homemade lathe, that actually make things

  1. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    Ripped this off another forum I frequent, built this little lathe years ago for making air rifle parts, threading gun barrels and other little odd jobs.
    Hopefully will get someone by, when they cant find afford a machinist. Or maybe like me you just see it as a challenge and get stuck in?
    To start with you need a solid base with two uprights on it, and further upright on the back of the rear upright. I used 6" steel girder, with a 10mm base and 12 mm legs. Nice and solid ;)
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    As you can see i have already mounted my motor to the side of the bed, and i have ground out ( quite scruffily) slots for the spindle to sit in - i was not going to try and drill two 30mm holes precisely in this stuff!!
    Next is to attach the spindle - i picked 30mm ID 55mm OD bearings that are part of a transit van driveline ( the differential i think) so they should stand up to a few 1000rpm and sideways loads.
    I used 1/2 thick aluminium plate to mount them in - you could use a hole saw for this but as i made the holes too small, i had to finish boring them out on a mates lathe.
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    the bearing should just about drop through the hole - you dont want a tight fit.
    Next we drill two holes down the sides of the bearing hole making sure to go well past the halfway mark ( half the diameter of the bearing hole). then hacksaw the mounts in half leaving you with a big plate with a U on top and a small plate with a U on the bottom.
    Drill out the holes in the small plate so your chosen bolts can pass through and drill the bottom plate a bit deeper then tap for your chosen bolts
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    As you can see there is a slot in this plate and there should also be a slot in the other plate but running in the opposite direction. Hold the bottom part of the mount onto the support ( of the lathe ) and drop the spindle on top, and eye up roughly where it needs to be and mark the centre of the slot in the support for drilling. Do this either end and drill them to take bolts - i used M8.
    Now bolt on both the mounts via the slots and nip them tight-ish you will be shuffling them round with a hammer in a minute ;)
    pop your spindle in and tighten down the top parts of the mounts so its nice and solid, put some thing in the chuck and centre it using a run out gauge ( if you have a three jaw you will just have to trust it is straight)
    pop your slides or carriage way ( cross vice for me ) where they should go - roughly aligned with the spindle
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    now you start levelling the spindle out using digital vernier and a small engineers set square measure the distance between the bottom rail ( this is important that you measure the bottom rail and not part of the frame etc, the spindle wants to be level with the ground surface that the tool post slides SIDEWAYS on)
    Adjust the spindle mount by tapping with a hammer until you are sure it is very close to being perfectly level.
    once it is level look at it from above and make sure it runs parallel to the cross slides. I attached G-clamps to my mounts to stop them moving then drilled another four 8mm holes through the mounts and the steel, and fastened it in with M8 bolts, your spindle should now be rock solid in place.
    Now you have to align the cross slides with the spindle, i did this by tapping 6 x M6 bolts into the bed and then nipping the cross slide up.
    take a very small and slow cut of your test peice about two inches long and measure each end, you then tap the crosslide with a hammer until it is sat straight with the test peice and do another cut to check.
    I have got mine to 0.03 over two inches but its not finished yet so i will true that up later - if i can!
    Now double check your height measurements just in-case its moved whilst drilling, bolting etc, if it has moved and your spindle is already bolted securely you can use shims under the slides to level it back off.
    Once you are happy its all done tighten the crosslide down as good as you can - if its not cast iron like mine weld the ****** down!
    Finally pour over a tin of hammerite, do not attempt to brush it on neatly this is not how hammerite works - just dip your brush in an slap it on ;)

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    My motor and pulleys came from a wood lathe and provided speeds of 850,1200, 1600 and 2000RPM.
    All of which are too fast for machining steel or larger diameter aluminium. I could have just changed the pulley sets but they are opposite and equal for the different speeds. This means id either have to get two sets the same, or build a tensioner for the belt. I instead opted for a primary chain drive
    Firstly i decided by how much i want to reduce the speed which is a quarter. So i need two sprockets one three times bigger than the other i picked up a 17tooth and a 68tooth sprocket on ebay for well under a tenner ( mini moto parts :wink: :lol: ) and a 6mm pitch chain for about £4.
    The chain runs from the motor to a primary shaft and the belt runs form the primary shaft to the lathe slowing the lathe by roughly a quarter but still letting me choose three gears. ( id still have all four if i had used a smaller diameter lathe spindle)
    The primary shaft is a short length of M10 studding, the big mini moto sprocket sits on a machined peice of aluminium that has a bearing encased in to ( just visible between the lathe and the sprocket) and also include a 14mm shaft for the pulley to fasten on with.
    The smaller end of the pulley also has bearings on it ( but as its part of the lathe drive i couldnt machine it so i had to run the motor with no belt, and use a file to put in a taper on the end of the pulley set for the bearing to locate in and hold the pulley central.)

