Thread: Tight fit for bull gear ?

Hi,
On my Hercus model C the bull gear was a very tight fit on the spindle. To make it easier to remove/replace the spindle I've polished the bore of the gear so it is now a slide fit.

Can anyone tell me how tight a fit the gear should be and also any tips on removing the spindle when the gear is so tight.

Thanks,

The Spindle diameter should be I think 1.6250" +.0005"/-.000"

The Bull Gear bore should be 1.6245" +.0005"/-.000"

The Gear should be firm on the shaft.

What method did you use to remove the Spindle.

You can after releasing the bearing bolts and locking nut from thr rear of the spindle generally use a piece of Hard Wood and a heavy hammer and knock the Spindle free of the Bull Gear.Doing it this way you can place either your tool post of tailstock up near the front of the Spindle with an other piece of timber to stop the Spindle coming too far out after it frees the Bull Gear.

If you dont place something there or have someone to assist you may run the chance of the Spindle coming free of the Bull Gear easily and either damaging the end of the Spindle Threads or the lathe Bed etc.

Another alternative is to make up a puller.

A piece of threaded rod small enough to fit down the Spindle.

It would need a piece of hollow tube around 2" long at the threaded end of the Spindle to fit over the spindle and sit against the bearing housing,at the rear use a heavy washer or similar that will fit against the end of the Spindle,the washer and nut must be able to pass through the rear bearing.

Once every thing has been released/un done,tighten the nut at the Threaed end of the Spindle and draw the spindle through the headstock.

Originally Posted by pipeclay

The Spindle diameter should be I think 1.6250" +.0005"/-.000"

The Bull Gear bore should be 1.6245" +.0005"/-.000"

The Gear should be firm on the shaft.

What method did you use to remove the Spindle ?

Another alternative is to make up a puller.

A piece of threaded rod small enough to fit down the Spindle.

It would need a piece of hollow tube around 2" long at the threaded end of the Spindle to fit over the spindle and sit against the bearing housing,at the rear use a heavy washer or similar that will fit against the end of the Spindle,the washer and nut must be able to pass through the rear bearing.

Once every thing has been released/un done,tighten the nut at the Threaed end of the Spindle and draw the spindle through the headstock.

Thanks for the reply. I used the simple method of tapping the spindle out. I like the idea of making a puller using a piece of tube and a threaded rod. My concern about re-assembly was that I had to line up the keyways and I thought this would be much easier if I could rotate the gear on the spindle. So I polished the gear bore so it would just slide on the spindle.

I'm asking now because a friend has hit the same problem and asked me how I removed/replaced the spindle. He is worried about any impacts that might crack the headstock. I like the idea of making a puller. But how does one line up the keyways if the gear won't slide on easily and can be rotated until the key find the keyway ?

Thanks,

Mark the Spindle and Bull Gear with a suitable marker to aid in re-assembly.

Originally Posted by pipeclay

Mark the Spindle and Bull Gear with a suitable marker to aid in re-assembly.

It sounds like I was worrying about an imaginery problem. Marking the components and using the puller sounds good to me.

Cheers,