Spray freezing crank

Browsing the internet I came up on a tutorial, and if I remember correctly, the guy froze the crank with keyboard cleaning spray from Wal-Mart.

Then he slid on the bearings ,just like that! I failed to bookmark it. Has anybody here tried that?(edited)

Re: Spray freezing crank

I don't know about that. Now putting it in the fridge and setting the bearings in the sun does work.

Re: Spray freezing crank

can’t say I’ve ever used it for that, but im skeptical of the value of freezing a crank in general.. can say i used the upside-down canned air trick for pulling dents out of a magnum tank in combo w/ a heat gun, but even there a blood pressure cuff did the heavy lifting.

Re: Spray freezing crank

Yes. Did the freezer first time around. Looking for another method since she said it stunk up the freezer. :/

Re: Spray freezing crank

Dirty30 Dillon /

Freezer + heat works flawlessly. material expansion is real and effective.

That said, while the canned air will work, I imagine just leaving something in a freezer, or bagged in a cooler with ice, works just as good without wasting a can of air and the environment.

Re: Spray freezing crank

You want canned air/duster. It's just r 134 in a different can. Works great in ur cars ac too! Cools to -60 I think

Re: Spray freezing crank

80F78117-5B7E-4738-8E16-60BD3959C06B.jpeg
80F78117-5B7E-4738-8E16-60BD3959C06B.jpeg

Your right Dirty. Cleaned it nice and pretty hidden in a empty coffee can . Also I experimented putting the old bearings in a mason jar, set it over an old Lava lamp base for 15 min. Went to 140* . I think they will drop right on.(edited)

Re: Spray freezing crank

Brandon Weiss (Detective brandon to you) /
d84c0b21-0246-4383-a3cf-8c6698d67911.gif

Re: Spray freezing crank

> Les B. Wrote:

> -------------------------------------------------------

> Yes. Did the freezer first time around. Looking for another method since

> she said it stunk up the freezer. :/

dry ice in a cooler works, or just throw it in a ziplock bag for the freezer.

Re: Spray freezing crank

> Jeff Parr Wrote:

> -------------------------------------------------------

> I don't know about that. Now putting it in the fridge and setting the

> bearings in the sun does work.

This! ^ But put it in a sealed plastic bag first.

Re: Spray freezing crank

if room temperature's 75F (298K) and it's a 17mm ID stainless steel bearing

and SS has 12E-6 m/m/K thermal expansion

Taking the expansion as linear expansion of the inner circumference

heating to 400F (477K) gives you an extra 0.12mm circumference or +0.018mm radially.

So your inner diameter expands roughly 36 micron. thats alotta extra space to slip right on!

For comparison, the shittiest bearings have an ID tolerance of around 8 micron.

With a freezer you're at roughly 0F and that gets you another 4 microns of space (+23% more room vs not freezing it)

and with the pressure release from duster you can theoretically force cool down to like -60F, which gets you to ~26 micron additional radial expansion or +42% more room.

So yeah, freeing it helps, duster helps more, but you've got more than enough space if you're just heating it to the 400F drop grease and you prolly don't need to freeze it anyway

practically I usually just heat the inner race with a propane torch and drop it on, almost always works except for user-errors. only run into issues when it gets crooked or you dont get it down all the way before the shaft heats up and the race cools down.

Re: Spray freezing crank

Yes keyboard cleaner but you have to hold it upside down. I think its the co2 that You want. By flipping the can upside down all the heavy co2 will go to the nozzle

Re: Spray freezing crank

Brandon Weiss (Detective brandon to you) /

In the gif I posted above I used a heat gun on the bearing for about 30 seconds, dropped right on. It's important to make sure there arent any burrs or debris on the shaft, and that you oil it.

Re: Spray freezing crank

Saw the dry also. Dropped right on.

Re: Spray freezing crank

> Born to be WillD Wrote:

> -------------------------------------------------------

> if room temperature's 75F (298K) and it's a 17mm ID stainless steel

> bearing

>

> and SS has 12E-6 m/m/K thermal expansion

>

> Taking the expansion as linear expansion of the inner circumference

>

> heating to 400F (477K) gives you an extra 0.12mm circumference or

> +0.018mm radially.

