surfdabbler
11th February 2014, 08:25 PM
I have restored an old inherited lathe, and got it working again, and I have done a bit of turning to test it all out, and it's been really good, but just today, something has loosened. It's almost like oil has finally got into a significant part of the gears and loosened up a part. Anyway, now when I turn it on, it just spins the wheels, but not the chuck, which is super, but also bad. :? How do I get it back again?
I will explain in detail, referencing the picture below...
On the main shaft at the bottom, are 4 components - a small gear at the left, 3 belt wheels in the centre, and a large gear on the right, and of course the chuck on the right. On the second shaft at the back are two extra gear wheels which can mesh with the two on the main shaft, or can be disengaged by the lever on the very left of the photo.
Until today, all three components on the main shaft acted as a single unit. The pulley belt was used to select the speed via one of the 3 flat belt wheels, and this drove the chuck directly. The gears at the back were simply used as a locking mechanism, which was a handy way to lock the main shaft and remove threaded chucks. I thought it was a strange locking mechanism, but I have heard of geared brakes that are designed like this, so I just accepted it.
Now today, it is behaving differently. On the main shaft, the small gear wheel on the left and the belt drive wheels are disengaged from the main shaft, and spin freely on it, while still locked to each other. The large gear wheel on the right is still firmly attached to the main shaft. When I turn on the lathe with the rear shaft disengaged, the chuck will turn, but any pressure causes the chuck to stop while the belt and wheels keep spinning. In fact, it's quite easy to stop the chuck by hand with the lathe turned on, and it runs quite smoothly like this. Now the interesting part is that the rear shaft has now changed function. With the rear shaft engaged, the belt drives the wheels and the smaller wheel attached to it, which then drives the large wheel on the rear shaft, which drives through to the small wheel on the rear shaft. This then drives the large wheel on the front shaft, thus driving the chuck, VERY SLOWLY!
So, this is a nice feature, particularly if I want to do some metal turning. I no longer have to exchange pulley wheels at the back of the lathe - I could just engage this 2nd shaft in this manner. It was also very handy today as I am doing a danish oil finish on my first piece, so it was nice to run it slowly to wipe off the oil.
BUT, I don't know how to re-engage the belt to drive the chuck directly, which I need to do for normal wood turning. I have looked it over, and I can't see anything obvious to re-engage it. There is a bolt on the side of the large gear wheel, but that wasn't loose, and doesn't seem to lock it to the belt wheels. I don't want to pull the whole shaft apart to figure out what's going on there.
This is a converted Barnes #5 metal lathe from the 1890s, so there is no manual! Hopefully it is a similar setup to something that someone has seen before.
Does anyone know the trick?
I will explain in detail, referencing the picture below...
On the main shaft at the bottom, are 4 components - a small gear at the left, 3 belt wheels in the centre, and a large gear on the right, and of course the chuck on the right. On the second shaft at the back are two extra gear wheels which can mesh with the two on the main shaft, or can be disengaged by the lever on the very left of the photo.
Until today, all three components on the main shaft acted as a single unit. The pulley belt was used to select the speed via one of the 3 flat belt wheels, and this drove the chuck directly. The gears at the back were simply used as a locking mechanism, which was a handy way to lock the main shaft and remove threaded chucks. I thought it was a strange locking mechanism, but I have heard of geared brakes that are designed like this, so I just accepted it.
Now today, it is behaving differently. On the main shaft, the small gear wheel on the left and the belt drive wheels are disengaged from the main shaft, and spin freely on it, while still locked to each other. The large gear wheel on the right is still firmly attached to the main shaft. When I turn on the lathe with the rear shaft disengaged, the chuck will turn, but any pressure causes the chuck to stop while the belt and wheels keep spinning. In fact, it's quite easy to stop the chuck by hand with the lathe turned on, and it runs quite smoothly like this. Now the interesting part is that the rear shaft has now changed function. With the rear shaft engaged, the belt drives the wheels and the smaller wheel attached to it, which then drives the large wheel on the rear shaft, which drives through to the small wheel on the rear shaft. This then drives the large wheel on the front shaft, thus driving the chuck, VERY SLOWLY!
So, this is a nice feature, particularly if I want to do some metal turning. I no longer have to exchange pulley wheels at the back of the lathe - I could just engage this 2nd shaft in this manner. It was also very handy today as I am doing a danish oil finish on my first piece, so it was nice to run it slowly to wipe off the oil.
BUT, I don't know how to re-engage the belt to drive the chuck directly, which I need to do for normal wood turning. I have looked it over, and I can't see anything obvious to re-engage it. There is a bolt on the side of the large gear wheel, but that wasn't loose, and doesn't seem to lock it to the belt wheels. I don't want to pull the whole shaft apart to figure out what's going on there.
This is a converted Barnes #5 metal lathe from the 1890s, so there is no manual! Hopefully it is a similar setup to something that someone has seen before.
Does anyone know the trick?