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Most folk just call me; Orange Joe
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I unbolted the tail end support and was able to slide the feed shaft and leadscrew out together without having to move the drill. Four cap head screws and the apron drops off.
Took a while to get it apart, most of it is quite straight forward but there were a couple of bits gave me trouble. The pair of gears at the top are bolted together and held in place with a circlip, I took the circlip off but they wouldn't budge so I unbolted them in place thinking there was some kind of retaining feature trapped in the middle but there's nothing, nothing in the manual either so I just hit it harder and harder until it moved.
There's also a threaded pin which acts as an interlock so you can't engage the screw feed while the power feed in engaged, it's bent and the threads are mushed so it was a nightmare to wind out. I might reassemble without it and machine a new one, conveniently it can be fitted with the apron assembled and installed.
62 years of filth. All the unpainted steel parts got a wipe over to knock off any solid gunk and are now soaking in caustic soda, everything painted, printed or made of oilite will get scrubbed by hand.
Took a while to get it apart, most of it is quite straight forward but there were a couple of bits gave me trouble. The pair of gears at the top are bolted together and held in place with a circlip, I took the circlip off but they wouldn't budge so I unbolted them in place thinking there was some kind of retaining feature trapped in the middle but there's nothing, nothing in the manual either so I just hit it harder and harder until it moved.
There's also a threaded pin which acts as an interlock so you can't engage the screw feed while the power feed in engaged, it's bent and the threads are mushed so it was a nightmare to wind out. I might reassemble without it and machine a new one, conveniently it can be fitted with the apron assembled and installed.62 years of filth. All the unpainted steel parts got a wipe over to knock off any solid gunk and are now soaking in caustic soda, everything painted, printed or made of oilite will get scrubbed by hand.
Maker
Most folk just call me; Orange Joe
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Caustic soda does a fantastic job but I like to give everything a scrub and rinse by hand, as much to inspect it as to clean it.
All looks good, I don't think I've lost anything yet. I've WD40d everything to drive off the water and stop it rusting.
All looks good, I don't think I've lost anything yet. I've WD40d everything to drive off the water and stop it rusting.
MattF
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Steel, or cast iron?
Maker
Most folk just call me; Orange Joe
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- Keeler crater
It's back together, thought it would be a quick job but it took all bloody morning, all looks good now though.
I noticed a slight design (Or machining?) flaw, the casting is drilled from the top to supply oil from a gully to the shafts but the threading dial shaft has had steel bushings pressed in which aren't drilled. It doesn't look like it's done it any harm so I left it as-is.
I thought the worm gear arrangement was quite a clever design. The worm is fixed to the shaft with a pin but the shaft is slotted to allow some axial movement. Inside the shaft there's two stiff springs which bare against the pin and grub screws in each end to preload the springs. There's also a pointed pin in the side of the casting which sits in a vee groove in the worm, you can tighten the grub screws to locate the groove on the pin's centre so it's not rubbing. If the worm is being driven but it can't turn (Because the carriage has crashed for example), the worm will slide against along its shaft and push on the pin, which releases the power feed and disconnects the worm from it's wheel so it stops trying to feed and nothing gets broken.
The parts diagram shows the worm shaft installed from the right hand side which is what I did initially, but there's only clearance in the apron casting to install it with the shaft fitted in the left as shown above.
As soon as I fitted it, I took it back out again, because this shaft is locked with a grub screw from the bottom, and the gear can only be installed though the bottom.
Notice the hole on the right in the image above, that's where the interlock pin goes, so very easy to fit later once I've made a new one.
There's a hole in that gear which looks like it should have a grub screw, the the hole is plain and the shaft is fixed. I think it's there to slowly drip oil down onto the worm, the shaft has an oil point on the front which you're supposed to oil daily.
I figured out why the pair of gears were so stuck, the circlip had pushed up a burr on the edge of it's groove which was getting stuck in the oil channel in the bushing, I filed it smooth and it went back together fine. You can just make out a slightly polished area beside the groove, that's all it was.
The rest went pretty smoothly.
That gear right at the bottom in the worm box has oilite bushes in it which have worn to about 20 thou bigger than the shafts they ride on, they've also worn an incredibly sharp edge which sliced the tip of my finger . I think most of the gunk in the bottom of the casting was the missing material from these bushes. They run all the time the lathe is running (Rather than just when power feeding) so it's no wonder they've worn more. I might turn some new ones eventually, I thought about trying to get them out to measure for replacements but I think they'll need boring away.
I noticed a slight design (Or machining?) flaw, the casting is drilled from the top to supply oil from a gully to the shafts but the threading dial shaft has had steel bushings pressed in which aren't drilled. It doesn't look like it's done it any harm so I left it as-is.
I thought the worm gear arrangement was quite a clever design. The worm is fixed to the shaft with a pin but the shaft is slotted to allow some axial movement. Inside the shaft there's two stiff springs which bare against the pin and grub screws in each end to preload the springs. There's also a pointed pin in the side of the casting which sits in a vee groove in the worm, you can tighten the grub screws to locate the groove on the pin's centre so it's not rubbing. If the worm is being driven but it can't turn (Because the carriage has crashed for example), the worm will slide against along its shaft and push on the pin, which releases the power feed and disconnects the worm from it's wheel so it stops trying to feed and nothing gets broken.
The parts diagram shows the worm shaft installed from the right hand side which is what I did initially, but there's only clearance in the apron casting to install it with the shaft fitted in the left as shown above.
As soon as I fitted it, I took it back out again, because this shaft is locked with a grub screw from the bottom, and the gear can only be installed though the bottom.