>

> So your inner diameter expands roughly 36 micron. thats alotta extra

> space to slip right on!

>

> For comparison, the shittiest bearings have an ID tolerance of around 8

> micron.

>

> With a freezer you're at roughly 0F and that gets you another 4 microns

> of space (+23% more room vs not freezing it)

>

> and with the pressure release from duster you can theoretically force

> cool down to like -60F, which gets you to ~26 micron additional radial

> expansion or +42% more room.

>

> So yeah, freeing it helps, duster helps more, but you've got more than

> enough space if you're just heating it to the 400F drop grease and you

> prolly don't need to freeze it anyway

>

> practically I usually just heat the inner race with a propane torch and

> drop it on, almost always works except for user-errors. only run into

> issues when it gets crooked or you dont get it down all the way before

> the shaft heats up and the race cools down.

This is mind blowing, and over my head mathematically

But if you put the crank in a lathe and grab some emery cloth you can make a lot of magic happen with how those bearings and crank journal interact ;)

Re: Spray freezing crank

Wesley Ambrosini /

> Born to be WillD Wrote:

> -------------------------------------------------------

> if room temperature's 75F (298K) and it's a 17mm ID stainless steel

> bearing

>

> and SS has 12E-6 m/m/K thermal expansion

>

> Taking the expansion as linear expansion of the inner circumference

>

> heating to 400F (477K) gives you an extra 0.12mm circumference or

> +0.018mm radially.

>

> So your inner diameter expands roughly 36 micron. thats alotta extra

> space to slip right on!

>

> For comparison, the shittiest bearings have an ID tolerance of around 8

> micron.

>

> With a freezer you're at roughly 0F and that gets you another 4 microns

> of space (+23% more room vs not freezing it)

>

> and with the pressure release from duster you can theoretically force

> cool down to like -60F, which gets you to ~26 micron additional radial

> expansion or +42% more room.

>

> So yeah, freeing it helps, duster helps more, but you've got more than

> enough space if you're just heating it to the 400F drop grease and you

> prolly don't need to freeze it anyway

>

> practically I usually just heat the inner race with a propane torch and

> drop it on, almost always works except for user-errors. only run into

> issues when it gets crooked or you dont get it down all the way before

> the shaft heats up and the race cools down.

This is wiki material.

Re: Spray freezing crank

campeona del mundo /

i've always just used heat. no need for freezer

Re: Spray freezing crank

♣Slew Foot♣ /

Me caveman me just use copper or brass hammer and long socket...

It's not rocket science it's mopeds..

.

I wanna confiscate your sliderule.

Re: Spray freezing crank

> campeona del mundo Wrote:

> -------------------------------------------------------

> i've always just used heat. no need for freezer

yeah freezer is un-necessary

computer duster is isoethane, not freon mkay. i don't think it is destroying the planet but who knows. so are mopeds and everything else.

Re: Spray freezing crank

Slew knew! Ended up with 27mm socket and brass hammer with a little heat. 8)

Re: Spray freezing crank

Why not install the bearings in the case then the crank?

Re: Spray freezing crank

Brandon Weiss (Detective brandon to you) /

> river 2strokes Wrote:

> -------------------------------------------------------

> Why not install the bearings in the case then the crank?

Aluminum expands much more than steel for a given amount of heat...you have more clearance with steel bearings going into aluminum than you do with steel bearings onto steel shafts. it's much easier to install a heated aluminum case half onto the bearings that are already on the crank and other shafts, much less likely to bind things up. Makes a big difference with something as tedious as assembling two case halves together.

Re: Spray freezing crank

Dirty30 Dillon /

I also prefer installing bearings on crank first.

