Advantages of belt drive for a milling machine?

I'm thinking of investing in a small milling machine somewhere in the 500 - 750W range. Some seem to be gear driven and others belt drive, which costs more. I wonder what the benefits of belt drive are and if they are worth the premium?

Sorry if this is an FAQ, a search of the forum didn't come up with a definitive answer.

I had a gear head mill, converted it to belt drive after the gears broke while fly cutting...

Thats one reason for going to belt drive.....avoiding broken cutters if something goes wrong.....

I made my own belt drive conversion based on the plans on the net by Jerry Rollett....

Belt drive is much quiter too than gears whirring away....

I'm assuming you are talking about belt driven imported hobby mills rather than old iron. The ones with a direct belt drive will also tend to have the more upto date brushless DC motors which offer more torque at lower revs than the brushed DC motors. Due to this increase in torque they do not have to have a gearbox to provide more ratios to keep the motor spinning within it's power band.

One advantage is a quieter machine particularly when the cut is interupted for example when using a fly cutter or large dia insert tooling as on a geared machine they can crunch a bit as they are loaded and then unloaded. general running is also quieter.

No heavy gearbox makes the head a lot lighter so easier to wind up and down.

Some mills have plastic gears which some people have found tend to strip if you stall the tool or run a cutter into something you should not.

John pretty much has it, belts avoid breakages and are quiet.

On the other hand gears are 'better' for transmitting power because they don't slip. Fine and dandy unless you smack into something violently enough to strip the teeth. The downside of belts is that they slip and wear out.

I don't know why belt driven mills tend to be more expensive; it might be because belts take up more space than gears and make the machine a tad bigger = more costly.

Smaller milling machines often have plastic gears, which are easier to break. It's possible that some operators expect too much of small machines. If you're heavy handed, expect to do lots of interrupted cutting, or are always in a hurry it might pay to go for a belt driven machine.

One advantage of belts and plastic gears is that they tend to break first avoiding damage to more expensive parts of the machine.

Despite all that I bought a WM18 with steel gears. It's not particularly noisy and I haven't broken it - touch wood!

Dave

I think we're all guilty of expecting too much from the machine at one point or another :P

I would add that it's normally the type and power of the motor that matters a lot more than the method of transmission, dc speed controlled motors offer the illusion of slowing down the output speed without actually giving you all the beans at said speed.

I changed my 750W dc motor on the WM 16 for a 550W AC 3 phase induction. The difference is quite astonishing despite the fact it has a lower wattage than the original dc motor. The old one used to slow down or even stall on heavy cuts and materials yet I have chomped through a fair amount of castings on this one and it shows no signs of giving up.

It seems someone listened or cottoned on to the same idea because warco recently bought out a newer but very similar model to mine which uses a geared head and induction motor.

One thing I would like to do to my franken-warco is add more gear ratios for general speeds, as I only have a high/low (full and half) ratio as it stands.

I would also like to write up everything I've done to it and see if it's worthy of the magazine, but I'm waiting until I've got more modifications to talk about, because there's a number of ideas I haven't committed to yet, and could really work with any type of mill, generally based on my experience working on bigger mills and some of their features. 

Michael W

Edited By Michael-w on 13/10/2017 14:50:41

Quite of few of the smaller imported mills have toothed belts so slip should not be a problem.

Michael was your old motor a DC brushed or brushless one?

DC brushed, I'm certain I remember filing some different sized motor brushes to use as a replacement once :P

I certainly gave it a good try but in the end it clapped out, not sure if it's the motor itself or the control board that's failed. I still have them, if I can ever work out what to do with them.

Michael W

Edited By Michael-w on 13/10/2017 15:29:54

Interesting thread this one. Does anyone know of plans to convert a WM14 to belt drive?

Mick

I've got a VMC mill with belt drive (2 Belts) and never had a problem with slippage, after quite a few years they show no noticeable wear apart from some black dust in the casing. The belts are also cheaply available from motor factors or the likes of Halfords should I need them.

Thanks everybody for your thoughts and insights. I'm getting that belt drive (and brushless motor) is a nice to have rather than indispensable so I'll weigh up the extra outlay on that vs. more tooling or a getting a slightly bigger mill for the money.