Member postings for Clive Steer

Cotton sash cord has a braided outer sleeve and can be bought in several diameters. The beauty of cotton is that it can be dyed any colour and then using clear cellulose dope "fixed" in shape. The core strands can be extracted an replaced with rubber tube and brass end fitting to make true working hose.

CS

I'll have to check the Jack controller to see if it has any "hidden" parameters that aren't described in the rather brief user manual. In my investigation of Sewing machine motors I did get two different types. A Tysew (Jack 513A) and a Tansew (TH-550S-2) which looks similar the Husuper one that David has and has the same parameter list in the user manual. I was looking to modify the code to get rid of the low speed (jog) feature and the Jack controller uses a similar processor to that used on Arduino making the task easier!!!!!

CS

John. Sewing machines can have very high operation duty cycles and run at high power and since the motor is located under the work bench it may not have the best ventilation so hence the fan. However for our type of use the headstock bearings will probably get hotter than the motor and I've not noticed mine getting hot. On my Jack motor, which is a JK-513A, the fan is the other end of the motor to the pulley.

CS

Hi John

I ca't see how the chuck is fitted on your lathe. However for many lathes with screw on chucks an extra clamp is fitted to the spindle and links to the chuck. I had one on my Boxford lathe but can't remember exactly how it was done but I'm sure there may be other who can provide details. Having said that your lathe looks like an instrument makers lathe so probably would have mainly used collets. Another possible way is to fit a ratchet system to the drive pulley, similar to the freewheel fitted to bicycles, so when the motor stops the chuck can continue to "freewheel". Thee downside is you can't use reverse. Not ideal but if push comes to shove.

CS

If you look at my photos you'll find 4 related to the fixing of the Jack motor and control box to my Pultra. My arrangement is fairly complex as I wanted the lathe and drive to be "portable" so I can pick it up as one lump and move it from bench to bench. Also the motor is mounted close to the lathe so it doesn't need a great depth of bench space. I'll add a picture of my pendant circuit but you can just take the return spring off the supplied controller, that's designed to provide foot control, extend the lever and some friction device to provide hand control.

CS

John.

I did for the Jack controller using a 3 turn potentiometer and an on/off switch to effectively short out the speed set signal. A 3 position switch can be used, plus a few resistors, to give OFF, Preset SLOW SPEED (jog) and then on to full variable speed. My Jack motor system is fitted to my Pultra lathe and works very well.

CS

John. If you want to use a VFD you would need to buy that and a matching 3 phase motor plus some sort of control box (pendant) which has the forward/off/reverse selector switch and speed setting pot.

A BLDC sewing machine motor kit comes with motor mounting components, motor controller unit similar to a VFD and a manual control box.

The downside is that the unit doesn't have an easy way to select reverse as the direction of rotation is a set up parameter. As mentioned before the controller has 3 operating regimes, Off, a fixed preset slow speed and a variable speed preset range. You will also need to make/acquire a motor pulley to match the belt size your lathe uses.

CS

There is already a country wide water distribution network in place which are called canals. Unfortunately nasty substances can get in to these as also has happens for many of our rivers so maybe not so good for drinking water but OK for providing grey water. We may have to bite the bullet and install dual white and grey water system for both delivery and sewerage.

CS

A cheap way to get hot water with the weather we are having at the moment is to leave you watering hose laid out in the sun full of water of course.

CS

This William

The condenser lens converts the light from a point source such as an incandescent filament into a parallel light beam and the type of glass it is made from also blocks the Infrared wavelengths( heat) from the light . This arrangement is more commonly found on 35mm slide projectors.

Although one might want to restore to original condition using a Tungsten Halogen light bulb I found that a high intensity LED downlighter lamp works well on my Projectina projection microscope. They are more compact, use less power and therefore generate less heat.

CS

Greensands

The ferrite bead found on some computer cables are there to prevent the lead becoming an aerial for radio interference produced in the computer. The bead should not significantly affect the signals in the cable, which would normally be screened, but seems to in your case although other factors in the new cable may be the cause. However you can remove the bead with a nut cracker eg a large hammer, after removing the heat shrink sleeve that normally holds it in place. On some cables however this may be more difficult as the bead could be moulded in.

CS

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

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

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

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

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.

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

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

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

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