Replacing bearings in an aluminium pulley

[brewdexta]

I'm replacing the bearings in my Viceroy wood lathe, initially it sounded fine so I didn't bother, however once I had the VFD in place, the motor was struggling at low revs, even though you get less torque at lower revs further investigation revealed that the drive train wasn't what it could be.

The headstock bearings came out fine and although needing renewal, they weren't too bad, there was evidence they had been replaced before. However the bearings in the intermediate pulley are FUBAR, they are quite gritty and have loads of rolling resistance.

Here's a diagram of the pulley from Denford, the shaft has a 6205-2Z bearing on each end held in with circlips. The shaft thickens in the middle therefore I have to take the shaft and bearings out of the pulley block then pull the bearings off the shaft.

Here's a picture of each end of the pulley block with the circlips removed

I stuck the block in the oven at 120c for 10 minutes, hoping the greater thermal expansion of aluminium would give the press a chance. Here it is in the fly press, a bit of scaffold pipe protects the shaft and pushes the force directly onto the bearing

I gave it a bit of a thump on the fly press and no movement and its a big old press. I tried in both directions just in case there is a shoulder not shown on the diagram.

I don't want to damage the pulley block so I'm being a bit careful. I could turn the heat up a bit, any tips on how to get the tinkers out of the block without damaging it?

Cheers
Andy

 

[Ton-up]

Looks like you are trying to push the bearing through the pulley using the pipe!!

just push on the shaft which should push the shaft and the bottom bearing through the pulley and leave the top bearing in place.

 

[mechman]

Andy
I could be wrong here but it looks like you have to press the shaft out first taking one of the bearings with it then press the other bearing out the opposite way, maybe someone else can verify this before you go ahead.

 

[Spark plug]

Looks like you are trying to push the bearing through the pulley using the pipe!!

just push on the shaft which should push the shaft and the bottom bearing through the pulley and leave the top bearing in place.

That’s what I was going to say, then turn it over and knock the other bearing out with a punch.

 

[brewdexta]

Looks like you are trying to push the bearing through the pulley using the pipe!!

just push on the shaft which should push the shaft and the bottom bearing through the pulley and leave the top bearing in place.

That makes better sense, I shall give that a go next. Pulley back in the oven until tender

 

[RonA]

As above, try putting pressure on the shaft. Additionally alum alloy never make a happy combination for corrosion, try putting some plus gas round the bearing alloy interface. As you stated more temperature might make a difference, try a blowtorch on the pulley.
RonA

 

[frank horton]

looks like u need to remove the shaft and then push the bearings OUT.......normally a long'ish heavy rod/bar from one side to push the other breaing out then reverse it, a tapping stick will do it, easy....I tap the bearing in 3 -4 diferent places (oposite) so the bearing comes out straight.......look at the drawing the bearings rest on a shoulder inside the pulley..this acts as a stop when fitting new bearings.....
hope u've not done any damage those ally pulley's are a bit delicate.........
Frank

 

[Seadog]

I'd get more heat into it too.

 

[brewdexta]

It came out nicely with pressure on the shaft, there are circlips on the inside too so my initial way would have never worked, not that it was a good idea anyway

Many thanks guys

 

[mechman]

 

[Spark plug]

Was all that dwarf inside the pulley? If it was it would have me concerned as to ware its came from.

Have the bearings spun in the pulley?

 

[Windy Miller]

Was all that dwarf inside the pulley? If it was it would have me concerned as to ware its came from.

Have the bearings spun in the pulley?

Ha ha! Brilliant - DWARF!!!

 

[Spark plug]

Ha ha! Brilliant - DWARF!!!

Oops, you know what I mean

 

[Seadog]

I thought you said it was a wood turning lathe Andy That's one hell of a lot of swarf in there. Perhaps the part wasn't cleaned too well after machining. When I stripped my Boxford, I found a considerable amount of sand inside the casting of the intermediate shaft pulley.

 

[brewdexta]

There's no sign of bearings slipping in the pulley, I think it's from original machining, all washed out and back together now.

What it has highlighted is I need to get that fly press on a stand and I need to make some tooling, still incredibly useful though even with my collection of bits of old pipe.

Now where has that dwarf gone to?

 

[500e]

Lucky to still have a dwarf they were banned years ago

 

[Windy Miller]

Lucky to still have a dwarf they were banned years ago

Elfin Safety?

 

[Woody.v8]

Elfin Safety?

No they were sleepy, grumpy, dopey............