Member postings for andrew lyner

I don't want to get into the politics of the situation. That's almost certainly against Forum policy and we could find ourselves banned. Just using the technology that gives us this forum takes us into the same sort of territory.

My question was a general one about using new available technology. I am reasonably elderly and a lot of the people I meet in the pursuit of my hobbies, are even older. I notice a strong reluctance to take up 'new' facilities. I am a member of U3A and I've actually been impressed by the large number of 'really old' members who have embraced the new media. Initially getting through the front door of Zoom is daunting but they arrive at meetings.

I have looked at the thread about changing the forum and I see an amazing reluctance of members to it. So it's not too surprising that "like" is viewed with suspicion. But what a shame. I seriously can't imagine ME ever getting too populist. It's so 'deadly boring' - unless you are into it and then it is one of the best things since sliced bread.

I remember, perhaps forty years ago, at a Computer Fair in Brighton, hearing a guy 'explaining things' to his wife. He told her that a computer mouse was pointless and that he could do everything he wanted to with the cursor keys. I wonder if he ever got round to using a mouse.

PS How relevant to our lives is the encryption that's available on social media? Important transactions are pretty secure when we talk to the bank. It's quite simple to communicate with people with very high levels of encryption, if we are prepared to use appropriate private encryption systems. Does anyone really care about our WhatsApp threads being snooped on?

That post rather makes my point. How much more trouble did you go to, to register a non-specific approval, compared with a simple button press?

No one is forced to make use of new fangled bolt-ons (as with lathe fitments and CNC (???)) but they are appreciated by some of us.

I realise that the chill wind of change makes all of us shudder at times.

Do you use any other fora frequently? I use the excellent PhysicForums and most of the discussions are at a very high technical level with contributions from many professional Physicists and Engineers. Definitely not "populist". I also spent years on the Westerly Owners Association Forum. Both those fora had a like facility and I can't say it was anything other than useful to discussions. There are, of course, many (the majority of) fora that are simply dreadful, with or without a few bells and whistles.

To be honest, the quality of this forum interface is nothing like as good as the quality of the information that's exchanged and he level of knowledge of members. Would the membership change if the site were improved?

On a similar topic, It's amazing to see the reaction of some people against the Zoom / Webex etc. culture. My French and Astronomy groups all learned to use it and we have all felt the benefit in these dark times. Don't we need to move on, sometimes?

Andrew

"Like" is a quick form of feedback and very popular on many fora. How easy would it be to achieve it - if the MODS decide it's a good idea?

When I replaced that big steaming resistor, the board became even deader - no less lit and at least one chip looking charred. So I decided to get a new board from Arc Euro, (£138 ouch) despite their special email to me with a severe Caveat Emptor message. I carefully transferred connections from one board to the other, checked the operation of switches and the potentiometer (motor was working anyway). Damned thing did nothing when at switch on. Check, check and check all connections (I was getting quite familiar with the circuit by now) Check Volts across diodes and stuff. Finally I looked at the wire link across small green terminal block at the bottom. There was a VOLTAGE DROP across the screws. The U shaped link I had fitted was not making contact under one screw - pushed in behind rather than under the shoe. Sorted and I gave a sigh of relief that I hadn't returned the unit - potential great embarrassment.

Spot on - well done - the 15k carbon resistor is O/C. So none of the control circuit gets any power. Is the other resistor in parallel just a backup to keep some bias on the downstream bits?

Actually 2W rating doesn't leave a lot in hand (200V squared / 15K is 2.5W) so a bigger replacement may be a good idea. The way it's mounted implies they expect it to get warm.

Watch this space. I really don't want to have to spend 130 quid plus and I now find that the Sealey replacement part is around 180 quid. I just wonder if the 2335 in mine was a replacement and if the Sealey part (SM2502) is subtly different. Any ideas?

