I have a 12mm shaft that i want to use as an axle, as well as two matching bearings with ID=12mm. I have tried to see if i can slide the bearings onto the shaft, however it only makes it a few centimeters before it becomes impossible to move by hand. I hear that using force/a hammer is a bad idea as it may damage the bearing. What is the preferred method to slide a bearing onto a shaft? Should i maybe get a bearing that has a slightly large ID? Or maybe there is a type of bearing that is easier to slide than being press fit?
If the bearing is easily slipped on the shaft, then the inner part will spin on the shaft, rather than the bearing turning. Bearings are pressed onto a shaft or axel using a press of some type. Just hand pressing doesn't work.
Paul
Is it something that can be found in a hardware store? A one size fits all kinda deal?
You may be able to heat the bearing to expand it enough to fit onto the shaft. Freezing the shaft, as well, can help.
fleetscut:
Is it something that can be found in a hardware store? A one size fits all kinda deal?
Not really. How long is the shaft/axle?
I have in an emergency used a wrench with an opening a bit larger than the shaft to set on the inside of the bearing and then tap on the wrench handle, close to the bearing, and that is enough to move the bearing. Sounds like the shaft OD and bearing ID are close to being the same size.
Do you have a bench vice that can be opened to more than the axle lenght?
Paul
Shaft length is around 30 cm. Ill try what you suggested with the wrench. Im guessing a similar technique can be used in the event of needing to replace the bearing? Im also wondering if it might be worth it to get a bearing that is only slightly larger, like 1mm bigger in diameter and using shaft collars to keep the bearing from sliding.
I am also thinking of trying to get a bearing with a much larger ID and 3D printing a sleeve that i can use as a bushing.
I guess we have not established the type of bearing you have there. I was assuming ball bearings. But perhaps not. You keep trying to make a sleeve bearing, so I am confused.
Paul
I have a shielded ball bearing similar to this McMaster-Carr (though i got them from a local place not online)
If you can get a steel sleeve with an ID a little bigger than 12mm so that it fits easily over the shaft and presses ONLY on the inner ring of the bearing you can use a hammer on the sleeve to move the bearing with little risk of damaging the bearing.
If the "machine" is not going to be heavily loaded it may make things easier if you rub the shaft with fine wet-and-dry paper (to reduce its diameter a tiny bit) and then very thoroughly clean ALL the debris from it before trying to fit the bearing. The difference in diameter between a tight fit and a just-about-sliding fit can be very small.
Putting the shaft in your freezer for an hour or two may also help - but could also result in the bearing being stuck fast in the wrong place when the shaft warms up.
...R
Get a length of tubing that is slightly larger bore than 12mm (say 1/2") and use this as a drift to press the bearing on - if necessary you can use a hammer to strike the tube. Providing you only apply force to the inner (solid) section of the bearing, via the tube drift, you will not damage the bearing.
What does damage bearings is pressing on either the metal/rubber shields or the outer ring. The first bursts the seals and damages the balls/rollers and the latter damages the balls/rollers.
fleetscut:
I have a 12mm shaft that i want to use as an axle, as well as two matching bearings with ID=12mm. I have tried to see if i can slide the bearings onto the shaft, however it only makes it a few centimeters before it becomes impossible to move by hand. I hear that using force/a hammer is a bad idea as it may damage the bearing. What is the preferred method to slide a bearing onto a shaft? Should i maybe get a bearing that has a slightly large ID? Or maybe there is a type of bearing that is easier to slide than being press fit?
- is the shaft precision-ground? If not its not really suitable for bearings.
- An arbor-press is the normal tool for pushing bearings etc onto and off from shafts.
- Bearings should be a tight fit, certainly tighter than can be moved by hand.
[ And 4) Hammering a bearing ruins it - always press-fit ]
MarkT:
[ And 4) Hammering a bearing ruins it - always press-fit ]
That is a counsel of perfection.
If the OP is just making a "toy" that will get little use he can take a more relaxed approach.
...R
By that argument a bearing would be an unneeded luxury and a nylon bushing would serve.
Hammer blows are likely to damage the bearing surfaces which will then rapidly deteriorate.
Pressing a bearing takes accurate alignment which hammer blows seldom provide, leading to raising
an edge on the shaft, making it harder to get the bearing further on...
Ill go to the hardware store this weekend and see if i can find anything that can be used to press the inner race. I like the idea of using a pipe or piece of tubing. This is just for a home project, nothing that needs to be high precision so from what i can see something to push the inner race, and a hammer seems like it will work.
MarkT:
By that argument a bearing would be an unneeded luxury and a nylon bushing would serve.Hammer blows are likely to damage the bearing surfaces which will then rapidly deteriorate.
Pressing a bearing takes accurate alignment which hammer blows seldom provide, leading to raising
an edge on the shaft, making it harder to get the bearing further on...
All of that is true.
But it would not prevent me from using a hammer carefully (or not, depending on how frustrated I became).
My first preference would be to try to reduce the shaft diameter and, if necessary, glue the bearing in place.
...R
I bought something like this a few years back: https://www.harborfreight.com/12-ton-shop-press-33497.html
It's a big piece of machinery for a relatively small price. (How do they ship it here for that price?) It really only does one job: pushing bearings. But it is absolutely the right tool for that. Since I bought it, I've found a lot more bearings that need pushing where I would have used a hammer before.
Something that took an hour of careful hammering is now just a few pumps on the lever.
MorganS:
I bought something like this a few years back:
Impressive.
...R