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Member postings for Clive Steer

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

Thread: Hardening clock pinions in EN8 steel
06/06/2022 09:32:40

Back in the 80's I remember designing a controller for Atmospheric Hardening were an item would be heated in a retort with a precisely controlled carbon rich atmosphere and temperature to either provide case hardening or prevent surface decarbonising. Although this was a fairly expensive industrial process commonly used for aerospace parts I wondered if anyone had used this method for less exotic applications.

If I remember correctly the carbon potential of the atmosphere was measured with a Zirconia probe, probably similar to those used in car exhaust pipes and the temperature with a Thermocouple.

CS

Thread: What is "Mathematics"
29/05/2022 15:37:09

I'm not sure I understand Andrew's comment that mathematics may not be correct or consistent. As far as I understand, and I'm not a mathematician, mathematics is a rules based system and we have defined the rules so how can it be inconsistent. Similarly computer instructions are a set of rules if the program you've written using them doesn't do what you need the fault is with the coder not the code.

However I do agree that the "mathematical model" may not reflect reality exactly and if assumptions are made or important factors are not included the model may not even be close. What we don't know or make assumptions about may be inconsequential or disastrous. In the case of the Comet 1, metal fatigue was known about , but for whatever reason was not considered to be an issue or maybe the cost of testing for it was considered prohibitive. However after the event the testing was done.

When explaining to young engineers the need for extensive product testing I would draw a circle on a piece of paper and say that what is inside the circle is what you want the product to do but what is outside the circle is what you don't want it to do. Mathematics may be used to substantiate what the product should do but may not be so good a tool to find out what it shouldn't do.

CS

29/05/2022 10:35:54

I think the infinite answer questions are a classic case of "show your working" where the answer isn't as important as the way you got there. How does one test the "creativity" of a candidate to use the stand building blocks of engineering that the maths and other analysis techniques tought in schools allow you to understand. The real indicator of creativity is the translation of a requirement into a solution. A well designed product can be likened to a jigsaw puzzle where every piece links intimately to the next to make an efficient homogenous design. The worst situation, having just completed the 100 piece puzzle, is when the salesman asks you for the must have feature that requires it to become a 101 piece puzzle.

CS

Thread: Strange Miniature Bearing
24/05/2022 21:05:43

Anthony Randall wrote several articles in the BHI journals about his experiments using ball races in weight and spring driven clocks.

The Eureka clock, which has a horizontally pivoted balance wheel, uses three steel balls in each pivot and these provide electrical conductivity in the circuit for the drive coil. This produces a degree of electrolytic corrosion and rusting of the balls and unfortunately ceramic balls cannot be used to cure this condition.

CS

24/05/2022 20:51:39

I've found that if I just need a couple of balls I buy an unshielded ball race and press out the cage, move the balls all to one side and remove the inner race. Simples. The interesting thing I've found is that metric ball races often have Imperial sized balls ! This may be because the machines that make the balls were originally imperial and they never bothered to change the design but there may be other reasons.

Thread: A tyro desoldering question.
08/05/2022 09:31:34

A test needs to be made on one pin to check if the switch pin is a tight fit in the hole or the hole is through plated as removal is more difficult in these cases. One way to remove the solder is to heat the joint and then quickly tap the board on the bench which will make the fluid solder splash out. Start gently and preferably on a pin that has no tracking connection to save damaging the board.

If the pins are a tight fit the technique I've found best is to flood the pins with more solder and extract the device while the solder is fluid rather like the reverse of flow soldering. However this requires a degree of preparation as it needs to be done quickly. The switch body needs to be held in a vice and/or levering devices put in place to prise the board off the switch. Since in your case there are two rows of pins the soldering iron will need to be moved quickly down each row alternately until the solder around each pin is fluid and before starting extraction. The process may need to be done in stages as the board/switch may not come out symmetrically.

Best to use a good quality temperature controlled iron at around 300C to ensure solder become fluid but not too high a temperature to scorch the board.

CS

Thread: help wiring a 3 ph coolant motor
06/05/2022 08:43:25

It appears there are two groups of three wires from the motor winding which might be classed as start and finish. Identify with an ohmmeter which pairs are windings and connect start to finish in a ring to configure for delta (240)

CS

Thread: Ping - and a screw is lost
30/04/2022 18:31:04

For removing small watch items such as screws and click springs I tend to use a cocktail stick with a small blob of Bergeon Rodico on the tip. I can pick up the item and then use the tweezers to get it off the rodico nearer the tray or box it will be stored in.

