Member postings for Peter de Groot

Nick, I am saving up for a fog buster setup which does not cause misting (There's a couple of videos on youtube). But it is quite a big more expensive than the vertex setup so I'd be interested how you get on with the vertex set-up.

Well just to close off this thread:

I did use the Mill (carefully !) and it did pack up again, same as before. Chester have agreed to give me a refund so it's going back tomorrow for the third and last time.

Back to the drawing board.

Thank you all for your contributions, much appreciated.

Well I emailed the results to Chester Machine Tools, and their view is that 1) my tests are unrepresentative, 2) that the motor is working at it should be, and 3) that I should just use it.

So I did, lightly milling (the cutter did not heat up significantly) some aluminium at speeds of around 2000 rpm, with the motor cover off. Once the machine is warmed up, I can use it for about 30 mins (including the occasional stopping to brush off swarf) before it gets to 50 C, and it then takes about an hour to cool back down to 30 C or so. So a dutyr cycle of 33 % - at least when it at high refs. Perhaps this is what Chester Machine Tools means by the phrase 'Hobby rated' ?

I understand that the motor 'fan' on the Champion V20 is some bent sheet metal at the bottom end of the motor, and that indeed it doesn't produce significant airflow. Clearly a poor design, all for the sake of a few pence spent on a properly moulded fan and ventilated motor cover.

As this is how the machine is designed to work and since it is still in the warranty period I will try and keep the motor temperature down with a desk fan for the moment. Chester have been unable/unwilling to tell me what the maximum operating temperature for the motor is, so based on advice here I will stick to 50 C.

Thank you all for your contributions. I am now in the market for a robust and reliable bench mill by a supplier that understands and stands behind their product - any suggestions ?

Wow thank you for all the feed-back. The general consensus appears to be that there is something wrong with the motor - funnily enough I had not considered that option - just thought it's a poor design! I will contact Chester with the measurements tomorrow and ask them.

I will try and move the motor spindle while disengaged from the gears though I think the spindle may not be accessible. As you can see from the picture the spindle sits inside the housing. Will also measure amps later this week if Chester thinks the motor is OK.

Here is the motor spec:

To answer one of the questions: the reason I started measuring at 32 C was simple: the gauges run from 32 to 49! So I ran the machine until it reached 32 then did the first test, let it cool down, did the second test etc.

I know these tests are not realistic - they are 'best case' scenarios. So if the machine doesn't work properly under NO LOAD conditions then it will definately not work properly when it's loaded. And I dont want to test the machine to breaking point - I need it.

If any of you have a Chester Champion V20 I'd be interested to hear if you can feel the motor fan working at high refs - mine is barely generating any airflow. Again I thought this was a design 'feature'.

In the mean time I did some measurements today with the motor cover off. I just did the test on the HIGH gear at 2500 rpm on the milling spindle, as this was the most demanding of the 'no load' scenarios. Here's the result - it takes 20mins to get from 32 to 40 C, compared to 12 mins with the cover on. Better but still pretty poor, with no sign that the temperature settles.

0 mins - 32 C

2 mins - 33 C

4 mins - 35 C

6 mins - 36 C

8 mins - 39 C

10 mins - 40 C

12 mins - 42 C

14 mins - 44 C

16 mins - 47 C

18 mins - 48 C

20 mins - 49 C

Sorry Derek ignore that - that test was at 1500 rpm sorry. Must engage brains before fingers...

Derek,

I mill mostly aluminium so usually at high motor refs. As my measurements show, in LOW gear it goes from 32 C to 40 C in 10 mins, it would be interesting if yours did the same ? If not then there is something wrong with my motor!. Certainly the inbuilt fan does not seem to generate much airflow....

This is a follow up to a previous posting about overloading a Chester Champion V20 Mill: http://www.model-engineer.co.uk/forums/postings.asp?th=86758&p=1

In the absence of any information from the trading company (Chester Machine Tools) about a duty rating for the Champion V20 Mill ("It is hobby rated and not for extended use", I did some temperature measurements today, both on the control box and the motor. Stick-on temp gauges were affixed to the outside of the control box, and directly to the motor.

The first interesting result is that the control box did not reach 32 C during any of the tests ( ambient was about 20 C I guess), so any previous overloading of the control board was probably not temperature related. So for the moment I won't worry about cooling the control box and assume the previous control board failure was a one-off.