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    Quick video showing the changes the speeds between the different spindles, i know it can be hard to understand at first so i have stuck some tape to all the pulleys and sprockets so you can see how they rotate in relation to each other.
    God knows what sh** is on the radio it was almsot four years ago :wink:
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  2. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    I quickly got bored of that toolpost and made another one
    The old one was only 40mm thick so allowed the tool holder to "rock" slightly when machining, also i couldn't get my knurling tool in the lathe because it is quite long and i couldn't wind the holder far enough away from the workpeice. See below.
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    TO start with i took a big 1/2" thick peice of aluminium and bored a hole half way through it just ever so slightly bigger then the round peice of metal
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    This is the sort of fit you want, it just goes and will rotate but its just tight enough that the plate doesnt fall off.
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    next i machined a groove into the aluminium bar, and faced of both sides, finishing it to length
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    Well thats all the machining done so time to strip down the vice
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    And grind the top flat
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    Bolt on the plate, and add some metal "tabs" to locate and secure the aluminium Bar via the groove machined earlier

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    And its done! One very sturdy and rotate - able tool post!
    All i need to do now is add a pin to the tool holder so that cannot rotate on top of the aluminium bar, The four metal tabs grip the bar a lot better than a single bolt through the holder.
    You could use this method to add a third crosslide to the lathe to let you cut at angles ( i would have but didnt have space ).
    and then some tooling I made
    well today i finished my drill chuck and threading adaptor.
    I threaded a small piece of steel to take a drill chuck, and welded it 90degrees to another peice of steel so go in the tool post

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    A bit of fidgeting and i had the drill chuck with the threaded steel centred in the lathe chuck and i put the other bit in the toolpost and brought them together to get a tack weld So the centre height should be perfect :wink:

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    next i machined a big steel pin, around 16.50mm in diameter and 100mm long, it has the end turned to about 12mm to fit in the drill chuck and two smaller pins on the end one at abut 5.48mm and about 4.48mm, to centre itself with .177 and .22 calibre gun barrels :wink:
    Next i needed the threading attachment for it so a big heft of 2" aluminium was drilled down the centre at 16.5mm and the end bored out to take a 1/2unf split Die. The holes where drilled and tabbed for grub screws and the centre grub screw was turned to a point at the end to open the die. It was knurled after finishing for extra grip but the camer hasnt caught it very well.
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    Okay time to try it all out :lol: :lol:
    first a gun barrel was centred using a 5.5mm drill bit and and the dial indicator, then the "hand threads" that i tried ages ago where parted off

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    then the barrel was turned to the size of the threads 1/2" :wink:
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    and undercut using a thicker parting tool - if i used my brains i could have done this bit after i first parted off the end of the barrel
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    then it was recrowned using a weee- tiny little boring bar and half a litre of oil
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    Its ready thread, so the drill chuck and the steel pin go in the tool post and are aligned with the barrel
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    then the die holder is slid on and rotated to catch the first few threads - but i forgot a pic :(
    One it has two threads or so its all removed from the lathe and finished in the vice, i didnt take the die back out the adapter just used it as it was.
     
  3. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
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  4. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    had to scrap this not long ago as the ways were all worn out, must be ten years ago i made this now. I kept spindle and chuck incase I make another, will update with a load of bits made on it when I can find the pics
     
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  5. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    as promised just a few of the parts made on this lathe, made a good few lots of these, and sold them to fund newer tooling etc

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    air rifle bolt, and end caps


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    muzzle weight


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    don't remember what that one was for, it was one off for someone's gun

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    end caps

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    different style of end caps
     
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  6. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    I also made silencers, by the batch, with 1/2" unf threaded ends, and plastic cast "K" baffles inside, that I used to cast myself in silicone moulds.
    can't find any pics of them, other than on a gun and already painted.
     
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  7. Bill Edwards Member

    Messages:
    4,215
    Location:
    Scarborough, North Yorkshire
    Interesting little thing you made there, nice. Pity it had to wear out!
     