CS

Thread: Electric bike fault
30/04/2022 11:30:20

I'm not familiar with the Viking E-Go but when you say the power just switched off did the display, if it has one blank as this would indicate a reset often caused by low voltage. There may be some indicator or protection device in the battery so if there is an overload it protects the battery. Check that the connector for the battery is mating well and the contacts are clean and not corroded.

CS

Thread: It's About Time!
21/04/2022 11:02:52

If I remember correctly there is limited parking available at Soper Hall and although there are Morrisons and Waitrose carparks nearby these may have conditions attached. So anyone knows where parking may be found that would be helpful.

CS

Thread: Magnetic DRO-S7
21/04/2022 09:17:07

Thanks Michael for the link to the excellent article about magnetic scales and their sensors which has helped me understand some of the finer points of their operation.

I only use magnet scales for short distances (<300mm) where the magnetic strip can be well supported and distance between the head and tape accurately maintained. For longer distances I always use glass scales which can tolerate a larger amount of tracking error. However in all cases the read head does have to be very rigidly mounted to ensure there is no flexing due to connection cable tension/movement.

Newall sell an excellent and compact Magnetic DRO system but they are not cheap.

CS

Thread: Identity of static engine kit
18/04/2022 12:27:30

Unfortunately the bed plate and flywheel were not in the box. However I do have some 15mm thick Ali plate which although will need some chopping our won't need facing.

CS.

Thread: Electromagnetic Wave Interference
17/04/2022 19:13:11

Taking up Joseph's point the cable from the inverter to the motor should have an earthed screen bonding the motor casing to the inverter and to the machine to prevent radiated EM noise .

CS

17/04/2022 19:00:39

As far as I recall the EM noise emissions allowed for industrial installed equipment is far more that that allowed for Laboratory/Domestic installation. So Newton-Tesla may say their kit is designed for industrial installation. To meet domestic requirements they may say you need to buy a filter. An extremely crude filter can be made by simply winding the mains lead around a lump of steel rod and this may be sufficient to prove that conducted EM noise is causing the issue with the DRO.

CS

Thread: Identity of static engine kit
17/04/2022 13:51:54

Hi Paul

Many thanks and you are spot on with the model. I went onto their site and looked at the casting which bear the same numbers as those on the parts I have. I'm not a steam model builder so I'll probably sell the kit on to someone more likely to complete it in the manner it deserves.

Clive

17/04/2022 10:58:15

I've been given, what appears to be, a kit of castings and materials to make a static engine. Unfortunately there were no drawings or document identifying the model name or supplier. I've done a quick search on the internet and found it is not a Stuart model so I'm hoping someone may be able me identify it.

p1050964.jpg

Thread: Newbie looking for advice
16/04/2022 10:49:37

My advice would be to buy the biggest lathe your budget or space allows as you can always do small on a big lathe but not the other way around. Then find someone who has the lathe you are thinking of getting and ask what idiosyncrasies/problems the lathe has. Treat the lathe as a system so what you need to power it and the ease of obtaining tooling etc should also be considered. Do the leg work to see as many lathe types as you can including asking professional machine shops what they like best.

If you choose to buy a ex-industrial machine bear in mind that it will be 440V 3 phase so will need a phase converter, inverter or new motor to work from a domestic supply. The bigger the lathe the more difficult it will be to power it without special electrical facilities. Bear in mind an ex-industrial machine may have been worked hard but having said that they are designed for that so, unless abused, may still have plenty of lift left in it.

A good machine may be expensive to buy but should also be easy to sell.

CS

Thread: DRO readouts freezing when adding second scale
16/04/2022 10:01:12

Hi David

As a retire electronics design engineer I wouldn't mind checking it out to see if the unit has a fault or is not correctly designed.

CS

Thread: Wiring and connectors
09/04/2022 09:30:40

Aircraft crimp connectors can be bought from LASaero. The knife disconnect terminals are good for connections that only need to be disconnected occasionally.

Farnell sell the Deutsch range of multi-pin connectors often found in car wiring harnesses. These are well sealed but current carrying capacity is not high.

CS

09/04/2022 09:07:03

Farnell or RS components sell good quality connectors, wire, crimps and crimping tools although they are not cheap.

Aircraft component suppers such as LAS sell aviation quality connectors but these will be much more expensive.

CS

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