Well, the specification does say maximum drilling capacity 16mm, sorry New motor price depends whether it is the old DC brush motor or one of the newer brushless variety.

John

Edited By Journeyman on 17/02/2020 18:29:40

I dio not think I have ever drilled a 22mm hole and I have a Bridgeport (amongst other machines).

Much easier to start with what size drills easy and open up by boring (better accuracy as well).

My lathe has a one horse power motor. I was drilling a 22mm hole last week, over 50mm deep. ~6mm pilot and in aluminium. But not even using back gear. No problem whatsoever.

I don’t have any short drills to do that on the mill (my large drills are tanged).

Seems like those motors don’t cut the mustard when the going gets tough.

The problem with DC brushed motors

Agreed, likely overloaded, but nevertheless, I am confident my 3 phase motor would stand overload far better than these chinese offerings. Poor design – cheapness? – I reckon, for motors to go pop so easily. That is excluding operator abuse, of course, as I expect I could burn out my motor if I really tried.🙂

If these machines are so sensitive to overload, they should be fitted with a thermal cut out – many cheap welding sets even have one!

If these motors are run within their specified limits and duty cycles then there doesn't seem to be a problem with overheating. Again it comes down to price and what people are prepared to pay for a machine. Like most products the features and to some extent quality will be set to meet the minimum standard that customers will accept at a given price.

There are many examples of same problem manifesting itself even on tools supplied by respected manufacturers, a classic example was using mains powered variable speed hand drills at low speed and high loads for extended period of time. Result the same problem damaged motors or hot hands plus magic smoke. I don't whether it is the same now but in the past welding sets used to be issued with duty cycle information to restrict self heating and prevent damage to the machine.

Martin

Dave H

While the use of a power meter might give some indication of the instantaneous power and total power being consumed it is far from ideal and can lead to a very false sense of security. Primarily this type of digital power meter is designed to measure sine waveforms, as one would theoretically expect to be supplied by the energy company, and usually makes a good stab at it plus or minus a few percent.

However when the measured waveform deviates from a a near sine wave then the readings can be grossly inaccurate. This can happen when these meters are used to measure the power being absorbed by a phase switched load as the load current is now a chopped up part of a sine wave. Even what are supposed to be 'True RMS' digital meters have a limited form factor for which they are accurate.

The main problem with these and similarly cooled motors is that when run slowly the cooling becomes very inefficient couple that to being fairly heavily loaded and it spells problems. The current is going to be high, as are the I2R (I squared R) heating effects with limited cooling. I suppose a fairly good analogy would be using a car with the cooling system blocked off and towing a heavy trailer up a long and steep hill. Frequent stops to let it cool down and all would be fine but try it in one go and the engine would soon emit a different type of magic smoke irrespective of build quality.

The use of a Power Meter could be a good idea if they were anywhere near accurate when used under these conditions at least one could monitor the total power being used and set a safe maximum time v power limit.

Cheers

Martin

Edit as post crossed with S.O.D. Dave's post

Edited By Martin W on 18/02/2020 11:19:10

Edited By Martin W on 18/02/2020 11:20:13

Some of "these" machines do have an overload trip, my mill certainly does as I have tripped it a few times so should not assume that all DC motored mills don't have this feature.

I stalled the lathe a couple of times the first time I went to cut a 9 or 10" iron flywheel, soon learn what it's limits were and adjusted my methods to suit and have not had issues since and that was 10-12yrs ago. I've said it several times on here that they work better run a bit faster and with a shallower or finer cut in the end you get the work done in a similar time. They are quite capable if treated with respect and as hobby machines not treated and used in the same way as heavy geared or belted industrial ones.

For example the typical old advice was to engage back gear and take a deep cut to get under the skin of a flywheel or loco wheel casting. I'd be doing a 9-10" dia flywheel at 3-400 rpm and taking 0.5-0.75 deep cuts with carbide that can handle the speed and not bothered by the skin.

Same for holes I'll work my way up in 3mm increments starting at 6mm and then finish by boring. drills can be wound if at a good feed rate not having to use both hands on the tailstok to force them into the metal as per a recent thread so not a lot of time difference and less strain on the motor and electronics

Well I, just for the fun of it, just drilled a hole about 30mm deep with a 22mm drill into some non-descript steel after piloting with a 6mm drill.

