Missed my point there @Brad - I asked about using sealed Vs open bearings.
BTW, that scribing block I paid you for, did you send it, must be a month ago now?
- Thread starter RobCox
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BTW, that scribing block I paid you for, did you send it, must be a month ago now?
indy4x
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@minimutly the way I read it @Brad93 was referring to post #57 where original seals were reused
Do you have a 12v DC output on the vfd, if so you could use that and an automotive relay.
Brad93
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Usually 5,10 or 24v
RobCox
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There's a 10V supply with a current capability of 50mA available. The speed control pot is 4.7k so will only use 2mA so there would be plenty left to drive a relay. However, in a choice of new switch or a relay, I've gone for the simpler approach and just fitted the new em. stop switch. I'd have had to buy a relay anyway. The switch was only £7 so it's not an overly expensive solution.
The electrical panel is now all wired up, ready to install in the cabinet. I just then need to program the vfd to make it all work.
Em stop switches are a no no, for obvious reasons..
Edit too late, should be Normally open E stop switches are a nono...
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RobCox
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I have three switches in series wired to an input of the VFD configured as EStop. They are the footbrake, the headstock rear cover and the Em stop. The input to the VFD needs to be pulled to 0V to run.
Both the brake and cabinet cover Sw are NO and are normally pressed closed. The last in the chain, nearest the VFD input is the Em stop, NC, so any shorts to ground along the chain will not stop the em stop from working when pressed in anger (or desperation!)
RobCox
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The new seal arrived this week and is now in place, leak free. Wonderful how Royal Mail work. Previous order for bearings I went with free postage, ordered Friday, received Saturday. This time, I coughed up for 1st class as I wanted to get everything back together so I could get on with the next bit. Ordered Sunday, arrived Weds.
All the bits for the electrics came in so I got everything installed:
Before running for the first time I thought I'd double check with a multimeter to see that there would be no puffs of magic smoke. I found two problems, first I had the 6A fuse where the 20A fuse should be and vice versa (trivial) and secondly one of the contacts of the main input isolator wasn't making a reliable contact. A new isolator switch is an expense I really didn't want, not least because it keeps the door shut when on and an exact replacement is no longer available, so I carefully dismantled the old one:
From here it was easy to check each contact till I came across the culprit:
It looks like it had been turned off with the motor running causing it to arc. A bit of metal polish on all the contacts fixed it. After more checking I fired up the VFD for the first time and went through the 100 or so configuration parameters and got it running. Obviously it ran in reverse when it should have gone forwards, but the real problem came when I tried the brake. Normal deceleration I have set to 2.5s, brake/em stop 0.5s, both of which work, but the lathe starts again when the brake is released! I went through the config options for the VFD and concluded it couldn't be configured to stop until the on/off lever was returned to the off position, then enabled, so, nothing else for it, more bits and expense
. A relay and a small power supply to run it. The relay will be arranged to not operate until the lever is in the off position and will disable the VFD via the Em Stop control till then.
And so on to the saddle. It didn't look too bad, but it was. More fossilised oil. Two plus hours of scraping, brushing, scrubbing and cleaning out the oil galleries to turn this:
into this:
I've since given it a coat of primer to seal up the casting:
and it's now had the pretty bits done:
The apron will be next.
All the bits for the electrics came in so I got everything installed:
Before running for the first time I thought I'd double check with a multimeter to see that there would be no puffs of magic smoke. I found two problems, first I had the 6A fuse where the 20A fuse should be and vice versa (trivial) and secondly one of the contacts of the main input isolator wasn't making a reliable contact. A new isolator switch is an expense I really didn't want, not least because it keeps the door shut when on and an exact replacement is no longer available, so I carefully dismantled the old one:
From here it was easy to check each contact till I came across the culprit:
It looks like it had been turned off with the motor running causing it to arc. A bit of metal polish on all the contacts fixed it. After more checking I fired up the VFD for the first time and went through the 100 or so configuration parameters and got it running. Obviously it ran in reverse when it should have gone forwards, but the real problem came when I tried the brake. Normal deceleration I have set to 2.5s, brake/em stop 0.5s, both of which work, but the lathe starts again when the brake is released! I went through the config options for the VFD and concluded it couldn't be configured to stop until the on/off lever was returned to the off position, then enabled, so, nothing else for it, more bits and expense
. A relay and a small power supply to run it. The relay will be arranged to not operate until the lever is in the off position and will disable the VFD via the Em Stop control till then.And so on to the saddle. It didn't look too bad, but it was. More fossilised oil. Two plus hours of scraping, brushing, scrubbing and cleaning out the oil galleries to turn this:
into this:
I've since given it a coat of primer to seal up the casting:
and it's now had the pretty bits done:
The apron will be next.
