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Member postings for Mark C

Here is a list of all the postings Mark C has made in our forums. Click on a thread name to jump to the thread.

Thread: Elliot Omnimil DRO's
16/01/2017 18:57:18

And finally, here are some pictures of the machines so you can see how I fitted the controls for them etc.




16/01/2017 18:55:10

And the quill readout is just a cheap as chips thing attached as follows



16/01/2017 18:54:10

And my other machine has the vertical scale on the other side which makes life a little difficult with the lock but it is possible and would be better on the other mill as it has the old PTO arrangement for the table feed (unlike the later machine with a separate motor).




16/01/2017 18:51:07

More pictures it is then...








Thread: Lathe motor replacement
16/01/2017 18:43:43

Hywel, Rather than another thousand words, here are some pictures of my lathe installations. The VSL has an old inverter on the brick wall at the back but the other Boxford has the same sort of setup that you are doing (I think) with the inverter located in the lathe cabinet behind the control panel. The VSL is different in that it has the original rotary switch wired to the inverter to set direction and then start (the switch is 5 positions, centre off, detent in first position either side of off with a momentary start position if you keep turning the switch which then springs back to the first position - this is how they originally worked but it is all done by the inverter logic now). All my machines have a separate E-Stop fitted (wired as required by the inverters).


The lathe is permenantly wired as mentioned earlier and you can see the switched spur on the wall at the back on this picture


VSL looks like this (the white knob is the multifunction switch)


Hope this helps a bit


Thread: Aluminium Grades
16/01/2017 14:16:18

That is probably the wrong question - you need to ask "what material properties does the part need" and then find the most suitable grade for machining. There are more grades of aluminium than bits of string!


Thread: Lathe motor replacement
16/01/2017 10:31:36

Hywel, Reading your first post and looking at your pictures - I will take a guess that your lathe used to work by selecting forwards or reverse direction with the black knob and then pressing the green button started it up and the red button turned it off?

If that is the case then you are half way to having everything you need for an inverter. As you mention it is single phase I will also guess that it plugs into the wall socket?

If that is the case, then take the supply from the plug directly into the inverter supply side. Then, rewire the original direction, start and stop switches on the low voltage control side of the inverter. You will need to follow the instructions (there will be a wiring diagram in the manual) for the correct method of linking the two switches which will be "momentary" push button switches and need to be wired to latch (done internally in the inverter by electrickary). You then simply connect the motor directly to the inverter output and program the inverter with the correct parameters - another manual reading exercise unfortunately...

I hope that helps, I have two Boxfords wired like this (although mine do not plug in, they are wired permanently to switched spurs supplied from dedicated MCB's in the distribution board). Take care with the air flow requirements when you box in the inverter!


Edited By Mark C on 16/01/2017 10:32:40


Just read your manual, you need to read the page about three wire control wiring on page 10-5 (advanced section). I did not read it completely, you will need to check the inputs to confirm that is start, stop and direction switches but it certainly looks like it...

Edited By Mark C on 16/01/2017 10:38:37

15/01/2017 22:10:25

Thanks Julian.

I don't have any need of small holes currently but you never know what is around the corner.

I did need some aperture plates making for a confocal microscope some time back but that required extremely tight concentricity and size (and also a tapered cylindrical profile) which was done using photo etching on nickle foil.


15/01/2017 21:42:32

"For those of us who make small injectors for miniature locos this is not a problem"Thats a lot of help Julian...

For those of us with electron drilling machines it is not a problem either!


Thread: Meddings MF4 drill electrics
15/01/2017 19:40:24

You might want to stay out of our kitchen Michael, the hob draws 10 kW at full tilt... I don't know how far away from it you would need to be but I expect safe distance might be outside the house!


Thread: Need to get a Welder!
15/01/2017 19:21:12

I am not a trained welder but spend a fair bit of time having stuff fabricated. Michael is absolutely correct regarding stick welding, all the welders I know always take care selecting the correct stick for the job (material, welding position and environment).

I was advised to use Murex Satinex rods and they are very easy to weld with (which is why I was advised to use them! ). They work really well in most situations - if I was given a pack of any other rods, unless they were for a special job, I would probably decline the offer.


Thread: Meddings MF4 drill electrics
15/01/2017 19:10:58

Toby, the my output is better than that after a choke (I realise you are measuring the transistor drive voltage so it may well be different). I don't have any traces from the scope but the biggest error I saw was the shape of the wave (it was a little "stepped" and there was some offset or dwell at zero crossing).

