By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for Robert Atkinson 2

Here is a list of all the postings Robert Atkinson 2 has made in our forums. Click on a thread name to jump to the thread.

Thread: Dumb question from a none driver
02/09/2019 09:09:28

Anyone can PAY for insurance on a car but if they are not the owner the owner ust be named the benificary of the policy. This is common and happes hundreads of time every day.
What won't happen is multiple payouts if there are multiple policies covering the same loss.
What insrance companies don't like is someone with good history insuring a second car with a less experinced named driver. They (often rightly) assume the second car is actually the main vehicle for the higher risk driver.
So the non owner insuring a car as sole driver (as in OP's case) should not be an issue.. And this appears to be the caase as the OP has stated the car is insured his son.
Unfortunatly this post has turned into a bunch of opinons and anecdotes most of with are no help whatsoever to the OP who doess not drive.

Robertt G8RPI.

Thread: Cooled Astro Cam Conversion
01/09/2019 15:53:45

Joseph akes a good point about fan vibration.. Another issue is the high energy density and thermal gradient of small peltiers. Have you considered liquid cooling? just small pump and tank would be enough, you probably don't even need a heat exchanger if the tank has reasonable capacity and surface area.

Robert G8RPI.

Thread: Dumb question from a none driver
31/08/2019 16:50:20

I'd add the following,

When you son insured the car the insurance company will have asked who the owner was. Assuming he told them it was you there should be a record of that because in the case of ay a fire of theft claim the insurance should pay you, the owner, not your son. This is the same as if he had the car on lease or finance. Check the insurance documents.

As others have said, get a receipt for the sale to YOU at £700 from the seller with his name and address on it. It can be a scrap of paper torn off an envelope, push comes to shove it's up to any disputing it to prove it's fake, not you to prove it's real.

With insurance docs saying you are owner and a you having a receipt there shoul be no issue.

Robert G8RPI.

Thread: Cooled Astro Cam Conversion
31/08/2019 16:30:16

Plus one for camera CCD cooling. Called a "cold finger" .

Biggest issue with coolled LCDs is keeping condensation off the electronics. Hermetic + vacuum with bit of dessicant is ideal but hard to acheive. A separate container with replaceable large (0,5kg) silica gel bag piped to a reasonably well sealled camera head is a good compromise.

Robert G8RPI.

Thread: Mains power supply for 12v dc motor
31/08/2019 14:41:32

You don't need anything that fancy in reality. JJust a 12V transformer and a bridge rectifier will d just fine for running a motor. A 100VA 12V transformer will be big enough for intermittant use and a 150VA one for constant duty. A 25A bridge is recommened they are cheap enough.

Robert G8RPI

Thread: Which oil and oil gun
28/08/2019 12:39:39
Posted by Kevin Murrell on 28/08/2019 11:17:32:

Cleverer people than me will know the whole answer, but I believe modern engine oil is not suitable for your lathe. Those oils are designed to work at a much higher temperature. I suspect that the various additives in them wont help either!

Actually a modern 5 or 0 weight engine oil is probably OK and better than a engine oil comtempary to the lathe. Modern oils have fewer additives that might harm yellow metal bearings.

That said I'd still go for a good SAE32 hydraulic oil.

I just bought a 5l tin (lifetime supply for me) of OM33 (UK military spec oil similar to Nuto 32. Hyspin 32ZZ meets the OM33 spec) on ebay for £10

Robert G8RPI.

Thread: Battery longevity
25/08/2019 14:28:01

The battery has lasted because A: it was made before the total ban on mercury inn akaline cells and B: the battery is actually disconnected when the shaver is off.
Allaline cell made afetr about 2005 had no mercury added and as a result tend to leak due to hydrogen build-up. The mercury stopped the pressure build up IIRC it acted as a catalyst for a re-dsorbsion reaction. Any alkaline battery made between 2005 and about 2016 is likely to leak. Both Duracell and Energiser dropped their leakage warranties agound this time. They seem to have cured the issue though as recent batteries seem to be better and the warranties are oming back.
Modern electrnic kit discharges batteries when "off" because there is not real switch, the elecronics is active, just waiting until you push the on button.

