Shenwai SW-900/Belt Drive 12x36 Bull Gear Pin

[ChandlerJPerry]

Does anyone know what the bull gear pin on these models is supposed to be like? Mine is clearly something that was put together by a previous owner. They must have had the spindle out at some point, because the bolt is too long to be removed inside the headstock. Is it a 1/2-13 socket head cap screw with the head ground down. I would like to replace it if possible as it's a pain to use. I've seen references to a twist to lock style pin on these as well as some kind of thumb screw, but it seems like these parts are no longer available from Grizzly etc. for the style of lathe most similar to my machine. When the bolt is fully engaged there is around 1/8" of play on the cone pulley, so it's a slightly larger hole, maybe around 5/8" or so. I could be completely wrong and this could be all original, it just does not look quite right to me.

I was considering using a twist to lock style plunger such as this, but I am concerned about the amount of play the pulley will have with the pin engaged due to how large the cone pulley hole is. Is this an issue I need to worry about or would it be fine?

 

[markba633csi]

I'm pretty sure that can't be original- Usually the pin has a detent mechanism with a ball and spring or something similar
Probably the original broke and this is what was easiest to do at the time

 

[DAT510]

Here are some picts of my Jet-1024 the baby brother of your Shenwai. My pin is spring loaded to hold it in the "Locked" position and "Unlocked" by Pulling it out and twisting to hold it in the Unlocked position.

It looks like the previous owner may have just drilled and tapped the gear. I would check your gear to see if it has some reliefs cut into the gear to allow you get your fingers behind the Lock Pin. If it does, that's where the original lock pin should have been located.

 

[markba633csi]

Why is it that (some) machinists are the laziest sobs imaginable- you have a lathe that can make exactly that type of pin and what do they do? Drill and tap for a tree-trunk size screw LOL
Holy cow

 

[ChandlerJPerry]

Here are some picts of my Jet-1024 the baby brother of your Shenwai. My pin is spring loaded to hold it in the "Locked" position and "Unlocked" by Pulling it out and twisting to hold it in the Unlocked position.

It looks like the previous owner may have just drilled and tapped the gear. I would check your gear to see if it has some reliefs cut into the gear to allow you get your fingers behind the Lock Pin. If it does, that's where the original lock pin should have been located.

View attachment 495359View attachment 495360

Unfortunately there are no signs of those finger reliefs on my bull gear. I'm wondering if they're on the backside and the gear was flipped around on reassembly. It definitely would have had to come off to be drilled and tapped. I'm thinking the next step may be to remove my spindle and investigate exactly what's going on here. Also to inspect bearings etc because I've found several things on this machine as I've been refurbing it that indicate to me that the previous owner was unintentionally incompetent or pointedly neglectful. Does anyone have a favorite guide/technique for spindle removal?

 

[kiwi_007]

I have a Peerless and a Wey II version of this lathe and the lock pins are both different, the Peerless is a threaded pin so you unscrew it and a spring keeps it out (I think, I need to look to confirm that) The Wey II is a push in and rotate so a bayonet type action to lock and unlock.

For spindle removal use a length of threaded rod through the bore of the spindle and a tube with plenty of clearance that goes over the nose of the spindle and tighten a nut to draw the spindle out the front.
Make sure you unscrew any set screws that secure any spacers/tubes to the spindle.
I've just had the spindle out of the Peerless and the Wey II and they were both pretty easy to remove, getting them back in is a bit of a juggling act.

 

[ChandlerJPerry]

With a custom made wood block and a few taps from my trusty purse, the spindle came out without much trouble.

Unfortunately, I found that both spindle bearings are cooked, there was no oil in either reservoir.

Coming back to the issue of the bull pin, I am even more confused than before. There is no sign of any finger reliefs on either side or whatever the original mechanism was. The modification made to the pulley has somehow gone horribly wrong, one or both of the holes will need to be drilled and bushed, or a new hole drilled entirely.