Member postings for Ajohnw

Yeh - I usually start in October but we seldom eat any over the Xmas period. Instead of poking holes in it for the brandy to run in I went over it with a fork. 2 big table spoons full disappear pretty quickly now. I should have time for 10 or so of those.

I make the marzipan from scratch. Can't stand the bought stuff. Usually the icing too but they want the roll on stuff this year.

Xmas day is cook the turkey and make the stuffing for me. Hope I can find the thermometers. I use a web method from America. Hot for a rather short time and then rather low. It does tend to keep them moist. Not too sure about over night cooking temperatures that can go for as long as you like. Some still do that in Arga's.

John

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The gauge and flow bit's have arrived. The regulator can be adjusted. Small nut on the end of a big one locks the adjustment in place. For some reason the scale on the flow gauge faces the opposite direction to the gauge on the regulator when it's fitted. Suppose it doesn't matter really. The scale is marked Argon as is the regulator gauge. I suspect the one that goes to a higher reading will show mig and may be for CO2. There are some about with 2 scales on them but I have no interest in mig. Been there and done that and wasn't keen.

When I mentioned the flow gauge not being too sensitive to pressure I meant calibration pressure. Pressure change will alter the flow so it's case of how much the pressure changes. Maybe too much when the bottle gets low, Not much when it's full up if it's a decent sized bottle. It'll depend on how long the welder is used too.

That is it in the area of things to buy. Just electrodes to use left. I'm inclined to follow some advice on here ( I think it was on here ) 2.4mm as I have never seen some one use a tig welder and change size what ever they have been welding. They do change current. There are various suggestions on the web. I've seen one that suggests 1.6mm for all with an option of 1mm on thin stuff. It's may be a case of who to believe.

I think most people would change the tig torch. I suspect I'll get that from Cromwell along with gas lens gear.

There is another thread on here concerning the welder and tig

**LINK**

There may be another not sure. I've looked at several. Often it wasn't this particular unit. Another model.

One thing that might be worth mentioning is scratch start. The manual mentions HF discharge stopping once the arc starts. That is what the unit does. I assume this means it isn't a scratch start unit. I have never used one with hf start though. It does seem to strike very easily. The stick setting isn't too bad either but not up to what would now be a rather old industrial transformer one. I think that needs circa 70v.

The compressor I have now bought might be a mistake on a couple of counts, Have to see which will take a while. I do have a vague idea of what to do with it if it is - with a medium sized but.

John

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Snap

I have to make the marzipan for the cake tomorrow. It needs more brandy in the cake so can't do it sooner. Better late than never.

John

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I don't see where the worry about increased friction comes from Garry. Bearings on spindles should be run preloaded. Where it's possible disk springs are ideal. They tend to be far cheaper than springs that look the same and are sold for preloading bearings. Most disc springs are way too strong but there are thin ones about. They wont deflect much which is why a stack of them are used. From memory the unitmat uses a stack of convex to convex pairs.

I'm not going to think too hard about that. They face each other so that the pressure is applied to the bearings as intended without the need for additional bits. I think that means the rim of the springs contacts the bearing's outer and each pair also contacts the other via the rim but you'd best sketch it out and think.

John

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Pure maths doesn't really worry about the actual application John. A brief cut and paste from a google for it

Broadly speaking, pure mathematics is mathematics that studies entirely abstract concepts. This was a recognizable category of mathematical activity from the 19th century onwards, at variance with the trend towards meeting the needs of navigation, astronomy, physics, economics, engineering, and so

Applied which would have been far more appropriate for me wasn't taught by the OU. Instead it gave a very broad basis in a pure mathematical sense over a number of fields that some tend to specialise in. These days a course that would probably be more ideal for what I was after would be called applied maths possibly plus computation.

If some one does a degree is say engineering of some sort they will be taught applied maths related to the field the degree covers.

I'm not disagreeing with you. I agree entirely when it's needed. Taking the course wasn't a waste of my time at all really. It would have been nice to see some practical applications at times though. It pretty obvious in some areas but not so much in others. Sometimes that becomes clearer when I do see a practical use.

As to the quote I posted take a look at this link. It's still about.

**LINK**

A teacher at my son's school managed to persuade him to take a pure maths A level. I tried to dissuade him but failed. He did too, besides the point - it wouldn't really relate to the field he wanted to go into and a degree in that would cover any additional maths he needed adequately. He also dropped a course that he was sure to pass. I think the teacher was just drumming up numbers so that he could teach it - rather late in terms of exam time too. This for a kid that had won a maths challenge too.