Robert G8RPI.

Thread: Current leakage om CNC
25/08/2019 11:21:04

+ one for Joes comments. and as Dave says fault can develop, you arn't using an extension lead by any chance?

All metallic parts of the machine that might come into contact with a voltage ove 50V in the event of a fault MUST have a path to ground (unless the machine is double insulated which is unlikely and not the case ith yours as you have an earth). This path must be designed in and able to carry the full fault current. Just continuity becuase conductive parts hppen to touch .s not good enough. Unfortunatly many machines do not meet this requirement.
The use of a 110V spindle motor may indicate a more serious fault/ design issue if the main supply is 230V.

Sponges and saltwater have no place in any safety earth.

Robert G8RPI

24/08/2019 18:15:12

Commercial CNC machine or homemade?
5uA is enough for a shock. Assumuing you are in the UK or EU with 240V mains the 120V you are measuring is caused by the inut filter capacitors acting as voltage divider, The common of the filter appears to be connected to the machine metalwork but not the mains earth. This could be a fault in the machine or the workshop wiring.

Robert G8RPI.

Thread: Are there any left?
22/08/2019 18:23:46

Well if you want a gasturbine engine try Everett

I like small turbines and had several some years ago but a change in curcumstances and job move means I don't have any at the moment.

Robert G8RPI.

21/08/2019 20:50:51

Anchor are still in business but a tiny store in Nottingham compared the old one. They had a "museum" collection which was lost in the fire. Their Ripley depot is still there.

Robert G8RPI

Thread: Need a lot of help from you good people
21/08/2019 19:31:40

Allowing for losses and being conservative, three 18H 12V batteries would do assuming full load all the time. If you are optimistic then three 12AH would do.

However as noted above running a battery at it's 1H rate or faster is not good for it, Ii'd go for a bigger battery if you have space.

Three of these would be OK (I've never used this seller or brand)

Robert G8RPI.

Thread: Are there any left?
21/08/2019 12:56:36


J Bull "" have long ceased trading. I heard a rumour that the owner was in jail but don't know for sure.

Anchor supplies are still going but are a shadow of their former self. Again I think someone involved was in trouble with the law.
The shop in Lincoln is J Burkett **LINK** Limited opening hours these days.
Government disposal has changed several times over the years with various contracts, auctions and tenders (direct or via agents) being used.
Most stuff ends up being available on ebay but there are a couple of direct dealers:


Witham Specialist Vehicles ltd


Most of the "surplus" electronics dealers (M&B Radio, Johns Radio etc) have shut their shops (gone on line), closed down, or greatly reduced their operations.

Unfortunately this means the days of a weekend trip trawling through stockrooms for hidden gems have long gone.

Robert G8RPI.

Thread: What coating/grease for long term tool storage
21/08/2019 07:21:10

Plus 1 for LPS-3

It's available in the UK.

Robert G8RPI.

Thread: Need a lot of help from you good people
20/08/2019 13:41:39

If you know the power and RPM you can calculate the torque. I think a bike motor may run a bit fast and need a bit of reduction gearing. Be aware that their ratings can be optimistic and they may not be capable of the short term acceleration overloads the old ones could take.

A typical ebay "500W 24V DC 26.7A Electric Motor MY1020 + bracket for E-Scooter Electric Bike Is 640W in put power and 500W Max (continuous or 1min?) at 2500 RPM so torque is 1.91Nm or 1.41 lbf.ft

Robert G8RPI.

20/08/2019 07:39:15
Posted by terry callaghan on 19/08/2019 20:59:50:

Thanks Robert, I am in Somerset. Commutator skims, new brushes are way out of my knowledge. I have always been a hit it with a hammer type of guy and if that does not work, use a bigger hammer. Much the same goes for resistance checks. What I can’t get my head around is why into days world there is not a replacement 12v motor I can fit in. I would think that a lot of power would be lost with the locos old control system. Taking out and fitting in new motors I can do. Understanding what looks like 50 year old units I have not a hope.

