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31 minutes ago, LittleWatchShop said:

I picked up another lathe...just because I guess.  I did not have a motor nor tail stock.  I scavenged a motor from an old sewing machine I had in the queue for the dump (whew, glad I woke up regarding that).

I think sewing machine motors are good replacements, here is one of my “bigger” small lathes with a frequency controlled sewing machine servo motor (brushless). I use the original 5mm rubber belts for the EMCO Unimat 3 even if this is a 550W motor, it works just fine.
I have the same rubber belts for my Geneva style lathes too, they are really cheap. Think they are just a 100mm in diameter rubber gasket.
 

Modified_Lathe.jpg

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Here is my setup with copious magnification!  I am now at the point of being dangerous.  Quality tools in the hands of an amateur. When I was a kid, I would often play with this lathe, but never

The Geneva style lathes I mentioned above which I run with the same setup is an 8mm Lorch and a 6mm BMC, even if the motor is slightly more powerful, I think I get good enough control to cut a cannon

I love my WW bed Boley & Leinen lathe. From turning staking tool punches in the first video, to gauging the wobble and eventual straightening of a Valjoux 7733 fourth wheel arbor in the last

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6 minutes ago, HSL said:

I think sewing machine motors are good replacements

Nice.  Long term, I am going to replace it with a PWM driven BLDC--an overall better solution I think.  I have to reverse my sewing machine motor buy wrapping the belt in figure 8.  I could take it apart and reverse the field winding but that is a hassle.  Happy with figure 8 for now.

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Yes, the brushed motors from a sewing machine usually runs "backwards"  those ones one just can flip them 180 degrees horisontal. Then it runs the right direction... On the brushless you just push a button for the rotation direction.

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25 minutes ago, HSL said:

one just can flip

Yeah, that was the first thing I did.  Just lacked aesthetics, so I put it back the way I had it and put the belt into a figure 8.  Once I transition to the BLDC, all problems go away!

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1 hour ago, LittleWatchShop said:

Yeah, that was the first thing I did.  Just lacked aesthetics, so I put it back the way I had it and put the belt into a figure 8.  Once I transition to the BLDC, all problems go away!

Your is a watchmaker's lathe, so a powerful motor, belts etc are not important.  Very different from even an baby lathe like HSL's, on these you want to cut steel and the standard motor is easily not enough, there are other limiting factors, I know a old machinist that says "for each one his own". See if you can get to turn a cannon pinion to fit precisely the minute wheel, using just a graver. That is the kind of work it is made for.

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The Geneva style lathes I mentioned above which I run with the same setup is an 8mm Lorch and a 6mm BMC, even if the motor is slightly more powerful, I think I get good enough control to cut a cannon pinion or two, even made a new axis for an escapement wheel the other day.
Guess I got a bit lazy with age and think new technology to control the revs is convenient, but I still think these rubber drive belts work just fine.
I add a romantic picture of the babies too. 

Lorch_BMC.jpg

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You guys are heads and shoulders above me, but I am learning!

I have attempted a balance staff and failed.  Will attempt again.  I got close ?

The only pure success so far was to turn a couple of small brass rods down, leaving a head, to use as the pins in my Wave Cepter watch band.

I love these things.  Though I am an electrical engineer...I these mechanical things intrigue me and are a lot of fun.

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If you are going to work on vintage watches you probably quite fast will realize some parts is just not available any more, and one probably will turn a balance staff faster than waiting for one in the mail with some training.

I noticed you said your problems would be over when getting the setup fixed, I would say your problems are just beginning when you get the lathe running, it sometimes just can be so addictive your better half have to pull your away from it at 2 am. So, they might just begin ?

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I'm probably not a good example but I make parts on my lathe pretty much every day for both vintage/antique and brand new (prototypes). I have a small 3 phase motor for my lathe with a countershaft; 3 phase power is ubiquitous here so no issue  99/100 I use two speeds, about 1500 rpm or 700. I use a cross slide for 99% of the work. Everything turned to size, +0.01mm on pivots which get finished in the Jacot after heat treatment. The little 3 phase is smooth as silk, there's a scope over the lathe, and a quick change toolpost on the slide*. I do use hand gravers, for cutting off balance hubs when restaffing, for cutting conical pivots and rivets, chamfering things sometimes, a quick retouch if the slide isn't mounted on a screw length etc.

 

The slide is a massive timesaver.

 

*the quickchange is a copy of a Dorian post, which I copied from a friend's when I was in school. It repeats almost without fail within 2 or 3 microns, spooky. Dorian stopped making it, but Horia makes a copy still. Worth every penny if you make your living with it.

