "proper" clearance between shaft and bearing keeping in mind something has to be done to lock shaft & bearing to each other. So, loctite and/or peening or dimpling or "something?" IMO, even if shaft is only a tiny bit smaller than bearing (to allow for slip fit) there's still a chance the shaft could spin inside bearing. IMO, the two must somehow be locked together. Maybe with the right "proper" fit, only green loctite would be needed? Testing would need to be done. JM2C

 

[yamamarc]

Question is what is "proper" fit? Seems like a big question for debate? Lots of opinions. IMO, from an engineering perspective, the application needs a press (interference) fit to ensure shaft won't/can't ever spin in bearing.
BUT, that would add complexity to assembly process/disassembly process both at factory and in field. IF there is no press fit, then how much clearance is "proper" clearance between shaft and bearing keeping in mind something has to be done to lock shaft & bearing to each other. So, loctite and/or peening or dimpling or "something?" IMO, even if shaft is only a tiny bit smaller than bearing (to allow for slip fit) there's still a chance the shaft could spin inside bearing. IMO, the two must somehow be locked together. Maybe with the right "proper" fit, only green loctite would be needed? Testing would need to be done. JM2C

Imo a slight interference fit or shoulder fit would do the trick with a bit of retaining compound!!
The accuracy of the machining of bearing seat on a oem shaft is all over the map from one shaft to the next. It seem like they have a -.005" tolerance in the oem design.

Removal and installation wouldn't be bad
My bearing was locked on my shaft very tight and had to use a puller and heat to get it off (because of the retaining compound)

To
reinstall freeze the shaft a bit slide the bearing/caliper on and use the caliper bolt to pull it into position


This is from a millwright's point of view

 

[Turboflash]

Imo a slight interference fit or shoulder fit would do the trick with a bit of retaining compound!!
The accuracy of the machining of bearing seat on a oem shaft is all over the map from one shaft to the next. It seem like they have a -.005" tolerance in the oem design.

Removal and installation wouldn't be bad
My bearing was locked on my shaft very tight and had to use a puller and heat to get it off (because of the retaining compound)

To
reinstall freeze the shaft a bit slide the bearing/caliper on and use the caliper bolt to pull it into position


This is from a millwright's point of view

1..Would loctite still work if applied to a frozen (maybe frosty) shaft?
2. One advantage to floating bearing is after install there is no axial preload potential. With interference fit, there is potential for axial preload since when tightening caliper bolts you're pulling/sliding the ID of bearing sideways which could result in preload after it stops. Question is how to get bearing into final location on shaft so it ends up in neutral position against tunnel while inside caliper housing.

 

[justinator]

1..Would loctite still work if applied to a frozen (maybe frosty) shaft?
2. One advantage to floating bearing is after install there is no axial preload potential. With interference fit, there is potential for axial preload since when tightening caliper bolts you're pulling/sliding the ID of bearing sideways which could result in preload after it stops. Question is how to get bearing into final location on shaft so it ends up in neutral position against tunnel while inside caliper housing.

Ive used loctite on my forestry equipment in temps pushing -30F while being doubtful it would cure but weeks or months later upon dissasembly the bolts have been tight and came out with resistance of dry loctite. Being out in the constant cold Im sure it took a long time to cure and have no way of knowing if it ever cured to its full potential........but it did seem to work well. I would like to think it would work and cure much better in a situation like this as the shaft would return to room temp quite quickly. Oddly enough on the bottles I have at home theres no mention of “operating temp”, just temp required for removal.

 

[yamamarc]

1..Would loctite still work if applied to a frozen (maybe frosty) shaft?
2. One advantage to floating bearing is after install there is no axial preload potential. With interference fit, there is potential for axial preload since when tightening caliper bolts you're pulling/sliding the ID of bearing sideways which could result in preload after it stops. Question is how to get bearing into final location on shaft so it ends up in neutral position against tunnel while inside caliper housing.

I am talking shoulder fit or slight interference
Yes the retaining compound will set once the shaft is at Ambient temp!
There wouldn't be enough resistance to worrie about axial preload! The amount of tunnel flex on these sled probably wouldn't allow axial preload on the bearing..lol ! You hear of guys using a ratchet strap to get the retaining clip in the groove all the time!!
If we were talking about let say .003 interference fit then it's a different story

 

[Sevey]

Not sure what I don't understand about what Sevey said about a snap ring? There is a ring on the track shaft just inside the brake-side bearing. I don't understand how a snap ring would help fix the bearing ID to the shaft.

Often a snap ring on the shaft will pinch the bearing’s Id helping bind it to the shaft
Ms

 

[cannondale27]

Should be .0005 smaller than bearing ID and then use BOP wedge. Good luck finding a new shaft of proper size. They exist but not many.

 

[Mainway Solutions]

Val you should start making these shafts with a proper fit? I am betting it would become a full time job since all cat and yamaha have this issue

I am sure someone would donate a worn shaft to you for specs!!

Thanks for the invite but that would take some doing i think, The wedge seems to be the answer to some of these clearances. Peening the axle prior to installing and using bearing retainer will work as well. In my opinion proper fit would be ±.0015 this range of fit would allow a reasonable amount of press fit and still allow a slide fit with retaining compound. Either way i would use some retaining compound. The bearing width is only 16mm , I wouldn't want that shaft to float at all
I haven't personally measured the two mating surfaces but from a few of the measurements posted on TY there seems to be as much as .0097 clearance
Like i said when i help my buddy do his this summer i'll post my findings

 

[stevewithOCD]

That is my original shaft I drilled it as a preventive repair to give the compound something to grip too!
The 638 is a thicker compound works well imo!
I make sure both inner race and shaft was cleaned with alcohol , then coated the shaft , seated the bearing and left it alone till the next day to make sure it fully cured

This may work for some as they may have a better tolerance to begin with.
It did NOT work for me, Knapp or Rockerdan to name a few. These guys are NO joke.

I think as MrSled aka: Tom the Blade said; as soon as it gets home he has it sprayed & fit, would be the BEST solution.
I have a hard time spending this kind of money to get a sled in October to December and tear it apart to try to get these repairs done.
Just puts a BAD taste in my mouth.

I guess i could buy a shaft in advance & have it ready so the first weekend i can replace it. Then i'd have a spare ready to go.
Still a BAD taste in my mouth.

 

[stevewithOCD]

I've asked this question before.
Has anyone tried the Black Diamond shaft sold by Hurricane?
Does it have a better fit?

 

[Turboflash]

I am talking shoulder fit or slight interference
Yes the retaining compound will set once the shaft is at Ambient temp!
There wouldn't be enough resistance to worrie about axial preload! The amount of tunnel flex on these sled probably wouldn't allow axial preload on the bearing..lol ! You hear of guys using a ratchet strap to get the retaining clip in the groove all the time!!
If we were talking about let say .003 interference fit then it's a different story

ISO/ABEC recommended interference fit for heavy shockload on ths size bearing is only .0005-.0007" which isn't much. Under no circumstances would a .003" even work. Way too much. So even with my .0005" interference, I had to use my press tool to get bearings on. Remember I have interference fit on both sides. On my sled, I had evidence of shaft spinning inside even chain case side bearing. Both sides are .0005-.0007". From a manufacturing perspective, it would be difficult to control an interference fit less than a few .0001" or less. They can't even control a few thousandths.

 

[yamamarc]

I've asked this question before.
Has anyone tried the Black Diamond shaft sold by Hurricane?
Does it have a better fit?

I beleive Bram used a bdx shaft and it sheared on the chaincase side but It was the aluminum shaft!! I think they make a stronger steel shaft also? It would be definitely something to look into