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bertiedog

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Posts posted by bertiedog

  1. I don't think the chopping blocks are real granite, more likely it;s Marble or resin and marble dust, and Marble does react badly to acids, it eats into the limestone content, leaving marks. The resin mix type resist acid reasonably well, due to the resin.

     

    Oiling any marble first, will help if acid flux is used, the oil should a mineral oil, or grease.

     

    There are also flat Slate cooking blocks, usually composition slate, a resin and slate dust mix. Old marble mantlepeices usually have a good flat source, maybe broken from a building site or building material scrap merchants.

     

    Glass makes the best surface plate, short of the real thing, float glass is dead flat. Many glass merchants will have off cuts of thick grades, get them to grind the edges, or used a diamond sharpening plate to remove sharp edges.

     

    Stephen.

  2. Very nice, but not powered? I presume not required as they power easily I did two of these, which are very reasonable castings etc, within the usual K's limits. To get haulage, use Mike Sharmans method, a floating rear axle, lightly loaded front axles and weight transfer from the tender to the driving axle centre., result it will haul about 6 coaches, the limit was the small Mashima more than traction.

  3. The listing is breaking Ebay rules, no loading of postage to cover low bidding is allowed , the seller is open to a complaint being made against him. He should have quoted postage and placed a reserve start price to minimise his risk of a low value sale costing him money.

    People should read the rules on Bidding and Selling, they are not complex, but some sellers, especially Buy it now from the FE, load the postage to make the headline price low.

  4. http://cgi.ebay.co.u...e=STRK:MEWAX:IT

     

    Watched the above kit finish earlier today and am just shocked at the final amount

     

    Have bought three myself in recent times and never paid more than £15 including postage

     

    George would be astounded at that price

     

    I have got 2 of these.....must get them on Ebay, as you say George would have been staggered at the price, but they are rare now in un-built form, quite a nice kit anyway.

    Ebay has surprises, but often these prices have a stack of bidding, there is interest, and if people want an item they will pay for it. The annoying ones are the high start prices, and plain ludicrous reserves some sellers start with, quite out of step with comparable items.

    The other nuisance are private listings where false bidding is obviously being used to force prices up, quite illegal but done widely.especially on HK listings etc , mainly for new electrical items.

    Stephen.

  5. The bogies look too short.;)

     

    Different scales, different standards, O gauge is still split between course scale for tight curves and fine 7mm scale, and course scale stock often has a short wheel base, or the bogies are undersized to get the swing under the side boards etc. The price is pretty consistent with other coaches of the type on Ebay and Vectis auctions. I commented as it seems a fair offer for what is there. A kit un-built would cost quite as much, and might not include bogies or wheels. O gauge is expensive.........

  6. I wonder which precious metal was used? can't imagine how he arrived at that price otherwise.

     

    :O

     

    It is an O gauge coach, kit built , unspecified maker though, and average priced for such a 7mm kit built item, It would be difficult to find cheaper if it is well finished, and seems a reasonable start price.

  7. http://letsmakerobots.com/node/259

    Covers a simple conversion leaving the motor in the servo case, but it can of course just feed the motor via leads. Any servo can be used, but a clone of a standard Futaba may be best , rather than the sub miniature type shown, the pot can be left or the two resistors fitted to provide the null position. The case could be scrapped, or left if space allows.

    The standard Futaba sized servos contain a motor very much the same as the gearhead type that you are using to power the truck.

     

    Stephen.

  8. I have sent details by PM, but basically the ESC from Micron are for three phase AC brushless motors, not DC controlled Brushless motors, two very different types of motors. What is needed for the truck is a DC proportional controller as used in boats and robotics, and a miniature type as well. The solution may lie with a converted servo board, which has the correct action to work with any small DC motor as a controller with speed and direction control. Details of such conversions are on the net.