John

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I had a nose around on the web but it's pretty hopeless unless it's to buy something. Searching curve sketching might help but you'll see use of derivatives and probably few basics.

One other thing that I should have mentioned is something like f(x)=5x^2. That defines the function. There are probably variations on the same theme. What doesn't seem to be around is a good explanation of modern notation. I'd assume while it may be difficult to follow many people would have a grasp of the older styles. If not some cheap books going by the name of Schaum's Outline Series may help. They cover all sorts of things and probably go down to basics. They probably all aim at applied maths. The OU thingy was and may still be pure maths.

John

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You might get a good idea of one of the points John made by looking around for maths ignoring constants. Silly idea on the face of it but can be useful. For example

say something ----> 5x^2 all the 5 does is scale the basic function. The X^2 might be said to set the shape. The important aspect.

I used that sort of notation, -----> as the open university was mentioned. I did M100 that was later changed a lot because of a very high drop out rate. The -----> may be read as maps too. It an approach that allows more maths to be done on functions rather than numbers. So thw something above might be f and f is a function. not a=b etc. Things like integration look entirely different. That for instance is a big I. So you might come across something like I o f. Which would be read as I circle f. There is also a square. Never had much use for it so memory fades. Other things are also chucked in, morphisms and etc. I ^-1 is what you would expect it to be. It's inverse as would f^-1.

Just mentioned as I think this form of notation is more widely used now - by mathematicians. The OU course books cover this well. They also do a load of primers to get people to the same level. Good job too on M100 the scope covered was ridiculous. That may have changed.

I suspect your best bet really would be a book aimed at software people. Can't help there but I did work with some one who was into this as a hobby so do know that books are available. He was probably a higher level graduate inn electronics. That does in some cases cover some unusual maths but using old style notation. Maybe that's changed now but I haven't seen any signs of it.

Mathematicians aren't strange people really. Like most fields they have their own jargon and it's what they do - most if not all of the time. I have known a few graduates that wanted to do maths initially but didn't 'cause they thought it was probably too hard. What I found very difficult was that ok it may be wonderful that things are like that but what on earth do you use the maths for.

Oh forgot if this function f was used it might be shown as something like f(x)  read f of x.

John

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Edited By Ajohnw on 23/12/2016 13:01:07

Air guns are based around modified versions of hydraulic regulators. Usually into a small reservoir so that the pellet gets the correct pressure as soon as the trigger is pulled - or as near as they can get to that.

The gas saver one Bodge mentioned is this one

**LINK**

The general idea is that the output pressure of a regulator will change as the input pressure changes so 2 are used in series so the 2nd guage sees less pressure change. Argon cylinders can be up to 300bar. Don't know what the min pressure can be but it's a hell of a range for a regulator to cope with. I'd guess >>2 bar when empty.

The style of flow regulator plus gauge I have bought isn't too fussy about pressure only gas type. The output of the single stage regulator to go with it is likely to vary as the bottle empties but the flow control can be changed to suite. If the flow remains constant for a welding session that's ok. I think it will.

John

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This what the 2 gauge units I have seen actually are. It can be confusing.

**LINK**

The 2nd gauge shows 0-30L/min. Some go higher. I've also read that some think that this style of regulator isn't terribly good at low flow rates. That wouldn't surprise me. They describe the other type as suitable for a laboratory use but some do use them.

**LINK**

I decided to go that way. In places parweld suggest using it with the 2 gauge one as well, Think people will see that if they search their site. Probably mentioned in the catalogue.

However real 2 stage ones can be bought and will show outlet pressure on the 2nd guage. I have one for air riffles. I wouldn't rely on it charging them correctly without twirling the knob until it shows the correct pressure for the gun so I always back it off before using it. Have to use a certain type of grease on the connections as well to make sure the gun doesn't explode - same stuff as divers use. Petroleum products would be bad news.

John

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Edited By Ajohnw on 22/12/2016 23:42:15

I've wondered too. Some good posts and some nice work on a machine that some might find tough to use.

John

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Sorry Bodge - I have been getting some silly flack from some and wrongly assumed your post was more of it.

What I did was look what BOC sold. Took note of some comments about dual gauge with one showing flow, which looked useless going on the scale shown in photo's anyway. I did use mig for a while and aren't keen on it. I did waste gas out of disposable on that so wanted a flow gauge anyway. Wondered about adapting that to a disposable bottle regulator and went of the idea due to gas usage. Then I ordered the stuff. After all how long am I likely to have a welder active ? Even if crap it may well regulate well enough for that sort of period of time.

