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Member postings for Martin W

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

Thread: Chester DB7 speed control board? NVR switch doesn't lock
22/01/2020 00:26:34


Good news and I hope that they will replace the defective switch without too much faffing about.


Thread: Fradley Canal Crane Progress
21/01/2020 17:36:42

For them that's interested pictures can be seen here, if moderators think this infringes on IP then please delete.


Thread: Chester DB7 speed control board? NVR switch doesn't lock
21/01/2020 17:10:26


Going back to your first post you said that if the NVR was physically held in then the motor would run and that the fault was that the switch was not latching. Is this the case still? If it is and the motor responds to the speed control then there is nothing wrong with the drive electronics or the motor.

If the switch has the A1 contact then to activate the latching mechanism this must be taken either directly or via normally closed interlocks to contact 24. The other version of the KJD 17 NVR doesn't have the A1 contact and the coil is internally wired between contacts 14 and 24. In both cases the mains live and neutral can be connected either way round to contacts 13 and 23 without affecting the function of the switch or latching operation.

If I am teaching my granny how to suck eggs then I apologise.

I agree with you that they are cracking little lathes and seem to be nearly bomb proof; famous last words.



PS. With regard to that circuit from Chester, when they had a forum it was shown there until I suggested that it wasn't correct. They removed it from the site but evidently they didn't follow through to check where else it might raise it's ugly head. Unfortunately they closed the forum probably as it was not used a great deal however it was a good source of information regarding some of their machines especially some of the smaller lathes.

Edited By Martin W on 21/01/2020 17:21:48

21/01/2020 14:39:25


Had another look at your wiring diagram and it looks as if the 'Hold On' coil has been wired incorrectly. Your diagram shows contact A1 wired to contact 14 and therefore the hold in coil will have no voltage across it as it is effectively connecting mains neutral IN to mains neutral OUT across the hold in coil. This assumes mains neutral is applied to contact 13 and mains live to contact 24 that said connecting the mains the other way round will make no difference to the operation of the NVR. If you move the link so that A1 is connected to terminal 24 then it should function as intended as the mains will applied across the hold in coil when the switch is active/on.


20/01/2020 13:12:51


If you activate the chuck guard interlock by having the guard in the up position and then press and hold the NVR switch and the lathe starts then the interlocks are not in series with the mains feed to the NVR.


20/01/2020 11:50:00


I can, on my DB7, replicate the fault that you described above. With the chuck guard 'open' the NVR will not latch but if I hold the NVR down then the lathe will work. Your schematic shows the interlock in series with the mains feed to the NVR if this was the case then it would not be possible, certainly on my incarnation of the DB7, get the lathe to run by holding the NVR on with an interlock open.

The safety interlocks are normally wired in series with the 'Hold On' coil of the NVR and not as part of the mains power feed circuit to prevent overloading the interlock circuits and potentially leaving them live when the NVR has reset to OFF, a certain washing machine manufacturer put the full mains load through their interlock system and the result was a potential fire hazard.

The connections to the NVR in your schematic show terminals A1 and 14 to be linked, I would expect these terminals to be connected to any safety interlock circuits. It might be worth checking again how the wiring your machine is configured with regard to this. If I recall correctly the reversing switch does interrupt the mains feed circuit and is intended to stop the lathe from being switched directly from forward to reverse instantly.


20/01/2020 01:27:25


If any of the interlocks are open or perhaps have not closed properly then the NVR will not latch as the interlocks are placed in series with the hold on coil in the NVR switch as a safety precaution. Check the chuck guard and make sure that you can hear the microswitch activate or better still check that it operates with a DMM or something that can indicate continuity. UNPLUG from the MAINS before trying any of the above.

Hope this is useful.


Edited By Martin W on 20/01/2020 01:27:44

Thread: The Workshop Progress Thread 2020
16/01/2020 00:44:41

Screwfix sell this which looks like Mapp gas, complete withy the double 'p', but whether it is the same as the old version of Mapp gas I have no idea. May be worth investigating.


Thread: Stuck Chuck
09/01/2020 01:05:22

If the adapter has become that difficult to remove and this is due to the threads galling or having jammed because of swarf/detritus etc. then using force to unscrew the adapter could leave both the chuck and the adapter with damaged threads.

It's your choice at the end of the day but I know how I would proceed and it would be with a minimum of force.

Hope you can free it up without damaging the chuck.


08/01/2020 10:57:19

Even if you get the adapter out its not worth the risk of using it again so just accept that it is scrap. If it were mine I would find someone with a suitably sized lathe and get them to bore the adapter out and then remove what remains. Should be able to bore close to the root diameter of the thread so there is minimum material remaining to get out.

