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: Trembling laptop|
The above is incorrect and misinformed to put it nicely. You cannot possibly know if there is a problem with the OP's laptop / powersupply or not. Just because you were not electrocuted does not meant that your old laptop was OK either.
Don't give safety advice when you are not competent in the area.
This tingle is caused by leakage current from the power adaptor. The leakage current is often caused by interference suppession components, as has been mentioned by others, in particualy a "Y" capacitor across the isolation barrier. This current should be less than 210 microamps (0.2 mA 0.0002 A). and not normally detctable.
My concern is that this is a used device so you don't know it's history and the AC adaptor may have been replace at some time, possibly by a "clone" that might not meet current safety standards. From the photo it doesn't look the 4 years old that date on the unit implies and used latopts often come with "new" power supplies. Ideally you dhould have it checked.
If you have a meter that reads AC milliamps you can do a quick check yourself. Place the laptop on an insulating surface (plastic cutting board is good), switch it on with mains power and connect the meter (set to AC milliamps) between a known earthed object (e.g head of the screw holding down the mains socket) and an exposed metallic pat of the laptop. The OUTER metallic part of a USB socket is good, but don't put the probe into the socket itself. Use proper test leads and don't touch any metal parts when doing the test. If you get a reading of more than 0.2mA stop using the charger and get professional advice.
|Thread: Gluing metal|
4mm wide, but how long snd how thick? What is the bond area? That said a metal filled epoxy like JB weld, Araldite Steel is likely to be the best choice if you want a hidden bond as the glue line or fillet will look like steel. but from your described requirements any epoxy or super glue would work. For structural meatal bond toughned acrylic like Loctte 330 or Permabond TA435 are a good option.
|Thread: Basic Electrics|
Or even the 18th editon of BS7671(the curent one)
Also BS7671 does not cover the wiring of equipment, just the fixed installation.
|Thread: Glow plug driver|
You only need fancy drive circuitry if it's a flight engine where weight and endurance are important.
Phils radial engine circuit has issues, particuarly the 0.47uF capacitor across the gates of the MOSFETs. This stresses the mocrocontroller outputs and keeps the MOSFETs in their linear region longer increaing heating and battery consumption. Fo a simple sequential switch a couter decoder like a CD/HEF 4017 or 4022 would be easier to use.
For a flat four I'd run the plugs series / parallel. Put a link / busbar between the two plugs on each side then connect the battery (or other source), with a voltage twice the rating of each plugs, between the two links. The crankcase will be at half battery voltage but as long as the battery is isolated tthat is not an issue.
For bench running a transfomer can be used, glow plugs don't mind if power is AC or DC.
Edited By Robert Atkinson 2 on 12/07/2020 11:34:34
|Thread: Hallite washers|
Hallite washers are fibre wahers with a wire mesh reinforcement.
|Thread: I'm thinking of selling up, whats it worth?|
Listing at 99p start on ebay does carry some risk. The market for Myford lathes may be firm but you never know. The 99p start was common when ebay was primarily a auction site, but it is now a marketplace and the dynamics have changed. I have bought a lot on ebay comprising several bits of test equipment on ebay for 99p (no other bids) and sold ONE of the items for £1500 (Buy It Now taken, auction had £500 start) a week later.
Robert G8RPI. (ebay buyer and seller for 20 years)
|Thread: Laser DRO sensor|
One issue with mouse sensors is that their intended use has a human in the control loop by definition. This means that even faily gross error are corrected subconsiously. In the machine application even small errors will accumulate. A good high contrast, regular pattern for the sensor to look a would help but you may still accumulate errors.
Edited By Robert Atkinson 2 on 09/07/2020 16:19:04
|Thread: Jumpy readout DRO scales on WM16 mill|
The fact you had issues without the locking screw fitted indicates that it, or the metl it is forcing into contacr is providing the ground connection. This is not acceptable for a safety ground. The safety ground path shoud be properly engineered and not reliant on casual contact between parts. I wonder if it would have passed our test withut the screw fitted. While a DMM will identify gross errors, to properly test safety earthing a bonding test that passes significanr current, around 20A for a small machine tool, is required.
|Thread: Butterfly Bolt or Thumb Screw|
You can get moulded cps specfically to turn cap screws into "knobs"
Other suppliers do them too.
|Thread: Parvalux motor|
Personally I would not touch that with a barge pole (unless it was certified as insulating )
Clearly not compliant with regulations, it does not even have a part number. I would be concerned about it' safety.
Most, if not all Parvalux "DC" motors are brushed "universal" motors. This means they will run fine on AC, You just need a 24 V transformer (a dual 12V will do too).
|Thread: ISO Container for Workshop|
You can get "one trip" used containers fairly cheaply as many countries export more than they import. I know if a plasterboard plant in Nevada re-opened and are shipping mot of their output to the far east at minimal costs s otherwise the ships would be in ballast.
If you get refriderated contaner the first thing to do is add at least some fixed ventillation as they are airtight to the point you could suffocate nd fumes etc can't escape.
|Thread: Overview of fitting variable frequency drive (VFD) to a Myford ML7|
This is just based on review of the material on the Newton-Tesla website, but their ML7 Super7 prewired kits look quite good. They appear to have the inverter in a proper enclosure which is a safety requirement and not met by just buing an inverter, Chinese or otherwise. It also comes properly set up for the motor. Unless you are reasonbly skille with electrical systems I'd strongly recommend buying a pre-made unit like their AV750.
|Thread: ISO Container for Workshop|
I second Bo'sun's Comments. Plain ISO containers will literally generate their own climate including "rain" from condensation. You need to at least line it with wood and preferably insulation. A 20ft or two will be easier to handle and be moore practical, The extra end wall area means you waste less space for accesses. Fully stuffing a 40ft or 2x20ft gives the same volume, but if you have to alllow access to the contents 2x20ft work a lot better.
|Thread: Ultrasonics and citric acid|
Ed's suggeston is good and standard practice for cleaning small items in a ultrasonic cleaner. A glass laboratory beaker works well. Use hot water in the taank and cleaner, citric acid in this case in the beaker. Ideally float the beaker with a collar of closed cell foam. A thin (cheap) pressed stainless steel cat's food bowl works well too.
For non-ferrous alloys a dilute solution of ammonia with a drop of washng up liquid works well.
|Thread: Stroboscopic effect|
It was part of this patent
But we kept some information back
When I designed LED lighting for microscopes, I Used PWM control because of the efficency, but then filtered it to produce DC through the LED. Basically a switchmode current source with optical and current feedback. It was for quanttive fluoresence so hd to e controlled intensity. I've also used white LEDs as strobes, thay turn off slot faster than a conventional xenon flash lamp.
Going back on topic, I like others, would nor recommend using a stroboscope to "freeze" the lathe or workpiece.
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