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Member postings for Mike Poole

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

Thread: Simple table of potential hardness of metals
24/08/2019 14:54:26

Hi Chris, There are not many choices for cutting tools in the home workshop, Tungsten Carbide is probably the hardest but tends to chip easily, it is very resistant to high temperatures. HSS is readily available as square or round blanks to grind a tool of your choice, again it is supplied hardened and will still hold its edge at high temperature. High carbon steel can be supplied in a soft state like silver steel and gauge plate and fashioned into a tool and then hardened and tempered to your requirements and finish ground, excellent tools can be made but overheating will very quickly destroy the edge. Tungsten Carbide can be as simple as a brazed tip ground to a basic tool or as a preformed tip with a wide variety of shapes and characteristics, HSS has a number of different flavours to choose from. High carbon steel is available as mentioned and also various other hardenable tool steel alloys are available. The absolute hardness is only part of the story for making tools, toughness of a tool can be desirable and with High carbon steel the tempering process trades some hardness for increased toughness. A Tungsten Carbide tool will machine a HSS tool even in its hard state. Unfortunately Tungsten Carbide needs special grinding wheels as it is harder than Aluminium Oxide and silicon carbide, you will need a green grit wheel or diamond wheel which is probably one of the reasons to use preformed tipped tooling. The absolute value of the materials hardness is interesting but as long as the tool is harder than the material you wish to cut then all should be well.


Thread: Any one recommend a supplier of 1/4 inch lathe blanks
24/08/2019 14:15:40

All tool shops should be entered with great caution, even if you just enter for a browse you will find it very difficult to leave without a purchase. Tools are worse than kittens and puppies for wanting to go home with you.


Thread: Bandsaw blades
22/08/2019 21:31:50

Just had a look for a bandsaw blade butt welder, lucky I was sitting down, £1600.00 seems a lot of money but I suppose it is aimed at professional use.


Thread: Garmin sat nav
21/08/2019 23:52:32

My sons girlfriend at the time was amazed that I drove from Oxford to our hotel in Turin without a satnav or map, I did know the way as we had been two years previously. I also check where I am going before I leave home. Rather than put up with the wittering from the satnav I only turn it on for the last bit of the journey as roads signs get me close if I have some idea of the route. I do find it tempting to follow the satnav even when I think I know better and a couple of times I would have been better to use my own sense of direction which mostly is pretty good. The satnav did get it wrong on an over complicated junction in Aosta this year and cost me a tenner in tolls, perhaps I should put a claim in.


Thread: Your ideal holiday
21/08/2019 17:46:02

If you have a motorcycle then the IOM TT takes a lot of beating but obviously not everyone’s taste. +1 for lake Garda, drove down in June, it was a bit hot though 39°C. I feel that paying to use the French Motorways is worth it for a very relaxed drive but I also like just touring and see where we end up type of holidays but best done out of high season or you could finish up sleeping in the car. Some friends just drive their camper to Greece and tour for 2 months. If I win the lottery I think I would spend a year following the F1 races, a world tour and a bit of racing thrown in then next year follow MotoGP. I have always fancied visiting the four points of Britain, The lizard, Lowestoft, Dunnet Head and Ardnamurchan point and a ride to the Nord Kap in Norway always appealed. Lots to do and time is running out.


Thread: Torx head variant or faulty batch?
21/08/2019 12:16:42

Definitely a manufacturing fault that has escaped the rigorous quality control system, I am sure they will be happy to replace with no need to return faulty ones.


Thread: Hex Silver Steel/Tool Steel ??
20/08/2019 20:41:05

The Classic eclipse centre punch has a square end so start with a piece of GFS or square tool steel and turn and knurl.


Thread: Wasp trap - suggestions please
19/08/2019 21:49:32

They seem to like beer but I thought the one on Saturday was either a bit ambitious or just fancied a swim.


Thread: Which size drill bit
16/08/2019 22:46:55

Well we have a choice here of 30 thou ish from emgee or 15 thou from Neil or 3.5 though from Dave (SOD). Given that most drills tend to drill slightly oversize then you cold be living dangerously with a max of 3.5 thou to play with which may not be there if your drill cuts a bit oversize. I aim for something around Neil’s suggestion as you should have something for the reamer to cut but not too much, if your drills are cutting 15 thou oversize the I think it’s time to look at your drill sharpening process. It is useful to know what the size of a drilled hole is using your normal sharpening process and drilling technique.


