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Adventures with my Unimat(s)

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marshon: As a novice machinist, and unemployed at the moment, I have plenty of time .......... but very little cash. I have been 'allocated' one (upstairs) room in the house in which to assemble my workshop, so it's 'micro' for me. In the end I want to be able to machine parts for my scale models, so a lathe, a sensitive drill, a tiny mill (of sorts) and a bench drill seemed to be the order of the day. I doubt many will be interested, but I thought I might log my trials and tribulations in attempting to get this shop up and running. The wife (bless her), bought me a Unimat SL-1000 for my anniversary a couple of years ago. She paid £80, and bought some carbide insert tools for it. The column was missing, the quill handle was missing, and various other parts that would have been supplied with the standard machine were also missing. Nevertheless the basic machine was all there and after a clean up, I used it on the kitchen table and to my surprise everything was accurate and I could get +- 0.001" in brass. Cool. The machine was made in 1967/8 so its the better part of 40 years old ....... finding parts has proved to be a f*cking nightmare and the charges in the UK for them are extortionate, when you can find them. It has actually worked out cheaper to order them off a gunsmith in the states and have them shipped over! Way to go Randy you are a life saver. So I bought a 'Unimat 4' for £82.00 off ebay, the parts for this are readily available, and although it's a far eastern import and not a patch on the engineering of the Austrian ones, with careful setting up and adjustment it is on song. I have a number of rotary tools (Dremel type), and I had made some mounts for them to use for odds and ends of work, but I needed the bench drill. No money meant trying to find summat cheap. I got one that was destined for the scrap heap and gave the guy a fiver for it. The English Electric 1/4 HP motor was worth that on it's own, so I think it was a bargain. However it was covered in sh*t and I thought it probably would draw circles instead of holes. I decided to do a refurbishment job on it. So to the tribulations ....... I have learnt very quickly that my hand cut threads are crap. They are ALL out by a number of degrees, so some kind of giude for the taps and dies was needed. The two little lathes have no thread cutting ability, so something simple was required. The problem is that the distances between centres are very small, 5 or 6 inches at best. This means that the largest drill bit I can physically get into the lathes is 9mm (the chucks will take 10mm but it wont fit between centres). I could go looking for bigger drill bits that have a 10mm shank and are short reach, but they cost money and I don't have any...... So why oh why (Chronos and RDG) do you sell a boring tool listed as available for Unimat lathes, when it requires a starting hole 15mm in diameter??!! I could have bought a Glantz (lovely) but £13.50 is a lot when your on the dole, especially when you just forked out £5.75 on a Sorba that won't fit the largest hole that can be drilled on the bloody machines! So, without any knowledge or experience I have had to hand grind a boring tool using just the Dremels and some tiny grinding wheels. I used an old woodworking drill bit since it was made of tool steel. If it works I'll eat my hat. End of the first lesson .....

marshon: Well, I've eaten my Fedora, the damn boring bar worked above all my expectations! No-one told me of the satisfaction you can get from making a tool that actually works! Lovely swirly swarf and no squealing or chatter, at least I'm more confident of making my own tooling in future. Anyway, back to the tap guide for the Unimats. Here's what I had to work with, a bit of scrap aluminium bar (luckily for me it had a machine cut 8mm thread already in one end), an 8mm shouldered bolt and two cheap far eastern tap holders. I took a hacksaw to the ally, then faced both ends and skimmed the outside to give it a shine. The bolt also got the hacksaw treatment and faced off. Then used my super duper new boring bar to open up the hole from 7.5mm to a 12mm light sliding fit Finally assembled the bits, it needs another cross drilling for the small tommy bar, but there's enough meat in the body for that. Fits both Unimats and the drill press too. Cool

John Hill: Hi Marshon,  this is a very interesting topic and I am enjoying it immensly! :thumbup: I use those wood boring bits for aluminium too and they work quite well for that purpose.  Unfortunately I have never managed to get any use out of those Asian tap holders, perhaps I am not mounting the tap properly. :scratch: John

andyf: Hi Marshon,  :clap: :clap: for the ingenuity! As well as drills, spare Allen keys can be ground up into serviceable boring tools for the softer metals. But avoid the crappy ones like those Ikea include with their flatpack furniture. I have more trouble with dies than with taps when threading freehand; when beginning the thread, it seems harder to keep the handles of a diestock at right angles to the workpiece than it is to keep a tap in line. One thing you might try with dies is what I did before making a proper tailstock dieholder. Turn down a bit of scrap so that one end will fit in your tailstock, and the other end (which needs to be faced) will enter the diestock from the rear and press on the back of the die. With the workpiece held in a chuck on the spindle, use one hand to rotate the chuck, and the other to simultaneously wind out the tailstock ram and push on the back of the die. This is easier than it sounds, and  will keep the die square on to the workpiece as you start the thread. Of course, after a few revolutions, the workpiece will want to protrude from the back of the die and collide with the "pusher", but at that stage the die will probably keep itself straight if you retract the pusher and continue. Alternatively, a hole can be drilled in the outer end of the pusher, to swallow the newly threaded work as it emerges from the die. Andy

marshon: Thanks for that Andy, I may give it a try as a temporary measure. A tailstock die holder is in the pipeline, I just need to find some scrap ally of a big enough diameter, say 1 1/2", I also have to work out how to design it so that it will be short whilst still holding perpendicular. Simon --- Quote from: andyf on May 23, 2010, 06:47:03 PM ---Hi Marshon,  :clap: :clap: for the ingenuity! As well as drills, spare Allen keys can be ground up into serviceable boring tools for the softer metals. But avoid the crappy ones like those Ikea include with their flatpack furniture. I have more trouble with dies than with taps when threading freehand; when beginning the thread, it seems harder to keep the handles of a diestock at right angles to the workpiece than it is to keep a tap in line. One thing you might try with dies is what I did before making a proper tailstock dieholder. Turn down a bit of scrap so that one end will fit in your tailstock, and the other end (which needs to be faced) will enter the diestock from the rear and press on the back of the die. With the workpiece held in a chuck on the spindle, use one hand to rotate the chuck, and the other to simultaneously wind out the tailstock ram and push on the back of the die. This is easier than it sounds, and  will keep the die square on to the workpiece as you start the thread. Of course, after a few revolutions, the workpiece will want to protrude from the back of the die and collide with the "pusher", but at that stage the die will probably keep itself straight if you retract the pusher and continue. Alternatively, a hole can be drilled in the outer end of the pusher, to swallow the newly threaded work as it emerges from the die. Andy --- End quote ---

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