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Member postings for Simon Williams 3

Here is a list of all the postings Simon Williams 3 has made in our forums. Click on a thread name to jump to the thread.

Thread: Restoration and modifications to a Tom Senior light vertical mill
03/01/2019 20:44:55

Well, nothing venture nothing gained, so I have stripped the table off the cross slide, and suddenly all becomes crystal clear.

dsc_1632-1.jpg

Somebody had a major crash (tip over?) and broke the lead nut out of its casting. Somebody else devised a simple fix - put the lead nut in the other hole. What I have been seeing is the consequence of moving the lead nut 7 inches or so to the right.

Here's a closer view of the site of the break.

dsc_1633-1.jpg

Which strikes me as relatively easily fixed, though I do need another milling machine to make a flat area each side of the original bore for the nut. I can then make a half clamp and clamp the half nut back where it belongs. I'm toying with whether I can do this with my horizontal mill, don't see why not with a bit of patience.

However the interesting part of the riddle remains, as I believe all the parts are original. There is a number 14 stamped on the main column above the s/no, and the same number is on all of the bits of the knee, including the table and the gib strip. So I'm lead to think that all the bits are there, but not necessarily in the right order.

Keep you posted!

Regards to all

Simon

03/01/2019 19:10:28

Hi Miles, Ian

Thanks ever so much for your time and encouragement - Ian if you can easily take a photo or two that would be brilliant but please don't go to too much trouble as I think I can see what has happened (what has not happened) here. That second photo (Ian's post at 18:18) and Miles 9 inch measurement explain everything.

I'm out on the road tomorrow, but there's a sudden attack of enthusiasm on the horizon, as I think I see the answer to something which has been piquing my curiosity for years. It never made sense to me that nearly half the table was out of bounds, and now I think I understand why - and even better what to do about it,

I'll whip the table off tomorrow when I get back and see what it reveals. Keep you posted!

Best regards Simon

03/01/2019 17:20:06

Hi again Miles, thanks for the additional info. My leadnut certainly looks like it belongs where it is! But there is certainly something odd going on here., and I'm starting to wonder if the thing to do is to remove the table and take a photo of the knee. I still think the basic problem is that the leadscrew should be threaded for its full length, which is where I started. and maybe that's something to do with fitting the long table on the original design of knee. With my knees (now there's another story) sorry knee the lead nut is inside the right hand side of the casting by 2-1/2 inches. I'm guessing that the knee for the longer table has the nut well to the left to give the extra travel and I'm beginning to see this as an easier mod' to do than making a complete new lead screw. I feel a project coming on.

If you do take yours off during the course of your refurb' please take a picture and maybe we can compare notes.

Best rgds and thanks again for your help.

Simon

03/01/2019 16:36:16

Hello Miles, thanks for that. I've completely changed my theory that mine is a late model, as the serial number is V3485, which puts it off the scale into prehistory. I'd assumed given the 28 inch table that it was later rather than earlier, but who knows, maybe that isn't the original table!

The other revelation is that the table movement is 13 inches (12-7/8 actually) not 15, let alone any more. The stop going towards the right is the leadscrew tail bracket contacting the knee, the stop going left is the leadscrew running out of thread. Travel going right isn't the issue for me, the cutter is just about over the left end of the table by the time the movement stops anyway, but I don't understand why the right hand area of the table is out of limits, for the sake of cutting a thread the full length of the lead screw.. But your leadscrew appears to be the same so I'm assuming that's how Mr Senior meant it to be. Odd or what!

Oh, and I tried your trick with lifting the left hand supporting bracket, it's already high enough it isn't the problem as it passes the first recess anyway.

Best rgds Simon

03/01/2019 15:10:04

Hi Miles, well I can confirm that mine has the 28 inch table, and the view of the screw looks exactly the same. But where is the serial number?

Best rgds Simon

03/01/2019 12:07:21

Hello one and all, and best wishes for a Happy New Year.

I've got one of these little beauties, and I have moved the ram probably twice in the last ten or fifteen years. But it all depends on the size of work you want to get at.

