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TOPIC: Unimat SL Micro Lathe

Unimat SL Micro Lathe 5 years 11 months ago #25313

Jonny Retro wrote: Motor, bracket & pulley assembly - note 2-pin mains plug:
...

Actually the 2 pin plug is OK as the motor is double-insulated (see the square within a square symbol on the motor). You will probably find the earth wire is not connected internally anyway. Wouldn't do any harm to earth the bed of the lathe though.

Reminds me of doing an installation in Korea where I kept getting small shocks from the metal case of their PC. They use a strange mixture of European and American style plugs over there without any apparent logic where voltage is concerned (they use 220 and 110V, but either socket can have either voltage on it :blink: ). They had the PC's earthed EU plug plugged into a non-earthed, two pin adaptor, into an earthed American style extension lead :S , so the PC case was floating at about 40V.

Anyway, back on topic: Nice piece of kit. I want one now (and a milling machine ... and somewhere to put them :( )

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Last edit: by Jonny Retro.

Unimat SL Micro Lathe 5 years 11 months ago #25318

I sacrificed a sheet of 3mm styrene to make square beams out of (so I can make round things out of them) ... results aren't necessarily any better than with the Hobbyking 69in1 - but the 4-jaw chuck makes things a lot easier :)



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Re:Unimat SL Micro Lathe 5 years 11 months ago #25408

waterbok wrote: ...
edit: how about mounting the ball turn thing on the side off the crossslide that should gain some extra room.

Vintage info


I missed your edit... but yes, I see what you mean - a step off the side but fixing on top of the slide could work, and just by making it deeper it could potentially solve the problem of the centre of the slide not going over the centre line of the lathe. From the top of the cross slide to the top of the bed rails is 24mm ... I'd want a couple of mm clearance, and I'd think that the step would need to be at least 10mm thick for stiffness.

Having taken off the motor/spindle pod from the base, it's apparent the lathe has been designed with a 20mm riser block in mind - the post has a second fixing ring lower down.

The maths still doesn't add up for a ball turning attachment - 12mm originally + 20mm + 12mm step = 44 mm, and the smallest tool I've seen so far is still bigger than that (47mm + the cutter & potentially a bit more.

I'd need a bigger, gutsier lathe & mill to think about making my own in steel, though a lighter weight one in aluminium could be a possibility.

:)

That site does have some good information on it, even if it is badly presented & all over the place ;) Another good one (same caveats though) is www.lathes.co.uk/emco/

:)

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Unimat SL Micro Lathe 5 years 11 months ago #25411

I had a quick go at whizzing something up in nylon-66 - a Plastic Weld nofalldownerer ... it's of limited use as the bar I started with wasn't really big enough, so there wasn't enough left to taper the outside properly ... but that's not the lathes fault - the inside of the cup is smooth with a capital SMOO :)




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Last edit: by Jonny Retro.

Unimat SL Micro Lathe 5 years 11 months ago #25418

HI!... You need something like these J/R!!!! :woohoo:





We have a cutter at work that is "U" shaped, so making ball ends is easy.

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Unimat SL Micro Lathe 5 years 11 months ago #25818

I haven't quite give up on ball turning - but the methods I found for doing it without an attachment still wouldn't really work, one required precise angled cuts (I have no way to control that, & no space to fit something), or a very long series of cuts of very precise depths/lengths after some mathematical jiggery-pokery ...

My dad assured me that it was possible, for decorative work anyway (rather than the precision needed for balljoints) to just do it by eye ... I was skeptical but thought I'd have a go, first with some aluminium:



Gave myself a head start by tapering one end as much as possible:





Basic shape done, quite a few visible steps ...





... but after filing & sanding, it looks ok:





I tickled the other end a little & had a go at a 2nd one - they're not identical, but in purely visual terms (rather than mechanically) they're good enough. I'm going to use these as the basis for a couple of scale fire extinguishers - but as it'd be a shame to hide the shiny alloy finish, they'll be _very posh_ fire extinguishers;)










I've also been wanting to make a 1:10 scale air compressor with a big tank, starting here with a chunk of 36mm nylon-66 round bar, spun between the reversed 3-jaw chuck & the tailstock centre:







Cutting/shaping done, basic method was to make a series of cuts from right to left of increasing depth but of of decreasing length to start, then run the rest from left to right with varying depth ... I can't give you precise dimensions but it was something like 1 notch in, 5 across to start, ending with 5 in, 1 across at the end. On the final few passes I was getting the swarf off in almost one piece :y:






I didn't take intervening photos , so the next photo is skimming the entire length, after filing & sanding one end, and drilling & tapping to M4 so I had something for the the normal 3-jaw chuck to grip on:





Other end done ... I'm undecided about filing the screw hole or just using something much less obvious.




:)

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Unimat SL Micro Lathe 5 years 10 months ago #25869

I finally got around to checking the spindle bearings, intermediate pulley & the inside of the motor - I needn't have worried, the insides of the spindle & pulley were fine, so I just wiped off the slightly crusty grease from the outside edges of the bearings, regreased & reassembled.

The end cover has to come off the motor first, then the brushes have to come out to disassemble it, I marked the brushes, holders & fitting holes as I pulled them out so they went back in the same way.

The motor end bearing was a little drier than I would have liked (as was the felt washer that feeds grease to the nose bearing, but the dirt & swarf that supposedly collects inside the motor (thanks to being sucked in by the fan) wasn't there - just a bit of carbon dust from the brushes (especially on the capacitor). The brushes still have plenty of meat on them, as does the comm., I just gave that a quick tickle with used 1000 grit wet & dry paper - it sounded the tiniest bit rough for a couple of seconds, but must have bedded back in very quickly :)

I just realised that I should have taken a photo of the insides - it has field coils rather than magnets.




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Unimat SL Micro Lathe 5 years 10 months ago #25922

Sorry to go off topic a little Jon but i was wondering what this great little machine would be like at cutting down pistol barrels accurately?

Im planning on doing a little custom build on one of my crosman 2240 air pistols i have i wanted to make a short barrel build version and was going to cut the barrel down. I know ill lose a little fps but i really like the custom look of them. Im hoping on taking it from the first pic below to the shorter barreled versions in the later pics but wanted an accurate cut with a machined finish.

obviously the foresight would come off the barrel removed for cutting then reattached and the foresight put back on to the newly cut end.
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Last edit: by Jonny Retro.

Unimat SL Micro Lathe 5 years 10 months ago #25925

tamiya nut wrote: Sorry to go off topic a little Jon but i was wondering what this great little machine would be like at cutting down pistol barrels accurately?

Im planning on doing a little custom build on one of my crosman 2240 air pistols i have i wanted to make a short barrel build version and was going to cut the barrel down. I know ill lose a little fps but i really like the custom look of them. Im hoping on taking it from the first pic below to the shorter barreled versions in the later pics but wanted an accurate cut with a machined finish.

obviously the foresight would come off the barrel removed for cutting then reattached and the foresight put back on to the newly cut end.


It'd be theoretically possible, I'd need to get a steady for it though.

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Unimat SL Micro Lathe 5 years 10 months ago #25928

Some of the guys on the forums have taken a hacksaw to the barrel but that seems a little unscientific to me :silly:

If we could agree on a price to do it including the purchase of your steady ill take you up on it when i start the build :y: wont be until after the xmas period though :y:

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