Contact wheel bearing install

Kevin McGovern

Kevin McGovern

Joined
Jul 31, 2015
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I just got my 12" and and 6" contact wheels. I installed the bearings in the 12" and they went in but with more force than I thought necessary. I had used a wood block and hammer and had to use more than "light taps". Before I do my 6", is there a trick to this?
 
With wood you hit the inner race of bearing and that is not good . Use metal tube same Dia. as bearing freely but only on the outer ring.Maybe to heat little wheel ?
 
How much of an interference fit do you have? 1 thou is plenty for this. I'm assuming you chamfered the edge of the hole, if not this will make getting it started much easier.
I'm assuming an Arbor press isn't available, so what I'd probably recommend would be minimal interference (dead on the diameter to a couple tenths) and use loctite bearing retaining compound. It'll even tolerate a slight gap.

Of course this is assuming you have a lathe and are boring the wheel to fit the bearings. If not warming the wheel some, and throwing the bearing in the freezer overnight should probably do it.

One other thing I'll mention for people who haven't installed bearings before is that the thrust from the bolt holding the wheel to the arm shouldn't be on the outer race. I've seen bearings installed with a shoulder cut in the bore, and the outer race seating on that. The problem comes when you torque the bolt down it puts a tremendous thrust load on the bearing, which it isn't designed to handle. Friction will increase and the life of the bearing will decrease dramatically. The best way to do it is with a free floating spacer in between the inner races, and the outer race not being held up against anything. That way you can torque the bolt down as hard as you'd like without the bearing experiencing any extra load.

I've installed a metric crap ton of bearings, so feel free to PM me if you need any more help or a better explanation.
 
Put the bearings in the freezer. Might drop in without any fuss.

Otherwise, use a socket the same diameter as the outer race, or as already suggested, a piece of pipe, and tap them in.
 
Just noticed your other thread mentioning they came pre bored. In that case forget all the talk about interference fits and such.

Bearings in the freezer, heat the wheel (carefully) with a Mapp torch, and they should (hopefully) drop right in. Between cooling the bearings and heating the wheel, you should be able to gain 2-3 thou of clearance without too much trouble.
Using a socket or pipe won't hurt anything, but it isn't really necessary. In industry a flat plate is generally used when pressing in bearings. Tubes and such only get used when it has to go a ways onto a shaft. Bearings are ground to very tight tolerances, and if using a flat plate to press one in damages it, the bearing was defective to begin with.
 
You can use a nut and bolt and two pieces of plate with holes in them to draw them in.
 
A press is the best way, but not always available. Pressing evenly on the outer rim is important. As said, a socket can usually be found that will fit perfect.

I have used a jury-rigged press similar to kuraki's solution. Get a 1/2" bolt and nuts 3" longer than the wheel plus the bearing thickness. Get two large fender washers (or drill a hole in two pieces of plate). Find a socket that will match the bearing size. Chill the bearing and warm the hub. Assemble all together and tighten the bolt/nut heads.
 
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Alright, in an effort to dispel this common myth about installing bearings (one thing I actually know a fair bit about) I pulled out the surface plate, a test indicator, and a new skf bearing. Now it's not one of my Starrett indicators, but the result wouldn't change.


They are easily within a tenth of eachother.

Now like most myths there is an eliminate of truth to it. You never want to press through the rolling element of a bearing. However that doesn't apply for pressing a bearing into a bore. As long as your press plates are flat, there will be zero force taken by the rolling elements. Bearings have to have internal clearances internal clearances in order to function, and the inner race can move (ever so slightly) side to side. Provided there isn't a big lump right in the middle of the piece you're pushing against it with, the bearing won't even know it's not a pipe.

Hopefully this was helpful, if not feel free to do it however you like. Apart from it being easier to get the bearing in crooked, there is no harm in using a pipe or socket as long as you're careful. Personally I've seen more problems caused by using that approach though, so I choose not to use it unless absolutely necessary.
 
  1. Force should only be applied to the ring that is being mounted. ...
  2. When installing a bearing in a tight housing, force is to be applied to the outer ring only.
  3. Bearing, tooling, and mounting surfaces should be kept clean and free of all contamination.
  4. Mount bearings squarely onto shafts or into housings
 
Hundreds of thousands of Leeson motor bearings were pressed onto shafts in tooling I built that work as Geoff has described. AFAIK they're still being pressed on that way. There's no harm in contacting both races with a flat surface.

There can be significant harm in pressing only the race that is NOT being mounted, or in pressing the shield or seal. The easiest way to avoid slipping or making some other mistake that impacts the wrong race or the seal/shield is to use a flat plate across both races.

I never liked the socket idea because every socket I have ever thought to use in a press has rounded edges and tiny surface contact areas.
 
Thanks all. I cleaned up the inside of the hubs on the 6" with emory cloth and they went in easier. I used a flat Osage block and hammer.
 
kuraki said:
Hundreds of thousands of Leeson motor bearings were pressed onto shafts in tooling I built that work as Geoff has described. AFAIK they're still being pressed on that way. There's no harm in contacting both races with a flat surface.

There can be significant harm in pressing only the race that is NOT being mounted, or in pressing the shield or seal. The easiest way to avoid slipping or making some other mistake that impacts the wrong race or the seal/shield is to use a flat plate across both races.

I never liked the socket idea because every socket I have ever thought to use in a press has rounded edges and tiny surface contact areas.
Click to expand...

We've complicated a very simple thing :) We talk about small bearing .IF tolerance in housing is right , with little heat on housing ,bearing should drop inside just like that or with little tapping on outer race . These are small bearings and they don t like to be tight press in housing or on shaft .They will deform , and IF on your wheel bearing don t last long that was one of the reason .
I agree with you kuraki kuraki about using a flat plate across both races but that is must on big bearing and only in press not with hammer on plate .
 
The p,ate idea is fine, but I got into the habit of using a socket with motorcycle wheel bearings. They are recessed deeper than the edge of the hub. A plate won't work with this application.
 
" ... I never liked the socket idea because every socket I have ever thought to use in a press has rounded edges and tiny surface contact areas ..."

The reason I like a socket is you can quickly find one that closely matches the bearing/bore size. Hunting around the shop for a round plate .740" may be a bit harder.

I use the drive end of the socket against the bearing, not the nut/bolt end. It covers both races with a flat and smooth surface. I stick a 6" bolt in the socket and hammer on the bolt to drive a bearing in or out. This allows a firm grip keeps all lines of force centered. You can grind the head down on a larger bolt to make it fit a socket sixe you don't have a bolt to fit. Accuracy isn't important, as you only need to fit inside the socket.
 
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