Cheers Les. That diagram is very helpful. That sort of circuit is far from intuitive when it pulls itself up by its own bootstraps. I'm just wondering if it could be the speed adjustment pot or its connections. After all, the last thing I did before it wouldn't;t work any more was to use the switch or the pot itself.

In the light of the fact that the board show no signs of heat or damage and there's no funny smell anywhere I can now look at places on the board to check on the paths there and back from the pot. The only annoyance is that I won't be able to look at it till tomorrow pm at the earliest.

It would be really handy to get hold of a schematic diagram of this thing. I guess the makers don't want it to be very public.

I was always hopeless at getting a diagram from just a PCB and I am totally out of practice now.

I do have a scope and it's a very basic second hand analog one but it stands alone without needing a PC display.

At least the red box is plastic and the floor is dry wood!! I am scared of Mains - which is good for health.

I looked at waveforms and all I could see was AC, then half-wave rectified 0V to - 300V (ish). Nothing else. Perhaps the fact that it's not full wave / bridge rectified suggests there's a diode problem. I'll go out and have another poke around before ordering anything.

My motor (95D-1) iis rated at 220V DC so the voltage from the KBIC will limit top speed somewhat.

Ahh, it seems to be a PM motor, from a quick Google search!.

Many thanks for the input so far.

The board is an XMT 2335 and has 'Seig' marked on it. The mill seems to have much in common with the Seig.

I will check the motor to see if it's a Universal. I guess a PM would reveal itself to a steel screwdriver. It looks a pretty ancient design and a conventional shape. 7Ohms resistance when stationary.

If it doesn't run convincingly with a cheap controller, I can always buy a bridge rectifier.

Needing to replace a motor speed controller seems to be 'not uncommon'. The motor on my Sealey SM2502 stopped working after I tried using a 65mm slitting saw. The motor is OK because it works with 12V DC (Slowly but with plenty of torque.

I examined the control board and it has no signs of frying any components. I poked around with my Scope and, apart from the rectification of the input mains supply, it was too hard to trace any fault - apart from no output.

I'm tempted to try a twenty quid controller from eBay, which is ok of a 300W DC brush motor at 230V. I could try replacing the major active devices and the capacitors but it could easily cost me a lot of fruitless effort and the cost of the bits. I can't find a schematic diagram either, which makes it doubly difficult.

I understand that quite a few people have gone down this road, rather than paying a lot of money for a manufacturer's replacement. Are there any lessons to learn? I was wondering if some extra protection in the form of a MCP breaker might do the job as the available cheap boards don't claim to have any (afaics).

What's my chance of success? I really don't want to be without the Mill for longer than necessary.

@Simon Williams. You said it!!. A double / triple and quadruple whammy. But a lesson learned. Thanks a lot for the reply. This brazed carbide tools haven't been a lot of use since I bought them with the lathe but this time, although slow, it did the job. AS you say, with a bit of power behind them, they could shift material in a brute force sort of way

I did actually wonder about that hole and thought "If I was cutting out a disc, I'd put the hole on the other side of the circle." haha. I will put that in my review!! But I need slots in the edge so That hole can locate one of them.

I was wondering about how to grind the edge - just to get it more circular with no conical distortion - but I couldn't think how to do it. I considered my little dremmel style tool, clamped to the cross slide but flying grit into the lathe scares me and the burrs are so fragile. Freehand would be hard but I could have cleaned up the burned looking bits. I should have taken a photo of it before.

And thanks for the other answers chaps.

Edited By andrew lyner on 16/12/2020 22:54:13

You will probably say I deserve everything I get when ordering metal over eBay. I needed a chunky steel disc (120mm by 15mm thick) and I took a punt by ordering a plasma cut disc on eBay.

It was cheap (and free postage, of course) but had a really rough, uneven edge and even a notch on the periphery. An awkward size for my chinese lathe with 10mm chuck and I had to make up a plate to hold it. All good fun and drilling the disc for fixing screws went well and very accurate for me!!!