     

    Brushless AC motors have never found favour in model railway use, they are high power types, very efficient, but are non reversible,(not needed in aircraft), they run hot, and again this works well in the cooling airflow in a model aircraft.

     

    The brushless DC motors we use in Model Railways are still fitted with a commutator, and this allows them to work on DC and be reversible.

     

    Stephen.

  9. "Hi the date is 1/6/06, no not kept in a fridge as they would get moist. They have been kept in a larder in an air tight container, which stores our fresh produce. Thanks"

    So I can't even eat my £10.00 each Smarties angry.gif

    It is deeply worrying to think that there are "Smarties Collectors" out there , on the loose, and not under care and close supervision......

  10. The motors may become an issue , they are available from others apart from Robotic suppliers ....at the moment....they were used in cameras for Autofocusing, now being replaced by linear steppers, so have been dropped from manufacture.

    This company supplies a lot of new but surplus motors and gearboxes, many types and ratios.

     

    There are lots about, including occasionally the Nikon enclosed type, with a coreless motor. Ratios range for about 40:1 to 350:1 on the open frame gearboxes. Ebay feature them quite often, keep an eye on the size, bigger versions are still made.

     

    There are some other bevel gears from aeromodeller suppliers, and 3:1 spur gears from Ultrascale.... and commercial gear factors make small plastic bevels about 6mm diameter plus.

  11. As a general rule do not attempt to ream a slot with cutter of the right diameter, any out of true holding of the cutter will produce a wider slot than expected, and a bigger amount of material is removed in one go. On light milling machines, or lathes, it may also push the work aside a bit as it cuts, taking up play etc., and result in a slot not quite on the centre line that you intended.

     

    • Best practice would be to run a smaller diameter slot cutter or mill through the work, not quite to full depth as well, on the nominal centre line. The fact that the slot will be off centre etc., no longer matters, and the second cut should widen the slot towards one wall, with a final cut at the correct position for one side face, then go back and widen in the other direction. For the second and subsequent cuts lower the slot cutter or mill down to the final depth as well.

    I know this sounds a lot for a 3.5 mm slot! but it's the way to do any slot in milling work, and with 3.5 using the 3 would suffice with just three cuts at full depth. The first could be one side, but why risk it? Work form the centre out, it allows for corrections. Go too far and it will have to be packed out and glued, that's all in this case.

     

    • If you have the rods already then mill the slots wide anyway, put the bearings into place with axle with extensions through the rods in place, and then bed each bearing in epoxy, when set the bearings will automatically be in the perfect position first time.

    This works best with full width bearings, not top hat bearings at each side, and may not be possible with the driven axle due to the small space

    • With cast mazak, to get a good finish and not get grab on the mill, use a spot of lubrication, oil and paraffin mix etc., or water at minimum.

    Hope this helps,

    Stephen.

    • Like 2
  12. The motors came from autofocus video camera lenses, a role taken over by linear stepper motors now, so the market disappeared. Techobots are not the only supplier and quantities exist at the moment on the surplus market, but as time goes on..........

     

    The gearboxes are very good, the motors very reasonable, they can be replaced with coreless motors on some designs, but I found the motors fitted could deliver lots of power anyway due to the gear ratio. Generally very quite, unless revved up hard!!

     

    Slightly larger versions with epicyclic gear boxes are still available, in production, it is the tiny motored versions that are going to get more difficult to source in future.

     

    Stephen.

  13. On all lathes all chucks fit, within the size range, but each lathe will take them in a different way, the chuck is bolted to a back plate that is designed to fit the lathe nose accurately.

     

    The Lathe makers offer the backplate as a blank and it is fitted to the lathe and finish machined on the lathe, to match the back of the chuck, which will have a true round surface and hole in the middle. The bolts only retain it to the back pate, the removal is via whatever system the makers have fitted.

     

     

    I do not know what the Proxxon has, but it needs a back plate to suit the lathe, and then a chuck of the right diameter, to fit the lathe.

