Expanding Spindle Pulley Mandrel. Convert The Mini Lathe To Belt Drive
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- เผยแพร่เมื่อ 7 ก.ย. 2024
- See all the excellent benefits of making a pulley mandrel and converting the Chinese Mini Lathe over to belt drive with your own choice of motor. With the option of upgrading to a three phase motor & variable frequency drive inverter for speed control.
I did your lathe upgrade using the expanded spindle and vfd . And wow ! What an improvement. Thank you Steve for all the instructional videos . I also did your myford vertical milling upgrades. On my mini 7x12 lathe. Excellent instructions too.
Hi Mike, thanks for the feedback. I'm pleased you like it. It makes the lathe so much better having the torque and reliable electronics. I hope to do some more videos using the Chinese Mini Lathe soon. Regards Steve
Steve, another innovative modification to the mini lathe! Your technical background has served you well!
Hi Dan Thanks for your feedback Regards Steve
I have a craftsman 109 , With a 2 1/2 HP treadmill motor and the power and torque are AWESOME .. I full speed control and F/R as well , I will never regret the change over ..
Nice bit of mod Steve, I got one of those phase converters and they are the bees knees for sure. I like your adaptation of the pulley to the spindle bore, simple yet elegant, and easy to make to boot. Thanks for the vid, cheers!
Way to go....3 phase is so easy to wire up and control via a VFD.........a few years ago I got rid of most of my single phase motors in preference to 3 phase.
I converted mine from belt driving to VFD drive and never look back to belt driving and pulley. VFD is god send technology.
Yes, they are excellent.
Very clever, reminds me of when I was a kid and did not tighten the expanding handle bar tube and lost control of bike.
You have got a simple and reliable technical solution.
Smart-outside of the box thinking again Steve. To bad we don't have more people like you designing equipment. If we did the functionality and quality of machinery would be top notch. You've got me thinking more about installing a 3ph motor and vfd on my old South Bend 9a. Keep up the great work Steve.
Hi Thanks for your feedback. I think the VFD's are a great invention. I hope to get one set up with 3phase on my Myford as well, if I get time. Regards Steve
Hi Steve,
excellent video that gets you thinking, as always.
When I had built my first 3D printer (reprap design from Prof. Bowyer, UK), one of the first jobs I did was printing a complete set of spares...
Thanks for watching. The 3D printer stuff is amazing you must be skilled to make one. I don't think I would have time to learn how to use one! Regards Steve
I converted mine to a treadmill motor and used an intermediate shaft where the original motor was situated. The treadmill motor drives the intermediate shaft through V belt pulleys which then drives the lathe itself via the original toothed belt. ( Readily available on Ebay) I keep the hollow spindle and easy gear change and speed control is via a £14 240V AC to 200v DC controller. Plenty of torque and no problems at all after lots of use. Quite a compact unit too as the motor mounts in the same place as Steve's in the video.
Another excellent modification Steve, thanks for sharing.
I just finally gave up fighting with old used lathes and ordered a minila the. First thing I plan on doing is going thru it with a fine tooth comb ( or wrench as it were ) ...second task is reproducing your pulley and shaft idea for the inevitable later need...already have a treadmill motor and speed control waiting in the wings. Thanks to you for the great idea.
Great idea Steve and I have always thought the motor on the mini lathes was not properly thought out. This could of course still accommodate your hand crank into the design and on mine I left the shaft long deliberately, so that I could have an indexing system, the disc of which used an old change gear to make an indexing wheel. I have also made a probe assembly and this fits on to the cover as well, for when I use the indexing. So I think I will be going this route as well Steve. Seems a logical extension. you have some great and highly useful ideas Steve. look forward to seeing your exploits with the 3 phase motor
Hi Stephen Thanks, Yes I am going to make a new drive handle and a new indexing assembly when I get time. I am looking forward to getting a 3 phase and the VFD. I have been watching videos on TH-cam about them. I actually never knew the VFD's existed until I had this electrical problem. I wish I knew about them a couple of years ago, before I bought the new Myford motor. I would have put one on that lathe then. Still I may do that at some point as well. I can always sell the single phase motor. Its great that you have made an indexer.
