# Convert my lathe nose from D1-4 to Myford thread



## Blogwitch (Feb 8, 2015)

I use interchangeable tooling so that I can tranfer a job between my  lathe and mill with ease, including all the tooling in between, ie RT,  spin indexer, collet blocks etc.

My  lathe has a D1-4 nose, so the first thing that needed to be done was to  convert it (when required) to a standard nose thread, in my case,  Myford, which is a standard fitting on my dividing head.

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I need to make up a drawbar for it, this will stop it falling out of the spindle as I am working at the nose end.
As  you may well know, I use adaptable tooling, that can be swapped from  machine to machine, still with the piece part mounted, so I can turn an  item on the lathe, unscrew the chuck and screw it straight onto the RT  for further work, and vice versa.
What I have noticed, especially on the lathe, if I take a largish cut, I sometimes get chatter marks.
I am going to try to reduce the chatter as much as possible.

This  is what I am using at the moment, a chopped down 5MT to 2MT adapter,  with a 2MT mounting Myford chuck nose. I want to make it a one piece  job.






When a friend and myself had a morning out to visit another model engineer, we had to  stop half way there for me to stretch my legs. It just so happened,  right next to the rest stop was a scrap yard. So taking a leisurely  stroll, we found ourselves inside and confronting a young man sorting  out ferrous scrap. I had spied what looked like rams off hydraulic  cylinders, so the young gent climbed in the skip and retrieved me a  couple and I also picked up some nice thick pieces of plate. I asked him  how much, and I got the lot for five squid.
Anyway, I decided to use  part of the smallest and shortest piece of our find to make a one piece  unit out of. This is 2" in diameter.






A  quick date with the power hacksaw chopped off a slightly overlength  piece. I wasn't really worried about the overhang out of the chuck. The  chuck held it really rigid, and I knew it wasn't going to flex much. It  turned up fairly nicely.






The end was faced and centred.






Then it was drilled and tapped out to 12mm. This is for the drawbar I will be using.






I  will be using the topslide for turning the taper. But because I will  need all 100mm (4") of the movement to cut the taper, I had to turn down  the end bit.
That is the end of the turning at this time, I need to  set the topslide angle to cut the taper. So this piece was removed from  the chuck, and the original two piece part was mounted up with the  threads inside the jaws.







The  first thing I did was getting it to run true. I have said before that I  like these four jaw self centring because they always seem to run  accurately, this one was no exeption, less than 0.02mm (0.001") runout.  So as long I got it running true at different areas of the taper, I was  happy.







I set the touching part of the DTI as closely as I could to the centre line of the spindle by use of my height setting jig I use for setting my lathe tips.
The DTI was then run along the taper to set the angle up on the topslide, from near the chuck,







to the tailstock end. It took a little time, but I got it spot on and everything was locked up tight.







The original lump of metal was remounted in the chuck and trued up with a DTI.
Feeding  the topslide by hand, the basic taper was cut to size, but because of  the hand feeding and the tough material, the finish was only so-so.






To  clean up the cut, I decided to use my toolpost grinder. Here, I am just  dressing the wheel by feeding with the topslide to make sure it runs  parallel with the taper.







I put a cut on of 0.01MM (0.0005") and gradually hand fed along and back on the taper.






It  isn't as good as what I would normally do, but my hands were giving up  with all the slow feeding, so I decided it was plenty good enough for  the job it had to do. In fact the photo shows it worse than it really  is.






So after putting a thin layer of engineers blue on the inside of the spindle, I located the taper and this is how it came out.

That will do me just fine.






The next job is to modify the old drawbar, then with the taper locked in, I can start to shape the front end.



I had already done a little work before I took these photos, so this shows where I am up to.
I have already cut off the old smaller thread that was on the drawbar I had made for the old nose fitting.
At  the right hand end, a new thread fitting has been made and this will be  joined onto the bar when I get it to the right length.
In middle front is a bearing block to help prevent damage to my spindle and make things a lot easier to tighten and undo.







Before going any further, I will explain about the bearing block.
When  I made the drawbar originally, the turn knob sat directly on the end of  the spindle, and was very tight to slacken off or tighten up because of  the metal to metal friction.
This is an ali block that sits inside  and on the end of the spindle,  and has a ball race stuck into a recess.  So when the knob is tightened, it presses on the ball race instead of  the spindle end.







