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AndyID

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AndyID last won the day on November 10

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  1. Very nice Davey! Another advantage of using copper-clad is it can be used to make a split chassis. I have not tried it but it might be possible to make coupling rods and bits of valve gear from FR4 or even FR1/FR2. Andy
  2. Has anyone modeled valve-gear at 1:76.2 scale correctly? A servo could adjust the reverser position to replicate forward/reverse and cutoff. Technically it's possible with DCC. Personally I won't be bothering
  3. Driving down the pass on Interstate 15 on a Sunday evening with five lanes of maniacs coming back from Lost Wages is really scary.
  4. I think it depends on how much you paid for it. If it was close to what you might spend for a similar new loco, send it back. If you only paid a fraction of that and you like the loco otherwise it's probably worth the aggravation of getting it to run. It's unlikely the motor is completely shot. More than likely it Just needs brushes and springs, a brass retainer and reconnecting to the harness. There are lots of people here who can help you sort it out. Just don't buy anything else from that chancer seller.
  5. Wellll, I'd say my Woodpecker mill is great for PCB isolation routing and it seems to be quite capable of producing structural things like underframes from PCB laminates. It can also mill brass but I think that is pushing the limitations of the machine. I overcame the end-mill destruction routine by sleeving a carbide mill with a "saver" that only leaves 1 mm of the cutter unsupported. But while cutting brass there is enough vibration that the grub-screws holding the end-mill tend to slacken off. A collet would be a better idea. I almost managed to mill one tender frame, but it took a long time. So long in fact that we had a power cut before the operation completed! (We just had a rather violent snow-storm.) But, on the whole, the machine is probably just a bit too flimsy to handle brass effectively.
  6. Thanks Jim, I put my scope on the motor and based on the commutation pattern it look like top speed is about 10,300 RPM. I'll try dialing the speed back and try different speeds and feeds. Andy
  7. Not a lot of success with milling brass. I've been attacking 16 thou sheet with mixed results. Sometimes it looks like it's going to work then something goes wrong, usually snapping the end off the carbide mill. I've destroyed four 1 mm end-mills so far. Currently pondering my next move, or if there even is one. Based on what I've seen I think it might be practical but it will take a lot of mucking around to get the right recipe. I'm thinking HSS might be better than carbide. Also a larger diameter mill would probably help but that would impact the resolution although it might be OK for some things.
  8. Double-sided FR4 is pretty stable and quite robust. I don't think there should be a problem. You could also go up to the thicker 1.5 mm FR4 which would be stiffer but that might not be necessary. Yes, you'd have to bush the axle holes. I was interested to see if I could mill 2 mm holes with a 1 mm mill and they seem to be OK. One advantage of this method is the axle holes are positioned very accurately. I suspect with far more precision than is possible with a drill, but it's still early days.
  9. Hi Davey, Spindle speed at max. I'm not sure what it really is. The controller software says 1000 rpm but I think that's suspect. X/Y and Z feeds are 60 mm/min (1 mm/sec). That's the thin double-sided FR4 (0.75 mm) I used a cheap 1 mm carbide mill. IIRC the feed vertical feed was set to cut the holes in two passes of 0.5 mm. If you are using a Woodpecker (or similar mill) you might see that its a bit different from mine. I added those square plates to hold the angle at 90 degrees and the horizontal beam to reduce droop towards the middle of the gantry. The FR4 is attached to the MDF (a scrap piece of flooring) with hot-melt glue. I use a heat gun to release it. Also, the Woodpecker has a nasty habit of "pulsing" the motor off and on when the controller starts the spindle at full speed. I believe what's happening is the controller goes into overload because of the high starting current, turns off, then turns back on again. I seem to have solved it on mine by putting 1.3 ohms in series with the spindle motor. (It's actually a piece of nichrome wire and that just happened to be the value - 1 or 2 ohms might work just as well.) Cheers, Andy
  10. I've been playing with my mini-mill. It's very good for isolation routing to produce low cost PCBs but I thought I'd take a shot at something a bit more more mechanical. These should be frames for a Stanier tender. It's double-sided FR4. I'll take a shot using brass and see how that goes.
  11. A over T was the greater problem. Unfortunately the trailing arm suspension was only available in the 68 semi-automatic. Dad liked that version because mum couldn't burn out the clutch.
  12. I can give you a definitive date. It was the 68 model year in the UK. I know this because my dad bought one and 12 volt electrics was one of the reasons for buying it. Another reason was trailing arm rear suspension but that's another story.
  13. IIRC the 1968 VWs in the UK were 12 volt. The US might have been a year earlier. 6 volt systems worked well enough as long as all the connectors were in good shape. The biggest problem was that many people tended to overlook resistance in the return path. A solid ground connection between chassis and the transmission was essential for starting.
  14. I suspect it has resistance steps rather than variable resistance. If I buy it I'd rather not modify it. Steps would make things a bit tricky but not impossible.
  15. There's a very elegant HD battery controller on eBay (US). If the shipping cost was less I'd use it in an electronic controller. https://www.ebay.com/itm/Hornby-DUBLO-TYPE-B3-Battery-CONTROL-UNIT/303308217807?hash=item469e941dcf:g:nooAAOSwt8Jdllfq&redirect=mobile No affiliation.
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