MattF
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Be serious.
RobCox
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Oh yes. A mess and upheaval in the workshop
RobCox
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This last week's progress. First, the electrical bits arrived from RS. A 12V power supply and a DPDT relay, both DIN rail mounting. The PSU runs off the mains and powers the relay coil. It's arranged so that when power is applied the relay won't close till the fwd/rev lever is in the off position. Either of the cabinet switch, the em stop or the brake will cause the relay to drop out. The second contact of the relay controls the em stop input on the VFD. Here's the new wiring in all it's glory:
The grey box to the left of the VFD is the power supply, the blue one to the right is the relay. It all behaves as it should now. In the event of a power cut the lathe won't self start when the power comes on. Either the em stop or the brake being applied stops the spindle in half a second and it doesn't restart until the fwd/rev lever has been moved to the off position and then switched on again.
I haven't fitted a speed control pot yet as I can't decide where I want to put it, so the VFD is configured for a 50Hz output only.
I also bought a hyper bright LED for the power indicator. It needs a 14mm hole so use of a tapered reamer and a 14mm endmill in the cordless drill made a tidy job of enlarging the hole. The original standard brightness one I bought was so dim it was as much use as a chocolate teapot. This one's much better:
The grey box to the left of the VFD is the power supply, the blue one to the right is the relay. It all behaves as it should now. In the event of a power cut the lathe won't self start when the power comes on. Either the em stop or the brake being applied stops the spindle in half a second and it doesn't restart until the fwd/rev lever has been moved to the off position and then switched on again.
I haven't fitted a speed control pot yet as I can't decide where I want to put it, so the VFD is configured for a 50Hz output only.
I also bought a hyper bright LED for the power indicator. It needs a 14mm hole so use of a tapered reamer and a 14mm endmill in the cordless drill made a tidy job of enlarging the hole. The original standard brightness one I bought was so dim it was as much use as a chocolate teapot. This one's much better:
RobCox
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The next major part to be tackled was the apron. Judge for yourself if it needed cleaning:
I stripped this down to clean it and check all the bearings. The carriage feed wheel on an M300 pulls out to disengage the wheel, except it didn't work on this lathe. So it had to come apart. The manual says this has a rollpin. Either this one has been modified or this particular lathe was fitted with a taper pin. I identified which was the smaller side and gave it a good whack. Then another, and another. No go. And of course the pin end had mushroomed at this point. So, rather than go at it with brute force I put it on the mill, milled off the projecting parts and drilled it out carefully:
The end of the shaft is squeezed in the vice. After drilling 5.5mm (it's a 1/4" taper pin) and 6mm for the top bit a good whack with a soft blow on the end of the shaft was enough to shear the remains so I could get it out. Fortunately I have a 1/4" taper pin reamer so I could clean up the hole:
The shaft has two detents. The inboard one, the engaged position, had been worn to a semicircular profile groove with a sharp lip which the detent ball didn't want to climb out of, so it got a little chamfer on the lathe (it's invaluable having a second lathe when you're doing one up):
Then after washing everything in white spirit it was time for paint. This is what takes the time. 3 days to paint the 3 coats allowing 16hrs between coats.
Whilst the paint was drying I cleaned the taper attachment. This was gummed up solid so needed disassembly and cleaning anyhow. It has the 2 part cross slide feed screw, so is integral to the operation of the lathe. It's not just a bolt on goody for when you want tapers:
If you look at the leadscrew thrust bearing block in the above photo, the washer under the nut is one of the hardened bearing races. Turns out someone's been in here before and didn't put it together properly. The nut side bearing was missing the race against the mild steel block. The result:
Nice. At least this won't come and bite me in the backside when I'm using the lathe. Here's all the bits cleaned up:
I stripped this down to clean it and check all the bearings. The carriage feed wheel on an M300 pulls out to disengage the wheel, except it didn't work on this lathe. So it had to come apart. The manual says this has a rollpin. Either this one has been modified or this particular lathe was fitted with a taper pin. I identified which was the smaller side and gave it a good whack. Then another, and another. No go. And of course the pin end had mushroomed at this point. So, rather than go at it with brute force I put it on the mill, milled off the projecting parts and drilled it out carefully:
The end of the shaft is squeezed in the vice. After drilling 5.5mm (it's a 1/4" taper pin) and 6mm for the top bit a good whack with a soft blow on the end of the shaft was enough to shear the remains so I could get it out. Fortunately I have a 1/4" taper pin reamer so I could clean up the hole:
The shaft has two detents. The inboard one, the engaged position, had been worn to a semicircular profile groove with a sharp lip which the detent ball didn't want to climb out of, so it got a little chamfer on the lathe (it's invaluable having a second lathe when you're doing one up):
Then after washing everything in white spirit it was time for paint. This is what takes the time. 3 days to paint the 3 coats allowing 16hrs between coats.
