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Member postings for mgj

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

Thread: Lathe for Beginner
24/08/2009 23:19:50
Dave I'd earnestly advise getting all the features you can. While you start you don't have to use them. But, later, when you haven't gottem and you wantem - youm knackered!
 
If you take my meaning.
 
 I doubt an ML10 would be too much worn. Unless a model engineer actually abuses something, a model engineers lathe is unlikely to be inaccurate. Badly set up possibly, but actually inherently inaccurate, probably not
 
How old is old? I have a Super 7 B. Its rising 30 years old, and its absolutely spot on - much better than a thou per foot in taper - but then one false turn of a spanner on one jacking screw and it would be so curved it wouldn't see Xmas.  So before you do or don't make a decision on a machine, its worth getting a good look at it. 
24/08/2009 18:01:39
You said "For a start..".   Does that mean that later you want to go bigger?
 
The problem being that a lathe is just the start.. You make a lot of tooling, buy more, and in  reasonably short order you have a very considerable investment in one machine,  and you have to do it all over again, if or when you trade up.
 
 
Also, you can, within reason do small work on a big machine (depends relatively, how small and depends how big), but doing big work on a small machine is impossible.
 
Doesn't matter what sized machine you have, you always want bigger at some stage.
 
Just a thought, ...and you have to strike a balance somewhere..
 
(There is someone at our club who turns out very nice 5" gauge stuff on a Myford ML10, which is not a lathe you hear much about these days. Pretty compact, and you could I'm sure do some very good small stuff on that too. Might be worth looking at if one as available. 

Edited By meyrick griffith-jones on 24/08/2009 18:05:00

Edited By meyrick griffith-jones on 24/08/2009 18:07:30

Edited By meyrick griffith-jones on 24/08/2009 18:07:45

Thread: Annealing copper tube.
22/08/2009 18:41:08
Thank you. Just never had to do copper before. It's just to take out any work hardening from the process.M.
22/08/2009 11:54:10
This is just annealing copper tube so that a TE backhead can be plumbed in.
 
What is the process and when do I know its hot enough?
 
I have a torch and a small hearth, so getting it up to temperature shouldn't be a problem.
 
It's just the detail I need please.
Thread: Metal filler?
21/08/2009 18:00:18
Devcon Chris - that's the stuff. Exactly that. I used the Ali loaded stuff and its really good. Doesn't slump either - you can pack a hole or build up an edge and it stays put.
 
Like all ali work, it benefits from a good preparation - a good scrub with a CLEAN stainless steel wire brush as soon as possible before application. But thats true of doing anything with ali to beat the speed of oxidation.
 
Thanks also too to Buddy who pm'ed me with the name Devcon too. He mentioned that it's aircraft grade, which I didn't know, but says something for its quality.

Edited By meyrick griffith-jones on 21/08/2009 18:03:55

Thread: Movable lathe
20/08/2009 20:57:19
Are you sure its such a good idea?
 
I'm no expert in the mounting of machine tools, but my understanding is that you will need to shim under the machine to get it to sit dead straight and turn straight. In order for that shimming to be effective, the stand needs to be bolted to the floor, or else there is nothing to lever against. 
 
So the classic mounting arrangement is to lock the base down to the floor with some kind of damping material in between (high density cork being one of the best - and the best according to Tubal Cain is a thick bed of marine play). Then you shim, or otherwise adjust jacking screws to take out any taper.
 
So if the thing is on casters, or continually being moved, and not on a dead level surface (which a garage floor is not), how is the proposed system to allow the lathe to be set up properly and to within fine limits? - if that's a concern. 
 
 
 
 

Edited By meyrick griffith-jones on 20/08/2009 21:01:21

Thread: Really useful?
20/08/2009 17:56:29
Or perhaps the little GHT retracting screw cutting toolholder  I was given. Made beautifully by a very good friend, his daughter gave it to me when he died.
 
Not a general use tool, but it really makes screw cutting easy. 
 
That's a nice one to have.
 
The list does go on.
 
Chris - the DRO is lovely. Most most impressed with mine, especially the centre finding capability ( zero one edge, zero far edge, press the 1/2 button and just wind back to 0) but thats not a cheap item. Thats the kind of second hand old thing that needs to have a nought off the end of the price when it comes to declaring it in the kitchen. 
Thread: Metal filler?
20/08/2009 17:39:02
There is and I can't remember the name.
 
