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Hello, All, While it's not absolutely necessary, I feel that gear reduction on the mini-lathe makes it more like, as my friend Barry once described it, "a big boy lathe".? This is especially true when used with ELS, which can take good advantage of the higher torque.? I implemented one of John Lindo's gear reduction systems, which he was kind enough to build for me, back in 2015.? You can see it in the photos below with the cover and much of the headstock gearing system removed, as well as fully assembled.? This has proven to be very useful, enabling significantly heavier cuts, which translates to fewer repeated cycles for a given operation.? Just a thought regarding modifications that can make a real performance difference in the mini-lathe...   -- Regards, Charlie New Jersey, USA
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Charlie, what are the gears in front for? It looks rather complicated.
Ralph
Hello, All,
While it's not absolutely necessary, I feel that gear reduction on the mini-lathe makes it more like, as my friend Barry once described it, "a big boy lathe".? This is especially true when used with ELS, which can take good advantage of the higher torque.? I implemented one of John Lindo's gear reduction systems, which he was kind enough to build for me, back in 2015.? You can see it in the photos below with the cover and much of the headstock gearing system removed, as well as fully assembled.? This has proven to be very useful, enabling significantly heavier cuts, which translates to fewer repeated cycles for a given operation.? Just a thought regarding modifications that can make a real performance difference in the mini-lathe...
--
Regards,
Charlie
New Jersey, USA
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Hi, Ralph, The Gear Reduction unit itself includes just three gears; the pinion, an idler gear, and the gear/pulley that drives the belt.? The two larger gears shown in the photo were part of the threading setup that I didn't bother to remove for the photo.? Perhaps the photo below, taken a year or two after the GR unit was first installed, shows it more accurately. Incidentally, since the mini-lathe can be electrically reversed, you would think that you could do away with the need for the idler gear, whose only function is to make sure that the belt drives in the right directly when the lathe is electrically set to "Forward".? With no idler, you could theoretically just reverse the labeling on the electrical "Forward/Reverse" switch and save the extra gear.? BUT... Real Bull lathes put a resistor in the circuit to reduce the lathe speed when running in reverse.? I don't know if that is true of Siegs, but it is with the Real Bull.? So the idler is necessary. Also, you will notice the curved slots in the GR unit at the front of the motor.? These are for cooling, but are also used for setting the position of the GR unit before tightening the radial set screws.? You can see the three small screws going through the slots.? It is necessary to remove the front end cap from the motor and tap it for some small screws; I used 6-32, but M4 would also work fine.? As I understand it, Sieg lathes use a motor with a plastic front end cap, which cannot be reliably tapped, while the Real Bull end caps are metal.? For that reason, this gear reduction unit will work on Real Bull lathes, but not Siegs.? No matter, as there are numerous other gear reduction designs out there that work fine on the Sieg.? The point is to get the torque up there... this comes at the expense of top speed, but I have never been very comfortable spinning my 4-inch chuck at 2500 RPM anyway!  -- Regards, Charlie New Jersey, USA
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I think one of the problems with the Sieg motors is that the end bell is radiused, not flat. I believe the end bell is some sort of filled nylon.  A similarly designed plate that attaches to the end bell of a Sieg would look like this:  And a similarly designed, completed GR for the Sieg does away with the idler and is more compact...  ?(design and all photos by Robert F.) But I think possibly a more modern way of doing things is to use a BLDC motor ala LMS HiTorque machines, but I may be wrong.
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Hi, Fast Eddie,
Many thanks for the explanations and the photos.? I have personally never seen the end bell of the Sieg motor, and this clarifies a number of things for me.
If I interpret the mounting plate photo correctly, it it mounts by sharing the screws that hold the end bell onto motor?
That is a nice, compact gear reduction unit!
Re brushless DC motors (BLDC), they definitely have many advantages, especially (for our lathes) the fact that torque is flat throughout the rated operating range.? This eliminates the significant loss of torque at? low speeds that we get with brushed motors.? But I don't know whether that torque improvement is great enough to equal the doubling (approximately) of torque that occurs when adding a 1:2 gear reduction.? I agree with you that, if I designed a new mini-lathe today (well... way beyond my mechanical abilities!), I would absolutely incorporate a BLDC, even if I kept the two-speed gearbox, just for the flat torque curve.
--
Regards,
Charlie
New Jersey, USA
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Hi Charlie!
First off, let me be clear that this is not my work, but the work of a very talented man, Robert Fumanarek (sp?) (). John and Robert go back a ways, from what I gather...two gifted and creative people!
With that disclaimer out of the way, yes, the existing screws are removed when mounting the plate and (possibly) replaced by socket head cap screws that are 5mm longer. The motor is also rotated and shifted rearward via a motor adapter to retain the? Sieg OEM motor mounting method. As I understand it, the engineering goal was to minimize alterations to the mini lathe...an easier (if less elegant) GR implementation, to my way of thinking, is Ralph Patterson's jackshaft design ()...but I agree, a GR is very nearly a must-have on these small lathes.
--Ed
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Thanks Charlie, that is what I was thinking, that you had just not removed them.
I would be in the Brushless DC motor camp. But there still would be gear reduction, certainly do not need 4,000?+ rpm.
Ralph
On Mon, Aug 12, 2019 at 4:17 PM Fast Eddie < epinnell@...> wrote: Hi Charlie!
First off, let me be clear that this is not my work, but the work of a very talented man, Robert Fumanarek (sp?) (). John and Robert go back a ways, from what I gather...two gifted and creative people!
