Fitting Axles to Bearings

[AndrewK]

I've just acquired some miniature MR63ZZ 3mm inner diameter bearings recommended for the 3mm diameter steel rod axles belonging to a wagon I've just 3d printed.

My problem is how do you insert the axles into the bearings? I've just tried the sledgehammer/walnut approach (well it was a hammer!) and rendered the first bearing almost useless owing to the very tight fit.

Is there an easier way to do this? Any suggestions greatly appreciated.

 

[PhilP]

Sounds like either your bearings are under, or the axle is over sized?

Put your axle in a lathe / battery-drill.. Spin it up and use some emery paper to take a fraction off the axle. - Not a lot!
Also, make sure you have a (very) small chamfer on the end of the axle..

I would then press them on in a vice. Possibly both at once?

Our uses. apply very low forces and strains to things, So you do not need a really tight fit.

(True Engineers may baulk at that last statement)

PhilP.

 

[dunnyrail]

Best option is to use a reamer. This will get you out of trouble every time. A taper one may work a little better then the force of a vice should push things in place.

 

[PhilP]

Best option is to use a reamer. This will get you out of trouble every time. A taper one may work a little better then the force of a vice should push things in place.

I'm sure it can be done... But pray-tell how you hold/drill a 6x3x2.5mm 'ball-race' bearing to drill it? - Not having done much Engineering, I would have thought it quite difficult to hold the inner-bearing?

PhilP.

 

[dunnyrail]

I'm sure it can be done... But pray-tell how you hold/drill a 6x3x2.5mm 'ball-race' bearing to drill it? - Not having done much Engineering, I would have thought it quite difficult to hold the inner-bearing?

PhilP.

Yes I though better of the drilling option and updated my post as soon as I posted it. But of course I would use my lathe then perhaps some bodge to keep the ball race still likely using a small ba nut n bolt with some scrap that would fit between the chuck segments.

 

[trammayo]

Plus the bearings are hardened so reaming wouldn't work anyway. Another way to drive a bearing on is to have a piece of tube to the size of the inner race.

 

[JimmyB]

The engineering solution is freeze the axle (dry ice at -76C) and/or warm the bearing, not too hot to change the crystalline nature of the metal.

 

[dunnyrail]

Ok so reading the request again putting the axle in an electric drill and turning the end down using some serious emery paper ought to work. Just keep checking as you go and be very careful. Possibly best help if you can hold the drill in a vice.

 

[AndrewK]

Ok so reading the request again putting the axle in an electric drill and turning the end down using some serious emery paper ought to work. Just keep checking as you go and be very careful. Possibly best help if you can hold the drill in a vice.

With my very limited engineering skills I think my Dremel (constant motion) will help - along with the emery paper.

JimmyB - Your engineering solution is very interesting. Unless I'm called for a Pfizer vaccination in the next couple of days I will give that one a miss!

Many thanks to you all for sharing your knowledge and experience. I will update my results as soon as I can.

 

[Fred2179G]

Ok so reading the request again putting the axle in an electric drill and turning the end down using some serious emery paper ought to work. Just keep checking as you go and be very careful. Possibly best help if you can hold the drill in a vice.

I had that problem installing ball bearings in Accucraft J&S Fn3 coaches. Yes, spinning the axle in a drill and holding emory paper or other abrasive to it will make it easier.
I did squeeze the bearings on to the axles using a vise. The trick is to use a brass tube the same size (or close) as the axle so you are pressing on the center of the bearing, not all over the face of it.

 

[JimmyB]

I had that problem installing ball bearings in Accucraft J&S Fn3 coaches. Yes, spinning the axle in a drill and holding emory paper or other abrasive to it will make it easier.
I did squeeze the bearings on to the axles using a vise. The trick is to use a brass tube the same size (or close) as the axle so you are pressing on the center of the bearing, not all over the face of it.

I have used sockets, I.e. nut/bolt fasteners not electrical to assist bearings on, so a similar idea.