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  8. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    one of the pics above is marked 2010, so it was at least 7 years old, the ways where a cheap cross slide vice, and its lived outside about 5 years, undercover of course but still outside. Im contemplating another lathe build after I've finished this damn van
     
  9. cumbriasteve

    cumbriasteve Moderator Staff Member

    Messages:
    8,060
    Location:
    Cumbria UK
    The quality of what you have made and the fact you wore it out suggests it earned it's keep many times over...very impressive.

    If you do make another lathe charge the camera battery up and do a project thread please... I am certain it will be followed with massive interest.
     
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  10. Richard.

    Richard. Member

    Messages:
    12,463
    Location:
    Cambridgeshire
    Defo impressed with that.
    What a great little project and what's more you've built something that requires great accuracy. I would love to see you make another and be prepared to have some of those ideas robbed. Don't leave out any details.
     
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  11. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    it definitely earned its keep, more than once, if I remember correctly it cost me circa £150 to build, including having the spindle machined and buying all the parts, chuck included.

    believe it or not those brass end caps I used to make 10 pairs at a time every 10-15 days. They sold for £12 a pair posted ( postage was around £2 then and brass was a lot cheaper than it is now)

    took me a while to get the knurling some where decent

    I also used to clamp smaller stock in the tool post and mill it, the finish wasn't brilliant but it was acceptable.

    ill dig out more pics when im on pc, sure to be more on there
     
    Richard. likes this.
  12. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    ok dug through some old pics on the PC, some really crappy quality ones there, but they'll have to do...

    These are the K baffles that went into the silencer, 3-5 each one depending on the silencer length, 4 was enough to make the rifle silent ( it is just an air rifle after all ) some people just wanted longer ones to look good.
    There was a master that I machined from aluminium, or aloominum if your state side, on my little homebuilt lathe that would be fit for nothing, as I was told when trying to get input on building it. These where then cast from an RTV silicone mould I took off the master baffle, using a 2 part plastic cast stuff of ebay - apparently popular for little army men vs wizardry type games


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    These would be arranged as below. Turning a bit of thick walled aluminium tube down made a spacer for the front of the silencer, a small strip of felt was glued around the rim of each baffle to reduce vibration

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    the end where press fitted on, so the measurements had to be good to make sure the ends stayed in, and you didn't create a sealed tube of broken plastic - this was a "stubby" one I made for someone

    here is two "normal" length ones for plain barrels, 3 recessed grubs screws in a Y arrangement at the base of the silencer secured it to the barrel

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    When I got the knurling a bit better, I started to produce cocking handles, some of the cheaper guns just came with a thin plastic tube pressed over the cocking arm, which wasn't particularly comfortable or easy to grip.#
    I also made "barrel shrouds" which is basically a big centred pipe over the barrel to make it look chunkier. I experimented with drilling the barrel at the end, and trying to use the shroud as a "contained silencer", it worked but not as good as conventional one, and deburring the riffling afterwards made it pretty pointless in terms of time and effort.

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    With forum rules in mind ill end this post here, next one might vanish....
     
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  13. spencer 427

    spencer 427 Member

    Messages:
    2,717
    Location:
    uk colchester
    Brilliant project....I like that .
     
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  14. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    as said above this one might get took down, it has pic of air rifles, above post is just some metal tubes and plasti-cast parts

    These guns, used to sell for around £80-100 each, back when you could internet order them and ran on c02, as can be seen it has a bottle at the front, it also has one of my silencers on it. Other than it is standard

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    I figured out that 22mm hydraulic pipe was the same inner diameter as the tube that is closest to the stock on the gun ( this tube holds the hammer and valve assembly, and the gas bottle screws on the front).
    By carefully copying the holes and slots in the tube, the internals could be put into a much longer tube, which when fitted with a one way fill nipple ( paintball guns use these regularly) could also contain the gas and get rid of the bottle, making the gun much lighter and nicer to carry about, and also nicer to look at. A few brass bits and a different stock transformed the above to below - yes really it is the SAME gun ( I did get the paint finished but cant find a pic of it - but I did take my newfound modifications and ideas a LOT further) after showing off my new shiney parts and ending up making them for everyone and their brother, my gun wasn't so different anymore.

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    I touched up a few scratches with a marker pen, and I had made the silencer a loose fit so I pull it apart and experiment with internals without making a new one every time. when I was happy I epoxyied it back together and painted the rest of it black to match.