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12 hours ago, nickelsilver said:

The quickchange is a copy of a Dorian post, which I copied from a friend's when I was in school. It repeats almost without fail within 2 or 3 microns, spooky. Dorian stopped making it, but Horia makes a copy still. Worth every penny if you make your living with it.

Don't get me started on toolsposts or I'll flood this topic to its drowning. I'm doing a serious market research to chose one for the 250mm swing lathe and came to learn many interesting things about most, if not all types available. In the meanwhile I've got a Multifix AA set, which is now available for the reasonable price of about USD100. It's a bit too small for the 250mm, and a bit too large for the baby lathe, although it works on both. Ideal on a 180 - 210mm swing mini lathe - which I don't have (for now). 

DSC_0427_copy_800x450.jpg.2d65ca37f2ef09252c32ac58fa642697.jpg

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I posted about this on another thread, but will revisit it here.

Using my lathe, I attempted to make this rather large staff for a stopwatch.  The challenge started with how to make the slot in the staff.  I attempted it with a dremel.  Very crude.  I thought about using the cross slide and a cutting wheel on the headstock, but, alas, there is no Z adjustment on my cross slide.  Thus I was unable to figure a way to adjust for the right depth of cut.  Maybe I am out in the weeds on this--dunno.

Some of these tools you guys are talking about might address the issue??

The stopwatch repair is not a value issue...just looked like an interesting problem to tackle!

2021-02-26 20_24_22-Photos.png

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I love my WW bed Boley & Leinen lathe.

From turning staking tool punches in the first video, to gauging the wobble and eventual straightening of a Valjoux 7733 fourth wheel arbor in the last video. It can do it all!

I find using a countershaft in conjunction with a foot pedal controlled sewing machine motor keeps the torque up. There's also more control with tension on the pulleys/driving bands with a movable countershaft, I find.

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19 minutes ago, Jon said:

I love my WW bed Boley & Leinen lathe.

From turning staking tool punches in the first video, to gauging the wobble and eventual straightening of a Valjoux 7733 fourth wheel arbor in the last video. It can do it all!

I find using a countershaft in conjunction with a foot pedal controlled sewing machine motor keeps the torque up. There's also more control with tension on the pulleys/driving bands with a movable countershaft, I find.

I have the same setup but use the large wheel off the sewing machine motor.  This gives me more torque.  I also use a leather belt I made from a thick boot lace.  Did a video on how to do this...on youtube.  Way more quite and lots of grip.

 

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2 hours ago, jdrichard said:

I also use a leather belt I made from a thick boot lace

Leather is a good choice.  I tried it sewn together with Power Pro braided fishing line (20lb) which works really nice threading a sewing needle.  But my piece of leather broke (it was some old scrap I had lying around).  Then I decided to try 3mm TPU which I use for 3D printing.  Will see how it goes.  I keep my eye out for the parts to make a setup like yours.

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6 hours ago, jdrichard said:

I have the same setup but use the large wheel off the sewing machine motor.  This gives me more torque.  I also use a leather belt I made from a thick boot lace.  Did a video on how to do this...on youtube.  Way more quite and lots of grip.

 

The large wheel should give more speed, but not more torque. Probably the belt slips less on the larger pulley.

 

In the U.S. we used Habasit round belting in the school where I taught. It's heat weldable; of course there's a machine for it but you can weld it fine by heating a ~0.5mm strip of brass held in a vice, with a little torch, then press the two ends against opposing sides, they melt, and slide up to join. Hold till it cools, then trim the bead that's left. I have machines in the workshop with thousands of hours on their belt joined this way. Any good belting supplier should have it or know where to get it.

 

Leather is great too, less tolerant of pulley distance, but very good. If you have slippage issues rub solid beeswax on it as it's running. Seems counterintuitive but it works, better grip.

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21 minutes ago, nickelsilver said:

The large wheel should give more speed, but not more torque. Probably the belt slips less on the larger pulley.

 

In the U.S. we used Habasit round belting in the school where I taught. It's heat weldable; of course there's a machine for it but you can weld it fine by heating a ~0.5mm strip of brass held in a vice, with a little torch, the press the two end against opposing sides, they melt, and slide up to join. Hold till it cools, the trim the bead that's left. I machines in the workshop with thousands of hours on their belt joined this way. Any good belting supplier should have it or know where to get it.

 

Leather is great too, less tolerant of pulley distance, but very good. If you have slippage issues rub solid beeswax on it as it's running. Seems counterintuitive but it works, better grip.

I agree with everything you stated, with the exception of the angular force transferred from the large pully to the much smaller pully; it will provide a greater force and thus more torque off the smaller pulley.  I am an electrical engineer, so I will need to ask my son the Mechanical engineer to see if i am "full of it" :).  Thanks for the advice.

