Project Myford - the Fettling Begins...

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I figured that the chuck-speed of the old thing was a tad faster than I remember from the old setup in the  shed at Winson Street, so I did some fag-packet calculations on the pulley train versus the quoted motor speed and came up with a figure which seemed to back up that intuition: around 70 RPM greater than the 'average' 420 RPM that forms the 'centre' of the speed range for a lathe such as this. I decided to invest a small sum in a no-contact tachometer, which duly arrived today and indeed confirmed the chuck speed to be ahead of the game by the amount I'd calculated, adrift by a few RPM.

I reckon that either the motor spindle speed may be awry from that quoted on the motor plate, or my measurements of the pulley diameters was out by some - it matters not: a 2" or 2-1/2" pulley at the motor shaft should rein the thing in to around the required speed. I'm only likely to need slower speeds than the 420 RPM which will do for most of the stuff I'm likely to turn anyway, so I need to work out how to get the backgear working: I'm pretty sure Dad never bothered trying to use it, as the gear-set in the headstock is pretty gummed up with grease and dust: it's back to YouTube for advice, given the extreme age of the ML4. Oh, and there's still the question of setting up the change gears to slow down the lead screw: I'm missing the second shaft for the banjo. I guess that could be the first turning project, once I've got stuff chuntering along happily. I'll keep you posted!

Comments

  1. Joe Stoner5 July 2021 at 09:57

    Now you've got a tacho Kel why not invest in a motor speed controller to nail yer cutting speeds? I'd countenance a shroud of ANY kind over the exposed gears. SO easy to get a dangling dubrie caught in them or even dropping shit into them!!!

    ReplyDelete
  2. sideways5 July 2021 at 10:13

    Already on the gear-cover: just sketching one out! I suppose I could just build a speed-controller: I must have a circuit diagram around the place - or I could just Google it...

    ReplyDelete
    Replies
    1. Joe Stoner8 July 2021 at 21:30

      Google: STILL the best search engine. I'm getting increasingly annoyed with dim-wits telling me to Google something that they SHOULD know(part of their JOB)! AND making it sound like they're telling you about something you don't know about!!! Keep us posted about the speed controller mate; save me Googing it:):)!!!

      Delete
    2. sideways8 July 2021 at 22:07

      Speed control over single-phase induction motors is not straightforward or cheap, apparently. My best bet apart from the pulley change is to buy a secondhand three-phase unit and - guess what?- an inverter/speed controller! Sounds vaguely familiar, don't it?

      Delete
    3. Joe Stoner8 July 2021 at 22:17

      De-Ja-Vu all-over-again mate!!! Lock it to 60cycles and vary the tool speeds!!!:):)

      Delete

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