We used to use it racing to repair cylinder blocks. , especially where the water exiting the water pump used to gouge out a big cavern in hte base metal. Very tough, and machinable and threadable, being a metal loaded epoxy.
 
It is properly mixed (loaded) with ali, or steel depending on the type.
 
Grey box red band, quite firm - unusual cream coloured catalyst.  Sod to mix up - brilliant result.
 
Anyone remember it ?
Thread: Really useful?
19/08/2009 23:22:40
Just as a matter of interest, I was wondering what people might think was the best/really useful  small tool they have.
 
Yes, mills lathes you have to have, just to be in the hunt, and there's other larger items that you need at some stage.
 
Some relatively cheap or constructible item that one says "I'm really glad I got one of those?"
 
for me there are 2.
 
1 The GHT versatile dividing head, because its not just a divider and indexer. For the Myford  (3 1/2" lathe) owner it is one of the most useful centre finding, cross drilling, slot milling without pain work holders you can get. As well as an excellent dividing head.
 
Paid for itself - oh yes. Try getting a set of 3" traction engine  gears cut professionally! (Bit of a stretch getting a 9" gear on it - but then it is versatile!!!)
 
2.  The optical centre punch form Chronos/Axminster. Oh wow, does that not transform marking out? all of a sudden you can step measurements out with calipers/dividers, centre pop them and be sure two plates will fit accurately, and all the bolts will go through right first time. .2mm clearance - no easing. Super little tool. Wish I'd got one years ago - even before I needed specs..
 
 
 
 

 

Edited By meyrick griffith-jones on 19/08/2009 23:24:17

Thread: Metric vs Imperial - Practical or Traditional?
19/08/2009 18:28:43
Ah well - once you have that metric changewheel, you got it made!!!!!
 
BUT - have you seen a metric thread dial indicator - 3 different pinons, and however many lines and a whole darned chart, just for a few mouldy European threads. 
 
I rather like the 4 line Imperial job. Any line for multiples of the leadscrew, and opposite pairs for even numbers. Not bad for an illogical system.
Thread: Hss or Carbide Tooling?
19/08/2009 18:17:25
Ian - I agree totally.
 
A Quorn, for most (including me) is total overkill. Like I said, back in the early 80s a Quorn or a Stent was about all you could get. But, having got one, I find I use most of its capabilities(including oh cheapskate!!) resharpening carbide tips with a green grit wheel!!! So I'm very glad of it and I wouldn't get rid of it.
 
I've got Harold Halls book and his sharpening jig looks pretty good.
 
Were I to go the HSS route again, I think I'd get the Eccentric tool holder because that gives you a good turning tool and  both  55 and 60deg threading, and the appropriate sharpening jig. Next some kind of reasonable drill sharpener. Pretty much anything else is likely to be a one off and one can hand gind, unless you have very specific purposes in mind.
 
That would do 95% of any model engineers sharpening to a good standard.
 
Like all these things, its 90% of the result for 50% of the effort. If you want to be able to make reamers, or proper radiused cutters, or sharpen the edges of endmills then one has to think again. (and I do because it saves money and I can - but only because I can).
 
I also think that a lot of the need for a Quorn type cutter grinder has disappeared - if you want to pay the price. We have inserted tip milling cutters, threading tools. FC3 throwaway cutters etc. Of them all, the only one which is IMO a must have, is a tipped parting tool, because Quorn or not, I have never met a parting tool which matches the Sandvik tipped jobs (Greenwood, Sandvik etc)
 
However,  I would disagree with  those who reckon one can offhand grind HSS really effectively. Because one simply cannot.. And once one has used one of these decent grinders/jigs you know that to be true.
 
So its just a matter of how far down the route you want to go - but for sure, some way down it is essential.
 
 

Edited By meyrick griffith-jones on 19/08/2009 18:20:24

Thread: Metric vs Imperial - Practical or Traditional?
18/08/2009 20:17:45
More like £4.50, and that, even to this bunch of tax hiking, pension grabbing fiends is £4/10/0d which  they ain't earned but don't stop them spending.
Thread: Hss or Carbide Tooling?
18/08/2009 18:36:03
Depends on how you view it !
 
The tool and cutter grinder doesn't have to be a Quorn - that was one of the few around at the time. 
 
