HELP! Removing a worm shaft

[Dr.Al]

Thanks for all the replies; I'll try to spend a bit of time on it tonight.

Pulling or pushing still needs to be held

Yes, I'm pretty sure this is the function of the retaining plate as I said earlier - item 72 in this drawing (item 94 is the shaft with the worm on the end):

The forces on the worm shaft from cutting will be trying to push the worm shaft out of the gear box, i.e. pushing on the retaining plate.

Not necessarily.
As it's a bandsaw, it should only ever run the one way, so it could simply be relying on the force pulling everything against a boss.

@Dr.Al have you tried pressing the worm in, to see if it at least moves through the bearings?
If you've got somebody else to help steady things, another thing to try would be grip the shaft in a vise, then hit the housing.

I haven't tried pushing it in, but it might be worth a punt. It doesn't look like there's a lip on the inside, but I can't be absolutely sure. I'll get some more photos from different angles this evening.

I've got some ER collets and collet blocks, so I might try gripping the shaft with one of those (they hold all the way round, are very firm and shouldn't damage the shaft). That might give me something to work with.

Id cheat, drill a hole in the casting, inline with the shaft (itd remove the boss -so measure shaft to casting for reassembly). Peice of plate to fit in the gap with a m10 or m12 fine thread, screw a bolt from outside and you have a pusher. After, tap casting bigger and fit a plug.

Drilling a hole for a drift was one thing I'd considered, but I prefer your suggestion of the plate with a thread in it. I'm still going to leave this as a last resort as I'd rather not drill the hole, but thanks anyway.

got any more photos?

I'd knock it in first.... cut the inner bearing off with a grinder and then push it out... once the outside bearing is out it should pop right out?

I'll take some more photos tonight. I'm pretty sure the bearings are 6202 size: 15 × 35 × 11 mm. The reason I mention this is that there's only a 6.1 mm gap from the end of the worm shaft and the boss on the casting, so I won't be able to drive it in far enough to get full access to the bearing to cut it.

 

[8ob]

A dowel removing slide hammer/collets would pop that shaft out in seconds without damaging anything.

 

[Dr.Al]

A dowel removing slide hammer/collets would pop that shaft out in seconds without damaging anything.

Oooh, that looks like an interesting idea. I might have to see if I can make one of those.

 

[Dr.Al]

We have a winner! Hooray! Thank you @8ob: that was a great suggestion. Sometimes I'm really pleased to have a lathe...

When I got home from work today, I spent 2½ hours knocking up an ER32 slide hammer:

It took another 15–20 minutes to get the shaft out as it only moved a tiny amount with each hit and I had to occasionally re-tighten the ER nut as after a while it would loosen and slip (I'm sure this isn't the intended use of an ER collet really).

Nevertheless, about 10 minutes ago I was finally rewarded with this:

and a nice empty bore (I can confirm there is definitely no lip on the inner edge and the thing (apart from a **swear-word** lot of friction) holding the shaft in place is the outer retaining plate):

Even after the first bearing and the oil seal had popped out, it was amazing how many hard hits it required to get the shaft out. Can't have done the bearings much good, but they're going in the bin anyway.

Thanks all for the advice and suggestions.

 

[Kram]

Nice to see. I have tried ER32 collets for this before without luck, I was intending to buy some spare collets and broach/grind some teeth for stuff like this.

 

[8ob]

Sometimes I'm really pleased to have a lathe... When I got home from work today, I spent 2½ hours knocking up an ER32 slide hammer:

Nice work Mr Al. I like a slide hammer and a bag of nuts

 

[slim_boy_fat]

and a bag of nuts

So....no allergies, then