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Model Forum / General / Models / May 2007Machining A Ball And Socket On A Lathe
Hi, A project requires me to produce a ball and socket joint but I am stuggling as to how I go about produce the socket... (Ball diameter is 150mm to give you an idea of size) Is there a tool that you can you use to cut an internal radius on a lathe? I've seen the one's for external radii such as the Universal Radius Turning Attachment Arc have - but have never seen one that can internal radii. I'd like to use Aluminium - but I'm now thinking it would be easier to cast it out of polyurethane from a mould.... Cheers, Michael > Hi, > [quoted text clipped - 13 lines] > > Michael What on earth are you upto now? - That submarine of yours got legs? <g> >> Hi, >> [quoted text clipped - 15 lines] >> > What on earth are you upto now? - That submarine of yours got legs? <g> lol - Still the submarine. It's for the 'two axis gimballed contra rotating propulsor' - the idea is to have this ball and socket control the direction of water out the back when connected up to some linear actuators*. This is the last bit that needs to be designed so I can start working on the internals ready for a launch this side of Christmas (this year). *Unless someone else can think of a better method for channelling water through 45 degrees in two axis with a 110mm bore? Michael > *Unless someone else can think of a better method for channelling water > through 45 degrees in two axis with a 110mm bore? Here's an idea you might like to kick around. Inspired by the head on a Huron milling machine. Take your pipe and make a swivel joint so the one piece can rotate about the common axis. On the end bit make another swivel joint but this time at 45 degrees to the axis of the pipe. By rotating the second joint you can get any angle of deflection between 0 and 90 degrees. By rotating the first joint you can then make it point in any direction. I'll leave you to decide how to make it and how to control it! Henry Dragon Wrote: > > *Unless someone else can think of a better method for channellin > water > > through 45 degrees in two axis with a 110mm bore? > > Henry The old kitchen rudder control used two half buckets for speed contro (like thrust reversers on a jet). For direction they pivoted around th propellor with the blade line of the prop aligned with the pivot poin of the rudder above and below. If you mount the propulsor ring in a gimbal mounting you will be abl to turn it 45 in any direction. If you want to get really smart use a differential single mount. Use flexible carbon fibre push pull rod to control horizontal directio mounted at the equator, rotating the rods to control vertica displacement. Alternatively, since you aren't worried about extreme accuracy, mol the mounting in composite material, mounting it in cutless rubbe (slippery when wet) CR is good enough to run real warship propshaft in and I doubt you are going to descend below 60 feet -- rss >> *Unless someone else can think of a better method for channelling water >> through 45 degrees in two axis with a 110mm bore? [quoted text clipped - 11 lines] > > Henry I didn't quite get what you were describing - but after a quick Google I understnad now what your saying and must say I'm liking it more and more. Threw together a quick model of it today out of foam board and it's very tempting route to follow. The only issue I have is the shear complexitity of the control software in order to get it to work probably. For example to go left you have to rotate one section through 90 degrees but at the same time the other section through 45 degrees and back again based on the other section's position so that your only affecting one plane It'd certianly take up less space as well as cause less turbulance to the jet through.... Very interesting.... Cheers, Michael >> Here's an idea you might like to kick around. >> Inspired by the head on a Huron milling machine. >> I'll leave you to decide how to make it and how to control it! >> >> Henry > Threw together a quick model of it today out of foam board and it's very > tempting route to follow. > > The only issue I have is the shear complexitity of the control software in > order to get it to work probably. Now you know why I left that bit to you! I looked at your ball and socket. It seemed that there would not be much socket left after you cut away enough for the nozzle to move 45 degrees in any direction. In fact with your dimensions ( 150mm ball and 110 mm nozzle) less than half, so some other means of keeping the ball in place will be needed. There would not be much ball left after you cut away enough for the water to enter unimpeded whilst deflected 45 degrees in any direction. Again less than half so now ball and socket will not meet! For the edge of the ball not to emerge from the edge of the socket the pipe/nozzle diameter must not exceed 38% that of the ball. So your 110mm pipe needs a 290mm ball at least. Have you figured out a mechanism to move the ball 45 degrees on two axes? BTW tried to send you a picture of the Huron head but could not decipher your email address. Henry >>> Here's an idea you might like to kick around. >>> Inspired by the head on a Huron milling machine. [quoted text clipped - 28 lines] > > Henry Hi, Yes that's why I said it looked very appealing - I tried the ball and socket with a card cut-out and even with the largest circle I could get on A4 paper I found it was still too small for the full 90 degree swing I was looking for. I've only recently changed the design from the original contra-rotating setup to a twin jet setup (as pictured: http://mhims.co.uk/Images2/TwinJetScreenShot.JPG The assembly uses 110mm and 160mm underground drainage pipe and fittings to minimise fabrication) which means the bore had to be increased even further to 160mm which meant there was just too much 'space' in the socket which I feel will really affect performance. I was planning to fit it inside a gimbal and then control that with a set of linear actuators originally. Though I'm now set on this new method and I think a couple of geared down motors are best pressed into action with some form of feedback on the motor (most probably Hall Effect) so as to control it proportionally. (Yet more electronics to design and write) I must say I can't quite picture this new method yet but it'll certainly look unique <g>. I'll work on the design tomorrow and over the weekend and I'll be happy to send you some initial designs if you'd like? Next week I won't be doing any work as my new Model B Super should have arrived.