The measurments on the motor were even more interesting and contrary to the experience of some people on this forum. In essence the problem is with high motor speeds and apparently NOT low motor speeds.

Temperature was measured in the range 32 to 40 C ( in one case to 49 C) under NO LOAD condition, with various gearing and spindle rpm settings. All tests were made with the motor cover in place.

Interestingly this shows that at slow motor speeds the motor temperature goes up slowly and then stays at the same temperature.

However at high motor speeds, the temperature goes up rapidly and keeps going up - I stopped measuring at 49 C in one case! In the case of the HIGH gear setting at 2500 rpm on the milling spindle, the temperature went up 17 degrees C in 12 minutes. All of this without any load. And it then takes a whole hour before the motor temperature comes back down to 32 C - and that is with the motor cover taken off.

So at higher speeds the amount of heat generated cannot be dissipated so the machine doesn't settle down to a stable tmperature. No wonder the trader didn't want to publish a duty cycle, it would be something like 'Use for a couple of minutes, then leave to cool down for an hour'.

Passive cooling would be the preferred first solution (the Mill is still under warranty) and clearly the current motor cover prevent this, so I will take some more measurements this week with the motor cover removed.

Here are the measurements:

LOW gear - Milling spindle at 500 rpm

0 mins - 32 C

2 mins - 33 C

4 mins - 33.5 C

6 mins - 34 C

8 mins - 35 C

10 mins - 36 C

12 mins - 36 C

14 mins - 36 C

16 mins - 36 C

LOW gear - spindle at 1500 rmp

0 mins - 32 C

2 mins - 34 C

4 mins - 35 C

6 min - 36 C

8 mins - 38 C

10 mins -40 C

HIGH gear, Milling spindle 500 rmp

0 mins - 32 C

2 mins - 32.5 C

4 mins - 33 C

6 mins - 33 C

8 mins - 33.5 C

10 mins - 33.5 C

12 mins - 33.5 C

14 min - 34 C

16 mins - 34 C

18 mins - 35 C

20 mins - 35 C

22 mins - 35 C

24 mins - 36 C

26 mins - 36 C

28 mins - 36 C

30 mins - 36 C

HIGH GEAR - Milling spindle speed 1500 rpm

0 mins - 32 C

2 mins - 33.5 C

4 mins - 35 C

6 mins - 37 C

8 mins - 39 C

10 mins - 40 C

12 mins - 42 C

HIGH GEAR - Milling spindle 2500 rmp

0 mins - 32 C

2 mins - 34 C

4 mins - 36 C

6 mins - 39 C

8 mins - 41 C

10 mins - 47 C

12 mins - 49 C

Gentlemen thank you all for your contributions, I did some measurements today with interesting results which I will post in a new thread.

Thank you Andrew, I have been thinking about variators, simple yet versatile, and if it works for a Bridgeport and scooters....

Thank you Mike. I may be missing something but there does seem to be something very daft about a machine whose virtue is variable speed but where the slow speed cannot be used because the motor overheats and its fan is ineffective at that speed! Sounds like mechanical speed reduction is a superior technology to its successor of electronic vairable speed. I also seems odd that the motor does not have any cooling ribs as many do, and that it is encased in a barely ventilated metal box. Some may say it's a poor design. I guess none of this matters for a 'hobby machine' which apparently is not expected to be used. Anyways some temp measurements first....

Update:

I emailed Chester to ask for Duty Cycle information for the Chester Champion V20 and this was their surprising response:

"duty cycle is not available for these machines as they are hobby rated and not for use in any kind of setting where the machine needs to run for extended periods of time."

I take this to mean that the only safe use of the Chester Champion V20 is to not use it at all.

I asked them what periods they can be run for but there has been no response to this.

Chester also said that "the capabilities of the machine are listed in the manual". So I checked the manual but there is no duty cycle information in the manual. Nor any information about thermal cut-off so I have to assume there is none.

I thought I would see what other Chester Machine Tools Mills are 'hobby rated'. On their model engineering section (One assumes these are hobby rated) it lists everything from the Micro Mill at £ 268.80 inc vat to the Model T turret Mill at £ 6156.00 inc VAT. Wow, that is a lot of money for something that has no defined duty cycle. And I thought that spending £ 816.00 on my Champion V20 would buy a machine that has a defined performance however limited.

OK so I have learned my (rather expensive) lesson - don't buy Chester Machine Tools (or any other machine tools!) without a documented duty cycle.

