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Post by Deleted on Sept 19, 2014 14:59:03 GMT
Hi matey !!------------ What a lovely bit 'o kit to be sure !!----------Now THAT'S what I would recommend as the ideal M/E lathe and yours seems to be almost as new as well-------Even the headstock rubber mat looks to be unused ( Being Ex- College then it's not had the obligatory Cup-of-Tea stood on there either,I'd imagine )........ ENJOY !
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Post by andyhigham on Sept 19, 2014 16:03:55 GMT
The rubber mat is an essential part of the lathe, It stops the bottom half of your tea going cold
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Post by ettingtonliam on Sept 19, 2014 18:37:52 GMT
Yes but you need a mug with a lid on to stop the swarf going in. Getting swarf stuck in your teeth is bad, but when theres cutting oil as well---.
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Post by springcrocus on Sept 19, 2014 18:53:57 GMT
I remember using a Bantam at college. A real lathe (unlike the lathes beginning with M) What - Mascot, Master and Mastiff? Steve
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Post by Deleted on Sept 19, 2014 19:20:03 GMT
Yes but you need a mug with a lid on to stop the swarf going in. Getting swarf stuck in your teeth is bad, but when theres cutting oil as well---. ----------------------------------------------- swarf brightens your teeth, cutting oil gives you fresh breath as well.........what's not to like ??
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Post by andyhigham on Sept 19, 2014 21:48:51 GMT
Swarf in tea is no problem until it hits a filling
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Post by Deleted on Sept 19, 2014 22:20:32 GMT
Swarf in tea is no problem until it hits a filling --------------- enough electricity to run a new lathe on !!------------- which is where we came in .
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Sept 19, 2014 23:32:11 GMT
Sean.
You have done very well.
Worth spending the money and putting a VSD system on it.
Advantages of a VSD system More flexible than gear or belt changes with discrete steps. You can get very low speeds quickly for tapping or running dies. You can speed up as the working diameter gets smaller during facing and parting off or if the work piece has stepped diameters. You can slow down if the initial cutting speed is too fast. You can speed up for roughing, get the chips really blue.
Regards Ian.
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Post by Roger on Sept 20, 2014 7:15:00 GMT
Don't underestimate how many times you'll do the things Ian lists here, this is not an academic exercise, you'll do this stuff all the time. In fact, I'd wager that most of the time you'll run in one gear and use the drive to get the speed you want. It's only when you need more torque at the lower speeds that you need to change to a lower ratio. The one Ian didn't mention is deliberately choosing a higher gear at low motor RPM to reduce the available torque when parting off.
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Sept 20, 2014 9:28:06 GMT
---------- swarf brightens your teeth, cutting oil gives you fresh breath as well.........what's not to like ?? Nothing I suppose - I just cannot imagine how attractive the women find it. No doubt you have more success than us mob. Report from the invisible Joyce needed here, before we all start using it! Yes, Ian and Roger have it right - I did not realise how good VFD would be until I had it. People theorise on here forever and I did the same for a while but, yes, I have not needed to change gear for ages (including socks). I spent a while agonising about low speed torque, calibrating the speed etc. but those things turned out to be unimportant in my world. Then look for DRO - also has downsides on here, but mostly upside for me. I know - I am an amateur and professionals may say differently, but I am using a Myford (Yes Andy) - and they would have something more substantial and more versatile - and many amateurs of course! All IMHO. Running for party this afternoon at the club - looks like waterproofs are needed! Come and join me.
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Post by Roger on Sept 20, 2014 9:55:49 GMT
You've got it absolutely right Tony, theory is one thing, practice another. It doesn't matter how manly your lathe or mill are, adding VFDs DROs or CNC to them transforms their usefulness, often in the most unexpected ways.