Because  I need the tightening knob to act on only the centre of the ball race, a  small flange was cut that was smaller than the outer race, but larger  than the inner.






Using  my rotating tailstock chuck, I mounted up the drawbar so that I could  give it a going over with emery cloth to make sure the surface was  smooth enough to allow it to run thru the ballrace.







So now the rod had to be made to the correct length for it to tighten up and do it's job.
The  new screwed end was put into the tapered adapter, and that was then  stuck up the spout and given a light tap with a lead hammer to get it  into the right position.







This shot shows how the bearing block works, it sits between the knob and spindle end.
The rod was pushed forwards until it hit the new threaded fitting.
The  amount of gap between the knob and block is how deep the hole needs to  be drilled in the screwed end fitting. This was just over 18mm (3/4"),  so if I drill the fitting to 25mm (1") deep, that will give a nice  tightening up allowance.







That is what is being done here.






The first thing I had to do was put the bearing block on the shaft, because it won't go on after it is all put together.
The  now drilled screwed end was fitted onto the end of the bar and a cross  hole was drilled, and a roll pin fitted to allow disassembly if needed.

It was tried out, and it worked just right.






So now this bit is finished, the main part can now be done.


So  now that the adapter is solidly fixed into the spindle nose, I can now  concentrate on finishing off the nose end. Making it so that a Myford  fitting can screw onto it.

The first job was to get the back face  made that the chuck or fitting will run up to. This face needs to be  very well finished, as it is this which straightens the chuck up to it's  final running position.






I  measured three different backplate fittings and noses that I have in my  possession, and they all came up with the same basic figure, 0.12mm  (0.005") clearance for fitting on the spigot.
Whether that is  intentional, I don't know, as it looks a little excessive to me, so I  decided to go with 0.05mm (0.002") clearance instead.







And that is what I turned the spigot to. A nice, smooth sliding fit.







Topslide set to 27.5 degs (half of thread profile angle) and everything  exactly as before. This time I will be cutting 12TPI.
If you look at  where the leadscrew is, you can see just how little movement I have  towards the headstock. If the original leadscrew guard was on there, I  wouldn't have been able to do this job.






On  the forwards planning to do this job, I had no experience of using this  machine to cut imperial threads, so I had purchased a cheap die to  bring the threads down to the correct size. But flush with the success I  had with the first thread I cut, I decided to bite the bullet and not  use the die, but the machine to cut the thread to finished size.







I don't think I could have got a better fitting thread by using the die. It was spot on.

Confidence now super boosted. I have no further worries about single point cutting of imperial threads on this machine.
I now need to check out the metric side of things.








I  will eventually be making an ER32 collet fitting to go onto this stub  nose. So I drilled down as far as I could with a 9/16" drill. This will  allow me to hold something like a 150mm (6") length of rod in the collet  chuck.






The old and the new.
Raw material costs, less than a squid.
Amount learned about screwcutting on my machine, priceless.







So that is another tuit out of the way. 

Further ones from this series will soon follow.


John


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## ShopShoe (Feb 9, 2015)

John,

Did you make your rotating tailstock chuck? I have been contemplating one made with a drill chuck, but comments on questionable precision of drill chucks have had me holding off. It looks like your use of a 3-jaw lathe chuck has more use.

I only have a mini-lathe at this point, so my version would have to use a small chuck (maybe one of the 2-inch ones) and I don't know how good one of those might be.

As always, thank you for all your posts and I'm glad you're back to posting.

--ShopShoe


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## Blogwitch (Feb 9, 2015)

SS, 
I did make it myself, and as far as I remember a couple of angular contact bearings were involved somewhere and I fitted it with an 80mm three jaw.
It is great for holding large tubes or just quickie jobs like I used it for in this post.

They can now be bought, and aren't too bad a price. If they had been available in MT3, I most probably wouldn't have made mine. Go to the bottom of the page on here.

http://www.arceurotrade.co.uk/Catalogue/Chucks/Lathe-Chucks

John


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## ShopShoe (Feb 10, 2015)

Thank you John

--ShopShoe


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## methuselah1 (Nov 16, 2022)

Chronos sell a revolving centre with a 60mm Soba chuck (with reverse jaws) for £76. It does grieve me that many suppliers don't know the difference between a revolving centre and a live one though!

-Andrew UK


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## awake (Nov 17, 2022)

Nicely done!


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