I got some temp gauges today and will be doing some measurements on motor and control box with and without load to try and figure out what the duty cycle of this thing is without mods. I am stuck between a rock and a hard place. If I modify the Mill I will void the warranty - If I dont modify it then it will most likely break down again!

Thank you Mike, Yes i am talking with Tony about the lathe and he has cleared up a couple of questions for me. It turns out the lathe has a fairly unique feature for a lathe of this size which is a two ratio selectable back-gear.

Tony has put some pictures and description of the lathe on his archive: http://www.lathes.co.uk/lineker%26winfield/

This lathe was bought in the thirties, and unfortunately the old motor was scrapped. I was told it had a single sliding and lockable pulley and no countershaft. Does anyone know if that would be a typical configuration for small lathes of that vintage ?

Also any views on likely colour for a simple 30s lathe would be appreciated. Sofar I have found:

- Black on the bed with light green underneath,and dark green underneath that.

- Light green Hammerite on the banjo

- Light Green and dark green on the cariage

- Dark Green on the topslide

- Grey on the changewheels

- Black on the back gears

- Red around oil holes and handles

Any views ?

I recently bought a Lineker & Winfield "gap utility" lathe for restoration/renovation, and I would like to contact fellow L& W owners to compare notes about some of their details..

There are some initial pictures in my album.

Gentlemen thank you for the additional advice on temperatures, I will measure and experiment and report back...

p.s. I really like the dodweld fan mod - nice and simple.

Thank you all gentlemen, based on your feed-back I am going to first measure the temperatures inside the motor enclosure and control box over time, then see if passive venitlation (vents!) keeps them down sufficiently (I am guessing below 50 C) and add thermal cut outs to both for added protection.

What is a good cut out temperature ? 50 C ?

John yes that is one of my questions: what is a practical duty cyle for one of these mills ?

Jason I mill Aluminium only, and I take care not to take deep cuts where the mill appears to strain. Inevitably this means that I have to go over it several times and that means prolonged running times.. The machine did not stall at any time.

Clive with a 1 HP motor and specified max drilling and end milling of 20 mm and table of 700 X 180 this is hardly a toy. I understand the need to work within it's limits, my challange is to understand what those limits are (ie what is the duty cycle) and what the warning signs are for impending overload. I have emailed Chester today to get answers to those questions. Having said that I am keeping my eyes open for a good second hand grown up mill. I did think of trading up with Chester but felt I probably shouldn't dig myself a deeper hole.

Russell,

Yes they are separate issues, and I was aware that some people have had problems with overheating motors, just not overheating control boards. It is difficult to say if they are fit for purpose or not as the purpose is not specified in detail by the supplier other than it being in a 'hobby machine' category, and I just dont know what that means in practice.

So I'm still interested if people let their mills cool down at regular intervals or watch for some signs of stress like hot quils, control box or motors - anyone ?

All good questions Coalburner - unfortunately not questions I can answer. Nothing like that is stated in their documentation hence my questions about practical experiences of owners.

Jason yes the cooling fan is the sort of thing I was thinking off, and it's interesting someone else has done that already. My guess is that the control board 'blows out' if the power transistors run too hot, and they are in a closed metal box so just extended running of the machine will heat them up (they are not mounted directly to the control box), almost regardless of load. Thank you also for the advice about not running at low motor speeds. I am milling aluminium and have kept the gearing set to 'High'. I will try it on 'LOW' gearing with the motor running at max refs, and a big mill.

I am about to have my Champion V20 Mill back from repair at Chester tomorrow. I was told by Chester that the control panel blew out, possibly due to 'overload', and that the Champion is 'only a hobby machine'.

Would any Champion (or equivalent) users comment on this in particular do you let your mill cool down at regular intervals or look for signs of overload ? Also is there any other way to avoid this e/g better cooling of the control panel ? Have any of you replaced the Chester controls by third party system or replaced both the motor and the controls for this reason ?

As an aside Chester have been very good about repairing it under warranty, but not having the mill for a month is a nuisance and this is the second time in three months it has gone back for repair (previously the power cable to the motor had frayed inside the Mill (!). Before that I had an intermittent loose wire. I think I may have the Monday morning machine...

Peter

Phil, Brian

Thank you Gentlemen. Yes I have already removed the spindle and looked at the manual which explains how to adjust them but not how to remove them. From the diagrams it looks like there is nothing to retain them so I will take phil's advice and encurage them!

Peter