Fine-Feed for the Mini Lathe
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- เผยแพร่เมื่อ 17 พ.ย. 2023
- This is quick little upgrade to my Mini Lathe. The original gear combination for the power feed on these type of lathes is quite a bit fast for some applications. So I thought about a way of slowing down the feedrate a little bit. My first attempt with an extra gearmotor wasn't succesfull as the motor was way to weak to drive the leadscrew under load.
To install a real electronic leadscrew with stepper motor and controller I'm just not ready yet. Instead I have plannings in mind to build a complicated feed gearbox to easily provide all the common thread pitches and feedrates. But that's a longer story and not for now.
Instead I thought about the geartrain to the leadscrew and tried different combinations. To my surprise I found out, that with just a little bit of work it is possible to install another reduction stage in the geartrain, resulting in a lower feedrate.
I thought that might be interesting for other Mini Lathe users as well. That's why I'm sharing this here with you.
I hope you find that interesting. Feel free to comment and ask your questions and suggestions below in the comment section.
If you want more of this Mini Lathe and hobby engeneering / toolmaking content, I invite you to subscribe to the channel.
Thank you very much.
WCDTB
Support me via Patreon: / wecandothatbetter - วิทยาศาสตร์และเทคโนโลยี
Thanks for demonstrating the results of different feed rates and how it impacts the finished surface. I now have some adjustments to look into. 🙂
Thank you very much for your kind comment and feedback! I really do appreciate that :)
Just use the gear motor from the wiper of any car by putting a gear of 16-20 teeth on the motor shaft, and the machine's running screw is 80, plus a speed controller and you can get small feeds up to 0.01 mm per revolution.The guitar must be disconnected from the spindle and you will be happy.
Thanks for that tip. Sounds really good. I should try this in the future.
I thought about this very topic a lot with my old lathe. Never did I think that there was enough space to fit an extra set of gears on the banjo. Good stuff. Also, what everyone else is saying, I can back up that a wiper motor would be strong enough. I have used several of those 24v wiper motors with gearboxes and they have heaps of torque. cheers
Hi and thanks for your comment! Great to have you here :)! The wiper motor is something I will take into consideration for the future, yes :)
Great improvement for the lathe! I always wondered if there was a slower feedrate hiding in there. FYI, the next time you are milling an on-size slot like those keyways, try using a 2-flute endmill (aka slot drill) to achieve a truer result. George H. Thomas has a chapter dedicated to why this is so in the Model Engineer's Workshop Manual.
Keep up the great content!
Hi and thanks for your kind comment and the hint about 2 flute cutters. I didn't know that. Is this Model Engineers Workshop manuel you are referring to somehow available?
@@WeCanDoThatBetter Yes, re-printed by Tee Publishing, available online from their site, or several other model engineering sites. About £32 plus postage. It's a collection of a selection of articles from Model Engineer magazine (to which he was a very frequent contributor), one of two such collections that was published.
@@thisnicklldo Thank you for the information.
To expand on @thisnicklldo's comment...the MEWM is the best book on machining I've ever read. GHT is a gifted writer and photographer, and some of the projects in that book are very impressive. The offset-geared quick-retract compound slide comes to mind...I'm hoping a courageous TH-camr attempts that one some day.
Të lumshin duart, e mendja,mjeshtër.respekt për ju.
An interesting solution and a great result. Thank you for sharing. 👏👏👍😀
Thank you very much for your comment! I really do appreciate that :)
If your lathe has a metric leadscrew, the original feed is 1,5×20×20÷80÷80 = 0,09375 mm per revolution. You added the 20÷60 ratio, resulting in 0,03125 mm feed.
Btw, your solution is brilliant. I've already bought two 100 teeth gears to reduce my ratio from 1:16 to 1:25, but it wouldn't be as cost effective as your additional transmission step!
Thank you very much for your comment and your calculations. The calculated values are pretty much the same as what I measured. That's a good sign :) To buy larger gears was one my considerations as well, but I think the solution I found now is even more convenient or versatile.