No brute force or special tools required and much gentler on the chuck


PS If this has already been suggested then ignore this post

Edited By Martin W on 08/01/2020 10:59:06

Thread: Heatshrink tubing
20/12/2019 22:54:34


Just do a search for WISH, click on it and something like Ebay should pop up. Requires you to 'sign in' to access the products though.



Edit; to correct errors

Edited By Martin W on 20/12/2019 22:56:01

Thread: Tapping a nylon hole.
02/12/2019 15:30:53


I had noticed that and totally agree that the statement was correct in this context. I was just broadening the description to include the lack of matter in virtually any parent material. nerdwink 2. That said I am not sure that this definition would apply to a black hole which theorists predict contains a lot of matterdont know

Cheers Martin

02/12/2019 11:26:49


That is only true, as in this case, when specifically applied to nylon. Might it not be better to say that, "The hole is an absence of parent material" wink 2


Thread: Holding screw-end end-mills/slot-drills
24/11/2019 19:57:31

Another option is to use the "ER Collet Nuts with Ball Bearing - Type B" as sold by Arceurotrade. I use ER25 size collets and I have never had a cutter move, slip or come loose even when taking some fairly heavy cuts and that's just using the standard C spanner. As to age on the high side of 75 and that's me not the mill. Standard disclaimer re Arceuro, just another happy bunny.


Thread: Has to be seen to be believed
05/10/2019 01:50:22

Well made, perhaps made in a well with no light; like the comment that water has been poured in and none leaked out. I can get the same result with a plastic tube and some duct tape. I do hope that some unsuspecting person doesn't decide buy it.

Martin W

Just had another look and I can't see a hole where water could have been 'poured' in. Perhaps I have missed it though it might have been down one of the boiler tubes cheeky. Missed it there is a hole above the tubes on the "smoke box end".blush

Edited By Martin W on 05/10/2019 01:54:05

Edited By Martin W on 05/10/2019 01:56:54

Thread: Vickers Bl 8 inch Howitzer cannon of 1917
02/10/2019 13:07:06

Absolutely brilliant, not so much a model but more a work of art. I look forward to each installment.


Thread: WM16 DRO cheap
26/07/2019 15:23:00


Tried to ring you earlier but you seem to be out/in the workshop/kipping on the sofa. Could be interested in the scales if you still have them.


Wroxham variety

Thread: Metal de-coroder
28/06/2019 14:49:08

A further bit of digital digging has shown that chelation is a very specific process where a large molecule will form at least two bonds to a metal ion. One definition found is :

  • A chelate is a chemical compound composed of a metal ion and a chelating agent. A chelating agent is a substance whose molecules can form several bonds to a single metal ion. In other words, a chelating agent is a multidentate ligand.

Also an entry can be found in Wikipedia here . There are many other descriptions of chelation but they all describe the same process

Hope this helps.


26/06/2019 11:14:42

Just been rummaging around on the web and found a list of sequestering/chelating agents, see below.

"The main types of commercial sequestering agents are:

  • Aminocarboxylic acid base products
  • Phosphates and phosphonates
  • Hydroxy carboxylates
  • Polyacrylates
  • Sugar acrylates"

The last entry might explain why molasses works as a de-rusting agent. I have looked but as yet have not located a complete list of compounds found in molasses. It could be that it does contain 'Sugar Acrylates' but there again I may be barking up the wrong tree, again blush.



edit.  another quote from the web.

"Molasses owes its properties to cyclic hydroxamic acids which are powerful chelators of iron. More of these compounds are found if the molasses is derived from sugar beet rather than cane sugar. The plants from which molasses is made presumably use these chelating agents to help them extract minerals from the soil."

So maybe the sugar acrylates aren't the main agent. Must check the trees before barking frown.

Edited By Martin W on 26/06/2019 11:43:36

Edited By Martin W on 26/06/2019 11:48:10

Thread: Telephone / Internet Scams
10/06/2019 13:42:36

This morning my wife answered the phone to be greeted by someone, a male, who claimed to be a police officer. The conversation went along the lines of, 'Sorry to disturb you but are you xyz etc., which of course was correct, as any fool could find that data on the net if they wanted. He then went on to say that 'We have arrested some people in London and found in their possession a VISA credit card in your name'. My good lady being pretty streetwise asked, before entering into any conversation with aforementioned "officer", to identify which bank/building society the card had been issued by.

This proved too much for "said officer" who immediately hung up. What amazed me is that he didn't just reel off a high street bank as a wild shot; not the brightest con artiste out there evidently.

So be warned they may start to smarten up their act, but knowing my good lady they will meet a brick wall when it comes to her supplying any important data; still sharp at 70 plus.


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