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Re: Motor swaps?
I have a couple of the Consew motors, I have "thought" about putting?one on my mini lathe. But I have so much to do that I probably will not get around to doing it. The Consew gives full torque at slow speed. Ralph On Sat, May 25, 2024 at 3:04?PM davesmith1800 via <davesmith1=[email protected]> wrote: The other part is a mini lathe has very little speed control? |
Re: Lipstick on a pig?
One of the nice things about?iGaging DROs , at least?the ones I have, is you can cut them to any length?required, they do not have to hang over the end unless you need the length?to measure travel. My DROs use TouchDRO which uses a processor with bluetooth. I have never had any problems with interference. If the DRO is slightly off in mounting you will have tension (twist). Ralph On Sat, May 25, 2024 at 4:45?PM Jacques Savard via <jacquessavard=[email protected]> wrote: On Sat, May 25, 2024 at 01:14 PM, Bruce J wrote: |
Re: speed control
I have an 11" Logan with a Reeves drive. It is an effective mechanical solution.
I can see why electrical solutions have replaced them. It is quite noisy for one, it also takes up a fair bit of space. 3 phase w/ VFD or a brushless motor is just a better solution, more compact, quieter, less maintenance, probably more accurate speed control and I'm guessing also cheaper. If the Reeves drive ever fails on mine, I'd most likely just replace it with a 3 phase motor and VFD. |
Fixed steady rest
I've been working on reducing the vibration in my Chinese 8" bench grinder.? Adding collars for the inner wheel flanges to rest against and making new flanges (ala Harold Hall's "Tool and Cutter Sharpening").? I was cursing having only the 1" rest, when I re-found the steady rest mod doc in the Files section.? Did not have a need for this mod until now.
Putting the rest in the mini-mill vise, with the middle slot edge aligned with the left side of the vise, it was just some up and back on the Y to give me a nice opening for my grinder shaft to fit through.? I wound up with a generous 0.885", and I could have gone even further, since I left about 1/32" on each side.? Maybe one day I'll build a larger rest with a nice flip top like many of the Myford guys have. Mike |
Re: speed control
开云体育Several of the larger metal manufacturers used Reeve's drives , Logan , South Bend I believe Clausing to name a few . animal On 5/25/24 2:16 PM, Miket_NYC wrote:
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Re: speed control
I have one on my Shopsmith Mark V. It works well and provides enormous torque sown low. But I've relubed it on occasion and I definitely wouldn't call it "simple." The CONCEPT is simple, but changing the diameter of s rotating pully requires many parts.? Mike Taglieri? On Sat, May 25, 2024, 4:19 PM fxkl47BF via <fxkl47BF=[email protected]> wrote: i've followed the thread about changing motors |
Re: Lipstick on a pig?
On Sat, May 25, 2024 at 01:14 PM, Bruce J wrote:
Bruce Johnson Bruce Johnson? I can? use? this kind? of magnet?? tey came? from? hard? disk positionner? very? easy? to? recycling? it also? about? you? problem of? changing? motor? the other post? I use a moteor? from a photocopier? ?whit? about 300 rpm? output?? and? I put a? stepping? motor? on? the input? shaft? like? this? the? stepping? are? vert? powefull?? and? i control? the? speed? esyly? at all? the? rage? also? my? next? step? are? to? use a pwerfull stepping? from? waching machine? tahat? the? dreem jack 47 71 |
Re: Lipstick on a pig?
开云体育Or free, often with convenient mounting holes included. Computer hard drives offer some really nice ones; older server-grade ones can have phenomenally strong ones. ?Be very careful to not let them ’snap’ together; they’ll shatter into a million razor sharp shards.A small selection of my collection (along with one of my late favorite pizza joint :-(?
--? Bruce Johnson "Wherever you go, there you are." B. Banzai, PhD |
Re: Motor swaps?
The other part is a mini lathe has very little speed control?
Some have 2 speed and others have 4 speed . The rest of speed control is done with the motor control.?? I am using 1 hp and 1000 rpm just simple.? The belt on 1000 rpm and 1 hp if turn control to 500 rpm ? hp. At 250 rpm ? hp. At 125 rpm ?hp. The motor stay at same torque? Hope helps to see why the use a large motor? Dave? |
Re: Motor swaps?
I agree?
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Working with light lathe you different techniques over a larger lathe. On large I run the slower and take a massive cut. The mini lathe I can run at higher speed and take light cuts. The down side if you are in production you need to replace or sharpen the tool bit more. After all the mini lathe weight? is 60 to 200 pounds.? A larger lathe is in tons. Dave? On Sat, May 25, 2024 at 10:47 AM, Chris Albertson wrote: I think the reason we don’t hear a lot about using different motors is that places like LMS sell stock motors. ?If you need to replace your motor the easiest way is to buy an exact replacement which is easy to get. |
Re: Motor swaps?
