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Member postings for Martin Cargill

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

Thread: What Did You Do Today 2019
28/07/2019 17:15:41

I have both internal pullers and insert pullers that need you to break the bearing cage to insert a small flat sided ball into the space where a ball should be. However I have also managed to remove blind bearings by using an expanding masonry fixing bolt to grip the inner of the bearing and then improvising a slide hammer to shock the bearing into releasing. What is the bearing in?

Martin

Thread: Three phase motor checks
26/07/2019 19:04:20

LU is probably (from memory) undervoltage, it would show this if the power supply to it has tripped i.e. the RCD has shut off the supply.

Martin

26/07/2019 18:20:12

I would think that the fault probably lies with the inverter. Is there anything else connected to the circuit that feeds it? The RCD will trip at 30ma but some of the 30ma could be coming from something else. The inverter (if its a modern one) should give a fault code and switch off, if it detects something being wrong with the motor

Martin

Thread: Omnimill 00 Opinions
30/06/2019 16:08:54

I don't know if this helps anyone but I have an Elliott U1 universal mill. It has a removable vertical head that would probably put a dent in the NHS budget if I tried to lift it off !!!

To keep all of my internal organs and bits in the right places I built myself a small hand wind crane that clamps onto the overarm dovetails and a stand that holds the vertical attachment standing up when its not on the machine. The head lives on a trolley when its not being used (£10 from Aldi or Lidl). To mount the head I take the table all of the way to the left and then use the crane to lift the head up to the required height. The table is then wound back to the right and the head lowered onto it. The head can then be moved into the exact position using the X,Y and Z axes. Once its dovetails are screwed into place the table can be dropped away and the stand bracket removed. Removal is a simple reversal of the process. Changing the machine from H to V takes around 10 minutes.

I can take some photos of the arrangement if anyone is interested

Martin

Thread: Sump Plug
01/05/2019 17:55:35

Make sure your turning it the right way. A friend once tore the threads out of a motorbike sump because he didn't think about which way he needed to turn it to loosen the plug...….

Thread: Long drills
05/04/2019 20:30:50

I have a cheap chuck type tap wrench that I use for hard to reach places. I modified it by making the sliding T handle removable and then filing a 13mm hex end on the wrench. The wrench still works as normal but for difficult and awkward holes I can use a 13mm socket (with as many socket extensions as required) or I can use it with a ratchet spanner. Obviously you need to be careful not to snap taps when using a single sided driver but with caution anything is possible.

Martin

Thread: New drill-1PH to 3PH wiring
09/03/2019 20:39:55

First you need to check that the motor on your drill can run at 220 volts three phase. Have a look at the nameplate on the motor and check that the voltage is rated for 400/220 volts. A 0.45 kw drive will be suitable for a 0.25kw motor.

The control circuitry will probably be 24 volt and does not handle any significant current, it is normal to make a control pod with start/stop/ direction and speed control. A light eight core cable is the norm for connecting the pod to the invertor. Your invertor should be mounted somewhere safe (inside a housing )where it will not have any chance of having swarf etc falling into it.

Martin

Thread: Colchester Student Lathe Help
09/03/2019 11:13:10

Nobody yet has mentioned the idea of clamping a piece of bar in the chuck before you remove it. It gives you a "handle" sticking out of either side of the chuck to make lifting easier. It also allows you to push the back end of the bar into the headstock and then lift the front to get the chuck started onto the LO taper.

Martin

Thread: Inverter Rating
13/02/2019 20:35:23

If the price difference between the two is small it may be worth going for the bigger inverter. You never know when you might want to upgrade the motor or the machine.

Martin

Thread: Overload trip
08/02/2019 22:01:56

Have a look on Ebay there are loads of thermostatic switches available in a range of temperature settings. One of these fastened to the motor and wired into its power supply will be able to cut the power if the motor overheats. Wired in this manner it will reset and try again once the motor cools down but it will cycle like this without letting the motor reach any serious temperatures.

Martin

Thread: Alternative to a QCTP?
04/02/2019 18:11:04

Thank you all for taking the time to reply to my post.

Having considered the options that I have, I've concluded that:

1. My original idea of making some four way toolposts is still a valid one, although I will probably use them equipped with two tools. This will depend on how the working clearances pan out. I've considered making three way ones but I don't think the complexities of making them outweighs their advantages.

2. I hadn't thought about the logistics of changing the posts but as my lathe has a "T" slot for holding the toolpost then its probably worth making a bolt and a handle for each one.

3.The toolposts I'm going to make will be from solid blocks (because I have the material) and I have a horizontal mill that will chew them out pretty easily (I have a Victoria U1).

