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Member postings for ChrisH

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

Thread: What did you do Today 2018
15/01/2018 17:32:24

clogs, good luck with the puppy hunt, we spent several weeks at it; our very first dog, a border collie, went at 12 years about 32 years ago now and we still miss him, was in fact the best we have had up till now, they are lovely intelligent dogs.

Chris

15/01/2018 13:53:12

Not today but yesterday. Signed up new apprentice. 9 weeks old tomorrow. Supposed to be SWMBO's but she (new apprentice, not SWMBO) follows me around like a shadow so I can see her spending time in my shed yet.

Pictured asleep on the settee cuddled up next to SWMBO.

All together now, say AHhhhhhhhhhh.

Chris

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Thread: Things must be getting tight for the scammers.
11/01/2018 22:07:40

Qué?

Thread: What did you do Today 2018
08/01/2018 19:25:56

Journeyman John's picture of his slide rule and case looks very much like the slide rule I bought from the SU office at Plymouth College of Technology when I went there in 1962. We had to buy one (and a load of expensive text books that we also weren't told about before we got there) before we could start our OND course. The slide rule cost £3 I seem to remember. The two coloured plastic case was so distinctive. Had it for years and it served me very well before I left it on one ship or other. Now have my Dad's Faber Castel, if only I could remember how to use it.

Chris

Thread: When is 9mm not 9mm?
06/01/2018 22:43:03

Spelling and grammar - how does that work for engineers?

Thread: Christmas Considered Harmful?
28/12/2017 22:27:11

Dave W - Senior Management and I have separate emails, so no problem there. Like you though I suitably 're-locate' incriminating emails to 'unlikely-ever-to be-seen' mailboxes, 'just in case'. Often incoming parcels with tools or stock are hard to avoid being seen, or even she having to be signing for them, but the tricky and definitely essential bit is to make sure the invoice never appears anywhere where it can be seen and then commented upon! My Father was wise to this, it was amazing how much stuff he 'just happened' to pick up dirt cheap 'down at the market' essential for his various hobbies, not that I, or anyone else as far as I am aware, ever visited this magically cheap market, or found out what market it was even; I learned a lot from my Dad!

Chris

Edited By ChrisH on 28/12/2017 22:28:45

28/12/2017 12:31:40

I also, like SOD, bought some of SWMBO's pressies on-line, plus a couple of items bought in one shop (on a pretext of looking for something completely different) whilst she was grocery shopping elsewhere. On-line excellent only if able to hide the delivery away from all seeing eyes, better is delivery arrives when she is out.

Managed to wrap all her pressies whilst she was out shopping (again) and hid them in a cardboard box in my shed - so she was in total ignorance of what I had got, if anything at all, and when. Only when I brought the cardboard box in - whats that you're holding? looks like a cardboard box dear, just a moment whilst I lock the door and I'll check, yes dear, it's definitely a cardboard box I'm holding here, said all Basil Fawlty-ish - did she twig I had got her stuff.

Bonus arrived Christmas Day when she was delighted with all her stuff, as I was with the ER collet set I got that I had thoughtfully suggested would be good to have........... One has to work the system to one's advantage........!

Chris

27/12/2017 23:52:54

Having a tee-shirt which declares me to be a Founding Member of the Grumpy Old Mens Club, I am one with the feeling of SOD; my family are quite used to my Bah Humbug approach to Christmas.

But I do not hate Christmas as such. I hate Christmas for what it has become. The whole message and magic of Christmas has been lost. Children getting bigger and bigger more and more expensive presents which the parents can't afford and the children expect but don't appreciate. Compare that with our youth when parents were hard up and we were more than happy to get anything at all.

Christmas adverts from end of August onwards, shops stuffed with Christmas goods for months before, compulsory Christmas music blasting from every shop for weeks, and then the shopping. Horrible. Hide in the shed time. Tons and tons of food bought, because we 'must have some of this' or 'some of that', how much goes to waste, must stock up as the shops will be shut for one whole day.. How much do we over-eat and drink? We buy as well bottles of booze that never gets drunk for ages, plus that bottle of 'whatever' that no-one drinks but we'd better get a bottle in 'just-in-case' cos Aunty Whoever drinks it and if she turns up'....