Where did you buy the 100t spur gears? I'm also thinking about going a similar route as you did
The 100 tooth gear might not fit in the available space, or the cover may not fit. Some measurement would be required.
That shaft extension piece was cleverly done, thanks for sharing! 👍🙂
Thanks for your kind comment!
If you need a high torque, low speed and low cost DC motor then take a look at car windscreen wiper motors.
Thank you very much for the hint on a suitable motor. That sounds good!
@@WeCanDoThatBetteroom
Dang only 43 hours of run time on the lathe. It's not even broken in yet. But I do appreciate the videos.
Haha, well observed ;) The hourmeter is not installed from the beginning. In one of my latest videos about the new electrical cabinet I installed this working hour meter. So since then, it ran 42 hours :)
Great solution as always
Hi and thank you so much!! :) I always admire your work!
@@WeCanDoThatBetter Thank you, it's mutual (Google translator)
Nice! going to do this tomorrow since I already have an extra set of gears to use. Update= it worked perfect. With some fine tuning of the parts and some button head Allen screws I was even able to install the cover back. Thanks so much!
Most excellent.
Very doable idea
Thanks for sharing
Cheers
Thank you very much for your feedback.
Good work master
Thanks!
Nice job!
Thanks!
I want a mini lathe too, as soon as the manufacturer implements all your upgrades 😉
haha, :D Don't know if that's a realistic hope :)
Nice work ,
Thank you very much!
Well done. I have the same exact gears that you have. I might try and do the same thing to see if I get better surface finish.
Thank you, good luck for your project.
For the kind of 'powerfeed', I made a small handle on the guitar to not-connect the gears and on the right side of the screw I made an extension on which I put an old battery-powered drill. It thus gives me a independend feedspeed in both directions, still using the haflnut. It can move fast or slow too.
Since my old drill is Ni-CAD original, I use Ni-Mh batteries in it (just some penlights) with not soo much power but enough to do pretty well work. I will probably hook it up to an adapter in the future to never have to charge them.
For threading, I just de-attach the drill and move the gears back into action. No need to change gears between threading and powerfeed this way too.
(yes, I have the intend of making a small video about this setup ;-) )
That sounds good, thanks for this idea. When you made a video about your setup I would be interested in.
Looks good.Thank you.
Thanks!
Interessant, bitte weiter so!
Dankeschön :)
I've come to the conclusion the spacing on the banjo differs between mini lathes. The distance between the main gear and secondary gear means they are too far away to mesh using any combination of gear sizes. I think i can file enough out to make them fit but I'm going to make a new banjo specifically for fine feeds that will clamp to the lathe around the leadscrew housing. Will make adjustment easier.
Hi, interesting video. What did you use to improve surface finish @ 4.50. and what lubrication. thank you
Best tip here - look at nanoels ,very simple and quite cheap to build..if you understand basic computers and own a 3dprinter,its a fun weekendproject and works extremley well
Thanks for the hint. I'm not very experienced with electronics but the advantages of a els are worth considering.
Very good.
Thanks!
Great Job, also good option is hand made norton gerabox. The best option is ELS from Maxim Kachurovskiy
I have plannings in mind about a gearbox, not norton but like on other industrial machines. We'll see if this is doable :)
Off course, an ELS would be much easier.. :)
Very nice job! I would have opted for a stepper motor but then it would need a lot more work
Thanks! Yes, perhaps some day I will change for a stepper motor.