Whilst the paint was drying I cleaned the taper attachment. This was gummed up solid so needed disassembly and cleaning anyhow. It has the 2 part cross slide feed screw, so is integral to the operation of the lathe. It's not just a bolt on goody for when you want tapers:
If you look at the leadscrew thrust bearing block in the above photo, the washer under the nut is one of the hardened bearing races. Turns out someone's been in here before and didn't put it together properly. The nut side bearing was missing the race against the mild steel block. The result:
Nice. At least this won't come and bite me in the backside when I'm using the lathe. Here's all the bits cleaned up:
RobCox
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So as not to cut corners I stripped the paint off the two castings. Someone on here recommended this Strypit stuff. It's pricey, but boy does it work:
More painting... yawn:
And finally onto reassembling the apron. I hadn't taken out the feed engagement mechanism as I could clean it in situ. I did decide in light of the headstock input shaft oil leak that I'd change the seals though. Couldn't get them out with the shaft in place, So this section had to come apart. This requires drifting out the spindle and one of the bushes. Again, the working lathe is invaluable for making the right size drifts so things don't get damaged. Once apart, the seals were ease to pry out. Did they need changing? Uh, yes:
Old one at the front, replacement at the back. For anyone else trying to sort out an M300, these are specified as 1.25" OD, 7/8" ID and 9/32" thick. Unobtanium these days. I watched a video by Samuel Fielder where he refurbishes his M300. He bought the seals from the 600 group, as they're non standard. They supplied, apparently, 1.25 x 7/8 x 0.25" ones, a standard size. So mine came from BearingsRUs, £2 each plus postage! Goodness knows what the 600 group markup would have been.
Unfortunately, having taken out the shaft for the feed, I discovered that one of the thrust bearings was badly worn, so until the replacements arrive it won't be going back together. I did buy new taper pins. Turns out the one I didn't molest goes in a bit far:
Consequently I've got a much longer 9/32" pin on order and I'll cut it accordingly to fit. It would probably be ok, but I'm in this deep already. Didn't fancy making my own. I've done it before but didn't fancy all the faffing about, there's enough to do already. So here's the apron as it stands:
The lathe is now gradually going back together. I've fitted and adjusted the saddle:
To remove, refit and adjust the saddle I made a tool:
The adjustment is easy with this. Hole through the middle for the securing screw allen key and flats for a spanner at the same time:
More painting... yawn:
And finally onto reassembling the apron. I hadn't taken out the feed engagement mechanism as I could clean it in situ. I did decide in light of the headstock input shaft oil leak that I'd change the seals though. Couldn't get them out with the shaft in place, So this section had to come apart. This requires drifting out the spindle and one of the bushes. Again, the working lathe is invaluable for making the right size drifts so things don't get damaged. Once apart, the seals were ease to pry out. Did they need changing? Uh, yes:
Old one at the front, replacement at the back. For anyone else trying to sort out an M300, these are specified as 1.25" OD, 7/8" ID and 9/32" thick. Unobtanium these days. I watched a video by Samuel Fielder where he refurbishes his M300. He bought the seals from the 600 group, as they're non standard. They supplied, apparently, 1.25 x 7/8 x 0.25" ones, a standard size. So mine came from BearingsRUs, £2 each plus postage! Goodness knows what the 600 group markup would have been.
Unfortunately, having taken out the shaft for the feed, I discovered that one of the thrust bearings was badly worn, so until the replacements arrive it won't be going back together. I did buy new taper pins. Turns out the one I didn't molest goes in a bit far:
Consequently I've got a much longer 9/32" pin on order and I'll cut it accordingly to fit. It would probably be ok, but I'm in this deep already. Didn't fancy making my own. I've done it before but didn't fancy all the faffing about, there's enough to do already. So here's the apron as it stands:
The lathe is now gradually going back together. I've fitted and adjusted the saddle:
To remove, refit and adjust the saddle I made a tool:
The adjustment is easy with this. Hole through the middle for the securing screw allen key and flats for a spanner at the same time:
Barking Mat
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Most impressed by the restoration, fair play.
I'm more a wire it up and use it until I find an issue.
Nice, meticulous work.
I'm more a wire it up and use it until I find an issue.
Nice, meticulous work.
RobCox
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Thanks. I hate things going wrong while I'm using a machine. This ones had its fair share of gremlins, so I've dodged a bullet or two there.