     

    Chronos and other suppliers do small diameter chucks, it does not have to be an expensive one if conversion to soft jaws is involved. Small chucks with soft jaws are rare, but you can get the hard jaws modified by having mild steel faces welded on and drilled and tapped to take aluminium faces.

     

    There are expensive 4 and 3 jaws of watchmakers size from Cowells, that would fit via the backplate, and Burnerd do make new, at a high price in any fit and jaw type.

     

    Stephen.

    • Like 2
  14. When using soft jaws, don't forget that gripping a wheel by its tyre may still not be secure, the tyre may be tapered, and the three point contact may be able to distort the rim on some wheels, unlikely on spoked cast iron, but quite possible on a brass, steel or nickel rim.

     

    Wheels should be held in a collet, a single split collet will do fine, or a bell, or step collet chuck, this evens the grip, and places it more securely on the shallow taper.

     

    Soft jaws can also be made by bolting dural bar to each mild steel jaw, the dural bar is more than strong enough.

     

    Another method is three slices of hex aluminium bar bolted to the face of the jaws, and close on a spacer, with the shape machined into the face. The resultant special three jawed collet will be the best possible grip on round objects and accurately repeatable. The hex shape can have the flats turned to face each other, or the points meet at the centre, and you can re-machine them many, many, times.

     

    Three round bars slices can be bolted to the jaws to provide a generous blank are to machine recessed groves to take wheels gripped by the flange to face outward for finishing the front.

     

    All of this demands spare jaws that are drill-able and tap-able , most makers can supply soft mild steel. If not then get a spare set of hardened and get an engineering shop to cut away the faces, and weld on mild steel strip, it can then be machined in the lathe to give basic jaws, that will take further soft dural jaws.

     

    For most amateur work a home made split collet, made from scrap, is easiest to make, and offers the best grip for most round work, and completely compensates for worn, or out of true 3 jaw chucks, ANY chuck will do.

    • Like 3
  15. At a glance there is no adjustment on the Proxxon, the screws at the back merely retain the machined sleeve unit for the tailstock screw.

    If there was an adjustment it would be in the base, a split, that would have two screws, fore and aft, able to move the whole tailstock backwards and forwards, with a locking screw.

    Without any screw means it is expected to be in alignment, but does impose a limitation of not being able to turn tapers by the setting the tailstock over method.

    However a special tailstock morse mounted centre would overcome that easily, the device can be home made, a disk in the mounting that can be re-set.

     

    Basically they have left it so that the tailstock is always aligned, so the tailstock chuck should line up first time.

     

    A simple test is to place a metal scrap point in the chuck, turn to accurate point, and gently clamp a disk of brass between the point and the tailstock centre point, and then rotate the headstock mandrill by hand, the disk should not wobble, if it does it is out of line. (Try two or three times to ensure no false readings).

     

    Stephen.

    • Like 2
  16. I bought a live steamer 5 inch gauge 062 many years ago, and found a leaking regulator.It had come from Kennions in Hertford, and when stripped from the boiler found the regulator was a Stroudley pattern with a floating plate over the pipes ends in a block of steel, not gunmetal, the floating plate seemed to be solid carbide!

     

     

    The block would need grinding flat to work, so I removed it and tried to reface in the lathe first, but discovered that it was Inconel, and harder than carbide.

     

    To get it to work I replace the whole thing, and all was well for the boiler test.

     

    I wondered why Inconel was used and having a theory, I asked Kennions were the model came from, and it turned out to be right, it was near BAE's factory, the old De Havilland plant, and the builder worked in the jet engine dept!!...made from old turbine engine blades......

     

    Stephen.

  17. Yes, it may corrode, but with luck not!! you can rub over with WD40 occasionally, it does help. If the mazak does not have mazak rot it will be all right, there is no predicting it.

    316 should machine with carbide tips, and 3mm bar should be quite easy, it's the tube that is worst.

    Stephen.

    • Like 1
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