Yes I think the VFD and 3 phase motor is the way to go Steve.
As you say top speed is not really a problem, but slow speed is. Particularly for things like screw-cutting, (though of course the hand crank can be used for that, as shown in one of your other videos.) But larger drill sizes are just not going to work at the pulley speeds unless the RPM is reduced considerably.
Fortunately I have a friend who can repair the main boards for me, but both our lathes are different to yours and i am told yours uses a totally different board, Probably still repairable though.
My Friend who is into electronics was telling me it is usually the mosfets that go as they get to hot in the main board enclosure.
He made a larger enclosure for the main board and included fans inside the enclosure on his lathe and since then he has touch wood suffered no more fried boards.
I got a couple of spare mosfets for my board at his suggestion for when my board finally goes the way these boards go. So he can just replace them for me. I think they cost about £2 each on ebay
I think though you are on the right track with this modification as it is going to be much less hassle than messing around with expensive electronics.Regards
Steve
Hi Steve, Its good that you can get them repaired. I would have tried a fan if I had thought about it. I was going to sell my faulty boards off on Ebay. I like the Idea of the VFD's as it is something new to try and at least it gives the options to get the lathes going again. My Mini Lathe electronics always faulted out when I was just half way through something really important...:)
The video really makes everything look much larger!!
Another grate idea! I to have bought way to many parts! Thanks!
Hi Danne Thanks, yes and for what they are charging for this lathe and parts is very costly especially in the UK. Someone could make a great business by importing the lathe without any motor or electronics and selling them like that, so that people could put their own parts on. This way it would eliminate returns for the seller and the customers would have an excellent lathe without all the faults they have.
Three phase and a vfd are a brilliant set up and can transform many a machine
there is a presentation by David Haines ' adding a motor to a mini lathe ' (I think?). He machined a stub shaft that screwed onto the end of the lathe spindle to take the drive VEE belt pulley. This would allow total access through the spindle. His solution is more complex than your expanding mandrel but does have the benefit of spindle access. Having said all that I enjoy your videos hugely.
I love your ideas. You done it, again.
nice conversion Steve, well done and thanks for sharing.
Hi Jim thanks for watching....Regards Steve
I love the thinking behind your problem solving process.
As others have already said, great conversion.
Thanks,
John
Hi John, Thanks for watching and your feedback....Regards Steve
Hi Steve
I made an extension to the spindle of my mini lathe which was essentially a tube that threaded onto the end of the spindle in place of 1 of the lock nuts and then the pulley was fitted to a split threaded collar which then fitted onto a thread on the end of the new extended spindle which enabled me to keep the bore of the spindle clear, I posted a video of it working on TH-cam if you are interested, but no longer have the lathe as it wasn't getting the use it deserved but I understand that the new owner is very pleased,
Dave.
Hi Dave, I did watch that one. It is a very good set-up. The buyer must be well pleased. What diameter was the large pulley you had on it. My one is 7" but I would like to get hold of an 8" pulley. Regards Steve
Hi Steve,
The pulley was 150mm in diameter and was a picador pulley that I found in a second hand tool shop in Wimborne, the motor had a 55mm pulley on it I think but the motor had the ability to turn slowly but still with high torque, this set up gave a speed variation between approximately 75 and 2100 rpm with no belt changes, it transformed the lathe into a quiet and smooth machine....
I do like the simplicity of your solution though.
All the best and thanks for the time you put in to bring us your videos,
Dave.
My point your right that works like normal set up, Steve missed this one.
You should post you direct video of what you did so we can see it without hunting for it on TH-cam.
thenet0120002 unfortunately I never had time to make the video showing what I did before I sold the lathe sorry...
Steve, you've made so many improvements and mods, I was wondering when you might be mounting steer horns on the head stock. Keep it up sir, I truly enjoy.
Simply super Steve ! I don't have a mini-lathe but have a mini-mill and I am on my second control board and second potentiometer... although (fingers crossed) since I disconnected the optional add-on tacho it is working okay ( just guess the speeds :)
Great conversion, a win-win situation.
