Lathe rebuild October I wanted a small lathe to turn parts for rockets esp. I also needed something I could lift and carry up the stairs into my workroom, which is in the loft. I plan to convert the lathe to CNC, but retain the manual controls. I have already experimented with CNC with my 3D printer build. I expect that adding CNC will enable me to make complex and curved shapes such as a de Laval exhaust nozzle, as well as make thread cutting easy. I will focus on the MD65 lathe here and cover the mill in another post.
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Lathe rebuild October I wanted a small lathe to turn parts for rockets esp. I also needed something I could lift and carry up the stairs into my workroom, which is in the loft. I plan to convert the lathe to CNC, but retain the manual controls. I have already experimented with CNC with my 3D printer build.
I expect that adding CNC will enable me to make complex and curved shapes such as a de Laval exhaust nozzle, as well as make thread cutting easy. I will focus on the MD65 lathe here and cover the mill in another post.
The mill table is VERY heavy and will have to go into my garage. For now I have sprayed it with silicon spray and put a paper bag over its head.
The Taig in particular appears to be highly regarded, and is extremely capably for its small size have a look on youtube for Taig lathe videos. However, I had a niggling doubt about distance between centres — I wanted to turn threads or circlip grooves into aluminium engine casings, which I expected to be about mm long — this is out of reach of all of the micro-lathes. So I looked at mini-lathes which are heavier at around 45kg but more capable, and with enough stiffness to handle steel more easily.
All these mini-lathes are Chinese made — online consensus seems to be that quality has improved markedly in recent years, but that they still require some fettling to get the best out of them. The mill came with the block to mount it to the lathe, and also with its own substantial milling table. A few calls to engineer-type mates and some googling confirmed that this was a good model, and the range of accessories made it a good buy.
So I bought it. The guy I bought it off owned it for two years but used it only twice. He bought it off an old boy who was retiring from model engineering. It came with a range of accessories including the small t-slot milling table that attaches to the cross-slide, plus a 4-jaw chuck, several drill chucks and an assortment of arbors and mills.
Above is a pic of the lathe and mill — the mill table weighs more than the lathe and mill head combined. There is not a lot of info about these machines online compared to other makes — I could not find anyone who had published information on a full CNC conversion. Apparently the East Germans sold them at a loss to bring hard currency into the country, after reunification quality went down and eventually they were no longer made as they were not profitable.
I like it that these machines were made in the year the Berlin Wall came down — I imagine that the people who made my machines were hopeful about their future.
Parts are available in the United Kingdom via Essel Engineering. There is an excellent summary available at www. There is also a Yahoo Group for these lathes: prazi-machining.
There is good info in the archives of both groups, but new posts should into the active group. Owner reviews: www. Adding a auto carriage stop: www. Some information on a CNC conversion using the existing leadscrew not ballscrews , some plans and photos of disassembly but no pictures of the finished product: danielbauen.
The lathe was caked in dried grease and metal chips — a combination of brass, aluminium and steel. The previous owner was a big fan of grease — white, grey, black. The leadscrew was coated in sticky white grease, and even the oil holes in the cross and top-slide were packed with grey grease.
There was some surface rust on various parts but none on any of the ways, and it all came off easily with a little WD40 and a green scourer. Underneath the filth and staining the lathe was in good condition.
The leadscrew had a coating of sticky white grease. The gearbox was as dirty as the rest of the lathe but again in good condition — no missing or broken teeth on the nylon gears. I cleaned most parts with petrol and a toothbrush, or WD40 and a rag. Petrol is smelly but really cuts through thick grease. I used petrol to clean the tailstock block and main carriage — this is verboten!
To remove surface rust on steel parts I used WD40 and a green scourer. I used pipe cleaners and a small bottle brush to clean out the holes. I used a can of compressed air to blow gunk out of holes — not as good as a proper compressor however mine is buried in the garage oh for a proper workshop…. I was not sure how to clean the ways, which on this lathe is a solid block of round steel with a flat milled on top.
I gave the end an experimental light rub with a green scourer, and found that it left visible scratch marks. There was a ridge of gunk on the underside which corresponded with the pinch gap in the main carriage. The way had some small dents where sharp tools had been dropped on the top, however it looked like these had been stoned flat as I could not find any raised areas also the bore of the toolpost slide was not scored. Disassembly was straightforward except for removing the leadscrew, which proved to be a pain.
The taper pin in the gearbox side of the leadscrew was bent in place, and moderate tapping would not release it from both sides, as it is indeed tapered. In the end I drilled it out. The next challenge was the little wire c-clip that sits under the inside part of the dog clutch. I worked around with a small screwdriver, and the clip was off.