A more significant restriction to me is that the X leadscrew isn't fully threaded. As a consequence there is an area about 12 inches wide at the right hand side of the table I can't traverse under the head. Is this the case with yours?

I've been considering remaking the lead screw to improve this, but it's a lot of work and I haven't yet summoned up the courage to cut my first ever square thread. And it's metric, my lathe has got an imperial leadscrew.

However I'm really curious to know how many speeds your mill has got. Tony Griffiths' archive says these had 5 later six speeds, I reckon mine is a fairly late model but it only has four speeds selectable by moving the drive belt within the head.

The modification I did carry out after a lot of thought was to change the bearing supporting the driven pulley atop the quill to needle rollers. The original bronze bearing was pretty poorly so I needed to do something with it and decided to go for gold. There are pictures in my album of the results.

All the best Simon

Thread: Measurements from the past
31/12/2018 21:56:01

And then there is the circular mil, which is a unit of area used as a measurement of wire diameter. IIRC one circular mil is the cross sectional area of a wire 1/1000 of an inch in diameter, and thus is equivalent to 5.07 * 10e-4 mm2. Beware of the confusion abounding when the author means circ mil but writes mil

Happy New Year!

Thread: Bearing puller from hell
22/12/2018 17:21:31

Good evening gents, and ladies as well.

I've been playing with this for some while, having bought a cylinder (ram) and hand pump from a car body straightening kit. I haven't adapted it for bearing pulling as yet, as I want it for pushing.

dsc_1627-1.jpg

It's shown here with a simple folding attachment. It's essentially two cheek plates in 10 mm MS plate carved out with the gas axe, with 50 x 25 cross spacers in BMS, threaded each end for M12 HT bolts. The top spacer got bent fairly quickly because there is a gert hole through it into which the nose of the cylinder fits (threaded) so it has been reinforced. The cylinder is single acting - i.e pressure extend, internal spring return.

However I have discovered that the working pressure is the key to having something useful. Hydraulic steering on cars mostly seems to work sub 1000 psi, agricultural tractors auxiliary hydraulic service is typically 2000 psi max, this simple hand pump works to about 5000 psi on a good day, the Enerpac proprietary system works on 10K psi. With 10,000 psi you can break things, but the hand pump is a useful compromise.

My experience is that you need the pressure to get the urge.

Season's Greetings one and all

Thread: My ford lathe problem!
22/12/2018 11:00:27

Good morning John, if I remember right this is a blue cam switch, with a three position knob on the front of a silver fascia plate. I've just tried to lift a picture out of the K & N catalogue but it only comes as a pdf which I can't put in an album.

It's some while since I had one of these switches to pieces, but I think that the detent mechanism is behind the switch fascia, There is a nylon cam and a spring which controls whether the cam mechanism stays put or returns to centre or what, and it sounds as though this has failed or got worn out. Whether it is repairable is a whole different can of worms.

Don't take the black switch body to pieces - there is any number of little bits of brass and things hiding in there waiting to jump on the floor.

If you want to have a go at the detent mechanism take the knob off the front by loosening the little screw in the centre of the knob, don't undo completely it's only a clamp, then pry the silver fascia out of the black surround at the front of the panel. This exposes four screws which mount the switch to the panel. Undo them and push the switch body off the back of the panel. Now you should be able to work out how to take the front off the switch cam to see the detent mechanism. The down side of this of course is - quite apart from the intricacies of getting to this point - it may not be obvious what is missing.

Last time I tried this I managed to get it to bits but gave up trying to put it back together, I needed more hands than an octopus. You'd be better off buying a new one, but be careful to specify the right thing as they all look the same on the outside, but the arrangement of the internals is crucial. I think City Electrical Factors are agents for K & N.

Alternatively this looks like the right thing, **LINK**

and at least you know where you're starting from. I would think you want the 2 pole changeover for a single phase reversing switch so that looks like option CO202 (20 amp 2 pole). It may not be obvious how to connect the new switch to the old wiring, it should come with a diagram which describes what to do.