However, what became clear to me was that decent tooling was a must and I was never able to offhand grind a good tool every time.
 
I built the Quorn so I could sharpen tool accurately so I could build an accurate mill (the Dore Westbury.)
 
Any sharpening jig is worth the investment. Where a proper cutter grinder paid ( and this cam as a sort of accidental discovery) was in the sharpening of drills, making radius cutters that worked first time and so on.
 
You don't have to sharpen many  1/2 drill bits, or slot drills, or 3/4 3MT shank drills to make your money back.
 
I know also that some say they can sharpen these drills free hand. Well there is sharpened and sharpened. And there is also cutting dead straight and to dimension. If that is important to you, Ok, build a Quorn or Stent or Worden. If its not, well thats fine too.
 
It's just two different points of view - but I wouldn't sell that Quorn!.(And since I have one, I don't need to make another)
 

 
 
 

Edited By meyrick griffith-jones on 18/08/2009 18:38:27

Thread: Metric vs Imperial - Practical or Traditional?
18/08/2009 18:10:38
Am I not right in saying that the metric pipe thread is actually BSP? Many metric cars actually use 3/8 UNF on brake fittings.
 
And the dairy and food industries, who sell their products in grammes and kg,while using a few SMS and DIN fittings, mainly use RJT. Which are imperial.
 
And the US who still use some imperial (but different in some respects from ours) have a military who have metricated. 
 
When you buy a car, do you want to know how many kw it has, or do we not all think proper horsepower. Thats decent SAE BHP horsepower, not some DIN european fakery type rubbish. 
 
There is no more logic in metric than imperial surely? Things happen per unit distance by unit time/area etc or whatever.  People argue that with all to the base 10 its easier. That is so on hte face of it, but start converting from kg to newtons, or using gas laws and constants, or aerodynamic functions. In no time at all you are into "illogical" figures, simply because the physical world is like that. Nowadays with computers or calculators, whether you multiply by 9.81 or 32.2 is really of no consequence.
 
People argue about dropping the decimal point somewhere with metric -well yesssss. but then the lbs to lbs force and back is to me a lot more dodgy.
 
So doing engineering calculations I prefer to work in metric.
 
And when munching metal I think in thous and inches. And mostly use metric fasteners for convenience, and metric drills too.
 
 
Who cares- at the end of the day its only a figure on a dial, either way.
 
As for tooling in inch sizes - well there is a lot of stuff that uses them. No one will change a system of tool holders for some CNC machines. Nor will I buy 6mm tool steel, when all my little holders are 1/4". So hopefully good christian units will be around for a long time to come. 
 
Then we can all use what we want
 
 

Edited By meyrick griffith-jones on 18/08/2009 18:11:20

Edited By meyrick griffith-jones on 18/08/2009 18:18:44

Edited By meyrick griffith-jones on 18/08/2009 18:20:09

Thread: Coolant
15/08/2009 16:36:18
I use Morrisons Unison Edgeplus, which isn't smelly at all. It stays as an emulsion pretty well.
 
For what its worth, I was told always to add the water to the oil - or the other way round. Apparently its important!
 
The trick to stopping the solubles from going off is to circulate them.
 
The big lathe has an agitator paddle on the coolant pump spindle - that stuff never goes off. 
 
The tanks which do the big mill and the  other two bits of kit don't have agitators, and the oil used to be inclined to separate after  a bit. I solved that problem by circulating the coolant. When I go into the workshop, I turn on the pumps for half an hour or so, even if I'm not using the machine. Problem gone -  it doesn't go off.
 
The problem to fix is actually an oil skimmer to collect up lubricating oil - I daresay I'll get round to building a little weir trap one day! And I'll attach a little agitator blade to the 2 untreated spindles.
 
I have to say that I have never used the neat stuff - the soluble works well for me. Doesn't rust or stain the machine, and is cheap (Very -  diluted at 20-1!) I can't be doing with a dab here or there with a brush - done that, trying to turn and cool with three hands. Parting benefits from a decent jet. Milling even on the lathe one needs a bit of a jet to clear the chips so a pump or gravity feed is helpful. As soon as one does that one runs the risk of squirting it onto chuck or milling cutter, and the stuff is all over you or the floor. Its a lot cheaper to lose soluble! I can see that neat is possibly better, if ones cutting is all under covers or in  cabinets, or otherwise well contained - but I'm not as neat with it as that.
Thread: DRO
15/08/2009 09:14:17
I suspect we need to differentiate between milling and turning.
 