There is not this hype in France, or at least the part of Brittany we go to. Things are so much more calm, the lack of hype and great expectation means Christmas is so much more enjoyable, though still expensive!

Whatever happened to the message of Christmas, to peace and goodwill to all men? It has all ended up as one huge raid on my wallet, depriving me of essential workshop goodies and depriving me of essential shed time, that's what's happened to Christmas.

Bah Humbug to you all.

Chris

PS. When we moved to our present house 10 years ago some idiot had planted a Christmas tree in the garden years before which by then was 45 foot tall, give or take a yard or two. Dominated the garden, took masses of space and light, hid a beautiful copper beech tree behind it. Cost £400 to have it cut down, but well worth it. Beware, those thinking of planting this year's tree. Ours is a suitably plastic and fibre-optic jobbie, will give years of service, none of this £25 plus a tree rubbish you end up putting on the tip 2 weeks after Christmas Day - why clutter your house with it, shedding needles, why not go straight down the tip and just throw £25 in the skip and save the mess and wastage. Bah Humbug. My wife really loves me, this time of year...........

Thread: Single phase to 3 phase motor conversion.
23/12/2017 00:27:05

I have calculated the likely speed ranges, using a set ratio on the intermediate to spindle pulleys and just using the top, third and fourth down pulley sheaves on the motor spindle with a 3ph motor and VFD. This calculation showed that 100rpm spindle (quill) speed could be achieved by 20Hz on a 4 pole motor; in other words, plenty of torque for the vast majority of time, so a 0.75kw motor would be OK I think. On the odd occasion I would need more torque I will just have to take lighter cuts, which is my natural fallback anyway, so no problem there! Re the hole drilling, yes, further thought has suggested that if planned properly with some forethought then the work sequence is eminently doable with the kit I have, so another plus for the 0.75kw motor instead of a bigger one.

The regime I am looking at would see the belt on the intermediate to spindle being set for the vast majority or work and only the motor belt being changed, utilising the top, third and fourth pulley sheaves which are relatively easy and quick to change using two belts, one for the top and another for the bottom two sheaves, and therefore no worries there to do. Only very really do I envisage a situation where the intermediate to spindle belt would need to be changed. I have thought in the past of using a link belt to reduce vibration, but have not bought one yet to try; if I did I take note of the warnings to use the belt guard!

It maybe that I need to make another motor pulley sheave set and would tackle that when the need arose, but forewarned is forearmed and I will look at that possibility ahead of time I think. I do thank you, all who replied but Simon in particular, for the help and advice you all have provided.

Chris

Thread: HMS Queen Elizabeth: Leak found on new aircraft carrier
22/12/2017 23:50:07

Gees, everyone seems to be getting all hot under the collar about this story but in reality, no-one here really knows anything. All we have is a flimsy press report and we all know how dodgy they can be, in fact, generally are. The only people who know are the Navy boys and they are saying nothing. Six pages we have here, all on about something we all know nothing about. We must all be mad. Have we not got sheds to go and play in? Why don't we just leave leaks in warship to those who know a bit about them to sort out quietly and properly; we have better things to occupy our time do we not? Not as though we are blessed with unlimited time, most of us.

Chris

Thread: Single phase to 3 phase motor conversion.
22/12/2017 15:46:44

Simon, I have to agree that belt tightening is not very clever on these machines if yours and mine are anything to go by. The motor belt I can get reasonably tight by pushing hard on the motor whilst doing up the crude adjuster; that was an unexpected bonus of having to resite the motor to the RH side of the mill/drill. The top belts from intermediate pulleys to spindle pulleys are a pain - having to stand on a stepladder and slacken two socket head bolts, try and hold the intermediate pulleys with sufficient tension whilst tightening one of the socket head bolts is awkward to say the least. Your excellent belt tightener idea would be very useful on this section of belt drive Simon. I get a bit of vibration from the belts but very rarely belt slip, and I can see the motor is vibrating a little too. I am sure a 3 ph motor will not vibrate nearly so much and will run a lot smoother. A 3ph motor with a VFD will make changing that belt and re-tensioning a greatly reduced occurrence, as you have pointed out.