Thread: Meter Probe
16/08/2019 09:44:45

E-Z Hooks were one of my favourite small probes for bench repair work E-Z Hooks


Thread: Should I begin with mild steel on lathe?
15/08/2019 18:52:28

As an apprentice we were started off on ordinary mild steel but we had the benefit of an instructor to oversee us so that advice could be given if we had not listened or were having trouble putting it in to practice. There is plenty of guidance in books and sources like YouTube. Being sure of what you are machining is important as steel looks much the same but the machineablity can vary widely depending on its specification. There are many variables in setting up a tool and all need to be correct to give yourself the best chance. Correctly identifying the material will give you the figures for speeds and feeds depending on your chosen tool material, if you are hand grinding HSS tools then the material you are working will define the angles needed for your sharpening. If you want to use carbide tipped tools then you need to select the correct tip, some are pretty general purpose and some are very specific purpose, fitting a random tip could be a problem if it is unsuitable for the task. If you follow a process to get the tool set up with minimum overhang, correct edge angles and tool height and the set the correct speeds and feeds then you have a starting point. The recommended figures are a good place to start and if things aren’t working out then adjust things methodically until you are satisfied. Treat recommended settings as a starting point and adjust to suit your machine.


Thread: Digital calipers made in same factory?
15/08/2019 18:20:00

If the CE mark is now a complete waste of time then it may as well be dispensed with, it has no value to me as it is so widely faked, the rubbish about China Export is probably because they got caught out and just manufactured a lie or deliberately set out to deceive. The part of the CE process that has any value is probably the documentation that demonstrates compliance. Perhaps the symbol should be changed and then if that turns up faked then it would be obvious that a deliberate fraud is going on and not an accidental similarity which I am sure was no accident.


Thread: strange power socket
15/08/2019 09:53:28

The factory I worked in had most of these socket variations as believe it or not people would steal the standard 13A plugtops. People would also use kettles and radios of their own which was not approved of and unplug factory equipment to make their tea. The other crazy thing in the factory was the use of red for the earth cable, apparently during and after WW2 cable supply was difficult and red was the only colour that was usually in a cable so it was selected as earth, you can see some sort of logic to this but for anyone not aware could be very dangerous. I served my apprenticeship in the early 70s and did encounter a convector heater with this standard, this required a mandatory rewire to the current standard.


Thread: Digital calipers made in same factory?
14/08/2019 23:22:45

I bought a Mitutoyo calliper 30 odd years ago and it is still an outstanding tool, I bought two in Lidl for an outrageous £8 and some pennies each and have got a freebie from someone with a rotary table, the best value one was from Machine DRO and has a large digit display and very smooth operation, checking against my Mitutoyo slip gauges it acquits itself very well, not bad for £26.


Thread: Blown Fuse
14/08/2019 18:20:59
Posted by Neil Wyatt on 14/08/2019 16:23:35:

It would have to be very fine swarf to burn in air.

What type of lathe is it? I can't think of any machine that doesn't have a metal to metal path between tool and spindle.

They are probably not going to turn up in the home workshop but machines have been built that run on PTFE pads, most likely there is still an earth path through the ballscrew or other equipment mounted on the table like the inductosyns etc. One thing welders were careful about was where the weld current return path was going, we did have a few occasions when the return clamp made a poor connection and the weld current fried the earths in the equipment wiring, they were also careful not to have weld current flowing through ball races as they could arc and it was goodnight to the bearings.


Thread: Aircraft General Discussion
13/08/2019 14:40:07

The Martin Baker Meteors are out having some fun over the village, they both came over very low wingtip to wingtip.



Thread: Blown Fuse
13/08/2019 14:09:45

My audio amplifier gave a loud bang and cloud of smoke, after a good look round I could see no problem and powered it up and it worked perfectly. After a second coat of looking at I found the capacitor across the mains switch had failed, apart from the ear splitting bang and smoke the only physical damage to the cap was a hard to see split. It might be worth a very close look at things as not everything fails with dramatic burn marks and catastrophic physical damage.


Thread: Meter Probe
13/08/2019 10:07:55

Testing has become increasingly difficult as the requirements for shrouding have become more onerous. Needle points are useful for checks on PCBs that have been lacquered, they can also be useful for piercing the insulation on cable, obviously this must only be used where the pinhole left will not compromise the safety and integrity of the installation and personnel. Sometimes you can have fond memories of slate backplanes and rigid bare interconnections, accessibility was easy but so was an accidental touch when live testing.


Thread: Grid Frequency [mains electricity]
13/08/2019 09:40:21

I am under the impression that the supply also guarantees to supply the correct number of cycles per day to avoid clocks accumulating an error.


Thread: Myford ML7 - Size of Mandrel Through Drilling?
12/08/2019 21:32:03

The 2 morse taper in the nose of the spindle would be compromised if the spindle is bored larger and there is not too much meat on the other end. The bore increase would be small which is probably why Myford did a major redesign when they made the big bore version.


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