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Member postings for John Haine

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

Thread: ER25 v 5C Collets
16/02/2019 23:05:09

Charles, you don't need the reference. ER collets have 4 slits from each end, offset by 45 degrees. You simply find a collet slightly bigger than your square bar and tighten it down so the corners fit in the slits. Maximum gripping length is rather less than the length of the collet since the slits can't go the full length (collet would fall apart).

You can probably hold hex too but it won't fit in the slits so may not be so accurate.

I doubt this is very good for the collets.

Thread: Warco Super - Major Vario inaccuracy
15/02/2019 18:31:01

What's the spec, did it come with an inspection certificate?

15/02/2019 17:37:34

Lower at front or back? Remember when cutting that the forces will tend to tilt the column back, so it could even conceivably be made that way. But for an out of the box Chinese machine tool that doesn't seem too bad to me.

Thread: Stepper Motor Controls
15/02/2019 08:22:41

If you're doing a shaper, looking at Joseph Noci's posts here may be enlightening too.

Thread: Emco 50 CNC Mill ...Increasing X and Y table travel ?
15/02/2019 08:19:19

Steve, would it help if you had more table area so that you can get workholding clamps out of the cutting envelope? I don't know what size the Emco table is, but over on the Denford forum someone described adding the Sieg long X1 table available from Arceurotrade on top of the Novamill table to give more length and I think a bit more width. Of course it eats up a bit opf daylight under the quill. You could do something similar by using a slab of aluminium or steel, with threaded holes outside the work area for clamps.

By the way, you don't really need to reduce the stepper current as you describe, steppers are very tolerant of hitting the buffers if you are moving slowly.

Edited By John Haine on 15/02/2019 08:21:02

Thread: Buying lathes direct from China
13/02/2019 15:51:57

Warranty? "Yes, sir, of course we'll fix it if due to a manufacturing defect, please arrange shipment back to us so we can check"!

Thread: Using metric threads
13/02/2019 13:48:29

A tip which might work for threading out small nuts - I have used it to drill out M2 nuts to make short spacers.

Chuck a socket that fits the hax in your 3 jaw or better a collet. Stack a row of the nuts into the hex and feed the drill into the threaded hole in the tailstock. As each nut gets drilled out it slides on to the drill. You can do as many as will fit in the socket in one go.

To thread I guess you'd drill out like this if needed, then put the nuts back in the socket and feed in the tap.

Thread: Emco 50 CNC Mill ...Increasing X and Y table travel ?
13/02/2019 08:55:35

What limits the work area Steve? Certainly on my Novamill it isn't the length of the ballscrews, but possibly the position of the ballnut. But you'd need to make sure you had enough engagement of the dovetails.

Thread: Stepper motor and surface finish
12/02/2019 17:50:46

Not significant compared to other effects in my experience. Actually once they are moving at any speed the motion is more like continuous thought the speed will vary during the step cycle, depending on how well the microstepping works. If you approximate curves by straight line segments you can get visible facets but these are much coarser than the step size. For circular arcs most controllers coordinate the motion of the axes at varying relative speeds to form helical arcs, using G02 and G03 commands. It would be nice if they could do more complex interpolation but I don't know any that can.

Thread: Quorn Castings
11/02/2019 16:49:42
Posted by Baz on 11/02/2019 14:06:00:

John Haine, can the Worden or Acute sharpen the side flutes on milling cutters?

They could with an appropriate fixture. But the Quorn can't either, very easily, because it is very hard to get a smooth spiralling movement where the work head mandrel turns smoothly and the tooth is held firmly against the tooth rest. I've tried it with mine and never succeeded.

I have seen a Quorn at an exhibition with a chromed mandrel and other modifications to allow this; and a series of US articles about making an air bearing spindle which isn't very easy either. But apart from the very end of the cutter the side flutes don't generally get much wear at least in our usage, it's the end teeth that get worn.

11/02/2019 11:37:30

IMHO, the Quorn is over-rated. It was designed to grind a wide range of cutters including some very tiny ones that Prof Chaddock needed for one of his engine projects. A challenging project but if what you want to do is re-grind cutters and get on with your main projects, then the Eccentric Engineering Acute or the Worden from Hemingway do the job. I built one of the first in a couple of weeks, there's a build thread on this site about it. BTW I also have a Quorn, inherited from my dad, it took him a couple of his retirement years to make and then he hardly ever used it.

Thread: Single to 3 phase invertor and smart meters
10/02/2019 22:32:23
Posted by Samsaranda on 10/02/2019 21:50:20:

John, in the UK there is no facility for monitoring how much generated power is fed back to the grid with domestic metering, the government assumes that 50% of kWh that are paid for with the feed in tariff will be exported to the grid so they pay every PV generator for the deemed 50%. That could change with smart meters if they can detect exported kw hours.

Dave W

I wonder what the new little kWh meter installed next to the main meter when the solar panels were installed, the reading on which I have to enter when the FIT claim is put in, is measuring then? And the online monitoring page also says how much is being exported. So there is certainly the facility in the installation to monitor it.

As for things interfering with radios, it's a fact of life that electronic devices radiate. Anything like a smart meter will need to meet emc standards. Unfortunately the same is not true of a broadcast receiver, and if it is in a place with low signal strength it's going to be affected by locally generated noise.

