Author Topic: Lathe build project  (Read 951 times)

Offline NormanV

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Lathe build project
« on: May 05, 2018, 08:58:12 AM »
I decided that I needed a small lathe to make small parts as my Loughborough lathe has a slow top speed. I was thinking of something around 50mm centre height. Then on my daily scan through Ebay I came across an Emco Compact 5 lathe, just the bed, headstock, spindle and leadscrew at a good price, I offered 2/3rds their price and they accepted.
I already had in my possession an unidentified piece of equipment, hardly any use, that had two slides that could be modified to suit.

Offline NormanV

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Re: Lathe build project
« Reply #1 on: May 05, 2018, 09:03:21 AM »
I modified the two slides and made them to fit giving me 90mm feed on the cross slide and 70mm on the topslide. I haven't any photos yet as it is apart for another machining process.
The next was to cast an aluminium tailstock that mounts on a steel sub-base. Hole through the centre if roughly drilled, undersize, for machining in situ to achieve alignment.

Offline NormanV

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Re: Lathe build project
« Reply #2 on: May 05, 2018, 09:05:44 AM »
To machine the tailstock bore I made a temporary tailstock and a between centres boring bar. This bar is a bit on the thin size but it had to be that size to fit through the bore.

Offline NormanV

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Re: Lathe build project
« Reply #3 on: May 05, 2018, 09:11:11 AM »
The motor that I shall be using is a 180volt 1/2HP DC motor that I have with a speed controller. Thus doing away with the necessity of shifting belts to change speed. (I have already used one of these motors and controllers on my milling machine and I know that it will be good.)
I am using poly V belts for the drive as they run quietly without slipping.
I have fitted new bearings to the spindle and I used one of the old ones to make an idler pulley to tension the belt.

Offline NormanV

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Re: Lathe build project
« Reply #4 on: May 05, 2018, 09:14:27 AM »
As I have not yet wired up the motor and wanted to get on with boring the tailstock I made a handle to fit the spindle bore expecting it to take a long time but it has not been too bad. I have just taken a rest after approx. 45 minutes work. I am on the final cut with just a spring cut to go.

Offline NormanV

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Re: Lathe build project
« Reply #5 on: May 05, 2018, 02:27:15 PM »
Here is the lathe saddle showing the cross slide and top slide. The top slide can be swivelled for turning tapers. It is not terribly convenient to do as I have to retract the topslide half way to expose the central locking screw but it did enable me to keep the size down.
Also due to the design of the slides the handles move with the slide which accounts for the long overhang of the cross slide handle. It won't affect the use but it does stick out a bit.

Offline vtsteam

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Re: Lathe build project
« Reply #6 on: May 05, 2018, 10:05:23 PM »
Good work Norman!! :thumbup: :beer:
I love it when a Plan B comes together!
Steve
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Offline NormanV

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Re: Lathe build project
« Reply #7 on: May 06, 2018, 03:22:22 AM »
Thanks Steve. :beer:

Offline krv3000

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Re: Lathe build project
« Reply #8 on: May 06, 2018, 04:15:11 PM »
its getting there brill work

Offline NormanV

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Re: Lathe build project
« Reply #9 on: May 07, 2018, 04:47:37 AM »
Thanks Bob.
Yesterday I made the tailstock ram. The only material that I had was a piece of 1 1/2" Dia steel. This had to be turned down to 25.7mm (that was what the tailstock bore turned out at) and drilled right through. It weighed less than a third of the original weight by the time I had finished.
I drilled it first and then mounted it between centres to turn the outside. I was delighted to find that over its 220mm length I could not measure any variation in the diameter! It slides silkily smooth in the tailstock.
Today I am going to bore the front end MT2, that should be fun.
Just in case anyone wonders why I have made it so long, I intend having a lever operated tailstock as I understand that it gives a more delicate feel when using small drills. Is that others experience?

Offline kayzed1

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Re: Lathe build project
« Reply #10 on: May 07, 2018, 03:45:40 PM »
I have in a plastic bag under the S7 the old  tailstock ram if you want it..Dad must have changed it some years ago...looks ok to my duff eyes.
Lyn.

Offline NormanV

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Re: Lathe build project
« Reply #11 on: May 13, 2018, 05:52:26 AM »
Kayzed1  PM sent.

Latest job was to make the box to contain the speed controller. I don't have any equipment for sheet metal work so I used my angle grinder to cut out the 2mm sheet aluminium and to score grooves for bending. It turned out very well for me, even the lid fits!
There is enough room for the circuit board the on/off switch and the speed control knob, it should look quite smart.

Offline John Rudd

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Re: Lathe build project
« Reply #12 on: May 13, 2018, 05:59:57 AM »
Speed control board looks like one of those Chinese jobs from ebay?
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Offline NormanV

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Re: Lathe build project
« Reply #13 on: May 13, 2018, 06:57:53 AM »
It's one of two that I got from you. The other is working very nicely on my milling machine with an identical motor.

Offline John Rudd

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Re: Lathe build project
« Reply #14 on: May 13, 2018, 08:39:22 AM »
It's one of two that I got from you. The other is working very nicely on my milling machine with an identical motor.

Ahh.....I see..Very good, carry on then... :lol:
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Offline vtsteam

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Re: Lathe build project
« Reply #15 on: May 13, 2018, 09:06:17 AM »
Coming along Norman!  :coffee:
I love it when a Plan B comes together!
Steve
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Offline NormanV

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Re: Lathe build project
« Reply #16 on: May 14, 2018, 02:39:30 PM »
Whilst my main lathe is out of action I have been working in wood. This little lathe is very small and this would mean that I would have to bend over to use it. I decided to make a chest of drawers to raise it up to a comfortable working height and to provide storage.
I was lucky to be given some 20mm plywood so I made the carcase and two drawers. The other four drawers were a problem as the plywood had run out and I didn't want to buy more when scrounging would do. I managed to acquire a panel from some sort of industrial boiler that was made from 2mm aluminium. I used this to make the sides and bottom of the drawers, I had already made the fronts and backs of the drawers from the plywood.
I have ended up with a very heavy and very sturdy stand for the lathe at no cost.  It is not beautiful but it does the job!

Offline vtsteam

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Re: Lathe build project
« Reply #17 on: May 14, 2018, 09:17:42 PM »
That was fast!  :clap:
I love it when a Plan B comes together!
Steve
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Offline NormanV

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Re: Lathe build project
« Reply #18 on: May 15, 2018, 01:00:36 PM »
Yes Steve, it was fast but not very accurate, but good enough! I am good at that sort of thing.
I am thinking ahead. Screw cutting, I had originally thought that it would be good to build an electronically controlled leadscrew. Then I realised how many complications are brought into that.
My latest idea is to use timing belts and pulleys. I don't want to make an unlimited range of threads. Maybe just a few to start with, .5,.75, 1mm. If there is a need for a special thread later on I can purchase the needed pulleys. I like the idea that it would be very quiet running rather than gears that rattle. Is this a practical approach? Has anybody tried it? Surely it would be accurate enough, it is used for timing camshafts on car engines.

Offline kayzed1

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Re: Lathe build project
« Reply #19 on: May 15, 2018, 02:27:50 PM »
Posted today Norman.
Lyn.

Offline NormanV

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Re: Lathe build project
« Reply #20 on: May 15, 2018, 03:09:39 PM »
Thanks Lyn

Offline vtsteam

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Re: Lathe build project
« Reply #21 on: May 15, 2018, 06:02:42 PM »
Norman, you probably can do that, but if you think about it you'll likely use the same number of timing pulleys and the same sizes as you would change gears. And it might actually be a larger package overall in size, since gears mesh, while pulleys need to stand apart.

But certainly would be cleaner to change-- which is, I think, a great advantage.
I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Lathe build project
« Reply #22 on: May 15, 2018, 06:11:55 PM »
A threading system I've often thought about for a small lathe is the "master thread" type of spindle attachment.Basically you attach a threaded piece to the pulley end of the spindle, arrange a follower in it. Like an old style gramophone needle. That follower is on a rod that extends out to the carriage, and pushes it along (it is disengaged from the leadscrew). So whatever pitch thread the "master' has is duplicated on the work.

 I think they were used on the Unimat lathes. I've seen a fancier version on a larger lathe, and kept the picture for years -- don't remember where I got it from.....see below.

I love it when a Plan B comes together!
Steve
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Offline Fergus OMore

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Re: Lathe build project
« Reply #23 on: May 15, 2018, 06:29:46 PM »
Ned Westbury described an attachment in one of his small books -Lathe Accessories???

Again, I suspect that Prof Dennis Chaddock did something similar in his Quorn Book

Probably it all came out of from Holzapffel.

So it is not new but certainly interesting. I DID Maudsley and Holzapffel in 1946 as part of my studies which suggests -- ornamental turning too

Regards

N

Offline vtsteam

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Re: Lathe build project
« Reply #24 on: May 15, 2018, 09:20:06 PM »
Timing Pulley type:

Norman, Knaell made a commercial set of toothed pulley types for the Taig lathe. Doesn't seem to be around any more, but pics of it still can be found and will maybe help you figure out a similar system.

Go here and click on the picture links:

http://www.cartertools.com/minimech.html


Thread Copying Type:

Deciphering the photo above that I attached -- it consists of:

1.) A long steel push rod that passes through a bushing on top of the headstock and one on top of the tailstock.
2.) Brass collar stops on that push rod at headstock and tailstock to limit its movement to the length of the "master screw" when resetting it.
3.) A follower toothed arm that sets in the master screw.
4.) A lathe tool holder attached to the pushrod.
5.) An adjustable vertical steel rod that serves as a rest and support on the topslide. I see a wingnut on the topslidethat retains a smooth plate. The end of the vertical rod slides along that plate with the topslide stationary, I believe. I think this rod sets the depth of cut. Not sure how pressure is applied to the lathe tool, but maybe it's just the weight of the attachment.

That's pretty much it.

Master screws could be made up on another lathe, and in some cases could be made from commercial threaded rod for the larger common sizes.
« Last Edit: May 15, 2018, 10:20:10 PM by vtsteam »
I love it when a Plan B comes together!
Steve
www.sredmond.com