Turning I can quite agree that a mic is still necessary - and you have to remove spring from either job or tool, especially when boring.So a DRO would simply be a convenience.

Millling  - well its a lot more difficult to measure to a turning degree of accuracy - think of a slot with its radiused ends. How long is it - exactly? Also when turning, you really only have one axis in operation at any one time, and when you don't its easy to make or set up a stop. Milling, mostly one is cutting on 2 axes, and sometimes on three.
 
Next point is  (and mine is the budget one - there is a more swept up version), a DRO will calculate co-ordinates for laying out a line of holes, and at an angle. It will do PCDs as well. So its a set of sine bars  and half a dividing head - all these sorts of things. And the metric conversions.
 
Again, I can quite understand that one would want to use a mic to check, in the same way that one uses one to check the result from the feedscrews. And yes, of course one can do without - I did for 25 years - but it don't half improve life when you do have one.
 
Oh indeed - .
 
(Its a bit like the difference between using a slide rule and log tables compared with the modern scientific calculator. How many would go back to a slide rule for their long multiplication and trig? Me - well I could do Fourier and Laplace transforms if I had to (signal processing and aerodynamic control systems being my MSc), but I'd rather let a pre-programed chip do it.......better still, one that someone else has programmed!)
 
 
 
 

Edited By meyrick griffith-jones on 15/08/2009 09:18:28

15/08/2009 00:29:55
Sorry - 6 ends of slots.
 
Proof of mental decay and need for DRO.
14/08/2009 19:15:54
Yes - if you already have scales and a box,  if you look at the tech specs, it will give you the voltages and pin functions/numbers on the connectors. You might (hopefully) find that you could use some of your existing stuff. you could possibly rewire a D connector. Give them a bell- they were very helpful.
 
Those who have used these things will know, but the grief I went though milling the steam face for the traction engine. 2 Faces at 2 levels. Three steam slots of different widths (cutter dia) so while the are all the same length the cutting distance each side of zero is different. Then the inlet and exhaust slots are of different depths - and you have to mill all that and the steam pocket and not loose zero. It was a seriously concentratious exercise - not difficult, but one really wanted to keep ones marbles in hand.
 
Now I just set up 10 SDMI points and enter the co-ordinates from datum - 4 pocket corners, and the 5 ends of the slots - having adjusted all the slot lengths for the cutter diameters, and it counts down for you. When you get to  X0Y0 you have reached the end of hte cut. Its repeatable so if you have to cut a steam slot in several passes, you'll never lose datum or distance. Sorry to rave on about it, but this thing is just the dogs.....
 
No more having to take my socks off when I run out of fingers so I can use toes as well - it has a decent calculator all built in.  Just marvellous.
 
Now now Circlip - you still have to know how to do it. this thing just stops you from forgetting where you've go to while you were remebering.

Edited By meyrick griffith-jones on 14/08/2009 19:18:33

13/08/2009 18:29:35
No, but I have just bought one from DRO Systems who advertise in ME for the mill, and that is just fantastic, and a genuine 24 hour delivery.
 
1 Mistake - I bought a 2 axis one because I had already put a digital scale on the z axis. I wish now for convenience, I had put all 3 in one box. 
 
I am going to put one on my lathe. Not because of the accuracy and turning to shoulders, but to turn a modern metric machine into a  proper imperial machine at the touch of a button. I accept I may have to do a bit of conversion for the last smidgen if being super precise, but its a lot better than having to convert completely. And for most purposes the DRO will be fine without converting to metric. And of course, I can feed figures in, in Imperial, and have them metricated at the touch of a button and work in metric from then on. Lot of conveneience for me.
 
These scales read in tenths, and the resolution is 5 microns which is about .2 of a thou - or a bit less. 
Thread: Hss or Carbide Tooling?
09/08/2009 21:55:09
Well there's obviously more than one way to skin a cat.
 
I was taught never to take a shaving cut, and got into the habit of doing so, because a lot of the materials I have used Ti, 13/18 aluminium armour, RHA and stainless all workharden like fury. So one just learned not to.
 
I know I have fouled up a surface by taking a shaving cut, so ......actually my real point was that if you set up the final 2 cutts correctly, you never need to take a shaving cut.
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