Belt or Gear driven

[RiekieRhino]

I'm saving up for a lathe but need some advice on which is better.

I have been looking at lathes at: http://www.adendorff.co.za/Products/Engineering-Tools/Lathes/Lathes-Steel

But not sure what would best suite model building application.

Regards
Rikus

 

[Mechanicboy]

I will select the 500MM 0.55KW GEARED HEAD S/CUT BENCH LATHE since it is big enough for model building. The geared head is to change speed of lathe both high and low revolution + it has belt to change speed depending on cutting speed of difference material.

 

[Niels Abildgaard]

A 60 year old belt driven VFD lathe

[ame]https://www.youtube.com/watch?v=SEetSzkiK_E[/ame]

No gears in my home

 

[Mechanicboy]

No gears in my home

Niels, you forgotten the set of change gear in your lathe for feeding/treading

Rikus..

My Lathe Sieg C-6 has belt to drive the spindle + the set of change gear set for feeding/treading. No problem

 

[RiekieRhino]

Hi Mechanicboy. Thanks for your input. What would be the difference between the one you said and the last one on that page. From what I can see the motor is bigger and the price is more. The rest looks much the same

 

[Mechanicboy]

Hi Mechanicboy. Thanks for your input. What would be the difference between the one you said and the last one on that page. From what I can see the motor is bigger and the price is more. The rest looks much the same

The motor at 0,55 kW is not big and do not cost much in consumption of electric price, it is strong enough for all work with lathe. My Sieg C-6 has 0.55 kW and i am very satisfied.
Yes, it cost much.. There is difference brand of lathe in about same size with cheap price. I am not sure what is available in South Africa when you are seeking after the good price at the lathe.
If you are not making the big model engine or big projects and need a cheap lathe with feeding/treading for small model engine etc.., the lathe at 250-300 mm between centers is big enough to example this MAC-AFRIC*™ BL180 Engineering Lathe.

Forgotten to write about belt or gear, the lathe with gear cost more than belt driven lathe. Belt driven lathe is smoother (and no noise from gearbox) in small lathe. The geared lathe is often to find in industrial lathe, unnecessary in hobbyshop.

 

[RiekieRhino]

In South Africa there isn't much available. Most of the hobby size machine's needs to be imported. Which is expensive because of the rand dollar exchange rate

 

[Blogwitch]

Don't be put off by the noise made by a geared head.

When I had installed my machine (Chester Crusader) I had to wear ear defenders because of the screaming gears, but no worries, after a couple of hours running in and an oil change, it settled down and is now to a level where I hardly notice it. It was just the new gears bedding themselves in.
With a geared head you will find it much easier to control almost everything, just a few knob turns gets everything you need, not only spindle speed but full control of your leadscrew as well for when cutting threads.

I used to run a belted lathe for many many years, and thought I would never need a geared head one, how wrong I was, it has made my machining much easier.

John

 

[Niels Abildgaard]

Don't be put off by the noise made by a geared head.

With a geared head you will find it much easier to control almost everything, just a few knob turns gets everything you need, not only spindle speed but full control of your leadscrew as well for when cutting threads.


John

VFD allows my belt drive lathe to go from 50 to 1500 turning one knob

 

[Mechanicboy]

With a geared head you will find it much easier to control almost everything, just a few knob turns gets everything you need, not only spindle speed but full control of your leadscrew as well for when cutting threads.

John

There are 2 alternative to create the pitch of treads: As John wrote about to select pitch of threads either in millimetere or imperial with knob (gear selector) on lathe. And the other is the set of change gear to set up the required pitch of threads.

With set of change gear will provides more possibilities to get the thread pitch that is not on the table on the lathe when calculating gear ratio for getting a required thread pitch to example treads for BA, quadrat threads or worm gear etc. We can not do with lathe with gear selector for the thread pitch with a fixed table for thread pitch in millimetere and imperial. To get more possibilities you can have lathe with a set change gear. Some lathes are supplied with both gear selector + a set change gear for thread pitch.

 

[Blogwitch]

Neils,

I already have all the bits to convert to VFD drive, just waiting for a friend to come down to help me fit it. Only because I am now getting slower with my reflexes, so slowing the spindle down for threading will be a massive bonus rather than the 68 RPM I have at the moment.
What I was on about was the difference between a geared head and belt drive. OK, some of the smaller lathes do come with variable speed, but without gears in the head system, or a quick change gearbox, it is usually a PITA to set all the change gears up for what you need with a belt driven lathe. I did that for over 40 years, and the geared system changed all that for the better.
If you can afford it, geared head lathes should be considered as a good option.