Notice the hole on the right in the image above, that's where the interlock pin goes, so very easy to fit later once I've made a new one.
There's a hole in that gear which looks like it should have a grub screw, the the hole is plain and the shaft is fixed. I think it's there to slowly drip oil down onto the worm, the shaft has an oil point on the front which you're supposed to oil daily.
I figured out why the pair of gears were so stuck, the circlip had pushed up a burr on the edge of it's groove which was getting stuck in the oil channel in the bushing, I filed it smooth and it went back together fine. You can just make out a slightly polished area beside the groove, that's all it was.
The rest went pretty smoothly.
That gear right at the bottom in the worm box has oilite bushes in it which have worn to about 20 thou bigger than the shafts they ride on, they've also worn an incredibly sharp edge which sliced the tip of my finger
. I think most of the gunk in the bottom of the casting was the missing material from these bushes. They run all the time the lathe is running (Rather than just when power feeding) so it's no wonder they've worn more. I might turn some new ones eventually, I thought about trying to get them out to measure for replacements but I think they'll need boring away.
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Maker
Most folk just call me; Orange Joe
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With that all back together I took off the saddle, I've wanted to check under it for years, I know the bed wipers are knackered and there always seems to be fine brass swarf trapped underneath.
The ways don't look too bad, they're clearly worn but there's no deep channels and no swarf embedded in it. The area with all the swarf stuck to it doesn't contact the bed, it just bridges the area where the tailstock goes, the black crusty bit is the exposed section in the middle of the bed.
The saddle strip has snapped where the locking bolt screws in, maybe someone overtightened it once? I had no idea there was anything wrong with it, it still locks fine so I'll just clean and refit it.
Naked lathe! Good opportunity to clean the bed properly.
The ways don't look too bad, they're clearly worn but there's no deep channels and no swarf embedded in it. The area with all the swarf stuck to it doesn't contact the bed, it just bridges the area where the tailstock goes, the black crusty bit is the exposed section in the middle of the bed.
The saddle strip has snapped where the locking bolt screws in, maybe someone overtightened it once? I had no idea there was anything wrong with it, it still locks fine so I'll just clean and refit it.
Naked lathe! Good opportunity to clean the bed properly.
Maker
Most folk just call me; Orange Joe
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Assuming these two surfaces were once at the same height, there's actually about two thou of wear on it.
I can't be certain they were the same height, maybe the way portion of it was ground slightly lower, but it does look like it. I am also measuring that with a depth mic which might be influencing its own measurement, I don't have a surface plate to check it properly with an indicator.
I can't be certain they were the same height, maybe the way portion of it was ground slightly lower, but it does look like it. I am also measuring that with a depth mic which might be influencing its own measurement, I don't have a surface plate to check it properly with an indicator.
Maker
Most folk just call me; Orange Joe
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Refitting that I noticed there's cracks along both the bolt holes which hold it against the saddle, it seems to be staying in in place so I've bolted it all back up but I'm half expecting it to break into four next time I try to lock the saddle. I reckon it's the wear that's done it, it probably only had to flex less than a thou to lock when it was new but now there's 2 thou missing from the saddle and probably some missing on the bed, it's got to bend much further to contact the underside of the way and lock up. I'll try to make a new one with a closer fit, or perhaps with a thinned section it so it can bend more easily.
A few questions:
Can you buy cast iron as "bar stock" to be machined to size or would I have to get something cast?
Does it actually need to be cast iron? Steel would be easier to get hold of and less likely to crack.
Will a milled finish do or will I have to get someone to surface grind it for me?
JMS1972
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You can buy cast iron as bar stock, probably will wear less than steel.
As for machining rather than ground it depends on how good the rest of the machine is I guess.
Obviously the answer is scraping but you might not want to open that can of worms
As for machining rather than ground it depends on how good the rest of the machine is I guess.
Obviously the answer is scraping but you might not want to open that can of worms
Maker
Most folk just call me; Orange Joe
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I might have a lead on a surface plate actually so scraping isn't absolutely out of the question, I'd rather not though.Obviously the answer is scraping but you might not want to open that can of worms
Just had a quick look on eBay, I can get a bit of "Meehanite" bar for a tenner, never heard of it but Google suggests that's the stuff I'm looking for.
JMS1972
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Sounds like the good stuff, can't remember the details but I think close grain continuous cast grey iron are some of the words to look for.
I assume you only need to get one surface flat so probably an ideal first scraping job, if a bit narrow...
Maker
Most folk just call me; Orange Joe
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- Keeler crater
I used the lathe to clean the lathe. 
Had it turning at probably 100rpm while I scrubbed the threads with a toothbrush, dirty rag to catch all the shish. Leads screw and feed shaft both seem dead true which is reassuring. Fixed steady is getting cleaned now, it was so grubby I needed pliers to adjust it. Unfortunately it's aluminium so it can't go in the caustic soda.
Picking up that surface plate this weekend too, I doubt it's flat enough to be a scraping reference but it's probably good enough for everything else I'm likely to do with it. "Picking up" might be a poor choice of words, it's a 4" thick lump of granite.
Had it turning at probably 100rpm while I scrubbed the threads with a toothbrush, dirty rag to catch all the shish. Leads screw and feed shaft both seem dead true which is reassuring. Fixed steady is getting cleaned now, it was so grubby I needed pliers to adjust it. Unfortunately it's aluminium so it can't go in the caustic soda.
Picking up that surface plate this weekend too, I doubt it's flat enough to be a scraping reference but it's probably good enough for everything else I'm likely to do with it. "Picking up" might be a poor choice of words, it's a 4" thick lump of granite.