One horse power motor, no problem at all. Lathe only slowed when thick continuous spirals were being turned out – OK with thin continuous spirals. This was in normal speed range, not back gear.

IMO, a 1 1/2HP motor should be up to the job. Methodology, and edge on the drill may have been factors. Otherwise these motors are just not up to the job. I wonder whether the motor rating is input or output. Anyone know? If it is input, what is the motor efficiency?

Seems like it may have been a very expensive hole!

Petro1head

I do have a motor and speed control board that I took off my wm18 that you can have for a good price

all working

i fitted a 3 phase and vfd to mine

Drilling a 22mm hole on a lathe or mill with a one horse power motor should not be a problem if it is fitted with a gearbox or belt drive speed reduction as the motor is running at full speed and the internal fan is cooling at 100% but if using a variable speed motor, at a slow speed the fan air flow is reduced and can lead to overheating.

Even though the DC motors have good torque at low speed it is less than what you would get a reduction drive system. The WM18 mill has a 1.5kw variable speed motor and is only rated to drill a 16mm hole. My RM-45 mill only has a 1.1kw fixed speed motor and gearbox drive and can drill up to 31.5mm holes. I used to have a Seig SX3 mill with a 1kw motor and to drill bigger holes, up to 36mm, I used a rotabroach instead of a twist drill with no problem.

Paul

Do the purveyors of these machines point this out to prospective purchasers? NO, THEY DON’T! There is inter-company competition to attract the buyers with as much cheap hype as possible, this being just one facet.

Nobody(?) runs their machine at highest speed, at the chuck, all the time – unless the spindle speed is lacking (mine is only 1750 which is ‘slow’ and plain bearing machines are even slower). Carbide tooling is not best served at low speed, of course.

Not a lot different to band saws, which might appear to have twice the power, but are really no better than the ones which actually provide half the output power.

Little different to the compressors which, to some, appear to be far more efficient (by quoting ‘air displacement instead of the far more useful ‘free air delivery).

Unsuspecting punters are often being hoodwinked into buying machines that are not quite what they think they are.

There is one well recommended seller (by forum members) that does not, at least, over-hype their machine power by over-rating the drives. There are likely quite a few that do.

Years ago, small stationary engines from one manufacturer were rated differently to competitors. They eventually had to reduce their ratings because they got so much flak from dissatisfied owners – that their engines were ‘gutless’ – and their reputation suffered as a result (they reported ‘flash’ output, not a continuous output).

This is likely why ‘old iron’ is often better than buying new. OK if the buyer is aware and able to make fair comparisons. Not so good for the new starters, with no basic knowledge of this advertising hype. Mechanical wear is another problem for the ‘non-mechanicals’, of course.

Just ask any myford owner how many motors the machine has gone through in its lifetime of 50, 60 or 70 years.🙂

I’m still awaiting any reply on whether the figure quoted for this machine is actually to the motor or usable power out – or even power to the lathe, not necessarily to the motor, even. My current lathe has had a motor change (guessing simply from single phase to three phase) and my previous was likely still on its original (the direction change-over switch was a three phase type and certainly more than thirty years old when I bought it) and the instruction manual did warn about reduced motor life if started on a high speed setting, instead of reducing the speed before switching off. My first lathe only had its original motor (although its position was not ideal re magnetic swarf collection&#128578.

Old is not always good, but is almost certainly more reliable.😉

The fact they say "max drilling capacity 16mm" is quite clearly giving the limit of what the machine should be expected to do.

Other suppliers have ratings such as Craft/hobby/trade or model engineer/engineer and a lot state hobby use only or non production runs etc.

Sieg know that some people won't read the instructions so also put the max capacity on the front of the mills head, you can't point it out much more obviously than this. Unfortunately there are still those who know better and that is why we tend to get more posts by people with problems with their machines than by those happy with then and that distorts many peoples views of these machines

I would say Warco list Input to the motor not output from what has been said here over the years.

Still like to know what lathe you were using?

And once again I will point out that the WM18 is a mill as you still seem to think it is a lathe.

Edited By JasonB on 19/02/2020 12:30:30

Edited By JasonB on 19/02/2020 13:18:36