Thanks again for your input.

Martin

02/02/2019 21:06:33

I have recently acquired some old forks for forklift trucks, with the intention of making a QCTP and holders for my Viceroy lathe, I have cut the best sections out of the forks and milled them square/flat ready for further work.

I have stopped work as I have just had a thought. Is there any mileage in making, say, six (or more) standard four way tool posts and simply swapping the complete tool post over instead of swapping single tool holders. I realise that I would loose the ability to have height adjustment, but as all of the tools would be permanently mounted in the tool posts then they would be packed permanently and would not need to be altered (apart from changes caused by tool sharpening).

Any thoughts?

Martin

Thread: Fitting a Reversing Switch to a Motor on a Myford Lathe
02/02/2019 19:45:36

A couple of points regarding this.

Whilst its not the best idea to change the reversing switch on a single phase machine capacitor start machine while the lathe is running it won't do any harm because the start winding is switched out (by the centrifugal switch). Any time you change the switch it won't take effect until the motor is started again. N.B, three phase motors are different and reversing the switch will have immediate effect !!!

You can use a simple two pole on/off/on toggle switch as a reversing switch. You wire a pair of crossover wires between the two end pairs of contacts and then feed live and neutral to the middle pair. The feed to the capacitor and start winding goes onto either of the pairs of end contacts. Switching the switch from one end to the other will reverse the motor.

My own lathe does not have centrifugal switch built into the motor, instead it is supposed to use an external current sensing relay to switch out the start winding once the current drawn by the winding allows. Not having this fancy relay (they are still available but they seem to be used/available only in the U.S.A,) Instead I have an extra set of contacts on the back of the start button that power the start winding. Pushing the start button for a second or so holds the start winding energised during start up, once you release the button the start winding drops out leaving the main winding held on via the NVR contactor

Martin

Thread: Tempering
31/12/2018 11:35:14

I've tempered knife blades in a domestic gas oven before. It worked quite easily and with reliable results, as the items could be held at quite a precise temperature (rather than using a flame where temperature control is difficult) the only problem was that the item (a larger knife blade) was laid on the grille in the oven and where it touched the bars of the grill it reduced the temperature thus creating a series of temper variations along the blade.

Martin

Thread: Rotary table
26/11/2018 17:33:27

Thanks for the replies. I think my table sounds like the Criterion that you describe. I have a cheap 4 jaw chuck (quite a flat one) that I can fit to it (just need to drill 4 holes in it and make some spacers to hold the chuck high enough to clear the threaded boss on the back). I should then be able to centre the table to the mill using a large ball bearing sat in the centre of the chuck and lined up with the MT3 vertical head in the mill (or use a wiggler ). Then I can centre the chuck to the table using a DTI.

Martin

25/11/2018 17:53:10

I have a un-named 8" horizontal rotary table. The centre of the table has an M12 screw thread, and it also has what looks like a very big screwdriver slot running across the centre (either side of the threaded hole). I'm just trying to work out how I centre the table to my mill. Is the part I can see in the centre likely to be a screwed in plug of some kind? Is there a chance that there is a morse taper in the centre of the table. Any suggestions would be helpful.

Martin

Thread: Fitting an adjustable damper to my power saw
22/11/2018 18:30:08

Pneumatic cylinder idea has a downside in that the two ends of the cylinder don't have the same volumes ( because of the piston rod). I've seen machines using this idea but they have a second cylinder that the fluid uses as a reservoir when the capacity of the rod end of the main cylinder capacity isn't enough. Filling and bleeding the system can be a bugger to do though.

Thread: 3 phase converter help needed please
24/09/2018 19:10:35

Just a thought. Some controllers won't start the motor if the start switch is pressed when the controller is powered up (modern controllers have a parameter setting that allows this if required). Try adding a simple on/off switch between LI1 and +24, then close this switch after the controller is powered up and shows RDY.

23/09/2018 20:49:42

George. That's fine, please continue to try the instructions that John Rudd gave you. My concern was that you had managed to include the old switchgear into the circuit, most convertors don't take too kindly to having their output switched by contactors.

Martin

23/09/2018 20:29:13

George.

Don't do anything yet with regard to trying to start the motor. We need to know a bit more about how you have the motor wired. What you have shown so far is the power wiring, As John Rudd has pointed out the control side of the wiring is missing. What I'm not sure of just now is how you have connected the motor. Does the wiring run directly from the converter to the motor, or does it go through the original switchgear? Does the power supply to the converter go through the original switchgear or direct from the mains?

Martin

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