If you ever want to evaluate the torque needed to turn a shaft, especially a shaft with a threaded bore or a threaded end, just grab a hex fastener appropriate to the thread and get a torque wrench... A baby torque wrench is likely going to do well enough... You can also do the same and get a socket adapter for your cordless torque limiting hand drill, which allows you easily shift within a pathetic range best suited for torquing down screws in plastic, like when you change your car`s engine air filter and have to gently torque the lid of the filter housing down to 4-8nm... A smooth running small carriage with bearing supported leadscrew should not really require a lot of torque, but if the hand drill and it`s quick set torque limiter arent enough, a small torque wrench with 1-50nm should do perfectly... From that you can extrapolate the exact amount of torque on standstill that the motor has to have to nudge the carriage... You should also consider checking if the value changes as you cut into decent steel, as steel will be one of the better indicators of real requirements, being a tough material and a good margin to aim for... Just getting the motor to run a carriage on oily ways is one thing, having it run a proper cut in proper material is another... A digital torque wrench would do marvels in this situ, as most of them can just track the max torque rather than trying to click over at a pre-set, expected amount(which you can speculate on, but can hardly pull out of your ass if that is exactly what you are trying to find out in the first place)...
Other than this little bit of advice, as always, a pleasant video!
I am wondering if the lower feedrate if you can dig deeper when taking material off as it would reduce tool pressure
Very cool addition!
Keep em coming!!!!
Thanks for your comment! Yes, I think especially for these small machines a slower feedrate is overall better for the machine, especially when machining steel. The faster, the more toolpressure and power is needed I guess.
Muito bom !
Oh yes !
This is a clever solution but I see two other possibilities.
Put the little drive motor on the top gear, removing its key and welding a hollow tube on to the gear as a means of coupling the motor.
Measure the actual torque required by first engaging the cutting bit with a part and then turn the lead screw with a torque wrench. It’ll perhaps take a little red neck engineering to engage the torque wrench but nothing a clever red neck can’t figure out 😊
Please reach out once you're ready to try an ELS 😀
Haha, yes thanks ;)!
An ELS ist the best solution. The lower feed does not always make the better surface finish. Depending on material and cutter geometry you need to find the sweet spot.
Schön, wie immer, sehe ich mir gerne an.
Ein paar Gedanken:
Das mit dem Getriebemotor kann nicht sein, den dürftet du nicht festhalten können. Mit einer verlängerung schon, aber nicht mit 2 Fingern. Ich denke dein Netzteil ist viel zu Schlapp, liefert zu wenig Strom oder geht in die Strombegrenzung.
Bei Spindelantrieb muss man sehr vorsichtig sein. Ansonsten brechen bei einem Crash sofort die Zahnräder. Ist da irgenwo ein Scherbolzen drin oder rastet die Mutter früh genug aus?
Ich überlege bei mir einen Servoantrieb einzubauen (Spindelsynchron), meine Maschine ist aber noch viel kleiner als deine
🙃
Hi, mich hat das auch sehr gewundert, dass der Motor so schwach ist. Ich habe ihn mit einem Labornetzteil betrieben und den maximalen Strom auf 1A begrenzt. Laut Anzeige wurde dieser Peak aber garnicht erreicht. Ich kann es mir nicht erklären. Und die Idee mit einem Überlastschutz ist gut, da sollte ich mir etwas überlegen.
automotive windscreen wiper motors, cheap, powerful and easily modified and 12v and easily speed controlled
Thanks for the hint! I will look for it.
👍👍👍
I do envy that extra large test dial indicator of yours. I have had a look through a lot of machine tool suppliers here in the UK and as yet no luck with finding one. To make my search easer could you let us know the diameter of it please, for me and any other person interested.
Hi, at least someone who has noticed this comicly oversized dial indicator :D Thanks for this ;) I found this one on the used marked and found it so funny that I had to buy it. It has a dial diameter of 100mm and the brand is "Käfer". In Germany you find it with the keyword "Großmessuhr" which means "big dial indicator". Käfer GM 100 or GM 100/10 or GM 100/30 are types of the 100mm diameter dial indicators. Good luck and thanks for noticing ;)
aaaand this is exact reason why i never ever considered buying a lathe without three proper gearboxes. Sadly, there is just one such benchtop model (WM250G)
If only there were small lathes with power feed compound...
Unfortunately there is no such a small lathe with proper gearbox. That would be cool.
@@WeCanDoThatBetterIt's not that much bigger and weighs just ~120kg.
How does the forward reverse lock in place? You removed the original locking pin to make room for the control box. Is it just the screw seen here 0:29 on the left clamping the plate?