I disassembled and cleaned both chucks 3 and 4-jaw , lubricating with silicon spray. The 3-jaw was in great condition. Some of the threads on the 4-jaw were pitted and chipped, so I cleaned them up with a small file. Also one of the jaws was binding about halfway in, I used a file again to remove a little material from the jaw which made it run easily in the chuck body.
The manual advises against unscrewing the chuck face plate, because if it is not re-assembled correctly there could be problems with alignment. It is easy enough to get to if needed, and I was keen to get back to a working machine.
Rebuild and lubrication My engineering-type friend Rob recommended giving everything except the ways a coat of silicon spray. Chips will tend to slide off silicon, instead of sticking as they would with grease or other oils. Silicon is also a great rust protector, and is odorless very important for me, if I want to continue to keep the lathe in the house. I have read that silicon spray should not be used for wood lathes as it mars the finish.
Online consensus seemed to be that hydraulic oil, chainsaw oil or compressor oil would do, but proper way oil was better. It was about the same price as motor oil so there seemed no reason not to use the good stuff. I applied it using a 6mm paint brush, a thin coat only but making sure I got into all the nooks and crannies. The Gang of Four — awaiting the firing squad. Reassembly was fairly straightforward. I had a couple of false starts around the change gears and main leadscrew power dog clutch, where I had assembled in the wrong order and had to start again.
The cross and top-slide bosses are secured with two cheese-head screws, the tailstock and main leadscrew bosses are secured with four cheese-head screws. This first happened on the cross-slide the first time I wound the handle all the way in.
As the cross-slide got near the end of its travel, the handle became harder to turn. I stopped and checked that the gibs were not tight, but when I tried to turn the handle again it was stuck — I ended up using some heat and gentle tapping to free it from the leadscrew.
Close inspection showed that a chip of metal from leadscrew shaft had come up and dug into the boss I cleaned up both surfaces with a fine file and emery paper. At first I cursed myself for not properly oiling, however even soaked in oil the leadscrew began to bind again as I wound the cross-slide closer to the carriage. I guessed that because this was happening only as the leadscrew was wound all the way in, that there was some misalignment between the nut in the base, and the boss in which the leadscrew rotated.
This was causing the leadscrew to bend and put pressure on the boss in which is was rotating. There are no bearings in any of the leadscrew assemblies apart from a brass bush for the main leadscrew, mounted inside the headstock.
This misalignment was caused because I tightened the backplate and boss screws to the top part of the slide e. The lathe came with a boring bar with a removable 3. I also bought some cutting fluid — CT I have no idea how good or otherwise it is, but it was widely available on eBay so I guess it is at least commonly used.
I also bought some round stock — aluminium round and tube, and some mild steel. This stuff is not cheap! Must find a local supplier. Also must try not to think about all the bits of metal I have discarded over the years… Next steps I really enjoyed the rebuild process, there is something very satisfying about cleaning and oiling a machine.
The whole process described above took about 40 hours.
HOBBYMAT BFE65 PDF
Meshura Top tips for machining Bakelite:. Thats pretty quick for a small table. The head came with a variety of bracketry which made mounting it a doddle. In the end I rubbed it down gently with some oil and fine emery paper, and left it at that. I stuck one side to the aluminium cover seen in previous picand the other to the adjustable stub of aluminium angle that you can see in the photo above.
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Also available: belts , spare parts and the slow-speed attachment BFE 65 Milling Heads The same vertical milling head with its , , and r. When set up as an independent unit, a mm x mm co-ordinate table was employed, equipped as standard with rulers on each axis. Early heads were very reliable, with reports of them being in continuous service for over 25 years, Unfortunately, heads made after approximately were fitted with "improved" plastic gears in place of the earlier fibre type and theses can suffer from loose bushes that allow them to slip down and partially engage the face dogs of those beneath, so locking the drive. Fiddling with the control levers and twisting the spindle backwards and forwards usually enables the machine to start up again - and run in an apparently normal manner. Even if stopped and started several times the symptoms may not reappear so, if you are contemplating a used example, warm the miller up by running it for ten minutes on top speed and then do a stop-start test at least a dozen times on every speed. Only then should you accept it as satisfactory.
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The lathe was also made in a wood-turning version as the MD described here - this too being branded in a number of different ways. During the early s the Chinese made an exact copy of the MD65, even to painting it the same shade of yellow - however, it can easily be distinguished from the real thing by its use of a very heavy cast-iron base-plate, poor detail finishing and a lack of standard accessories. The Bulgarians also got in on the act with the ZMM Company offering the green-finished "Hobby Sliven" - a machine based on the MD65 but with a number of significant differences including a round main bed with no flat, the carriage being stabilised by small diameter, bed-length bar to the rear. One notable improvement was the use of a very much more robust lever assembly to engage and disengage the leadscrew dog clutch.
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