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28 minutes ago, jdrichard said:

 angular force transferred from the large pully to the much smaller pully; it will provide a greater force and thus more torque off the smaller pulley. 

The other way around ?

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2 hours ago, jdrichard said:

I agree with everything you stated, with the exception of the angular force transferred from the large pully to the much smaller pully; it will provide a greater force and thus more torque off the smaller pulley.  I am an electrical engineer, so I will need to ask my son the Mechanical engineer to see if i am "full of it" :).  Thanks for the advice.

C'mon, if I  understand correctly you're an engineer. Pulleys are levers (and gears are pulleys with teeth), the fulcrum remains the fulcrum. You're seeing the big pulley as a bigger "effort" and the smaller one as a smaller load, but it's reversed. For a pulley of 3.14" diameter a pulley of 1" diameter from the motor has a mechanical advantage. More torque, 1/3 the speed.

In a watch the barrel with 90 teeth drives the center pinion with 12 teeth, the pinion does 7.5 turn per turn of barrel, but you can stop the center wheel with a toothpick. Try stopping a fully wound barrel with a toothpick. Speed increase, torque decrease. It's why Accutrons wear themselves out- it's power from the (super fragile) escapement- by the time you're at the 3rd or center wheel there's almost limitless power. Torque increase.

 

On edit- electrical engineer, still, most of the old fart sparkies I know get leverage haha (joshin _ just a bit_).

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17 hours ago, nickelsilver said:

C'mon, if I  understand correctly you're an engineer. Pulleys are levers (and gears are pulleys with teeth), the fulcrum remains the fulcrum. You're seeing the big pulley as a bigger "effort" and the smaller one as a smaller load, but it's reversed. For a pulley of 3.14" diameter a pulley of 1" diameter from the motor has a mechanical advantage. More torque, 1/3 the speed.

In a watch the barrel with 90 teeth drives the center pinion with 12 teeth, the pinion does 7.5 turn per turn of barrel, but you can stop the center wheel with a toothpick. Try stopping a fully wound barrel with a toothpick. Speed increase, torque decrease. It's why Accutrons wear themselves out- it's power from the (super fragile) escapement- by the time you're at the 3rd or center wheel there's almost limitless power. Torque increase.

 

On edit- electrical engineer, still, most of the old fart sparkies I know get leverage haha (joshin _ just a bit_).

Got all of that and in fact studied all of this in my first 2 years in university.  So big wheel to small wheel on the counter shaft can generate more torque at a lower angular velocity. ant then small wheel to Lathe big wheel retains this torque as the wheels are pretty much the dame diameter.  Sewing machine motor is a very small wheel but spins like hell.  gear changing on a 20speed bicycle is a physical model of all of this.

"Sparky" is used in aerospace for the aircraft electrical guys.

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21 hours ago, LittleWatchShop said:

Leather is a good choice.  I tried it sewn together with Power Pro braided fishing line (20lb) which works really nice threading a sewing needle.  But my piece of leather broke (it was some old scrap I had lying around).  Then I decided to try 3mm TPU which I use for 3D printing.  Will see how it goes.  I keep my eye out for the parts to make a setup like yours.

Great, thanks for the note

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Are you saying that on your countershaft you have a large pulley and a small pulley (that's normal), and you are driving the large pulley from a small pulley on your motor, then from the small pulley on the countershaft to the lathe? Yes, that would increase the torque coming from the motor, while reducing speed. The way I read it you had a large wheel on the motor.

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Just now, nickelsilver said:

Are you saying that on your countershaft you have a large pulley and a small pulley (that's normal), and you are driving the large pulley from a small pulley on your motor, then from the small pulley on the countershaft to the lathe? Yes, that would increase the torque coming from the motor, while reducing speed. The way I read it you had a large wheel on the motor.

That is exactly in...as i have shown in the youtube video attached.

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1 hour ago, jdrichard said:

Force to stop the small pully in motion on the countershaft is much greater than the force to stop the large pully.....

Consider that when you try to stop a spinning wheel you introduce two more factors in the equation, friction and inertia. E.g. https://www.physicsforums.com/threads/flywheel-disk-brake-system.817113/

Now for a more basic example, try going uphill ona bicycle with a big gear at the crankcase, and a small one on the wheel. And then.. the other way around ?

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17 minutes ago, jdm said:

Consider that when you try to stop a spinning wheel you introduce two more factors in the equation, friction and inertia. E.g. https://www.physicsforums.com/threads/flywheel-disk-brake-system.817113/

Now for a more basic example, try going uphill ona bicycle with a big gear at the crankcase, and a small one on the wheel. And then.. the other way around ?

Correct.  feet pushing big wheel:).  All we need know is vector diagrams!!

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