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Post by Deleted on Sept 20, 2014 10:08:36 GMT
A "Blue Chip" enterprise eh, ??------------- next it'll be Swimming Pools & Movie Stars, which reminds me of these people >>>>>>>>>>> www.youtube.com/watch?v=NwzaxUF0k18 ------------- Sorry guys, I'll go peacefully >>>>>>>>>>>
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Post by Deleted on Sept 20, 2014 10:23:09 GMT
Quote}--"Report from the invisible Joyce needed here, before we all start using it!" ---------- "It works for me" she said >>>>>>> ------------------------------------- OK for her, but it's given ME a slight depression >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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Post by ettingtonliam on Sept 20, 2014 10:40:48 GMT
I've got a Denford 280 with a 1.5hp 3 phase motor, currently running quite happily from single phase via a very old Jaguar inverter, so old it doesn't have speed control. Mostly I don't need the speed control via the inverter drive, because the lathe itself has a variable speed pulley set up controlled by a lever on top of the headstock, so I can change speed 'on the run' without torque loss. Bottom speed is 65 rpm, which is OK most of the time, but I do turn big iron castings, and it would be nice to get bottom speed down to about 30, but I still need good torque at that speed. Eventually the old inverter is going to pack up, so what would you guys recommend to replace it? I'm not that bright electrically, so I'd really like something thats a straight replacement for the Jaguar and doesn't need messing around in the control panel which works at the moment for forward/reverse, stop, start and for the suds pump.
Richard
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Post by Roger on Sept 20, 2014 13:34:52 GMT
Gosh, that does sound old if it doesn't have a variable speed. Don't be so sure that the drive is going to die any time soon though, some of these things last forever. Any modern inverter sized for the motor will be more than adequate, and you'll only lose a small amount of torque at half the rated RPM. I'd be very surprised if you need anywhere near the amount of torque you currently have available, you get whatever is a consequence of such a low gear ratio. I don't have anything like the reduction you have yet my Warco has loads of torque low down. Don't take any notice of those who say inverters don't have any torque at low RPM, it's not relevant when you have a geared machine. It's only an issue if you have a poorly designed machine that tries to use the motor to provide all the speeds without any mechanical reduction. You only need to drill a hole in your existing control panel to take a multi turn wirewound potentiometer, you can use all the existing buttons even if you have to slightly change the wiring. Modern inverters require the interface to provide +ve voltages to enable them whereas in the old days you usually grounded the signal wires. That's considered dangerous these days so you are likely to find that you won't be able to drop something modern into its place without a few simple modifications. There's nothing difficult about it. I use Control Techniques drives because they are so flexible when it comes to the interface.
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bhk
Part of the e-furniture
Posts: 458
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Post by bhk on Sept 20, 2014 19:24:24 GMT
Alan your humour is always welcome on my threads, life's to short to be taken serious! A DRO is one of the things I would rather spend money on. I may have came up trumps with drive but will have to wait till next week to find out. Watch this space. Spent yesterday cleaning and polishing again, machine is looking great. Also got around to poking around the motor terminal box few pictures for those interested.
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Post by Roger on Sept 20, 2014 19:57:34 GMT
So that's a 2-pole / 4-pole motor then but it's still at 415v so I guess it's of no practical use to you. Any luck finding the price of a 220V 3-phase motor and inverter to suit?
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bhk
Part of the e-furniture
Posts: 458
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Post by bhk on Sept 20, 2014 20:46:41 GMT
So that's a 2-pole / 4-pole motor then but it's still at 415v so I guess it's of no practical use to you. Any luck finding the price of a 220V 3-phase motor and inverter to suit? I had a look at this website www.inverterdrive.com/ and I could do that setup for £ 250 which is awesome price and one I can't beat here in NZ. But postage is very high. I have found a drive here in NZ its a no name china units but it is a step up inverter so would run the current motor, its on a auction website and if I get for near the current price then it's worth a punt.
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Post by Roger on Sept 20, 2014 21:01:25 GMT
I have to confess that I haven't come across any step up VFDs so I don't really know what they look like. I imagine there's a pretty chunky inductor on the front end of the drive to step up the voltage. I'm sure you'll check the specification and make sure it's suitable. I don't think there's any problem with those Chinese drives, the ones I've come across seem to work ok although I haven't bought them myself.
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Post by andyhigham on Sept 20, 2014 21:19:53 GMT
To my knowledge a step up inverter doesn't exist. An inverter works by first rectifying the mains to 230v DC then chopping it about to vary the frequency and on time vs off time(PWM)
You could stick a 3 phase step up transformer after the inverter but it would cost several times that of a new motor
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