I started to radius it but the indexed turning tool just seemed to bounce off it without really cutting the surface. I did make a bit of progress, though. I then tried a HSS tool and that actually cut quite impressively but the edge didn't last for just one pass; It was just worn down. Eventually, I dug out a brazed carbide tipped tool and that finished the job. Cut depth needed to be about 0.05mm in order not to stall the motor but I can accept that.

Once I cut below the heated level, the steel was more manageable. I realise I was asking the lathe to punch above its weight but this workpiece was so tough. I have to conclude that the plasma cutting had put in some surface hardness.

A Google search does tell me is can be a problem but it doesn't;t seem to be a common forum topic. What's the general opinion (not about using eBay) I only paid £7 for the blank). Metals For U is great value when you start to buy a lot but a single piece does cost you.

My feedback to eBay won't be gushy but I know that was my fault and there are some good deals there/

I had a look at them but I worry about where the readout will be. How readable is it if it's mounted low - or, alternatively, when mounted higher, how vulnerable would it be to things going on on top of the milling table?

The price is pretty attractive, of course.

I am just basking in a sea of smug today. My second hand Sealy milling machine had a very iffy speed control but I have just replaced the switch / pot and it works a dream. I feel more inclined to do some more things on it, rather than with it!!

Andrew

Mains powered LEDs all (all the ones I've seen, anyway) flicker because the there's no crashing need for a really smooth DC supply and LEDs have no 'memory'. A thin stream of water from the kitchen tap breaks up into apparent drops. But the problem in multi-user workshops was that the background noise made it impossible to know if your machine was running or not. Working on your own is a lot safer in that respect.

If you really want good DC then make up your own lighting circuit in the workshop with a float charged 12V car battery. That will give you a good DC. Never found any problems on my boat. (Otoh, no lathe or bench drill on board)

I remember the lathe in our lab used to have a 24V transformer and a low voltage filament lamp. The flicker was much less detectable due to the greater mass of the filament.

Never complacent about anything whirring round.

Since my new white wheel arrived I don't even have to press hard to shift metal so there's even less stress (mechanical and mental)

@SOD Good comments about perceived risk. Problem is that people just do not understand statistics - why else would Lotteries make money? It was good to read all the above posts; I guess the topic needed an airing.

I realise that my noddy 150mm bench grinder is a lot lower risk than massive, highly stressed wheels but, as has been said, it's no hardship to do a quick 'genuflect' when I turn it on. At this level, in the market, quality control and pricing will not be too much of an issue so I am probably on reasonably safe ground and the horror stories seem always to involve idiots and big machines (as with most things male).

I am particularly conscious of the wheel at the mo because I replaced the 'fine' grey wheel that came with the grinder 25 years ago with a white 'sugar wheel'. Such good value!!! It quietly shifts HSS quickly enough for me to get proper looking faces on cutting tools and it also took no time at all to re-do my wood plane and a chisel without overheating.

Dressing it was very satisfying and there is less vibration than with the old wheel, ever. I'm making a better rest for it which will improve things even more.

Money well spent.

I religiously stand to one side when I turn on my bench grinder and I see other people do the same on YouTube. I wonder how dangerous those things actually are, though.

I only heard of one specific case of a grinding wheel exploding and it was pretty horrific. A relative of mine had to rebuild a guys face - which was seriously damaged.

I am always pretty careful about using my wheel and would never hit is or push hard against it but what about the issue of using the side? The drill sharpening jig I bought seems to work only when mounted so as to tough the side of the wheel so what about the 'only on the front ' mantra that you seem to hear pretty regularly.

A higher apparent risk is with angle grinder discs which have various words of warning on them. But, on YouTube again, you see all sorts of antics used by some of the DIY 'performers'.

I never actually had a proper course on grinding and I know they are given to all professional too users. Is the risk real or is it just the fear of litigation that makes managers so careful about grinding? I am at least as careful as the next man (not the one with only one eye).