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Do I need a special machine or tool for this bearing?

Posted: Nov 27 2020 9:40pm
by ebike11
Hi guys
I have an extra qs205 side cover that i may paint and install but it came from qs without the seal and bearing.
If i order these parts can i use simple hand tools to i stall them? I have access to a bearing press or heavy machinery.
Thanks!

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 27 2020 9:54pm
by markz
I installed a new bearing on my mxus 3kw
All I did was take the existing bearing to a transmission parts shop and they matched the numbers.
To put it back in I just made sure it was always level, used a hammer and a block of wood.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 27 2020 10:16pm
by ebike11
markz wrote:
Nov 27 2020 9:54pm
I installed a new bearing on my mxus 3kw
All I did was take the existing bearing to a transmission parts shop and they matched the numbers.
To put it back in I just made sure it was always level, used a hammer and a block of wood.
Hi..im not sure of the qs205 bearing but wood and hammer is at least what i have haha

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 27 2020 10:51pm
by markz
It is the most common way to "press" something into something else. Another way is a U-clamp, bench vise, car jack after a certain friction level is met, an actual mechanical or hydraulic press but the hammer method is commonly used in automotives. Just always make sure its all level, so hammer and look, hammer and look not that its really that critical in a cover plate bearing, the key is once you feel it is set, look at the final product and see that its level.

edit - I have also seen tv car mechanics use a freezer as cold shrinks metal and heat expands metal. Freeze the bearing, and slip it in. Still problems, heat the cover plate. But the tolerances and interferance rates arent that precise with hub motors.

ebike11 wrote:
Nov 27 2020 10:16pm
Hi..im not sure of the qs205 bearing but wood and hammer is at least what i have haha

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 12:46am
by MadRhino
Hammering a bearing is not recommended. You can hammer out the old one, but you should press the replacement.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 1:36am
by motomech
Markz touched on it.
Freeze the brg, gently heat the cover, use the correct size socket on the outer race. You shouldn't have to strike it very hard.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 3:18pm
by 999zip999
Yes a right size scoket is key for the outside race and not on bearing in the center or the inner race.
Only for other race. Squared up make sure the covers level and it's an easy job yes all the old-timers would freeze a bearing stick in the freezer. Even heat in the oven the cover 150 degrees. But not needed. If it's too hard to set the bearing then it is probably a bit crooked.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 3:47pm
by Warren
markz wrote:
Nov 27 2020 10:51pm
I have also seen tv car mechanics use a freezer as cold shrinks metal and heat expands metal. Freeze the bearing, and slip it in. Still problems, heat the cover plate. But the tolerances and interferance rates arent that precise with hub motors.
Wow! Thanks for the flashback. That is what we old machinists call a shrink fit. All you need it a hot plate, and a freezer above your 'fridge. Oh! And heavy leather gloves.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 4:08pm
by markz
MadRhino wrote:
Nov 28 2020 12:46am
Hammering a bearing is not recommended. You can hammer out the old one, but you should press the replacement.
You are right but that is ideally, be nice to always do things ideally but thats not the way things work out. For a more precise fitment, a press 100% but ebike cover not that precise.
If you dont use a lot of force and not pound on it hard and just use light taps going all the way around the bearing, using something softer then hammer head steel on bearing and it goes in should be fine. Ideally a press, but tapping it is fine.

Find a socket the right size is a common practice to use to hammer bearing in.

--------
Temperature

You can use anything, a big construction blow torch, a plumbers blow torch, a normal kitchen stove, a mini toaster stove, sometimes even just the sun heat, other times the time of day helps, even if you tarp an area and use btu heater, a little fire and place object next to it or in flame or in coals, place object on stovetop coils, place a brick in boiling water pot and object on brick so no heat shock, heck I bet even a lighter would do the trick for a small hub motor cover plate bearing. But in all honesty, you shouldnt need to take advantage of temperature. You also need to remember what exactly is made up of what you are trying to heat up/cool down. Different styles of bearings might damage if heated.

For making things cold. In colder climates just having the items outside in the snow over night or for days and days. Your kitchen freezer, your storage freezer, your garage beer fridge freezer, liquid nitrogen if you want to get fancy.

Warren wrote:
Nov 28 2020 3:47pm
Wow! Thanks for the flashback. That is what we old machinists call a shrink fit. All you need it a hot plate, and a freezer above your 'fridge. Oh! And heavy leather gloves.

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 4:46pm
by MadRhino
A simple bolt with 2 big washers can press fit a new bearing in a hub motor cover. No special tools required. Hammering a bearing is not dramatic. It will work, but it is likely to have a shortened life. Cheap bearings stand hammering better than high precision, heat resistant bearings. The more precise it is, the stiffer the seals, the more carefully it does need to be fitted. The fact is, most hub motors are coming out the factory with 6$ bearings. But when the time comes, most of the time we end up replacing them with much better ones, and those deserve proper installation in order to have the full benefit of their cost. Let’s put it that way: if you spend 75$ for a bearing, better use your brain than a hammer to install it. :wink:

Re: Do I need a special machine or tool for this bearing?

Posted: Nov 28 2020 5:42pm
by markz
Yeah your right on that part, I instantly thought some pressing machine but theres other ways.
That washer, bolt and nut idea is a classic, I've done that many times. Even be done with headset or bb on bike. The c-clamp press I've done on auto brake calipers. Lots of ways to skin the pressing machine cat.