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| Proxxon PD400 |
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| Fergus OMore:
Have you a faceplate? If you, that is a rather big catchplate. If you haven't, use the three jaw with a centre in it. Hope you enjoy your GHT.book |
| wongster:
No, Norman. I don't have one yet. I can order one. The Centre Turning Accessories sold by proxxon are not that expensive. Just the waiting time for the fulfillment of the order. Maybe I'll go get a MT3 centre later. Regards, Wong |
| andyf:
Hi Wong, The drawbar: If the hole in the gear cover B is ~3mm larger than the outside diameter of the spindle, you can make a nut with a boss projecting from it. The boss will have two diameters, one being about 24.5mm to pass through the hole and push on the end of the spindle, and the second about 21mm to fit inside the spindle bore to locate the nut. If the hole in the gear cover is too small for that, either enlarge it to around 25mm or make a nut as above, but with the hex section of the nut smaller than the hole. This will allow you to tighten the drawbar and then close the gear cover. Or do what many of us would do - run the lathe with the cover open, and keep your hands clear of the gears and pulleys. I think you had a Sherline, and they don't have a cover over the pulleys. If you still have all your fingers after using that lathe, you will probably not lose any of them with the Proxxon. Andy |
| Miner:
Wongster, With a MT 3 arbour and drill chuck in the spindle, Work fixtured to the cross slide and at the correct elevation, Your only drilling into the work. That end thrust helps to keep the MT taper tight. Using a MT-3 type milling chuck to do milling that would put side loads on your taper and chuck would require a drawbar. After looking at your pictures, You could machine something that fits the outer end and inner bore on the left hand end of your spindle like a stepped washer. Buy a long enough bolt that matches the drawbar threads in your MT arbour and then machine the bolt head to thin it enough so that your lathe door will open. You also DO NOT WANT TO TIGHTEN THAT DRAWBAR UP REALLY TIGHT. There's no need. That drawbar is only to prevent the MT from moving out and becoming loose. The tighter you have the drawbar then the tighter your wedgeing that male MT in place. That would then require very hard hammering on the end of the slightly loosened drawbar to push the MT out enough so it's released from the bore. All that hammering is REALLY bad for the lathes spindle bearings. As far as the scrap metal and machine it to at that 60 degree angle? That's the most accurate way so you'll have a point machined true to the lathes center of rotation. It's been machined while rotating within the spindles own bearings. But!!!!! It has to be machined and left in place. As soon as you remove it from the chuck you'll have to slightly remachine it true each time you want to use it again. Work can be held on the lathes cross slide and be machined in the exact same way as it would in a normal vertical milling machine. All you have is a small, short travel, vertical mill lying on it's back. Work size, table travel, and rigidity is obviously far less than a compareable weight vertical milling machine. A proper lathe milling attachment that fit's your lathe would give you an easy way to set the work to the correct elevation. But it's not a great substitute for a proper milling machine. I mentioned the use of drill chucks, milling chucks, boreing heads, etc with a MT-3 arbour as a few examples because you had asked what that headstock bore could be used for. Believe me, After reading thru GHT's book even once, Then all of this will make far more sense and be much more understandable to you. I've edited this to add, That GHT book isn't the only information you'll ever need. I'm certainly not trying to complicate the issues or sidetrack them off elsewhere. But machining as a single subject even at the hobbiest level is so vast that you'll never learn it all. That's what keeps it interesting. If you stick with it you'll never quit learning. Pete |
| Fergus OMore:
Might I add a little bit to Pete's excellent comments? Initially, when one bought a lathe it came with a pair of centres and a faeceplate as STANDARD. None of this rubbish about 'get a three jaw chuck' and then the rest will follow. Frankly, nothing can be further from the truth. The next bit of the armoury is a FOUR JAW INDEPENDENT CHUCK. With either a faceplate or a 4 jaw, you can hold a drill which you can with three jaw but you can hold round or square stuff, make a boring bar, hold odd shapes for facing and a multitude of tasks like making nuts and bolts, tool holders and so on. Before moving to 3 jaw stuff, probably the next thing is a drill chuck or two and a heap of Morse taper blanks. True, you are making your lathe into a drilling machine and as Pete says, a milling machine. In all honesty, the use of a lathe to work between centres is the last thing on most minds. Think carefully, but if you are going to work 'between centres' you are going to need a fixed steady and probably a running one and - some means of slowing your lathe down to screwcut- without having a heart attack! You can make the steadies with either a faceplate or a four jaw but you are going to be very skillful to do it all on a three jaw. Maybe I'll get banned or burned as heretic or something really exciting. Or get a lecture on the merits of carbide tooling or even parting off. These will really be a treat. We'll see. Meantime, enjoy GHT. |
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