Member postings for Ajohnw

LOL Don't buy anything I bought. It all looks pretty promising actually but the only place I could weld is outside at the moment and that wont change for a while. All I've done is check for sparks just to make sure it does spark.

Seriously I wouldn't take much notice of all tig below £300 is rubbish. At some point some one may be able to state which ones are worth buying. At the moment there is probably a risk even above £300.

Not sure on inverter stick welders but getting to grips with stick isn't easy on the old cheap hobby transformer ones. I was lucky perhaps. I had tuition on a small industrial 3 phase one at work so at least I know what I should do when I get one actually welding.

Before I bought a mig welder I hired one. They had engraved what to do if it did this or that on the case. One thing was spatter. I asked them if they wanted to sell it so bought it after the hire period was over. Same model as they used at work most of the time at a decent saving. I've since sold it. I'm not keen on mig.

One thing I would say is get yourself a proper flow gauge and that the disposable bottles don't last long but at least you will be able to see what the flow is.

John

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With the 70mm sticking out I'm assuming that the bar enlarges away from the chuck.

0.005mm ain't much

When it's an error that small try running the same cut several times before you do anything else.

Before even doing this personally I would adjust all of the gibs for slight resistance especially the saddle on this lathe. You can get minor differences based on where the feed starts from / the saddle moving slightly when the cut starts etc. It can even twist slowly as the cut progresses. Various things can happen and depending on the lathe the taper it produces could go either way.

Tailstock - assuming the error on the headstock is that small I would simply adjust it over a turned length of 150mm or via a test bar. It's a very small adjustment to make though. A DTI can help with that so the amount of movement can be seen. A test bar is a good idea really because it allows the relative height of the tailstock to be checked by running a dti across it at several places. That can also give some indication of a bowed bed. Tailstcok centres are usually a tiny bit high. Some might strain the bed to correct it. Personally I would probably re ream the morse socket providing correcting the error doesn't enlarge it too much. But I have only done that on modern bed designs with vertical V guides. That makes suggestions on how to do it difficult.

I had one of these lathes when they 1st started coming over. I oiled the bed up, removed the lead screws and set the gibs up for slight resistance. It produced a nice finish but I was very unhappy when I started mic'ing work on it. The headstock was way out and the tailstock about 1mm too high, quill sloping as well. The headstock could be shimmed up. I eventually sold it to some one who just wanted to shorten bolts. It was an "improved" model over the original Chinese one- hand scraped tailstock and centre distance increased from 18 to 20" by chopping off the taillstock nose. Couldn't turn up to the end of work with a centre in then. Noticing that is when I though it's got to go.

John

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That link I posted should have been

**LINK**

John

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I sold my mig welder Jason and wont be getting another.

I just succumbed to one of these even though it's Friday 13th.

**LINK**

It's possible to pay a fair bi more for that model.There is also I suspect a lighter round tube model about.

One other reason for getting one is to prevent cylinders rolling about in the car LOL Afte all I do drive a subaru and the islands and main road merges in Redditch are nothing short of wonderful.

I may find I have to weld a bit more onto it to stiffen the axle.

John

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I was idly wondering about something the other day - just in case. Say I have this motor with a certain power doing some rpm or the other fully loaded and I wanted to work out the torque in terms of force via it's feet on the plate it's mounted on.

Thanks to this thread I was wondering if I would do the sums in metric or imperial.

John

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Edited By Ajohnw on 13/01/2017 20:13:19

I don't know if they will offer a W on Volkszone Murray. I do know that they wont offer an X. I'd prefer that as I don't want to have to hump 40kg about. Manageable ok but lighter would be better given my probably usage rates. I suspect that's why they don't offer X. They assume usage rates will be low so they wont be handling them that often.

Just to please JS I may well finish up with a cylinder trolley before I buy any gas. Xmas presents arrive on xmas not when it's time to use them.

Garage - when it was completely emptied for a new roof the bench got scrapped too. Woodworm and damp.

Jobs - when the weather looks to be dry I need to get some more plaster board. Then bags of premix concrete to fill in a trench that now has unused pipes in it followed by ???? bags of floor leveller. At that point I might be able to start installing kitchen units. After fitting a new ceiling.

John

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I wonder if we will ever see 100 million signatures and papers hacked as a headline.

I suspect it's just a paper keeping service really.

One interesting aspect of BOC's chat line is that a transcript of the conversation can be emailed so that users  can keep a copy. I'm pretty impressed with that. It's not a bad idea.

John

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Edited By Ajohnw on 13/01/2017 17:45:58

It's possible to organise an account via the chat on BOC's site. All done electronically even including a signed direct debit. I don't think any other supplier can get any where near the Volks prices. It would take a lot of years on rental and even then it might not break even.

I started filling in the web form but it looked like I was going to get a bottle immediately. It's too cold to work where I can weld at the moment and while the garage doesn't leak any more it needs some sorting out.No heating either. I asked and the lady said she would sort this out as soon as I sign up. I'll make sure she does. She entered a W sized bottle on the form. No way. Even the Y's are pretty heavy.

One odd aspect is called docusign. It's some method of signing a direct debit on the web. They offer a number of different signatures based on your name. If none of them suite paint your own with a mouse. Then agree to it's use. They say adopt it. Just hope there isn't some way that they can get my bank to change my real signature to what I can paint.

John

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What - me watch it entirely. I just made sure that the needle valve was there. More recently he has switched to some from China one for oil fired but mentions that air types are also available.

John

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There was a bit of talk about pipe fitting blow lamps a while ago. I found those well known super and often expensive pencil flame famous make ones that everyone must have pretty useless on 22mm and not much better on 15. This one is much better.

**LINK**

John

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I suspect this is why Myfordboy just adapted a cheap screw on blowlamp. It's shown near the end of this video.

I think he feeds this set up via a 2 bar regulator but that will be down to the gas jet. When on the original torch the needle valve uses what ever pressure is in the can. I'd guess that the cheap torch might have been shrouded in plastic when he bought it

Whoops should also mention that if the pressure after the regulator is lower than in the usual can which it will be the needle valve is likely to give finer control than it normally does.

John

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Edited By Ajohnw on 13/01/2017 16:21:14

Glad you included "if I could" in the quote.

John

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Then the chart I have is a load of bollocks. Looking now it is. 0.167 cp is reckoned to be 18.812 dp and then 4 mod. Looks like the american that did it dropped a digit or his spreadsheet has a problem.

I'd better find another chart or next time I'm bored and not much to do make up my own.

John

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No his not but ...............

For that sort of thing a needle valve is usually used as the pressure doesn't vary much.

They can be rather expensive. One cheap answer is to adapt a torch that would normally screw onto a can of gas. I have seen something or the other somewhere where this is being done. Might be Myfordboy on youtube or his site. Not sure. They may be a bit coarse adjustment wise. There are lots of real ones for various uses on ebay often for hydraulics and expensive.

You could also fit a pressure regulator upstream of the needle valve. That's usually done to limit power when torches and picnic stoves etc are connected.

I don't think one for welding eg argon would be much good as they are designed to work at pretty low pressures. Not sure off hand what the native pressure of a can of gas is.

John

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Well if it is 6 tpi - unusual that's close to 4 mod. Mod - metric gears. DP imperial. Oddly in terms of circular pitch mod often comes out the same a imperial thread pitches,

One thing for sure if you don't get the tooth count to what it should be and a pretty reasonable fit it wont be worth doing.

Plastic will probably be ok but I'd use metal if I could.

John

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I haven't fitted a contactor on mine by the way. I rely on the inverter and a switch. Mit list it as they do because this is often how things are wired, machine tools and conveyors etc. Metal boxed multipole isolator some where. A no volts switch, a contactor and a panic button plus any safety cut outs. People do wire the panic button to the inverter rather than breaking the supply and I understand some inverters say don't stop the machine by disconnecting the supply. I've not seen one though. The panic button wiring will vary according to the inverter. It need to stop the drive and prevent the start button from working. . Mit do a separate safety module but I haven't looked at the data so no idea what that actually does. Might be for something else.

What they effectively say is us a magnetic contactor to power the inverter, include a panic button and no volts type on off switching to the drive to that but start and stop the drive using it's controls. ie

What that means effectively is the usual no volts release switch and that it can be de activated by the panic button. They add a magnetic contactor because the inverter currents can be much larger than what these switches can handle. A NVR switch contains a contactor of sorts so the panic button can simply break the supply to that.

The current inrush when powered up will be there on all makes because of the capacitors in them.

If it sounds complicated I've heard unwiring even a simple Boxford that has been wired to the book can be a bit confusing. Most drop the lot.

John

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Providing it's for the same lead screw pitch one from any lathe will work. There is a but - if the tooth count on the gear is different you'll need the dial to go with it. Mostly on smaller lathes with 8 tpi leadscrews they tend to be the same. Some lathes though do vary but I've only come across something really different on a DSG which uses a much larger pitch leadscrew anyway.

