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measuretwice

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measuretwice last won the day on July 14

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  1. measuretwice

    Help finding lathe collets

    Happy to explain and you're at no risk of appearing stupid - none of us were born knowing this stuff. Forget about whitworth, metric etc for sec, they are just convention. Start with what defines a thread. Its a helical shaped groove and Its defining properties are 1) its pitch 2) its diameter and 3) its thread form. Pitch is the distance between crests, diameter is the diameter and form is the shape of the groove. There is more like direction, tapers on pipe threads, multistart threads, class of fit etc but just worry about those main three for now. A thread is a rather useless thing unless it properly mates with another. We can single point a thread of any pitch, diameter and form (and sometimes we need to), however since the whole point of a thread is to mate with something, the majority of threads we encounter today are done to some standard. The standard defines the three things; pitch, diameter and thread form. So if one plant makes the tap and other makes the bolt, the bolt fits the tapped hole. A 1/4" National fine thread is a 1/4" major diameter, a pitch of 28 tpi (actually that is the thread count, but in the vernacular its called the pitch as one is function of other: thread pitch - 1/thread count) and a form that is 60 degrees. An M8 - 1.0 is an 8mm major diameter, pitch of 1mm (distance between crests) and 60 degree form. There are many different standards, maybe hundreds, but all it is is convention, a standard defining those three things, pitch, dia and form. There is no law that if I make a product it has to follow convention. Too bad perhaps for lathe collets, one standard size would have been nice. The maker of your lathe made the thread 40 tpi and 5.5mm OD, likely not to any convention (they did that back in the early days, each lathe maker coming up with their own collets). Their collets fit their drawbar, all they thought necessary. More recently made stuff will almost for sure be to some standard (there are dozens maybe hundreds of standards), but it doesn't have to be to a standard....and the odds of an odd thread increase when you go back in time. What is it? Could well be a hybrid never seen before or again. All we know for sure is it has the three defining characteristics: a pitch diameter and form. Where does Whitworth and your gauge come into it? Whitworth is just one of hundreds of standards - a convention of diameter, pitch and thread form usually in a series. Unified National Coarse, Unified National Fine, Metric, Acme, BA, etc. One of the threads in the Whitworth series is 1/8" diameter x 40 tpi. The thread form for Whitworth is 55 degrees with highly rounded crests and valleys. All just convention. What your gauge actually measured was 40tpi pitch. For example, put your gauge against a #6 UNF bolt, which is also 40 tpi,and it will fit like it did the collet. But doesn't make the #6 screw a Whitworth, its still and UNF with a different diameter and slightly different thread form (55 vs 60 degrees, at 40tpi that might be visible with a loupe, ie the 55 gauge not perfectly fitting a 60 degree thread) SO....a thread standard like Whitworth is defined (basically) by three things diameter, pitch and form. Your gauge measures one of these tpi (or pitch). Your collet happens to have the same pitch, 40 tpi as a 40tpi x 1/8" Whitworth, but this is the extent of it, they just have the same pitch. For your collet to be a Whitworth thread (which its not) it would have also have the same diameter (for 40 tpi W = 1/8") and thread form. Its like if you had a set of Mack truck colour paint chips, and you spotted a BMW the exact same colour....the paint chips let you identify the colour (or the pitch of 40tpi) but it doesn't mean its a Mack truck. Ask away if not clear
  2. measuretwice

    Help finding lathe collets

    good to know, Were you thinking East German made? I've read their Boley knock offs were larger diameter beds
  3. measuretwice

    Help finding lathe collets

    right, because a standard whitworth thread is 1/8" diameter x 40 TPI so the gauge leaf is stamped as such, because its a Whitworth gauge . The 1/8" doesn't mean anything to your thread because its not Whitworth (its clearly not 1/8" dia.), it just so happened your thread was the same TPI as one of the leaves on your Whitworth gauge so it was useful in identifying the TPI. Threads are basically described as a having a pitch and dia, - you got a good thread description by using the gauge for the pitch (40 tpi) and a caliper for the OD (5.5mm)
  4. measuretwice

    Help finding lathe collets

    ok, I see whats going on. You used a thread pitch gauge that showed it 40 tpi . You can have a forty tpi thread of any diameter you want to make (in your case its 5.5mm), BUT the gauge you had was Whitworth and the standard for Whitworth for a 1/8" dia thread IS 40 tpi. i.e. a 1/8" diameter whitworth fastener will be 40 tpi and the leaf of Whitworth gauge assumes if you have 40 tpi dia is 1/8". btw its not a Whitworth thread but the gauge worked well to identify the pitch so mission accomplished (Whitworth is 55 degrees with rounded corners vs metric or imperial standard threads which are 60). Clear as mud? moot with a new set of collets and matching drawbar but I was wondering where the 1/8 came from
  5. measuretwice

    Help finding lathe collets

    I think you did ok and if Mark's idea works it'll be a big win, getting one with slide rest, even if the lathe wasn't that great for lack of collets, is probably worth the price. I had to google, I've never seen G used. Apparently it is a British Pipe Thread term referring to a constant diameter pipe thread (most of course are tapered). Pitch is 1/tpi so if its 40 tpi, pitch = .025", i.e. pitch of 1/8 = 8 threads per inch which is coarse, think lathe leadscrew I hope you find out the maker, its a mystery to me. The tailstock lock mechanism seems unique, at least I can't recall seeing one
  6. measuretwice

    Help finding lathe collets

    I don't think its a 6mm.....if the threaded section is 5.5 the body looks like 8 . There are not many listed collets close to those dimensions that are 8mm. There is the hopkins #3, but were they made Geneva style? A mystery lathe - nothing stamped on the bend ends? what part of the planet are you on/did it come from? It looks like a Geneva style? Its also an interesting tail stock, lever action but no gimbal - it looks like nothing can pass through the tailstock? I also don't understand the thread spec 40g 1/8th ", whats the "g", what the 1/8? A few more shots of the lathe might help identify it. Hell should have a special place reserved for those clods who separate a lathe from its tooling and accessories. I think finding collets will be difficult, but who knows, you may get surprised on ebay one day.
  7. measuretwice

    Anyone got one of these lathes??