Do you find that the 0.75kw motor on low Hz, say between 10 and 25 Hz, lacks torque when doing meaty cuts Simon? Because with respect to motor size, my thoughts of yesterday are now back in for re-negotiation, and part of my worry is low Hz torque with the 0.75kw motor.

The motor that would fit without any alterations would be the 1.5kw motor (I'm looking at TEC motors). But that is double the original 1ph motor and maybe a bit of an overkill. The 0.75kw motor would match the power size of the original and would be way smaller physically, which would be nice, but would it have the torque at low Hz running speeds? The 1.1kw motor is more similar sized physically to the 1.5kw motor, would presumable give more low down Hz torque, but would need the mounting feet holes in the brackets altering, which would not be a problem if one had another drilling machine or has faith in the ability to drill 12mm holes accurately with a 3/8" electric drill and a 1/2" battery drill which is all I have available in the absence of the mill/drill; not insurmountable, just blooming awkward. Plus, there is a cost element to factor in, like the 1.5 motor is £37 more than the 0.75kw motor, a not insignificant sum.

So, I'm back to, do I go with 0.75kw and risk insufficient low Hz torque, 1.1kw and buggar about with drilling holes or 1.5 kw, overkill and £37 poorer? If money was no object it might be an easy choice in one way, but would it be the right one? Perhaps I need to speak to TEC after Christmas and see what their views are on running their motors on VFD's at low Hz are re torque. One thing I do like about TEC motors, amongst others, is that the feet can be relocated 180 degrees around the motor body to move the connection box to the best, or least awkward, place, which will help me and is not available on the 1ph motor fitted.

Chris

Edited By ChrisH on 22/12/2017 15:58:13

Thread: EN32B Steel
22/12/2017 14:58:30

The use of stainless steel shim suggested itself from a video on Tom's Techniques website when he was case hardening a small part. He wrapped the small part complete with case hardening material in SS foil which he got from some craft shop/website. I couldn't seem to source it this side of the pond and thought SS shim, I have it in various sizes to 6 thou, would do (not done it yet!). You do have to fold it over and over and crimp it best as can to exclude the air, and he recommends putting in the parcel a little combustible material to deliberately burn and consume the oxygen remaining in the ss foil wrapped parcel. Not sure how thick the shim would have to be, too thick and it'd be a swine to fold and crimp air tight, too thin and I suspect it might burn away in a really hot fire.

Now an article in MEW on building a simple electric furnace would be very interesting, so +1 on that idea Neil!

Chris

Edited By ChrisH on 22/12/2017 14:59:51

21/12/2017 22:16:14

Yes Duncan, that did occur to me after, and not a silly question. Perhaps it might have worked if I had covered it in SS shim, which I have, before placing in the coals, or if I'd been able to fabricate some means of holding it above the coal. That process not thought through before I went for it!

Both alternatives have given me fuel for thought for the future though. What it has proved is that in my stove I can heat a really considerable lump of metal up to red hot glowing temperatures and hold it for a while, hours, if necessary, which I didn't think I could do, so that is progress in one direction. I had sort of given up on the lump anyway really. Now I know I can do it, the next stage is refining the process to get it to work for me, whether either annealing or case hardening. Wrapping an item in SS shim packed with carbon of whatever extraction and 'cooking' it in the fire or arranging a removable rack to place objects to be annealed or case hardened on is a reality to explore! Quite like the rack idea.

Had I an electric furnace all would have been easier but I don't now the money to buy one, even if I had ever seen one advertised which I haven't, like where do you scource cheap electric furnaces except perhaps ebay?

Chris

21/12/2017 19:59:01

Ooooh errrr! I had chance yesterday for shed time, so lite the fire in the shed stove, got it going well on smoke-less, chucked the tool holder with the hard bit in, threw some more coal on top, saw it a wee while later all - including the metal - very much glowing nicely (very) red and left it to burn through and cool down overnight. This morning I pulled the metal bit out the ashes and; Oh my word, I didn't expect this: - see photos below.

I chipped all the scale off and revealed what could be expected - the metal underneath was very rough. Set it up in the mill and tried a facing cut off one side with a flycutter and promptly blunted it, so, unwilling to sacrifice another milling cutter it now looks like I have another useful door stop. Another item now on the next metals order!