Well I was fitting new brushes in motors before I was even a teenager so I'm sure you can do it.

I suggest you take the rear motor out and post some more photos of it. We can then give step by step instructions. If you can get that one running on the bench it's a start.

I will be a little blunt here, if you want to get it running to use I'm happy to help, if you just want it running to sell it (you mentioned paint and ebay in another post) then I've better things to do.

Robert G8RPI.

19/08/2019 20:27:15
Posted by terry callaghan on 19/08/2019 19:26:01:

Ron, I think you are right the Sinclair motor is not man enough. I think that this is going to be too much for me to sort out as I am a complete donut when it comes to electronics. Sad to say that there is nothing useful in my location in the way of motor servicing. So I think I will get on with the repaint and eBay it. Thanks for your input.

What is your location? Maybe there is someone near who can help. If you are anywere near Cambridge I'd be happy tto a hve a look. Unless they have een cooked or soaked most big DC motors will respond to a clean, commutator skim and new brushes. You can then look at new control system.

Robert G8RPI.

Thread: Digital inclinometers
18/08/2019 15:04:05

There is third type of electronic angle sensor that uses a liquid bubble. These use capacitive or resistive sensing of a buble of one fluid in another fluid of difffering electrical properties. This could be a bubble of mercury in oil or air in a conductive solution. They use differential / ratiometric sensing so changes in bubble size with temperature do not affect accuracy. Personally I have a long base (200mm) electronic level (Craftsman from Sears in the USA), a vintage "engineers" sprit level and a Hilger & Watts pendulum inclinometer which are used depending on requirements. I could see a place for a Wixey in my collection though

Robert G8RPI.

Thread: Meter Probe
16/08/2019 11:09:45
Posted by Neil Wyatt on 14/08/2019 16:13:24:
Posted by John Haine on 14/08/2019 08:55:26:
Posted by Neil Wyatt on 13/08/2019 20:57:53:

Even my cheapest £5 'disposable' multimeter has shrouded plugs. Sobering that it is an order of magnitude + more accurate than my expensive old moving coil meters.

My better meter has shrouded plugs and only the very tips are bare - I find this style much easier to use TBH.


Or at least precise? wink

No, very much more accurate, at least if the agreement of multiple meters on a reading and the occasional test against an accurate reference voltage is sufficient test. Essentially, it isn't any more expensive to make them accurate to within a few tenths of a percent, so there's no incentive to make them less accurate.


Hi Neil,

I doubt any cheap meter is an order of magnitude more accurate than an expensive anlogue meter. A classical analogue meter like an AVO 8 has a specificed accuracy of 1% on DC volts. Even a good 31/2 digit DMM e.g. Fluke 110 series is only specified to 0.7 percent. plus 2 counts. Any 31/2 digit meter (1999 count) has only 0.05% resolution so with the best uncertanty of 1 count even if everything else is perfect they can only make 0.1% of full scale. Accuracy for AC, current and resistance is poorer. A single point check is not confirmation of overall accuracy.
Accuracy, precision, resolution and linearity all need to be considered. A great book on the subject is "Calibration Philosophy in practice" by Fluke.
I'm a bit of a ""volt-nut" I have meters up to 81/2 digit resolution, good solid state voltage references, Kelvin-Varley dividers etc.

Robert G8RPI.

Edited By Robert Atkinson 2 on 16/08/2019 11:11:09

Thread: Pet peeves!
16/08/2019 09:40:12

Half way is the ideal storage position, no more than 1/2 max turns no matter what you measure next.

My pet peeve is people promoting illegal car modifications like DPF / EGR deletion or LED lights on motoring forums without noting they are illegal

Robert G8RPI.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric Engineering
mid gard rail Jan 2020
Eccentric July 5 2018
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest