Emco Unimat 3 Lathe

Discussion in 'Workbenches, including workshop techniques.' started by P A D, 14 May 2019.

  1. P A D

    P A D Western Thunderer

    As mentioned on my Stanier 2 6 4 thread in area 51, I recently acquired this Emco Unimat 3 lathe. In good mechanical condition, it needed a strip down and good clean up to get it back to this condition. The spaces under the slides in the bed were the dirtiest and in the end I resorted to dunking it in a bucket of hot water and detergent, before scrubbing it with an old toothbrush to remove all the crud.
    20190512_174111.jpg

    The paintwork on the bed, tailstock and headstock came up like new after cleaning, but as seems to be the case with these machines, the paintwork on the motor had suffered. Not really an issue, I decided to match up the colour with enamels and repaint it.
    20190506_213847.jpg

    Although it came with both drive belts intact, they were showing signs of age so I bought two new sets which are readily available on line. As can be see on the headstock plate, there are two motor speed settings and 4 alternative belt settings giving 8 speeds between 130 and 4000 rpm.
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    Although the bed is cast iron, the whole thing only weights about 7 kg. To keep it from sliding on the desk top in use, I mounted it onto a piece of 3/4 inch plywood. I'll add a rail around the back and sides to contain the swarf and allow it to be brushed out from the front.
    20190514_191910.jpg

    For those who have never seen one of these machines in the flesh, here it is with the 2 6 4 to give an idea of the size. Quite compact and much smaller than the "Baby" lathe (Sieg CO) offered by Axminster. From memory, I would say it is a similar size to the Proxxon FD150/E. I have no idea how to use it, but I'm sure I will have fun learning.
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    There seems to be a plethora of these machines, parts and accessories oneBay, but whilst the machines can be picked up at quite reasonable prices, many of the accessory prices are grossly inflated in my opinion.

    Cheers,
    Peter
     

    Attached Files:

  2. ceejaydee

    ceejaydee Western Thunderer

    Cracking little machine and it can do all sorts of things.

    I'd recommend a couple of books if you are new to lathe work - 'Using the Small Lathe' by L.C.Mason and 'Unimat III Accessories' by Bob Loader but there are plenty of others and lathe work can become a kind of side hobby in itself.

    I have a 'Gate Machinery' Unimat 4 which is the same machine but manufactured after production moved to Taiwan.

    Enjoy!
     
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  3. P A D

    P A D Western Thunderer

    Hi Christopher,
    Thanks is for the heads up on the books. I will certainly need to buy some reference works and do some reading up.

    After reading the chapter on the use of lathes in the late Geoff Holt's book on loco building, I did some research on the internet. My impression of the lathe and its capabilities are as you said. It's a cracking little machine!
    Cheers,
    Peter
     
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  4. Overseer

    Overseer Western Thunderer

    Sharp tools are important to get the best from the Unimat. To get started you will need some steel or brass shim strips of various thicknesses to raise the cutting tools to centre height, especially if using tools like the one in your photos with the top surface ground off.

    The Unimat 3 is a very nice lathe to use, within its size limitations of course. They are accurate and not cumbersome to use on small items. I bought mine second hand 25 years ago, it has never looked as clean and unused as this one. It stays set up all the time with a plywood box cover over it when not in use.
     
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  5. Giles

    Giles Western Thunderer

    I've had mine for 35 years, and it's a wonderful little thing. I replaced the motor early on and fitted a 200v DC with variable speed, which is much more useful, and I bought the milling attachment which is also worth keeping an eye out for.
     
    P A D likes this.
  6. neaston

    neaston Member

    You've got yourself a good machine there but it seems to be missing the top slide.
    Not that I use mine anyway having replaced it with a two way toolpost where each holder is easily adjusted for height.
    I do most of my turning with a parting tool in a holder. It is about 2mm wide with square one end and rounded the other.
    Chimneys etc I use a graver as a handtool.
    Look out for a collet holder once you get one the collets can be bought very cheaply and you'll rarely use the chuck.
    Nick
     
  7. ceejaydee

    ceejaydee Western Thunderer

    Wasn't the topslide an optional extra?
    Pretty sure it was on my lathe so maybe that was the case with the Unimat 3 and previous owner didn't buy one?
     
  8. Giles

    Giles Western Thunderer

    The top-slide certainly was an extra, yes.
    They also did a dividing head, which i use a coiple of times every ten years, but when you need it....
     
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  9. P A D

    P A D Western Thunderer

    Overseer,
    Thanks for the heads up on the shims for centering the tool, but please could you explain why is it more important with the tools I have.

    Giles,
    I am aware of the limitations of the motor and the need to run it only intermittently, but I dont see it as a problem in my case.

    Neaston,
    The lathe didn't come with the top slide but I have ordered one and a collet holder.

    This afternoon I added a back and sides to the base to contain the swarf when in use. One the right hand side I cut it short of tail stock so as not to impede the use of the hand wheel.
    20190515_181618.jpg
     
  10. Overseer

    Overseer Western Thunderer

    The aim is to have the cutting edge of the tool at lathe centre height. If you grind off the top of the tool it lowers the cutting edge relative to the bottom surface of the tool, so more packers are needed to raise the cutting edge to the centre height. It is not necessarily a bad thing to grind the top surface of tools, sometimes you have to, for example if the tool blank did not have ground surfaces as delivered (not common now but old HSS blanks with rough black surfaces are still around and perfectly serviceable). The carbide tipped tools you have may not be consistent in height as it depends on their manufacturing tolerances, it doesn't take long to work out which combination of shims you need with each tool. Edge sharpness (or lack of) could also be an issue with the carbide tipped tools. I suggest that properly ground HSS tools are best for turning brass. I could do a post or two on grinding lathe tools if you are interested.
     
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  11. adrian

    adrian Flying Squad

    @Overseer has covered the need for shims - just my 2 penn'orth - you already have plenty of shims - just use some of the waste etch from the kits you have built. Simple method for setting centre height put a bar of steel in the chuck -get a 6" steel rule and use the tool to gently hold the rule against the bar. If the top of the rule leans away from the tool the tool is too high, if the top leans towards the tool it's too low. When the rule is vertical then the tool height is on centre. Hopefully all this is covered in the books you are getting.
     
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  12. mickoo

    mickoo Western Thunderer

    Easier (another option) to just use a piece of brass and face off, if your left with a pip then the tool is not centred. If you watch the tool tip closely you'll be able to see if it pops under or over the pip, adjust accordingly.

    I have a Chinese thingy with height adjustable tool post and it needs setting if you change tools on a regular basis. I use a piece of 10 mm bar, any smaller and there is the risk of the bar flexing and make sure it's only just sticking out if the Chuck, again to minimise flex.
     
    Last edited: 15 May 2019
  13. adrian

    adrian Flying Squad

    Well sort of, this is ok for fine tuning but it is better to get the height about right before you start any cutting. It's probably ok for turning brass but even then you need to use a big enough diameter of bar stock to minimise any deflection whilst turning and it's not a method I'd like to try for setting height for cutting steel or for parting/knife tools which seem to be more critical. The vertical steel rule is very simple test without placing any adverse loading on the machine.
     
  14. mickoo

    mickoo Western Thunderer

    Can't argue with that, but turning or parting I've always taken a thin skim off the face, it was the way I was taught. As a rough guide I just offer up to the end of the bar and you can quickly see if it's centred or close.

    As you say, centring is important for a smooth cut and tool chatter avoidance.

    Having said that, a toolsmith at work likes to set his parting tool a few thou below centre, but then he is parting off significantly bigger lumps :cool:. Set just right just the tool makes a perfect hissing noise and great big pig tails of swarf just roll off.
     
    Last edited: 16 May 2019
    adrian likes this.
  15. adrian

    adrian Flying Squad

    Not a problem with that as long as you are aware of the attendant dangers. I'm just going from past experience where I saw a student jam solid a 3HP Harrison lathe when he had a parting off tool at the wrong height. No doubt you have experienced bigger machinery and more impressive failures but I prefer to avoid these problems before I start to cut any metal at all.
     
  16. mickoo

    mickoo Western Thunderer

    Yes, check your decimal place on the LCD for the feed rate ;).

    Good practice is always good practice and for the beginner good advice to follow.
     
  17. P A D

    P A D Western Thunderer

    Wow!

    More tips and advice that you can shake a stick at. Many thanks to you all, that is most interesting.

    Overseer,
    A post or two on grinding lathe tools would be very helpful.

    Thanks again to you all.
     
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  18. paulc

    paulc Active Member

    Ohhhh I can see a huge can of worms opening up here , this could go on for weeks but I will be reading avidly as its something I cant do either .
    Cheers Paul
     
  19. P A D

    P A D Western Thunderer

    I've stained the board and sides and will slap on some varnish to seal things off, so it can be wiped down from it to time. The side piece at this end needed cutting lower at the rear to allow the safety guard to fully open for belt changing.
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    At the other end the side is cut short so as not to impede turning the lead screw hand wheel.
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    Although it's a pretty crude affair, I'm probably putting in more effort than is necessary for a simple base/swarf tray, but hey ho.

    Cheers,
    Peter
     

    Attached Files:

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  20. daifly

    daifly Western Thunderer

    Peter
    I realise that Leeds is a long way from Devon or Kent, but I found the basic lathe course extremely helpful. See my thread here.
    Dave