Chris Albertson
开云体育
This depends entirely on how your controller works. ?Back in the old days, we controlled motor speed by controlling the voltage we send to the motor. ? ?There are still many controllers that work that way. ? ? So the motor generates less power at the lower voltage. But today we have BLDC motors (no brushes) that are electrically commutated using MOSFETs in the controller. ?We can control the motor speed by controlling the rate of electrical switching and we can keep the current as high as we like even when turning slow or even with the motor stopped. ? ? ? Yes the BLDC motor can run at max current rating even when stationary. ?(think about stepper motors). ?A modern controller can control torque and speed INDEPENDENTLY. An example is the electric car. ? The reason a Tesla model X SUV can do 0 to 60 MPH in 3 seconds is because electric motors (with modern controllers) have their greatest torque at ZERO RPM. I’ll say that again, the motor has the most torque at zero RPM. ?The torque curve starts high and goes down as speed goes up. ? ?(assuming a well design controller) Yes, you can still buy equipment with old-style motors and controllers. ? People buy them because they are cheaper than equipment with BLDC (brushless) motors. |
Re: Motor swaps?
开云体育The tread mill motors are a good motor for a larger lathe . I have one on my South Bend 9" lathe & love it . For one of these 7" lathes I think a tread mill motor could be a bit much & could cause damage to the lathe . All the TM motors I've seen are 2 HP & up & that's a bit too much for these lathes . The Consew may be a better choice? , I know they go down to 1/2 HP on their motors .Maybe there's someone here that has done one of these motor swaps & has some time on the machine since can chime in . YMMV animal On 5/25/24 10:38 AM, Aaron Woods wrote:
This is simply curiosity, I don't currently have a 7" lathe, but I'm sort of a small lathe junky so it is just a matter of time.? |
Re: Motor swaps?
I've never been interested in changing to a treadmill motor and controller because, from everything I've seen, when you slow a motor down electronically it lowers the rpm and lowers the torque. When you slow a motor with a back-gear, a jackshaft, or similar mechanical methods,? it lowers the rpm and RAISES the torque.?? This problem of losing torque when you slow down the RPM definitely exists with the minilathe motors. Does it also exist with these treadmill motors? Mike Taglieri? On Sat, May 25, 2024, 1:38 PM Aaron Woods via <awoods550=[email protected]> wrote: This is simply curiosity, I don't currently have a 7" lathe, but I'm sort of a small lathe junky so it is just a matter of time.? |
Re: Motor swaps?
Chris Albertson
开云体育I think the reason we don’t hear a lot about using different motors is that places like LMS sell stock motors. ?If you need to replace your motor the easiest way is to buy an exact replacement which is easy to get.A few people might want to replace a working motor with something “better” but most people realize this is not going to improve the quality of their finished parts. ?The Mini Lathe is just not massive enough for higher-powered motors. ? The motor is not the “weak link”.
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Re: Lipstick on a pig?
"I am in the process of using an iGaging DRO on one of my Unimats. I am also experiencing some issues with mounting the system in a neat fashion.? "
Yes, these small lathes can be problematic in that regard.? I just learned about yet another approach, described in the January-February 2024 edition of The Home Shop Machinist.? I don't have the article itself, but it looks like the DRO extends off the back end of the cross slide.? This means that you need enough room behind your lathe to accommodate the scale.? The advantage is that it's pretty easy to include a cover to shield it from swarf.? I built my bench with scrap lumber and it is NOT deep enough to work with this approach.? As it is, it's pretty tight with the scheme I used. Mark |
Re: Lipstick on a pig?
Chris Albertson
开云体育Yes, it should be clear that you can’t mount the DRO at three locations and have them slide accurately unless you drill the mounting points with 0.0001 level precision. ? The “roller” was to be EXACLY parallel in both directions the what is moving and that is impossibly hard to do. ? The solution is two-point mouting. ?Fix one end of the rule and the slider. ?Let the other end of the rule float.It’s not tension on the rule, it is that you can’t expect to mount the rule parallel to the motion. ?? I think people try to hard to make the mounting strong. ?You can use 3D-printed plastic and magnets. ?Magnetic mounts if well-designed work well, Everyone use then on their dial indicators. Rare Earth magnets are now really inexpensive and you cn buy them on Amazon. ?These things are powerful enough to be dangerous if mishandled.
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Re: Motor swaps?
This is simply curiosity, I don't currently have a 7" lathe, but I'm sort of a small lathe junky so it is just a matter of time.?
The Consew and treadmill motors seem quite popular. I just haven't seen them discussed much in connection to the 7" lathes. Didn't know if there was a specific reason, or maybe I just haven't noticed. With other lathes it is often to add variable speed which wouldn't be a plus in this case. I just thought with the control boards apparently being unreliable that swaps might still be popular. The small compact size is another thought, a motor swap being a bit more involved than a small lathe with the motor mounted seperately. |
Re: Lipstick on a pig?
On Sat, May 25, 2024 at 11:00 AM, Ralph Hulslander wrote:
One thing I learned in installing them is that only one end needs to be fixed, the other end can float.I took that approach on all but my latest install, the one that's the subject of this thread (for a grand total of 5 DROs, three on the mill and two on the lathe).? I wasn't sure how it was going to work out but it appears to be OK.? The main problem I have encountered with iGaging DROs is their EMI susceptibility.? I have added additional bypass capacitors to all of mine.? That's all it took for the ones on the lathe, maybe because the stainless steel scales don't develop contact problems.? The DROs on my mill have the aluminum scales and they were a PITA when it came to EMI problems.? The only thing that reliably worked was to hard-wire the scales to the sensor's internal ground node. |
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