Jens,
You are quite right, geared head lathes do normally come with a few change gears, but not many, as mine does, but that is just for changing the machine from metric to imperial. A matter of direct swapping of two gears from top to bottom and vice versa, and turning a double one over, which takes no time at all. Then you use the knob selectors for setting up your leadscrew for speed of feed or screwcutting.
Mine also comes with 3 other gears that should allow me to change to BA or mod threads, but I have never had the need to use those.
The more you spend, the more selectable threads you can get ready built into gearbox on the machine.

John

 

[Wizard69]

I'm saving up for a lathe but need some advice on which is better.



I have been looking at lathes at: http://www.adendorff.co.za/Products/Engineering-Tools/Lathes/Lathes-Steel



But not sure what would best suite model building application.



Regards

Rikus

A belt driven lathe with a simple back gear option combined with a variable speed motor is a good option. The reason to consider a lathe with a back hear is to maintain torque at low speed which can be very important if you want to do a lot of threading operations or other things that benefit from speed control and the ability to go slow. Otherwise there isn't a lot of advantage to a lot of torque on these small lathes. The back gear simply allows highER motor RPMs to avoid speed control issues at low rotor RPMs that some motor and controller combos have.

Now a days ere are lots of motor controller combos to choose from that can be justified for driving a spindle. The old fashion brushed DC motor and controller is still a possibility but there are better options. The first step up would be a 3 phase motor with VFD controlling it. A rudimentary VFD and 3 phase motor can work well at low RPMs with a back gear.

Now to undo what I started this response with, you can take a different approach with a more advanced VFD, often called vector drives, and an optimized 3 phase motor. Here you may get good enough results without a back gear if you can set up a pulley ratio that gives you a good initial speed reduction. The reason here is that you can now run the spindle motor at a relatively high RPM, many of these motors can be driven 6000 RPM or more rotor speed, which after the belt drive reduction gives you a wide spindle RPM range suitable for hobby machining. If you pulley ration is 50% then a 6000 RPM motor would run you spindle at 3000 RPM. The low end will depend upon the drive and motor combo, plus how well the drive is tuned, however you should get good performance somewhat under 100 RPMs at the spindle. Over sizing the motor can help low end torque. In the end you need to play with ratios, drive setting and so forth to get the results you want.

Stepping up from VFD and 3 phase motors are various combinations of Brushless DC drives. Here you need to choose from a wide array of products that are usually more expensive than the VFD solutions. If you want to go this route you will need to brush up on the options. I tend to avoid this route due to the easy access to 3 phase solutions.

 

[Charles Lamont]

To put it simply, for hobby use you want a wide speed range. A Myford Super-7 has a standard range of 25-2000rpm (on 50Hz supply). (That was before I put a VFD on it.)

That is slow enough for machining a 10" diameter cast-iron flywheel and for any screwcutting, and fast enough to drill a small hole in brass.

 

[mikelkie]

A number of used machine tool dealers are listed on
the net in RSA. May be a better call than Adendorf

 

[RiekieRhino]

A number of used machine tool dealers are listed on
the net in RSA. May be a better call than Adendorf

Could you give some suggestions of these listings. Most of the listings I found is for big industrial machines

 

[Jasonb]

Not all geared head lathes have the feeds done via a gearbox. In the smaller hobby sizes (upto 11" 280mm swing)the gearbox only takes care of the spindle speed and you still have to use change gears for all threading and feed options, may get two or three options per geartrain but would need to alter that gearing between feed and threading.

For the amount of threading I do the few mins to alter the gear train is not worth the worry of looking for a lathe with screwcutting gearbox.

So Geared head does not mean Screwcutting gearbox

 

[mikelkie]

A good hobby lathe is a Maximat V10P geared for screw cutting app.220 swing with geared head
and norton box for screw cutting 600 cntrs.
Riekierhino check out "www otmar machine tools.co.za"

 

[el gringo]

I replaced the worn out original motor on my old 9" Southbend years ago with a DC drive motor off of a treadmill that I found in a junk store.
Lots of torque on both ends...Infinetly variable within the OEM range

Ray