10/02/2019 19:14:29

Spinning disc meters did measure power - see here. When I was a student we built a crude charger for NiCads with a half-wave rectifier - interestingly when connected to the shilling in the slot meter in our flat, the disc went slowly backwards (as long as it was the only thing conencted). However they were obviously wise to this and there must have been a ratchet in the gear train because the dials did not wind back.

Thread: "Vintage" CNC
10/02/2019 11:53:20
Posted by Nick Clarke 3 on 10/02/2019 09:50:47:
....................

As with the exception of the serial port which replaced the parallel port the Dragon was a clone of the Radio Shack (Tandy) Color Computer it inherited the graphics circuitry from that US model as well. It was not a case of building a better circuit but designing a different computer - hence the compromise.

....................

Edited By Nick Clarke 3 on 10/02/2019 09:55:07

It was more than a clone - I worked in the same company as the designers! It used the same graphics chip but surrounded it with extra logic to "convert it" to 625 line. For some daft reason they decided to use the same graphics clock crystal as used in the 525 line version which meant that the line time was too short by 0.5 microseconds. The PAL delay line then inserted a ghost version of the previous line 0.5 microsec too late, which gave a strange "echo" on every vertical line displayed on the screen. The designer was unaware until it was pointed out to him that every modern PAL TV set incorporated the delay line. The machine's display quality was roundly condemned in the magazine reviews and the manufacturers were extremely upset by the design error. I think in the end they fitted a SCART port to a later version so a direct video feed could be used, but it was too late by then.

Thread: Single to 3 phase invertor and smart meters
10/02/2019 11:39:48

The thing you see if the in-home display. This connects to the meter proper using, I believe, Zigbee RF. It is probably battery powered, but is unlikely to take much energy as it's basically a low power microprocessor, a Zigbee RF unit, and a display. You could always take the battery out or if it does use mains power just unplug it. According to Ovo Energy...and they indirectly confirm you can switch it off.

How much does it cost to run my IHD?

Your In-Home Display (IHD) is very power efficient. The average amount of power it uses when it’s switched on, including the plug-top power supply, is less than 0.5 watts. Over a year, this adds up to 4.38 kWh or 54p (based on a unit rate of 12.33p/kWh).

10/02/2019 09:38:29
Posted by J Hancock on 10/02/2019 09:32:09:

Question on Smart Meters.

Has anyone been given a cost, by the suppliers, on how much they cost to run £'s/annum ?

They are supplied with energy from the consumers side of the meter I presume ?

Hardly - would be a bit of a problem if they had switched it off!

Thread: "Vintage" CNC
10/02/2019 09:37:35

Do you remember the appalling graphics on the Dragon? That was because of a stupid mistake in the design of the graphics controller, which assumed that European 625 line PAL receivers wouldn't object if they were fed a video signal that was based on NTSC 525-line standards which had a slightly shorter line duration - 63.5 as opposed to 64 microseconds. Since every self respecting PAL receiver incorporated a 64 microsecond delay line to average out colour errors between successive lines, not surprisingly they did funny things. All to save a few pence on the price of a crystal.

Thread: Single to 3 phase invertor and smart meters
10/02/2019 09:27:18

<rant/>

The advertising for smart meters implies that they will save you energy by letting you see how much you are using through the in-home display. Well, you don't need to spend 20 billion on the smart meter infra to do that. I've had a couple of energy displays based on the clip-on sensor gadgets, they were useful initially but after a while I was finding I never looked at them and had absorbed the information on usage patterns as habits. Now we have solar energy we have a third system which actually gives us more information, so I still have no need for a smart meter - in addition it has an extra meter to read to claim the FIT, I'm not sure if smart meters cope with that.

My brother went for a smart meter because his electricity meter was in a place that needed a stepladder for the reader to reach. After a while a new reading company refused to read it for elfin safety reasons. After a year or so they came back to say that they wanted to replace the meter with one that could cope with gas as well. When the guy arrived, first he couldn't fit it because the space was too small, then confided that actually they were replacing all the meters of that type because the batteries were failing - after only a year! For meter systems to be viable the batteries have to work for 10 years or so, otherwise you have to send a truck which costs a lot more that you might save. (Yes you need batteries because the mains may fail over a large area and you need to manage how the load is reconnected.)

Many countries have had remote reading meters for years, using much simpler systems that work well and have been much cheaper to roll out. Because of our crazy supply industry structure that wasn't good enough so we had to go our own way. Even at the start when the (entirely predictable) cost overruns weren't recognised, the business case for smart meters was very marginal - today I suspect it is blown out of the water. Someone I know who was reviewing the project gave me to understand that the suppliers only agreed to support the project because it gave them the ability to switch non-payers off and on remotely. Well, if that's what they wanted it didn't need the complexity of what we have now. And there are remaining concerns about the security of the system and the wisdom of giving criminal or subversive elements the ability to switch off our energy supplies if (when) they hack the system

/<rant>.

Thread: Overload trip
10/02/2019 09:08:07

I like the suggestion of using a geared synchronous motor of the type used to operate central heating valves.

Rather than winding a chain/weights, have a spiral spring remontoir. If this was selected and properly geared it could drive the great wheel arbor, running at the same speed so the spring is always kept would the same. Or, use an arrangement as on Clock B where the motor runs a worm lifting a weight on a lever applying torque to the great wheel, with a mercury switch to control its level.

If you took the first approach, you could even dispense with most of the clock and just drive the hands direct...wink

I'll get my coat...

Thread: Talktalk new web site
09/02/2019 12:24:21

Assuming that you have a PC or MAC, just download Thunderbird and stop using webmail.

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