With that disclaimer out of the way, yes, the existing screws are removed when mounting the plate and (possibly) replaced by socket head cap screws that are 5mm longer. The motor is also rotated and shifted rearward via a motor adapter to retain the? Sieg OEM motor mounting method. As I understand it, the engineering goal was to minimize alterations to the mini lathe...an easier (if less elegant) GR implementation, to my way of thinking, is Ralph Patterson's jackshaft design ()...but I agree, a GR is very nearly a must-have on these small lathes.
--Ed
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Hi, Ralph,
I realize that there would have to be gear reduction to at least a 2500 RPM spindle speed (assuming the desire to duplicate the original mini-lathe speed), but what I was speculating about was whether a Brushless DC motor, geared to 2500 RPM, would produce the same torque as a brushed DC motor geared to 1250 RPM.? I don't know; I have no experience with BLDC motors in lathes.? But the fact it they are used in the LMS lathes, which are quite nice in my view, would make me seriously consider them without a two-speed gearbox.
--
Regards,
Charlie
New Jersey, USA
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I have the s on my Clausing 8520 mill (21/2" x 6" pulleys) and on my Delta 14" Bandsaw (21/2" x 16" pulleys) I haves lots of torque even down to 100 rpm on the motor. I can stall the bandsaw applying too much pressure.
I have two more of the same motors waiting to go on my lathes.
On Tue, Aug 13, 2019 at 10:24 AM CLevinski < clevinski@...> wrote: Hi, Ralph,
I realize that there would have to be gear reduction to at least a 2500 RPM spindle speed (assuming the desire to duplicate the original mini-lathe speed), but what I was speculating about was whether a Brushless DC motor, geared to 2500 RPM, would produce the same torque as a brushed DC motor geared to 1250 RPM.? I don't know; I have no experience with BLDC motors in lathes.? But the fact it they are used in the LMS lathes, which are quite nice in my view, would make me seriously consider them without a two-speed gearbox.
--
Regards,
Charlie
New Jersey, USA
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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From what I have read, one issue with BLDC motors at low RPM involves "cogging", so it seems a GR would still be very much on the plate. What I am really curious about, though, is this:
(and this may not be the proper forum for this discussion, so I mention it only in passing!)
If I were to embark on a project such as developing a gear reduction such as John's or Robert's, I would first model it and then make a 3D print of my design for proving before committing the time and effort in doing the machine work. But then if I were to use some high strength nylon or carbon filled filament to produce my design, maybe that alone would be adequate, or at least adequate to the degree that I could use it to aid in machining the final item.
That workflow is what I would use if I were to embark on the ELS path. I think some of the aluminum parts could be 3D printed and then perhaps replaced at some point in the future, once everything is up and running.
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Fast Eddie, this is forum for such discussions!! In fact that is the reason it was setup!
Or at least that is my understanding.
Ralph
On Tue, Aug 13, 2019 at 1:30 PM Fast Eddie < epinnell@...> wrote: From what I have read, one issue with BLDC motors at low RPM involves "cogging", so it seems a GR would still be very much on the plate. What I am really curious about, though, is this:
(and this may not be the proper forum for this discussion, so I mention it only in passing!)
If I were to embark on a project such as developing a gear reduction such as John's or Robert's, I would first model it and then make a 3D print of my design for proving before committing the time and effort in doing the machine work. But then if I were to use some high strength nylon or carbon filled filament to produce my design, maybe that alone would be adequate, or at least adequate to the degree that I could use it to aid in machining the final item.
That workflow is what I would use if I were to embark on the ELS path. I think some of the aluminum parts could be 3D printed and then perhaps replaced at some point in the future, once everything is up and running.
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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Hi, guys,
I agree, this is exactly the kind of thing this site is about!
I think that I would 3D model and then print it, too.? While I think some of the plastic parts would be adequate for the ELS if made in the right material, I doubt they would be adequate for a gear reduction unit.? Personally, I would print it anyway to test the design, fit, etc.
--
Regards,
Charlie
New Jersey, USA
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Perchance does anyone have accurate drawings/sketches of Robert F's Gear reduction for the SIEG 7x? I would like to redraw the parts in Fusion 360 and 3d print them for casting patterns for aluminum?castings. I did go Robert's blog and ask the same question.
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Thanks guys. What i will do is 3D print.a mounting bracket and a motor shoe. Real Bull only.check fit. Also clean up my MC 8 files Mastercam, then convert to DXF and see where we go form there. I have just CNC mill machined another motor mount bracket from billet, it?s needed for a guy in the UK, please see photos. Just need to profile perimeter to a fixed shape (see engraved profile lines ) CNC done, that allows the bracket to snug into the bed frame of the lathe. Charlie has sent previous photos of the final assembly. Gears supplied by LMS. I will check in later with postal replies if you need further assistance. What is also up for discussion is the retrofit of the standard Sieg or Weiss mills to CNC. But we need to save this for another set of posts, Richard Edwards UK has done a super job of retrofitting his Sieg mill, taken out all the Z axis feed nonsence and has a stepper motor to drive a Z axis screw. ? Please post questions to Richard, he will be most helpful. He is a member of this group. But in advance,? please search DDCS V3.1 motion controllers.and search DigitalDream. For the cost of a good night out with the family, these controllers are magic.and well within budget. They also have an on board full time CNC engineer Mr Yt Liu? and ex rocket science engineer, (truly) and also contact via Facebook, also they own there private Forum for motion control owners. I hope to discuss the CNC conversions as we move forward with this new group. I do not want to throw to much at you all at once as regards digital machining as it will not stick. As we say here "poco poco" or translates? to little by little.     Robert Furmanek? the Sieg GR expert has completely gone off the radar. Last I heard he moved from the Northern States to Florida.? He did have a "Roberts blog" with all the GR info appertaining to Sieg lathes.? Possibly search the web.?? If anybody can track him down, please forward my regards and ask him to send me a PM message. Regards. -- John
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John Lindo