Great Job. I am going to put a AC motor on my minilathe. But I am going to thread the gear to screw right on to the end of the spindle. Mine is a M27x1.5. Then use a two pulley rig to change gears.
This was a year ago...I screwed it up by running the die on crooked so the pulley was not running true ...ended up messing it up. As long as i don't try to screw the pulley on the end it doesn't hurt anything but ruined my ability of using that method of powering the lathe.
Yes the minilathe toothed drive belt and motor leave a lot to be desired. However, I frequently use the hollow mandrel for turning longer items. I would probably modify the fixing to allow at least 1/2" through. It would be useful to be able to disengage the normal motor so that it could be re-engaged e.g.. for threading or other slow turning requirements.
Good job Steve. Just proves necessity is the mother of inventions. Being that board is made in the USA and after a while it craps out, I guess we can say Cheep American junk rather than cheep Chinese junk. Lol
I have a washer that's only 2 yrs old that's broke, a expensive frig that's 7 years old that started freezing everything 4 years ago. It has more electronic crap in it than my desktop computer. USA manufactured products are made to fail now days. So they can suck more money from you to repair it or you buy a new one. That's sad. I remember when making it to last ment something.
Damn and blast planned obsolescence! Perhaps that controller was ASSEMBLED in the USA using low grade, pacific rim sourced, parts.
Let's be clear, not everything from the pacific rim is guano. For instance, made in Japan Nichicon & Panasonic electrolytic capacitors are SUPERB.
Excelent idea i have come to same conclusion, I am going to use the motor from a wood lathe , it has five gears run from a belt.
Very practical and much appreciated.
Great job on the adapter. You might need to tweak the pulley ratios to get the VFD to work right. They tend to produce less power at the lower RPM's.
Hi Stephen, Thanks for the info. I will keep that in mind. I may have to get a larger spindle pulley. Regards Steve
Very clever conversion. You might consider an intermediate jack shaft if you have room behind the lathe. If the driven end of the jack shaft had a step pulley like the pulley on the motor and a pulley on the jack shaft lathe drive side that was the same as the smallest pulley on the motor, then (just from a visual guess the smallest pulley to driven pulley has a ratio of ~1:4) the spindle speeds of the lathe would be from 87rpm to 1400rpm given a 1400rpm motor. A two step pulley on the jack shaft lathe side to go with the pulley on the lathe spindle presently would give you 8 speeds (though I don't know if they would have a satisfactory geometric spacing of the spindle rpms).
Thanks, I will look into that. I like trying all different things like this. The pulley side of things is a very interesting subject in itself. I'm keeping the head-stock gear set, just in case I may include those in something in the future.
Regards Steve
I enjoy your videos Steve. I'm using both a 3 phase VFD setup on a pillar drill and a DC motor converted mill. I've had no issues at all with the DC setup - the biggest advantage is the motors spin to over 4000 rpm so when geared down they don't load up too much and you get plenty of torque. I've found that the VFD setup is not as straightforward and has bugger all torque down low. I'm still messing around with the torque compensation to try and improve it.
If you manage to decipher the instructions and settings, let us all know! :D
Thanks, You have sound like you have some good set-ups. I thought it wouldn't be straightforward. The pulley side of things is an interesting subject as well as the VFD's. I only know a little about electronics, so I have to be really careful and slow to get things right. Regards Steve
thank you so much for your nice and perfect advise .
Hi Thanks for watching and your feedback...Regards Steve
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Looks like a winner, Steve. I know, in the U.S. a lot of fellows on the forum that, I belong to, (shopfloortalk.com), have picked up perfectly serviceable three phase motors for pennies a pound, from the scrap yard and used them to make three phase converters for their machines that came with three phase motors. Now that variable frequency drives have become so reasonable, they're going that route instead. It may be worth investigating your scrap yards for a used motor at considerable savings. I'm still setting up my new mini lathe so, I haven't experienced any trouble as of yet. I will however keep your solution in mind. My lathe does not have the high/low range that your's had. It has only one range and no shifter so, I wonder what the torque will be like. Time will tell.