More important really is how much excess pressure the regulator needs to function correctly 'cause that will set how low a bottle can be taken. Maybe BOC think 2 bars or maybe in practice it's over that. I did see a comment that presets can be adjusted. The ones I have seen at work can be anyway. Strongly suspect the one on order can be as well.

John

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I have got one set up where it's probably a good idea to have decent repeatability. Came with the lathe. There was a Myford fitting chuck and a home made morse adapter to allow it to be used with the boxford. The seller kept his dividing attachment but my dividing head and dore westbury miller both have Myford spindle noses. The chuck fits all rather well.

It also came with internal and external chasers to match the spindle nose.

I haven't had much use for the arrangement but if I do a steam engiine Jason style which is likely at some point the one I like the look of uses gears. The arrangement could be of use for other things as well.

John

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I've bought castings off them while under the original owner. Very good quality. Not so much finish which was fine but the quality of the cast iron. His cast iron bar prices were not too bad either.

I called in more recently. Phoned and told them what I wanted to collect. Served by a lady who did understand what I wanted. I'm 99% sure they had changed premisses since my first call in on them. I've only been twice.

Last time I phoned them a lady answered. One comment was something like do you know that this is now several companies. The other was that she had no idea what I was asking for - I could have told them the old catalogue page number. Followed by chatter in the background and the person who handles this is in the warehouse and will phone you back. They didn't.

I suspect that there may still be a black country service for iron casting and some about that can make the bits he sold. I do wonder if he has been selling off stock for a long time or even maybe getting small numbers of bits when needed. Given the right contacts that isn't difficult to do.

John

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Go search BOC for an argon regulator and see what comes up and what it's for.Like I said I didn't like the look of the twin guage ones that came up and sad but true I really do know something about the problems with regulators. People can make their own choice any way so why not post that way.

Eg Bodge wouldn't buy a single stage regulator so would by a dual and explain why. That would be useful to others.

Curiously if done correctly form 300 bar that will change rather a lot to some thing a lot lower a single regulator should have some compensation in it to account for pressure changes at the feed end. It wont be perfect. Few things in the real world are. Will it have, wont it have. I don't know. As mentioned if it turns out to be a problem I'll do something about it.

Wish the thing would arrive. I suspect they have sent it via a canal.

John

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The regulator I used to charge the air rifles is 2 stage.

John

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I know one thing for sure - I should have bought one when I bought a mig welder 'cause I wouldn't have waisted so much gas by guessing.

John

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I've got one for charging air riffles too but it's staying on the bottle. However I wouldn't expect that to charge to the same pressure as the air bottle runs down.

John

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Thanks Mark - some reckon I type to much. Something i do pretty quickly but I only have so much time and full explanations would mean even more typing.

As I saw it in order to be fairly certain of flow levels as low as tig needs a combined flow meter and needle valve is a good idea. They don't cost much. Some outlets only stock ones that go to over 14 L/min I assume these are really for mig. Some stock both types. Without the gauge I wouldn't have any idea how much I was using or if the welder had a leak but I do have some leak detector spray - we had a gas leak. Then comes the over run on the control valve. Not that I could do anything about that if it's stupid.

The problem with regulators is getting one where the output remains constant as the pressure on the input changes. Using 2 in series helps but perfection is still costly.

John

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The fact that I messed up the chuck register on one for my Raglan didn't cause me much grief Martin. The chuck itself just ran out more than it need do. I've only every changed chucks with work in it because I needed to make something else. Hardly ever happens - every now and again I do spend a lot of time on the lathe.

John

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Perhaps I should expand on that a bit. Regulators vary usually based on price. I didn't like the look of the twin gauge ones that I could see and would buy. I wouldn't be able to buy a single stage one that I would be pretty sure would work really well with up to 300 bar capability so bought a preset which takes it down to 5 bar. I understand that can be adjusted if needed. This brings the pressure down to a level where I wont have much of a problem finding a decent regulator to add to it - if needed. In fact the one that comes with it may be ok. That would save disconnecting at the back of the welder. Changing that on the welder wouldn't be straight forwards so it's best to use the tail end that is fitted to it. There are several possible arrangements.

As it stands I'd expect to have to tweak the flow regulation each time I have a welding session. I wont be welding all day.

One thing I wouldn't do is buy a good quality twin gauge that would cost nearly as much as the welder. Probably more going on regulators that I have bought - at work.

John

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