Re: Spray freezing crank

Wolf Wizard /

I got a cheap toaster oven one of my club members copped from a thrift store. It can fit a v1 case half in it. I just pop the cases in there and add a drop of 2T to the bearings outer race and they drop in directly. Also with e50 cranks I’ll instead pop the bearings in the oven and line the crank a hair. Ez pz

Re: Spray freezing crank

> river 2strokes Wrote:

> -------------------------------------------------------

> Why not install the bearings in the case then the crank?

i do cases like tomos and v1 and of course all the motorcycle stuff by pulling the shaft into the bearing with a variety of homemade tubes/puller/screw majiggers, so yu have lots of time to line everything up

Re: Spray freezing crank

> Graham Motzing Wrote:

> -------------------------------------------------------

> > river 2strokes Wrote:

>

> > -------------------------------------------------------

>

> > Why not install the bearings in the case then the crank?

>

> i do cases like tomos and v1 and of course all the motorcycle stuff by

> pulling the shaft into the bearing with a variety of homemade

> tubes/puller/screw majiggers, so yu have lots of time to line everything

> up

Yep. And with NO heat.

Re: Spray freezing crank

Brandon Weiss (Detective brandon to you) /

I like using heat, mainly because I'm afraid of galling the mating surfaces by forcing something together if it's very tight. Especially on crankshafts, where the bearing has to slide past the surface that the seals ride against

Re: Spray freezing crank

Hey whatever works. I like the bearings on the crank also. You can see that they set properly. And check to make sure the crank moves freely before the next step.

Re: Spray freezing crank

My only concern when putting the bearings on the crank first is then at that point you can’t seat the crank unless you get lucky with both bearings magically seating into their journals. It won’t magically seat itself after a heat cycle either, because thermal expansion will basically lock it in place.

And even if you do install the bearings first that doesn’t necessarily mean the crank is aligned to the center of the cylinder. Yes the big and small end bearing tolerance will allow the piston to move freely, but short of that there is no real way to dead center the rod with the piston and cylinder for perfect alignment.

That’s where the emery cloth and lathe come in.

Imagine sliding a main bearing on with little friction at room temperature. More free play means faster spin up when running. Do that to both bearings and install. There is enough free play at room temperature that you can slide the crank back and forth between the bearings in the assembled crank case.

I know this sounds like a loose bucket of boots waiting to happen BUT

The motor spins at idle, the free play allows the crank to perfectly align itself in the top end due to inertia, and when the whole system gets to temp thermal expansion will lock it in place. Now you can imagine what happens when a normal bearing shaft are mated the inner race will actually expand and press the balls or needles into the outer race and cause more friction - with a little bit loose tolerance the expansion the friction is minimal on both races. Picking up what I’m putting down?

The difference in revs is 100% noticeable

Re: Spray freezing crank

Wesley Ambrosini /

> river 2strokes Wrote:

> -------------------------------------------------------

> My only concern when putting the bearings on the crank first is then at

> that point you can’t seat the crank unless you get lucky with both

> bearings magically seating into their journals. It won’t magically seat

> itself after a heat cycle either, because thermal expansion will

> basically lock it in place.

>

> And even if you do install the bearings first that doesn’t necessarily

> mean the crank is aligned to the center of the cylinder. Yes the big and

> small end bearing tolerance will allow the piston to move freely, but

> short of that there is no real way to dead center the rod with the

> piston and cylinder for perfect alignment.

>

> That’s where the emery cloth and lathe come in.

>

> Imagine sliding a main bearing on with little friction at room

> temperature. More free play means faster spin up when running. Do that

> to both bearings and install. There is enough free play at room

> temperature that you can slide the crank back and forth between the

> bearings in the assembled crank case.

>

> I know this sounds like a loose bucket of boots waiting to happen BUT

>

> The motor spins at idle, the free play allows the crank to perfectly

> align itself in the top end due to inertia, and when the whole system

> gets to temp thermal expansion will lock it in place. Now you can

> imagine what happens when a normal bearing shaft are mated the inner

> race will actually expand and press the balls or needles into the outer

> race and cause more friction - with a little bit loose tolerance the

> expansion the friction is minimal on both races. Picking up what I’m

> putting down?

>

> The difference in revs is 100% noticeable

I follow the logic but it for sure sounds like

> "a loose bucket of boots"

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