Hi Dave, In the UK there are rules that stop the scrap yards from reselling any electrical items now. In the past I would have got one there easily. They won't even sell any voltage battery operated items either! There are so many EU rules now it has got ridiculous. I think they have done this, so people have to buy new items, to boost the economy, but they make out it is for safety reasons. It sounds like you lathe is the better version with the brush-less motor. The torque should be good on that one. Regards Steve
That's a shame that they regulate you so much over there. Kind of sounds like New Jersey. LOL. Yes, I thought that my lathe might have a brushless motor but, unfortunately, closer inspection revealed the little covers that contain the brushes. The motor looks just like your original motor. Rather disappointing. On a brighter note though, I received my new cast iron hand wheels today. One of the plastic ones that came with the lathe was broken, when it arrived. I didn't like the looks of them anyway so, I'm replacing both of them. Cheers, Dave
The motors are very good though. I have never had any problems with that. Its just been with that particular circuit board and the potentiometers. So it sounds like yours maybe a different set-up
Thanks this works great!
Most excellent.
thanks steve.
If you put two flats on the end of your mandrill you could use your bike crank for manual threading couldn’t you Steve? Nice mod to sort out the reliability of a mini lathe👍🏻👏😎
Hi Yes I hope to make a new handle and an indexer this week ti fit this set-up....Regards Steve
wish l had link to pulley Bought a 6” on amazon $21. l have 1 hp A/C.
Interesting idea but I wonder if it would be possible to use a stock spindle from sc3, since they're belt drive to begin with? Could still use whatever motor you want, still have a hollow spindle for long stock. Just a thought...no idea if it would fit without further messing about...
Nice job Steeve. But don't forget to install a safety guard over the belt and pulleys ☺. By the way you can find a rather cheap industrial inverter for 3 phase motors on ebay... I have done it on my lathe and never got any issues since... Greetings from France Laurent
Hi Laurent, Yes I will have a look for one on Ebay. Will any 3 phase motor work from a VFD, even if its not a modern type? Regards Steve
+Steve Jordan Hi Steeve as long as your motor is a 3 phase asynchronous type it's ok. Depending on your power grid available at your home (1 or 3 phases) make sure that the power input of the inverter fits. Concerning the power of the inverter choose 20% over the nomi al motorpower. Regards Laurent
Well done! Maybe a loctited adaptor, with means of extraction,could give you bore clearance?
Now you can make a handle that the arm replaces the washers under the 8mm nut for your hand turning like the other lathe.
Quick simple remove nut washers, place handle arm on , tighten nut, hand tap or what ever, reverse operations n back to motor power. Simple most likely less than a minute.
Hi Thanks, I hope to make a new handle and indexing system this week if I get the time. Regards Steve
What is writen on his hand?
Nice work Steve,
I notice in the Model Engineers Workshop magazine there is an ad from Transwave converters selling metric motor/VFD packages for about £250, don’t know how much research into pricing or availability you have done, but their a UK company might be worth a look. Have been thinking for a while about doing this to my Myford for that extra bit of speed.
Cheers
Hi Raymond. Thanks, Yes I think I will convert my Myford ML7 as well. I like belt drive but I don't like getting my hands dirty on change over. I have heard that the ML7 bearings are not designed for high speed so I think I will stick to a top speed of around 1000 RPM. Regards Steve
Steve Jordan in my Myford book they say 1070 rpm spindle speed with a 2 1/2in drive pulley on a 1750 rpm motor, given that the occasional spin up to about 12-1400 rpm should be ok.
Good luck.
Cheers
KB electronic boards are usually very reliable unless you got them on the cheap by Ebay. Most your need to match the resistor on the board to the horsepower or wattage of the motor. I guess the boards we used were for permanent magnet DC motors though. Wondered what bearings you have in the headstock as the extended pulley shaft will put a lot more overhung load on the bearings. I do wish I hade an idler pulley on my stock units to keep good tension on the belt without always tearing it down to tightened. Especially when you put on a new belt and it always need to be retightened.