Hi, yes it is held in place with the screw you see. This was needed because of the electrical cabinet on the back of the machine.
Much easier for me, 3D printing two even bigger gears. I was afraid they were going to break or wear quickly...but they are working fine for two years... still as new.
For threads it's very convenient to have an Excel sheet so you can have all the possible values and add any new gears you print.
Last if you are not comfortable with a torch, use glue...😂
Oh yes, I have to practice soldering:)
Where'd you find that awesome huge dial indicator?!
I found it on the used market and thought it would be funny to have one :)
Hello We Ca Do That Better, ¿What model of insert do you use to have a good finish on your home lathe? ¿Could you recommend me one?
Hi, sag mal was hast du denn da für eine nette Fräsmaschine bei Minute 06:30?? Wirklich tolle Projekte, die du da machst. Hut ab!!
Hi und danke dir für den netten Kommentar! Freut mich, wenn meine Arbeit gefällt :) Die Fräse ist eine Proxxon BF40E mit dem KT150 Kreuztisch. In anderen Videos sieht man sie vllt etwas besser. Sie tut gute Dienste, hat aber auch ihre Grenzen was die Stabilität anbelangt.
Nice work! That pesky high power feed rate is a horrible disadvantage to these little machines... I would go electric but then might as well go all the way to cnc then. Sensible compromise!
Yes, I think that bothers a lot of us Mini Lathes users so I thought about showing a solution to this problem. And you are probably right electronics and stepper motor would be even better.
@@WeCanDoThatBetter might be better but then again, might be over kill 💁♂️
@@WeCanDoThatBetter another thought would be to add a separate lead screw to the back side of the bed for power feed just to keep the wear off of the threading screw... If a guy was to go through all the trouble of the electronic power feed
@@britenrhodehouse8692 Easier to use a coupler to the handwheel-axle and move that with a reduction instead of putting another leadscrew with halfnut on that.
@@elvinhaak so your thinking driving it off the rack?
I used a type of motor and gearbox very similar to a windshield wiper for a car.
Combined with some gears and an old DC servo controller.
Also combined with a Length meter system, so it's programmable for a specific return position.
Here is a video, it's in Swedish, but you might get some inspiration anyway.
th-cam.com/video/PVT6TOrua9U/w-d-xo.html
Thanks a lot for your comment and the recommendation. Your video is a great inspiration. I will watch it, thanks!
Could you have attached a torque to your lead screw and used it in increments to see roughly the torque needed to turn it?
Yes that would be possible. I just have no torquemeter for this purpose.
what do you need that slow speed for? You are just rubbing at that point.
Нужна "электронная гита" , а лучше чпу , потому что это неизбежно 🙂
Cordless drill is plenty powerful enough.
That's an option too. But not that practical to hold the drill while turning.
90% of what people make on lathes is to maje their lathe work better!
Ich hab mir da einfach Zahnräder mit 100 und 120 Zähnen gekauft und die Abdeckung angepasst.
Das Messen kann man sich sparen, der Vorschub wird berechnet. Wechselradberechnung sollte man als Dreher mal gelernt haben.
Das war auch mein zweiter Gedanke (nach dem Getriebemotor). Allerdings sind selbst Plastikzahnräder mit 100 oder 120 Zähnen garnicht so billig und es wird schnell vom Platz her eng. Deshalb habe ich versucht, wirklich nur mit den schon vorhandenen Zahnrädern zu arbeiten. Und das stimmt, man könnte den Vorschub auch berechnen. War zu faul dazu und für einen Film eignet sich die Darstellung mit Messuhr auch etwas besser. Danke für das Feedback!
Hi if you have a 3D printer you can print a 100T gear. I don’t know if a 120T would fit with out modification
@@WeCanDoThatBetter Beim Conrad für 14,99, gar nich so teuer find ich.
@@andikupper3414 Ja stimmt, das geht noch. Jetzt brauch ich sie trotzdem nicht mehr :)
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