* For my email you need to remove the 'Q's: michaelHURONHEADhims@blueyonder.co.uk (removing the obvious) Cheers, Michael *Whilst I realise I have committed the 'sin(s)' that is ordering from Chester/purchasing a combination machine (please delete as appropriate). In my defense I did go with the old adage "Buy The Size Above The Size You Need" >>> Here's an idea you might like to kick around. >>> Inspired by the head on a Huron milling machine. [quoted text clipped - 28 lines] > > Henry Thanks Henry - the emails just came through. Cheers, Michael >> Hi, >> [quoted text clipped - 15 lines] >> > What on earth are you upto now? - That submarine of yours got legs? <g> By the way - I'm curious to know why you show a keen interest in the sub. compared to others on the group.... Do you have models of your own? Cheers, Michael >>> Hi, >>> [quoted text clipped - 24 lines] > > Michael It's the only submarine thread and it presents a different intellectual challenge to think about. The Harrier vectors thrust by rotating the jet pipes - do you need to vector the thrust in more than the one plane? >>>> Hi, >>>> [quoted text clipped - 28 lines] > challenge to think about. The Harrier vectors thrust by rotating the jet > pipes - do you need to vector the thrust in more than the one plane? Fair enough... Yeah - I'm trying to do anyway with both the sets of diveplanes and rudders and as I'm using a silicone skin for the tail section (abit like a fish tail) you can't easily install only one set of planes as there's nothing rigid to mount onto. Michael > Is there a tool that you can you use to cut an internal radius on a lathe? OK, here is a method I just evented for you! It's only 5 minutes old! Get some rod in the length of the radius (a bit longer, because you'll have to drill holes in, exactly the radius apart). Made that part? Get some rod that you can clamp in the tailstock's drill chuck. Bore a hole through one end and put a screw through that hole, connecting the first part and the second part. Now drill a hole through the lathe bit's shaft you intend to use (or weld some crap onto you can drill through). Put a screw through that hole and through part #1. You are finished! How to use it: Do not clamp the saddle, because the rod will push/pull the saddle to the proper position. Just use the cross slide to feed to the center. For feeding axial, use the tailstock' spindle. Brilliant, isn't it? :-)) You owe me some beer, if you should come to Munich! You can improve that with an adjustable rod and bells and whistles, but the principle should be clear. Problem with my maybe not so brilliant idea is, that you can't turn 180° of the socket, but just maybe 120° or so. Nick >> Is there a tool that you can you use to cut an internal radius on a >> lathe? [quoted text clipped - 30 lines] > > Nick Ok let's see if I've got this - presumably I haven't as I can't see it working...... http://www.mhims.co.uk/Images2/LatheTool.JPG Cheers, Michael >>> Is there a tool that you can you use to cut an internal radius on a >>> lathe? [quoted text clipped - 39 lines] > > Michael Forgot to add that the brown coloured part is the lathe tool..... >>> Is there a tool that you can you use to cut an internal radius on a >>> lathe? [quoted text clipped - 39 lines] > >Michael I think what Nick is alluding to is more like this:- http://www.test-net.com/radius.jpg I have modified Nick's concept to use the top slide for axial feed and to have the rod clamped between a cross slide slot and a clamp that goes on the bed. This would work more easily on a Myford than on an American style lathe. Unfortunately you want to turn a radial bush and, possibly, a radiused bore. Nick's idea can probably be adapted to this, especially as you will probably need a radius of about 75mm. Simply disconnect the cross slide leadscrew and orient the rod at right angles to Nick's concept. Turn the topslide around to line up with the cross slide and use it to put the feed on, then use the carriage or leadscrew in the normal way. At least, I think that's what he meant :-) regards Mark Rand > I think what Nick is alluding to is more like this:- > http://www.test-net.com/radius.jpg Yes, that's the principle. The extension is using the tailstock for feed along the spindle's axis. Sad that someone else came to this idea decades before. I was born too late. :-)) Nick >> I think what Nick is alluding to is more like this:- >> http://www.test-net.com/radius.jpg [quoted text clipped - 6 lines] > >Nick Don't feel bad Nick, most of this stuff was done in Victorian times. Most of the improvements to Victorian ideas have been in metallurgy and electronics -- Regards, John Stevenson Nottingham, England. Visit the new Model Engineering adverts page at:- http://www.homeworkshop.org.uk/ >>> Is there a tool that you can you use to cut an internal radius on a >>> lathe? [quoted text clipped - 39 lines] > >Michael Should work, it's been around for years, One of the Machinery books from the 1930's has it in but it probably dates back earlier than that. . -- Regards, John Stevenson Nottingham, England. Visit the new Model Engineering adverts page at:- http://www.homeworkshop.org.uk/ > Ok let's see if I've got this - presumably I haven't as I can't see it > working...... > > http://www.mhims.co.uk/Images2/LatheTool.JPG <G> This is a different gadget not yet found out what to be used for. :-) No, don't stick the parts together directly, but with bolts. The middle part has the bores right. The left and right part are missing them (similar to the bores in the middle part). Connect the 3 parts with bolts then. You can stretch that setup to be straight. If I would have a decent CAD (or any), I would draw it. But I don't have. sorry! Nick >> Ok let's see if I've got this - presumably I haven't as I can't see it >> working...... [quoted text clipped - 14 lines] > > Nick Ah - I now see where your coming from. Cheers, Michael |
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