Alan, I get them from Lamond Automation, I have not been able to get them cheaper anywhere else. The make is not important, you just need the correct amperage. These are recommended when using a non-inverter duty motor (as in the motors on our machines) and the justification is that the choke removes the damaging transients that might cause insulation breakdown on older windings and probably helps with the issue of arcing across bearings - not that I have ever seen that but I have been assured it can happen. There does seem to be an improvement in audible noise but that may be imagination.

Using soft plastic to cover the inverter panel might be OK if there are no hot chips flying about but in my workshop it would be ruined in no time!


Thread: Elliot Omnimil DRO's
15/01/2017 12:58:59

Philip, the pad on the knee is attached with some c/bored cap heads and the material you can see is two part epoxy "metal" (Pratly putty or equivalent). The block was filed and fitted to the knee and then the epoxy was used to "stabilise" the mounting along with providing a fillet that needs painting (a low priority job, albeit annoying to look at). I will take some better pictures if they help.

Mounting the scale on this side will show how much movement there is across the y axis but it serves to remind you to always make movements in the same direction!


15/01/2017 12:37:03

These may have been relatively new machines when you used them!

They get a lot of use (I have two of them) but they are often lacking shear size. I do not have enough head room for a BP or other "full size" machine so I have to make do. They make up for lack of size in flexibility but a more rigid machine would be better for the work I do - it would be nice to be able to get stuck in with decent sized cutters but hey-ho, such is life. If I get an industrial unit (which might be on the horizon) I will get a decent sized machining center and then I will be sorted... probably also get some bigger manual machines as well for one off and modification jobs.

I also have a couple of Boxfords, and these are always "just" too small. I have worked out that that is always the case with machine tools so I must also put up with that.


PS. last weekend I was busy altering a 25mm steel plate from a 120mm diameter hole to 160mm (that is why the boring head is still on the mill) with a series of tapped holes around the perimeter (which also had to be faced square to the bore). The plate was 300 x 400 and I can tell you that is probably what you would consider as "too big" for these mills!

Edited By Mark C on 15/01/2017 12:41:16

Thread: Meddings MF4 drill electrics
15/01/2017 12:28:28

Thanks for the compliment on my installation, there are a number of shortcomings in it but it is OK for my own purposes (it would not be acceptable for an industrial application).

I know you are only using the line in filter but I thought I would put the picture up to show what is needed for a fully filtered setup. The two large filters are the drive side chokes (drive reactors). They take out all the horrible digital synthesised waveform and turn it into a close approximation to a sine wave. I imagine that my installation would be significantly safer for Michael than an unfiltered arrangement! There are a lot of armature electronic engineers on here (and a few professionals I suspect from reading some posts), any of them with access to a oscilloscope can see for them self what the output looks like without a choke and then they can see the improvement if they buy one.

You might also notice I am using the cheap Hungyang inverters - I like them!


Thread: Boxford
14/01/2017 22:52:06

I think if you make the OD to fit the clutch cups you will find it works OK. I think they are are about 1/8" thick (3mm) and as Bazyle mentions, just make them progressively smaller until they sit at the correct angle (by eye will be good enough)


Thread: Elliot Omnimil DRO's
14/01/2017 22:45:11

I had a conversation with someone who has one of these machines and as I have a pair with DRO's etc I thought it might be helpfull to share information about them. In this case I have attached some pictures of the scales fitted to one of my machines.





Thread: Meddings MF4 drill electrics
14/01/2017 22:39:05

Inverters come up regularly as items of confusion or requiring questions answered. I thought I would take a couple of pictures of the installation on my milling machines, they are both done the same with both all motors (Horizontal, vertical and feed) running on inverters. They are all wired with a line filter on the input supply and a load reactor (choke) on the output. They are all stuck on the wall high up and out the way so they get a good air flow. Wiring is all done properly (IE. as required in the instructions)using 24 volt signals etc.




Thread: Unusual Engineers Block?
08/01/2017 20:59:47

Thanks Trevor. I might just try draining (if there is any in it) the oil and replacing.


08/01/2017 19:18:11

Tractor, You, Trevor & John are exactly the sort of response I was trying to get! It is easy enough to look on Google or whatever and assume what is what, getting a "real" experience is often hard on here...

Trevor, My chuck has wear in the mechanism (I think) and sending it for refurb is going to cost well over 200 quid, is it possible to "safely" repair the linkage?


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