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Thread: Nuttall Lathe adjustments.
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15th Jul 2017, 11:52 AM #31Most Valued Member
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Have you centred the bar at the outer end or just at the chuck end.
If just the chuck end then do it at the outer,then check the chuck end then the outer, you may find that you may have to tap the outer slightly to get it running true without touch the chuck jaws.
Any job hanging out of the chuck of any length will generally require a bit of mucking around to get it running true.
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15th Jul 2017, 12:53 PM #32Intermediate Member
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I centred it at the chuck end and also tried to centre it at the other end, by tapping and tightening it, but it wouldn't move. I have the, very little used 4 jaw, on. The 3 jaw, which I use most of the time, does allow me to move and tighten. After I had ground the jaws on the 3 jaw I couldn't get the work to move as much, by tapping etc.
If I centre at the end of the work then measure at the chuck end, wouldn't I get the same differential measurements.
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15th Jul 2017, 03:21 PM #33Golden Member
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The full weight pressing on maybe three rollers in the bearing and it's not going to crush even a few thou into the bearing race surface . Could easily cause a slight mark that eventually trashes the bearing some years later .
I do agree that it could damage the whole head stock and or put it out of alignment . Just not a away I ever want my lathe to be lifted .The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
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15th Jul 2017, 08:14 PM #34
What exactly are you trying to measure? There are a number of reasons this could happen. If you are measuring how true the lathe is cutting, put a steel bar in the chuck (any chuck), turn the bar down leaving a short section near the chuck and another at the end, just cleaned up with the rest 3mm smaller diam. Do a light cut on these 2 bigger sections in one run without touching anything. Measure them. That is how your lathe is cutting. The bar obviously needs to be big enough to avoid deflection.
Dean
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15th Jul 2017, 09:46 PM #35Intermediate Member
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I think it was just a coincidence that after centering my peice of 45mm near the chuck with the dialguage on the toolpost, l then wound down to the end and the reading was the same, zero. I was very happy until I turned the chuck 180 degrees and the dialguage read 0.015". When I turn the bar down as you have said shouldn't I get a reading of a touch under 45mm near the chuck and 45mm less whatever it takes to get the concentricity out of the other end.
I also have some bigger chrome bar that I can use 50, 60, 70, or 90. But I'm thinking that the 45 will not flex over that distance.
I will check it tomorrow.
Thanks again
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15th Jul 2017, 11:31 PM #36When I turn the bar down as you have said shouldn't I get a reading of a touch under 45mm near the chuck and 45mm less whatever it takes to get the concentricity out of the other end.
As Pipeclay said you need to adjust a long work piece in 2 places to get it to run concentric and this negates any measurement you may wish to take to determine how parallel the lathe is cutting.
Dean
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16th Jul 2017, 12:11 PM #37
adjustments
hi Slim I wish you the best of luck with your Aussie built Nuttall lathe . I am not a lathe expert in any sense but I'm a little confused about what you are trying to measure . If I did a static test like you did i.e. used a 4 jaw chuck and a ground bar and a dial indicator, I would be amazed if I got those results you did, chucks are not the ideal holding method for doing a static test , they are OK for the dynamic tests i.e. turning a bar down at each end and measuring the two diameters for taper .
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17th Jul 2017, 03:39 PM #38Intermediate Member
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4jaw (5).jpg
So here are the results, 44.420mm at the chuck and 43.985mm at the end (220mm apart). That's 0.435mm
What now? Do I tackle the headstock?
Slim
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17th Jul 2017, 10:40 PM #39
First raise the rear tailstock end floor mount a little. Put a shim under it if you don't have adjusting screws. I would be trying 1mm to start. It is a solid lathe and it may take some time to settle into the new position. If another floor mount lifts off the floor, wait for a day and see what happens. Try doing the cut again. You may need to do this quite a bit. A machinists level will help to tell if the lathe is going to respond to this or not.
I am no expert at this. I have read about it a lot, but I have yet to do it for my lathe. Another job is to make some adjusting screws so I can.
Dean
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17th Jul 2017, 10:47 PM #40
Slim, people have heart attacks and mental breakdowns when somebody mentions they are about to move the headstock on a lathe If your Nuttall is as bad as your test indicates then you might have to twiddle the adjusting screws . Deans advice is good but the beds on these Nuttall's are very solid with very heavy cross bracing . I don't know if the bed would twist ?
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17th Jul 2017, 11:12 PM #41Senior Member
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Hi Dean, I am going to politely disagree with you on this. I am an electrician, not a machinist so after I moved the lathe from dad's old shop to mine I got a very respected turner come and set it up and test run it for me. He brought his machinist level and parallel set and after he shimmed it up, we did a test cut and it was cutting a slight taper. He said I needed the experience of adjusting the headstock and believe me it was. He said it was a common problem with
Nuttals.
This may not be Slims problem, but at least he now knows that they are adjustable.
Rgds,
Crocy.
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18th Jul 2017, 12:01 AM #42
What is it that you disagree about? Are you saying that because it is a Nuttall you should just jump in and adjust the headstock? All I am saying is check first, because if the headstock does not need adjusting then you have just let yourself in for a lot of unecessary trouble. It is far easier to remove a shim that realign a headstock. Did you read Mikes post just before yours.
PS I would like to politely suggest that you check my spelling for Nuttall.
Dean
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18th Jul 2017, 12:25 AM #43Intermediate Member
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I did lift the foot/tailstock end, previously and set a couple of dialguages up on the bar in the chuck. The lathe was off the ground and both dialguages did not measure any movement. I have to agree with old croc, these old Nuttalls are built like the proverbial ****house.
The lathe isn't bolted to the concrete and probably would need to be so that it could be twisted (maybe)
Big job?
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18th Jul 2017, 11:09 AM #44The lathe isn't bolted to the concrete and probably would need to be so that it could be twisted (maybe)
Big job?
I have owned a Nuttall and I know how solid they are. It is my understanding that even the most solid lathe can twist if sitting unevenly. This is why proper setting up is recommended for all lathes.
Remember I am no expert.
Dean
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18th Jul 2017, 11:54 AM #45Golden Member
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All lathe beds can twist from their own weight the more solid the more weight so that cancels the thickness and bracing somewhat . If they never twisted and never bent slightly then no precision levelling would be required . No one is having any heart attacks over anything . Moving the head at this stage is stupid as the lathe could still be out of level , the chuck or jaws could be the problem a number of things could be out . Is the test bar even straight ?
The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.
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