They are generally are cut with angled straight teeth to match the helix angle of the leadscrew thread. Some are cut more like a worm. Straight teeth can be used if the gear is angled. You should get away with a 1 mod gear. The circular pitch of that is 0.1237 - pretty close to 1/8"

John

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Going on my Mitsubishi inverter the emc mains filter is optional and only fitted if required. It has a built in emc filter. Lots do have now. They also show the fitting of an AC reactor in the mains line if needed. A lot of this is woolly because there are variables outside of their control In other words if the unit does cause interference fit a filter and maybe also a reactor.

They show a magnetic contactor in the supply and point out that this shouldn't be used to start and stop it. It can be done but it will shorten the life of the unit. They also show a current trip pointing out that allowances have to be made for in rush current . Effectively some large very high quality capacitors are being connected to the supply when it's powered up.

Later they give some numbers if the mains to the inverted is disconnected via an emergency stop to the contactor. Life 500,000 cycles dropping to 25 times if used for an emergency stop. (AC-1 rated contactor.) They then go on to mentioning what rating of contactor should be used on the motor side if that is used for an emergency stop. They also discourage doing this. AC-3 rating for any contactor there.

Most of the em noise from these units come from the drive to the motor. They stress single point earthing and shielded cable. Plus earthing of the motor and inverter. Optionally filters can be installed in this line as well. A simple one or one I wish I could get my hands on, a sine filter. (1hp if anyone wants to give me one.) These may be needed I assume on long feeds to the motor.

The earth current flow may have an influence on the rating of any earth leakage trip that is fitted.

They give minimum motor cable sizes based on a max drop of 2% over 20m.

Then comes sensible routing of the control cables. In other word keeping them away from the others. >= 10cm. They show shielded cable being used to the speed pot or current drive and also on the analogue speed output. Not on the rest though as all leads go to the inverter and represent 24v being pulled down with a current of 100ma max. I ran mine in a shielded cable.

Single point earthing in my case was provided by a slab of aluminium by the connection block so was pretty easy. No need to try and take all to a single bolt etc.

Most modern up to date inverters have a self tune facility buried in the menu and also motor modelling to help prevent over heating. Random switching too in some cases. That reduces noise.

They also mention that higher switching frequencies increase noise but tend to make the drive quieter. Really here they must mean noise power levels as I would assume that the switching waveform has the same rise times what ever frequency it is running at but I suppose they could play with that but doubt if they would,

I did wonder but on my Meddings I changed the motor to a 240v. The main reason I changed drill was to get one with a back gear as on a few occasions I have wanted a lot more grunt at lower speeds. If I had gone the other way I would have wanted a more powerful motor - just as many do when they change lathes over to inverter drive from 240v.

John

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For anyone is mad enough to buy a hobby compressor that should give 100l/min at 4 bar and costs in my case a touch over £100 I've modified it a bit.

There was no filter or drier on it or output gauge. I was going to fix that with bent pipe and compression fittings. I nosed around and found Aroplus in Redditch. They stock a huge range of fittings for this sort of thing. Some items take a day to arrive but no min order and I could collect so no postage charge. Turns out it could be done with various BSP fillings.

The reservoir is vertical on this one so doesn't take up much floor space. The air outlet comes like this.

It's angled down which is why I though bend pipe.

Finished up like this.

The fitting on the right of the filter is a breakable joint. Sort of nipple thing with an O ring on the nipple so can be rotated as needed and tilted a bit. The hole in the plastic to the left of the first shot will probably be needed to add a bracket to stop the stuff tilting when the line air line is pulled but it seems solid enough.

I aught to tidy up the ptfe tape.

Not sure if it's a mad purchase really. If I graft a twin cylinder pump and motor onto it total costs are probably lower than buying one like that. Actually it might save getting on for £100 and in any case might be ok anyway. It'll look a bit odd if changed but still take up little floor space.

John

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When ever comments on things like almost crop up what always springs to my mind is these and others

In linguistics, an adjective (abbreviated adj) is a describing word, the main syntactic role of which is to qualify a noun or noun phrase, giving more information about the object signified. Adjectives are one of the English parts of speech, although historically they were classed together with the nouns.

That just leaves the matter of degree. Generally it signifies very little of it. What ever it is. So in real terms what's wrong with that.

Worse still in some quarters terms like begs the question just shouldn't be used. Really there is nothing intrinsically wrong with the phrase. That one causes problems due to this sort of thing

**LINK**

but clearly it generally isn't used in that fashion so can be contextually correct.

John

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