    This the first and only stock I made myself, I don't have the patience for wood work. I didn't fit a long-tube to this one as it went for sale, and not everyone had a supply of c02 to refill their guns with, although I remember it becoming increasingly popular as paintball gear came down in price.

    It is a bit more obvious it started life as the same model of gun in pic number 1

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    Quite liking the bids and offers I got on this gun - almost 3 times its cost, but not liking selling my "pride and joy" 3 weeks after making it, I set out to make something special. something unusual. something that has every mod id ever done all in one gun, but first I had to find a stock to hold it all together. Some of you may remember these spring operated guns from the 70's-80s I believe?

    a Jackal parabellum

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    not actually mine, just a generic image, but I managed to find replacement stocks for these things! One was quickly ordered and with a bit of butchering and fibreglassing, it would hold the internals of a xs79 ( the gun from pic 1 of which I had about 3 of in various forms of modification)

    As you can see the inside of this stock was completely butchered out, allowing the "long tube" mod to be used - that is a fill nipple sticking out the end to recharge it.
    Above is the end of the barrel - unpainted so the silencer sits on nice and squarely, you can see the "barrel shroud" clearly in this picture, as the barrel is only 15mm in diameter, and looks like a weedy peashooter

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    The problem with fitting a big shroud is the back of the gun wont fit together, longer pins must be machined, and also a raising block to hold both tubes together and parallel . it can just be seen in this pic, directly under the opening to load a pellet ( the breach), the angled flat is the block. Gas passes through it, and two pins connected to the loading bolt and hammer assembly, so it took me about 3 days just to make that little 5" piece of aluminium, and about 400mm of ptfe rod perfecting a gas tight tube to pass through it, from the bottom tube to the upper tube

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    I wanted a fancy silencer different to everyone elses, so I incorporated a "muzzle weight" into the end of it - completely pointless on an rifle but looked the part.

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    heres the full thing set up on the bipod

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    I think that is about the biggest project I've done on my little homemade lathe, all of them were eventually sold off as I had less and less time to go and use them
     
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  15. Bill Edwards Member

    Messages:
    4,215
    Location:
    Scarborough, North Yorkshire
    I'm not a fan of airguns as such, and certainly not making them to look like that. However, from an home engineering point of view, nice work.
     
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  16. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    I can understand that. A homemade made lathe is only as accurate as you make it. Fiddling around with these particular air rifles means anything you make or adjust must be able to hold 850psi at the bare minimum, as this is the approximate pressure of c02 in the bottles. It could reach 1000psi if heated up, left in the hot sun etc.

    also when threading barrels and making silencers etc, they have to be very accurate too, usually 2/10ths of a mm, much more than this would create "clipping", which is where the pellet would strike the silencer on exit and its impossible to shoot effectively.

    The pellets are 4.5 and 5.6mm in diameter or .177 and .22 inches. The hole in the end of the silencers where 5.5mm and 6.5 mm, sometimes nearly 8" inches away from the end of the barrel, so it took a fair amount of accuracy to achieve. Unfortunately it is the only real project I have done on the lathe that has needed this level of accuracy, or I would have chose something else to post about
     
  17. Bill Edwards Member

    Messages:
    4,215
    Location:
    Scarborough, North Yorkshire
    Oh I'm a shooter myself so no problems with it there, and I understand the accuracy requirement perfectly having fitted a mod before. It's just that I'm not a fan of pellet guns nor anything dressed up to look like assault gear, I'm into proper rifles :)
     
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  18. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    I get you, I never managed to progress to proper rifles, getting cabinets and licensed and a shooting permission etc, made do with the air rifles, still got the rabbits all the same
     
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  19. sardine

    sardine Member

    Messages:
    2,405
    Location:
    Buckinghamshire
    Having such a close tolerance to the end cap on a moderator is not something I've ever heard of when I worked as a gunsmith. Nor can I see much advantage to it, you're just making it more likely that it will interfere with the passage of the pellet / bullet.
     
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  20. gavcarter

    gavcarter Member

    Messages:
    221
    Location:
    Hartlepool
    the idea was that as little air as possible would follow the pellet through, trapping the rest in the silencer thus making it quieter. Most air rifle silencers available at the time are literally washers and springs inside a tube, with great big 10mm holes through them they didn't really do much. With c02 the problems worsens as it is still rapidly expanding as it leaves the muzzle, where as an "air" rifle this has happened within the first 6" of the barrel
     
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