Chris

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Thread: Single phase to 3 phase motor conversion.
21/12/2017 19:40:59

Simon - your response was just the sort of response I was hoping to get, someone who had been there, done it, and was happy with the result. Sounds like you got an 80 size frame motor of 1kw which is where I was thinking of heading; on reflection I think maybe 1.5 kw would be overkill.

Having got a similar set up on my lathe I am both familiar and pleased with the soft start and controllability. I agree with others that a larger motor should/will give better torque at low end speed and hz, which will be good.

One query Simon you will be able to answer I hope, is the 3 ph motor a smoother running motor? I am hoping so, the 1 ph motor on the machine now vibrates a fair bit I think, and this seems to transmit via the belts into the whole machine and I don't like that at all.

Chris

21/12/2017 10:29:27

Brian has a point but a smaller physically sized motor does have an advantage for me even though it means a couple of alterations for the foot mounting holes on the motor mounting bracket, as the machine is up against a wall behind it and I have had to relocate the existing motor already to sit to one side of the machine instead of behind as otherwise it wouldn't fit in the space available.

However, my greater concerns are with the power size, do I stick with 750w (which from Robbo's comment seems to confirm the existing size as stated on the motor) or go to 1.1kw or 1.5kw and the implications of possibly better torque at low revs/hz?

Chris

Edited By ChrisH on 21/12/2017 10:31:14

20/12/2017 20:09:58

My old Warco 'Economy' mill/drill has a single phase motor. It says it has a 750W motor, but the nameplate is also stamped 6.5 amps and a 90L - 4 frame, both of which suggest to me in my ignorance a 1.5kw motor. However, I don't have the original manual to check what it was sold as but have a Grizzly download manual of the same machine - all versions of the RF 25 I think - and that states a 1 HP motor, which is of course the real money equivalent of 750w. Confusing!

In the general scheme of things that would be a no worries situation if I didn't want to change things; however, I want to change to a 3 ph motor with a VFD inverter.

So what do I get? Looking at TEC motors, I could go for a 750w motor, a 1.1kw or a 1.5kw. The 750w is an 80 frame, the 1.1kw could be either a 80 or 90 frame and the 1.5kw is a 90 frame. Plus there is obviously a difference in cost for each power size. I forget what the advantages of a 3ph motor has over a 1ph motor has on power requirement, perhaps that can indicate a direction to go. An 80 frame would obviously have advantages in space requirements as well as cost over a 90, but a bigger power would perhaps have advantages in torque when running at low Hz (low rpm) settings from the VFD.

What do people think? Those who have done it, why did you go the way you went and did it work out well?

Chris

Thread: EN32B Steel
19/12/2017 18:37:08

Clive - I did say it was tongue-in-cheek, it was playing with letters to achieve a comment. I am aware of the origin of EN numbers.

What would be good is some standardisation of what all suppliers call each product. Some will say EN1A, others will only answer to 230M70 for example, both are arguably the same product.

I also appreciate that odd hard bits can and do get found in all sorts of types of steel at random intervals and that the problem is a very old one. I can never legislate to avoid ever getting a bit of steel with a hard bit in it, but I can try and ascertain what other folks do to get round the problem and use that knowledge to help myself deal with the problem when I experience it, which is what this thread is all about.

Chris

Thread: HMS Queen Elizabeth: Leak found on new aircraft carrier
19/12/2017 18:14:46

In the merchant navy they years ago gave away the idea of a wood lined tube, lubricated by sea water, sealed by a packed gland to keep most of the sea outside the ship, to support the prop shaft as it exited the ship. They were replaced with (very well) sealed tubes containing a totally oil filled bearing under a considerable head of oil. Therefore absolutely no sea water through it at all. If sea water was leaking through that shaft bearing and seal you were definitely in the mire! Hope this is not the case here but suspect so.

Chris

Thread: Steel plate distorting when machining surface
18/12/2017 23:39:05

Re Jason's comment "Better to remove the scale by pickling in acid" - what acid?

Would citric work or does it need something much stronger?

Chris

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