Good luck, and all the best Simon

Thread: Insulation tester - some guidance please
20/12/2018 22:14:16

If I remember it right, the IEE Wiring reg's say the test source for testing insulation of low voltage equipment energised at 230 V AC must provide not less than 500 volts DC into a load of 1 megohm, other loads pro rata. Sorry gents but I don't think your windey Meggers do this.

I take Phil's point about liking analogue meters - I happen to prefer my digital, but it's horses for courses. However I can't let the assertion that a simple multimeter is sufficient to prove the equipment is safe to energise go unchallenged, the Regs say otherwise. By all means go looking for a fault with a DVM, but the testing to prove that it's safe to plug it in to the mains has to be done at an elevated voltage. Phil's right, all you often need to find there is a fault is a sense of smell!

The use of 5KV (flash testing) would only be warranted if the equipment was being re-designed or modified, or there was some reason to believe that a simple insulation test was insufficient. Or you've got a particularly difficult customer!

Mince Pies out for Santa + 4 days!

19/12/2018 23:32:31

FYI measuring something with an ohmmeter and getting a varying reading is absolutely typical of having water in the circuit. Did I mention you need an insulation tester?

Seriously this is very much an example of where the high test voltage of a "Megger" (other makes etc) gives you an answer you can believe. With the high test voltage of a proper insulation tester you will (probably) get a more repeatable answer, though of itself the fact that the measurement is not constant indicates that the equipment should be withdrawn from service, even though the range of readings is otherwise acceptable.

Seasons Greetings to one and all

Simon

19/12/2018 23:05:45

If you want to know if a piece of equipment is safe to energise the insulation tester is the kit to reach for, as a low voltage resistance test using a Fluke DVM as an ohmmeter doesn't cut the mustard. Other makes are available. Quite apart from the regulations, you need that high voltage for the test to be a valid representation of the real life energisation using mains supply. So while the insulation tester isn't the most frequently used bit of kit an anyone's toolbox, when you need it, you need it.

The same goes for the continuity tester. A simple ohms check won't pass 20 mA (the specified minimum test current through a short circuit) through the earth continuity conductor, and won't find loose screws, oxidised connections and the like.

So it's a specialised gadget for a very specific purpose, being the final checks to confirm that an appliance is safe to energise. By all means do the best you can with a digital ohmmeter but bear in mind these are not representative tests of the satisfactory state of the appliance, and if you are taking responsibility for someone else's welfare (don't we all?) the tests had better be done in the approved fashion.

Don't agree about digital vs analogue, digital is much more robust, holds its calibration better, is at least one or maybe two orders of magnitude more sensitive.

Testing stuff with semiconductors exposed to the test voltage is a whole different ball game, well beyond the scope of the casual user. The possibilities for ending up with a piece of equipment which you know is safe to energise but now needs repair are endless.

As Phil has it above, if you are testing motors and heaters, an insulation tester is going to be essential, not least because it's the absolute first question anyone using the equipment should (will) ask. Has it got a valid insulation test? Second question is what is the earth continuity conductor resistance. Without confidence in the answers (for which read sight of a valid test certificate for the measuring instrument) cut the plug off.

HTH Simon

18/12/2018 19:53:17

If I remember my IEE Regs correctly testing domestic circuits normally energised at 230 volts AC is to be done at 500 volts DC, three phase industrial circuits subjected to 400 volts (line to line) is done using the 1000 volts facility. You might not need the latter but most instruments will offer the facility - they'd be no use to a commercial electrician if they didn't. Which kinds of begs the question of the quality of an instrument which doesn't offer the facility.

Insulation testing is about whether the appliance under test will kill you or not, and the same goes for the continuity tester which will likely be part of the same instrument and which performs an equally important test. At least with a calibration certificate in your hand you know if the information acquired from the measurement can be trusted.

As Emgee notes, if we could have some idea of your intended use for such measurements we could offer better relevant advice.

Seasons Greetings Simon

Thread: Change of direction a single phase capacitor run motor
14/12/2018 12:05:34

Sometimes you can do a mechanical swap by taking the rotor out of the stator, and replacing it back to front, then fitting the two end bells opposite way round. I did this for a motor where the wiring wasn't accessible though it does rely on the rotor having the same size and type of bearings both ends.