    If you see a U3 for 2x that, pounce....but be careful, its likely missing components. I get that its what its worth to you that matters, but I'm challenged to see how a machine selling for $150 could remotely be satisfactory machining anything accurately and U3's are really nice bench top setup, Austrian made and made well. Spending $150, getting frustrated and tossing isn't a good outcome either....whereas with U3 it still be worth what you paid for it Currently with 22 lathes from watchmakers to a 5200 lb DSG, I'm big big believer in carefully buying used quality machines as the way to get the best bang for the buck.
  8. measuretwice

    Lathe motor size

    that is a very nice lathe, congrats. I just looked at several watch makers lathe motors, they are all around 1/10 - 1/8 hp (say 75-100 watts) and speeds range from 6000 - 10,000. Looking at the size of the pulleys they are likely a 3:1 reduction to the spindle. There are Chinese made sewing machine motor for $30 but I agree 100 real or hopeful watts is not enough for that lathe. A key thing with electronic speed control ( by a VFD or DC PWM) is that it might be constant torque, but that means HP drops as the speed drops. If the motor is 1/4 HP at 3000 rpm, and you slow it down to 300 rpm electronically, you end up with 1/40 of a HP! Constant torque is great with say conveyors; with a machine tool you ideally want constant power - speed goes down, torque goes up. This is why mechanical speed reduction is always superior in everyway….but cost lol. The ideal is a 3P w/ VFD or DC motor and use the OEM belt speed reduction. I've a couple of Schaublin 70 and that’s what I did, best of both worlds - variable speed and full hp available If you get the oringal stepped pulley on the motor all the better. Nevertheless, if you want get electronic speed reduction, the idea is you put a much larger motor on it so it'll still have umph at low speeds. VFD 3P is an excellent way to go. A really cost competitive alternative is the 3/4hp Consew motor which I think is excellent (they are all over ebay/amazon). It’s fairly cheap, just over $100 US, and is a DC servo drive that max's at 4500 rpm. Given the pulley dia it seemed ideal to spin a small lathe at 4000 or 5000 rpm down to a few hundred. As a servo, the controller gives it more amps if the servo feedback shows its slowing down - it keeps the same rpm with a varying load. Some might think 3/4hp is too much buts not given you're using it for speed control, i.e low rpms it will deliver a fraction of 3/4 hp but still enough to do work on a little lathe. I've an extra unimat 3 that I'm readying for departure and it didn't have a motor. I put a Consew 1000 on it and am really pleased, so much so I've bought a second for my U3. That lathe was underpowered imo but not any more, irrc it was 1/10 of a hp. The Consew motor is intended for an under bench mount for an industrial sewing machine and has a lever to connect to a treadle for speed on/off. That I think is really important for watchmakers lathes, I currently use a miltifix but I dislike not having foot control and am thinking of getting a Consew and mounting it under the bench to drive watch makers lathes. For larger lathes like yours or the U3, mostly used with a slide rest (instead of a graver), I think speed control knob preferred. Fortunately its an easy mod to convert the lever speed control into a knob control. The black knob shown I added; its speed control and the lever just sits there disconnected.
  9. for sure, but the article does show how to make the tools to make the chain. You'd have to really want to make a chain, but with that article its doable. Model engineers sometimes do this, a chain will be needed to scale for some model. That's where i first came across the piece. Moot for the clock at hand if it doesn't use them, but I thought it an interesting write up, the only one I ever seen making fusee chain. It is a very beautiful clock. My question is around the finish. Is this original, i.e. maybe lacquered so it stayed bright, or has it been polished? If polished, I know people have strong views on other antiques, but what about clocks? Is polishing high end antique clocks consider ok or frowned upon?
  10. you can make one...:) https://drive.google.com/file/d/1lvAqoIr5wSt3AVtjnqIa-tSqvjITK8Fu/view
  11. measuretwice

    OT some larger scale craftmanship

    I have no idea, possibly a commission? art? reminiscent of historical creations back when a lock box really mattered? I don't think I'd set out to build one but in a way its lot like a finely made, expensive mechanical watch; you don't really need one to tell time just like you don't need that box to keep things secure , but you like them just because they are such a mechanical marvels of craftsmen, an achievement of the human spirit and all. Best I can come up with anyway
  12. I was impressed with the project, workmanship and video production and thought you guys might enjoy it. A neat piece work with a rather complex 'secret' stepped lock - hang in there to the end to see how it operates.
  13. measuretwice

    Tap and Die Kit

    that's what I figure, it looked like Margolisd's response that he might be thinking plug with solder which would make for a very weak thread
  14. measuretwice

    Tap and Die Kit

    to clarify, you're saying to soft solder ta plug of brass in, then drill and tap....not just fill the hole with solder.
  15. measuretwice

    Tap and Die Kit

    thats not a bad idea, something for the staking set that holds the tap - it would help with small tap breakage where not keeping it straight is the major cause. Its very common with larger, but still small and breakable, size tapping jobs to use a tapping stand to avoid breaking them As for tapping, that's a very small tap. How do tap a stripped hole the same tap size - do you close it in or bush it, or go a size bigger and make a new screw? .....as in if it is really stripped there won't anything left to tap....it maybe its just slightly damaged and needs to be chased/cleaned up?
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