I bought both my KB boards from Amadeal where I bought my lathe. Maybe something else was making it blow, as I know other people with the lathe that have had no problems with it.
I have large tapered roller bearings in the headstock now so the overhand doesn't matter.
I'm pleased I have gone over to the VFD set up as I haven't had any real problems since. Regards Steve.
hi, yet another great idea, is there a place where i could buy one of these off the shelf? regards mike.
i had the same problem with a chester 20 v mill changed it to 3 phase motor an inverter
Hi Gareth, It sounds like a common problem. The VFD and 3 Phase is the way to go I think....Regards Steve
Excellent adaptation Steve, £90!!! They aren't shy are they?
when i purchase my mini lathe, this will be the first thing i do. (plus the 3PH VFD, and tapered roller bearings)
i wonder, Steve, have you considered adding mass to the headstock to provide greater damping? somehow bonding some thick steel plate to the walls of the casting?
good conversion Steve. Question though; how do you draw your ER adaptor into the spindle? Is this setup prohibitive to a drawbar?
Billy T Hi Billy I think i can just remove the brass cone part and have the draw bar through the mandrel this will then lock solid on the shoulder and the back of the spindle. I will try it out later.
send me the dead controller so i can figure a solution/ modification that will last. the VFD is an excellent solution to many of these problems. thanx for the video.
I will put them on Ebay for sale if you are interested. There will be someone who can fix them and resell for a good profit. Regards Steve
Nice setup. I think I missed whether or not you can still drive the leadscrew for threading.
Hi Todd, yes that all works the same
Steve, have you given a thought on a method to use this expanding mandrel of yours, while retaining ability to use drawbars?
I have the same issue with the Lathes electronics,.. Speed control just died,. Its a shoddy design.
Hi yes I made a draw bar that I can use of needed. I haven't used it for anything yet though. Regards Steve
I laughed out loud when you said the board was US made!!!
Hi everyone, I just bought a Chinese mini lathe and noticed it does not have a thread dial. Does anyone know if I need one and if I don’t how do I go about threading without it? Thanks and great video Steve.
Adan Hi Thanks. Amadeal.uk sell them for £16.50
Steve Jordan thank you Steve!
What kind of belt is that that your using.
That was a plastic or nylon link belt. I've since changed it to a fenner link belt
hey Steve where did you nuy those pulleys on the spindle and the motor?
Hi Thanasis Yes I bought those. I just made the expanding mandrel to fit the spindle back bore. For the large pulley to go on. Regards Steve
Hi Thanasis I bought the pulleys off eBay.
Clever, but it''s a shame you lose the ability to hold long stock all the way through the spindle.
I AGREE LIKE THIS MOD IS GREAT FOR MILLING I WISH THERE WAS SOME WAY TO CONVERT AND STILL HAVE LONG BAR ABILITY.
I think you can machine the adapter to fit the rear spindle thread and remove one of the locking nuts before screwing it on the back of the spindle. This adapter then acts as the locking nut. With this method the adapter can have a through hole.
Although I have never tried it yet.
My point! You can make a tube that screws on to the spindle tube where the 2 flat lock nuts sandwich the bearings, then screw this new tube on to the spindles with 1 lock nut to the spindle tube then mount the pulley on this new tube. It will work like normal set up ,you will need a set screw in the tube so it won't unscrew as it spins.
I don't need through bar facility as the available length is quite adequate for me. So there is no need for me to do this. There would always be the possibility of the adapter unscrewing, even with a set-screw..when using reverse machining. Also one would have to take the pulley off the spindle adapter every time you want to get at the thread gears. I can still use draw bar tools by removing the mandrel thread expanding assy, so the draw bar thread goes right through my pulley mandrel and locks up at the back, pulling the MT3 taper into place. This set up has really made the lathe excellent and I'm so pleased to get rid of the electronic set-up that came with the lathe.
As much as i love it is it not a sign that you pushing the mini lathe just too much ?