Season's Greetings

Simon

Thread: It's not rocket science
12/12/2018 23:03:37

they were not mole grips, they were metal shears to cut through the aluminium meteorite shield.

Used with a bit of Gilbow grease no doubt...

Thread: 3 phase vs single phase
08/12/2018 13:52:52

All joking about tumble driers aside, the OP has raised an interesting question regarding the relative efficiency of single and three phase motors.

Given that a single phase motor is a fairly nasty electrical load, but a three phase motor on a single phase supply suffers the conversion inefficiency of the VFD, there's likely not much to choose between them in terms of converting cost of electricity into work done.

Does anyone have any in situ estimates of the actual efficiency of power out over power in for the sort of size motor (1 - 3 HP say) we are likely to encounter in a home workshop?

Best rgds Simon

08/12/2018 11:07:24
85 quid is about 300 hours running, so that's a month of 12 hour days. You don't need a smaller motor you need w holiday
Thread: Myford ML7, or Colchester Bantam/Boxford model A easiest to use?
04/12/2018 17:04:46

Buy any of them, they're all beautiful, especially if you don't have a lathe at all.

But there are pros and cons. For myself I can only sensibly offer an opinion for the Myford and the Bantam, as these are the machines with which I am familiar. Even that isn't entirely accurate as the Myford is a ML7 not a Super Seven.

I have two friends with Boxfords, they love them. I bought a Mark 2 Bantam to replace my aged Myford S7 because that was what I found on the market at the time. Needless to say I still haven't quite got round to selling the Myford - it still serves a turn and although I'm always struggling for space I'm still attached to the S7 and can't quite bring myself to dispose of it.

The Bantam in the links above is an early Mk2 so it has 5.5 inch centre height, not the 6.5 inch centre height of the later ones and of the Student. It looks a bit green in the pictures, but that's the lighting. The advert says its a good specimen - only one way of testing if they are telling the truth, go and see it. If it's not been bashed about it will be a nice machine, easier to use and more robust than a Myford, but accessories are like hen's teeth. Trying to find fixed and travelling steadies - certainly at any sensible prices - well you'd be better off starting a unicorn breeding centre. If you want to do milling in the lathe this isn't the place to start. Beware of buying changewheels for it, they seem to come 16 and 14 DP and I've never found out why - obviously you can't mix and match.

But the real reason for posting this is to introduce my experience with using the Bantam on a single phase supply. Initially I simply swapped the original motor for an approximately equivalent single phase capacitor start motor, but I was very disappointed by the crash start this imposed on the gear train, and converted it back to three phase with a VFD. This gives the advantages of speed control but also soft start which just works quietly and is docile and a pleasure to use.

In the process, I have forfeited the higher range of speeds. The basic Bantam is a 800 RPM top speed machine (the later one goes to 1000) with the motor running at nominally 1400 rpm, and the higher speeds are driven by running the motor at 2800 rpm. The original motor on mine was a two speed motor, with two separate sets of windings and the control gear included a multipole switch by which the motor speed was controlled. All very well, but this motor did not have a star point brought out the terminal array, so I ditched it because I couldn't connect it in delta to be compatible with 230 volts three phase derived from a single to three phase converter (VFD). Knowing a bit more about it I now know you can often "find" the star point and re-configure the motor for delta, but it's too late as the motor got lost in the last factory move.

So I get the higher range of speeds by over-speeding the motor - I.e. running it at 100 Hz, at which it struggles. But for almost all of what I want to do the four pole 1450 rpm motor run at 50 Hz is the bees knees, and it's not worth the cost and aggro of experimenting further with it.

Conclusion - running a three phase motor on a single to three converter is easily said, but think it through first.

Hope this helps, I do go on bit so I'll stop for now, if you want to know more post a reply and I'll develop this further.

Thread: Turning Welded steel
01/12/2018 22:38:45

 

 

 

A 6013 rod should be machineable straight off the arc, hot or cold. Having said that I hate ESAB 6013 rods and won't use them, simply because whatever the blurb says for position welds with this rod I can't help but get slag inclusions in the weldment. I've been using Oerlikon 6013 rods for years and never had this problem but (other than incompetence on my part) I don't know why the difference is so pronounced. Fincord M is a lovely docile rod, try it and marvel.

The "rutile" descriptor refers to the composition of the flux, which - as we all know - never ends up in the weld metal (ho ho!). If you google rutile you will see an explanation of what it is, and how it does what it does. Rutile is simply a mineral, with a complex composition which happens to make a nice flux coating for MMA. The presence of some manganese (for example) in the rutile doesn't affect the metallurgy of the weld metal, as the flux isn't incorporated into the weld pool. The composition of the weld pool is governed by the parent metal and the composition of the added weld metal from the rod core.

I doubt that the scaffold tube is anything other than mild steel, certainly it shouldn't have enough carbon (or anything else for that matter) in it to upset its machineability after welding. For this reason the idea of annealing post weld is irrelevant. If the weld is hardened by cycling through the weld zone there is something wrong with the metallurgy of the base metal. It's vastly more likely that the hard spots are slag inclusions.  A good guide to this with 6013 or similar is that the slag should fall off the weld as it cools of its own accord, if you have to do more than scrape it to get it to let go then the slag is contaminating the weld.

Please steer well clear of welding galvanised stuff, even grinding the coating off isn't guaranteed. I've had Zinc fever (no it'll be OK!!!). Never again. Oh, and zinc contamination will cause slag inclusions, it doesn't burn off completely, some of it gets trapped in the weld pool.

Damp rods (for damp read "not absolutely bone dry" can also cause slag trapping, but rutile is pretty tolerant of moderate damp and the act of passing a current through the rod to use the first inch or so will heat the rest of the rod up so much that any residual moisture is vapourised. Still, it's good practice to put the rods in the oven for an hour at 150 C or so immediately prior to use. It's also good practice not to let them get damp in the first place.

After that, you need to think about welding AC or DC, and polarity can also make a difference., But for my money all of these tweaks are missing the point, this is ESAB syndrome. They may be very good in expert hands, but I'm not that person and I like the results of following the gospel according to Oerlikon.

And, as ever and for the avoidance of doubt, I have no connection with Oerlikon, I'm just a satisfied user.

One last thought, if the rods were at all oily you're on a hiding to nowhere.

Good luck, HTH

Simon

Edited for yellow face eviction

Edited By Simon Williams 3 on 01/12/2018 22:47:35

Edited By Simon Williams 3 on 01/12/2018 22:49:38

Thread: Colchester triumph 2000 driving me crazy
29/11/2018 19:26:08
Posted by Frode N�stad on 29/11/2018 18:06:50:.

**LINK**

That's all very well, and I can buy it for a new lathe where the bed is straight and true, but bolting the tailstock on the bit of the bed which is nearest the chuck (on my worn lathe) is likely going to set it low. Having "trued up" the tailstock bore to that low position moving the tailstock to the end of the bed will set it high.

I recognise that this makes assumptions about the state of the bed, but that's my point, this does exactly that. Moreover if the axis of the tailstock is high there's nowt you can do to fix it, at least if it's low (which is where we started) shimming it will let you choose a workable compromise. It's laborious, but I'm going to have to find an optimum position by repeated settings and "home in" on something which is optimum.

Which is more easily said than done. I've managed to measure the out - of - alignment but only in one position of the tailstock on the bed. Measuring it over a range of positions (and making sense of the measurements) is far more difficult, and I wouldn't commit to cutting metal on the basis of some measurements I was unsure about.

It also occurs to me that the boring bar as per the video above isn't necessarily following a straight line path. If the bed is worn the saddle moves in three dimensions, and you could be boring the tailstock in a very odd direction.

So a reversible adjustment - either twiddles or shims - is a lot more attractive as I might actually make an adjustment without being too frightened that I was making it worse.

I'm looking forward to seeing how this could be done.

Best rgds Simon

Couple of edits to make my logic more logical

Edited By Simon Williams 3 on 29/11/2018 19:30:33

Edited By Simon Williams 3 on 29/11/2018 19:33:34

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