No it is just a bad electronic set-up, or was? I use the lathe most days but that should be quite ok for any electronics. It just faults out for no known reason. Others say the same and I was reading an article online that said the circuit board was not up to the job, (this may have been the case in the past?). Also the potentiometers are/were very poor and don't last. This all may have been rectified now. Mine does get a massive amount of use, and I would still hope to buy one if I didn't have this lathe
But having said that, I am not running the lathe down and have included a statement about the lathe in this comment section today. I would still hope to buy one if I didn't have one. They are great little lathes. Regards Steve
what about a treadmill motor keeping the main panel for speed settings. or a wheelchair motor it's dc and has reverse and its controls are on a joystick.
Hi Phil, That is a good idea as well, but after watching TH-cam videos about the variable frequency drive inverters, I am sold on that idea. They are really amazing with very little wiring involved.
You cannot run a rod thru the spindle if you want to cut a rod or add a collet with a pull together out the rear . It's more a quick fix but limited. The best is still variable speed with a good overall torque and RPM .
I never use long bar. There is plenty of room for what l need. It can use draw bar tools. You just remove the stud with the taper and the threaded drawer bar goes right through pulling the tool into the mt3 tapet and holding the pulley mandrel in the back
Another idea! i notice you have to remove the pulley to run a bar thru the center i know you say you don't run a long bar but if i did this so i can cut a 3 foot long round into smaller sections i would have to remove this pulley set up to do that. So , another way would be to make a tube that threads onto the spindle by removing the 2 locking nuts that pull the angled bearings together. Make a single lock nut then use this new tube to screw this sandwich together then tighten a set screw to prevent it from getting loose and mount the pulley on the tube . Now it works just like the original set up. You don't need a collet to release you don't need to mess with the pulley for operations.
It's interesting how different people tackle the same problem in different ways. When mine packs up, I plan to go with a 149KV Turnigy permanent magnet 3 phase RC motor as keeping everything within the foot print of the lathe and retaining the ability to move it around easily is important to me.
There is a great description here letsbuildone.wordpress.com/mini-lathe-motor-upgrade/
The comments below the article are particularly interesting.
Hello Steve, can you tell me what key-word should I use, to find this link belts. I check several relative words and the results was tenths of thousands and none of those links to "linked belts".
www.ebay.co.uk/itm/RDGTOOLS-WHITE-LINK-V-BELT-A-SECTION-FOR-MYFORD-LATHE-HEADSTOCK-ML7-ENGINEERING/290927357461?epid=1959205237&hash=item43bc9f2e15:g:9NEAAOxyaURTiGqB
www.ebay.co.uk/itm/Fenner-PowerTwist-Plus-Link-Vee-Belting-Z-10-A-13-Lathe-Myford-Drive-Belt-etc/142389725124?hash=item212716c7c4:m:mp1oqdcEpE2xL45rBUm1H8g
Thank you Sir....!!!
Do you have to remove the high/low gears out?
Hi Pete, No they just become redundant. This conversion is the best thing I have done to this lathe. I wish I had thought about it years ago. Regards Steve
Steve, That's a great idea but you give up the use of your spindle bore.
After seeing this I see why you have no gears. Must be looking at things out of order. I am surprised if the electronics board is a KB electronics they would not replace it as a warranty. But then it may have been made specific to Chinese requested spec. Wonder how much trouble shooting it would take to fix the boards
👍
You lose leadscrew/apron feed also?
Hi....No that all works the same as it did before.
terlalu banyak bicara,
It's getting to the stage when you're going to have to stop saying "Chinese mini lathe" and start saying "Jordan mk 5" instead. ;)
Thats very dissapointing.I ve just decided to give up my ancient Drummond and was going to collect one of those Amadeal lathes on Tuesday.
How soon I wonder could I be worse off just to get speed control!
I had mine for quite a while before I had faults. I don't know whether there are others that have had the speed control fault on their machines or whether they have improved the electronics since I bought mine. Regards Steve
I have the Chester conquest version which has been fine for about 15 years, it doesn't have the speed readout but has been fault free....