Member postings for Ajohnw

You speak as if it is already mounted so the advice to leave as it is an try to get the legs on the stand all sitting on the floor is good. The speed 10 and ml 10 are pretty solid beds as they come and the tray is more likely to distort than the bed.

I wonder about comments concerning shimming and bolting down beds to avoid distortion. I feel it came from a time when lathes were mounted on very rigid cast iron stands that might even weigh more than the lathe.

There is a simply way of mounting lathes in a stress free way without shims etc. It just needs longer bolts of the same size that the lathe normally needs for mounting. Fasten these to the tray or frame thread pointing up, fit nuts and tighten. I add washers. Fit another nut loosely, a penny washer ideally then place the lathe on them. Adjust each of the support nuts to that the lathe sits evenly on them. I do that by just adjusting lightly finger tight. Fit a washer and another nut to each and lightly tighten down. Maybe use nylocks. To be honest I don't and just do the top nuts up finger tight. They don't work loose.

Some lathes come with an adjustment just like this. The mounting holes in the lathe are threaded and accept a sort of flanged bolt with a hole through it. This is used to get the lathe sitting evenly and then it's simply bolted through.

Myford made a casting for these lathes that accepted the lathe and the motor assembly. On some of these lathes the motor assembly is just bolted to the tray. You might need to use the same arrangement on the motor assembly if you don't have the casting in order to get the belt tensioning to work correctly.

Lathes can also be mounted on items like these, there are a lot of different sizes available.

**LINK**

Much cheaper than lathe resilient mountings and will achieve the same thing. Personally I don't think they are much use unless they isolate any vibrations from the motor to the lathe itself.

John

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Edited By John W1 on 30/07/2015 15:43:10

There has been a lot of successful work done on storing hydrogen in metals and releasing it via slight amounts of heat. Many of the motor companies have done it and run cars around using it.

**LINK**

There seems to be more interest now in fuel cells for obvious reasons rather than simply powering a piston engine.

The companies who actually manufacture cars are an odd lot. They will often spend large amounts of money researching something new often badly and then do nothing with it.

I spent 15 years working on what may well be a mad electric vehicle but maybe not. I tonne vans with 1 tonne of lead acid batteries under the floor. The vans just needed the suspension beefing up. Vauxhall was involved. These vans were chosen because of the usual range requirements when used as delivery vehicles. Also did a coach, a taxi and a superior version of the van for HRH who liked to use it for driving round the royal estates. Several very famous names used to insist on having the taxi around to carry them about. The coach's longest trip was from B'ham to London and back. The vans were used by Royal Mail and some newspapers. The technology went to California and I have no idea what happened to it. Last thing I did on them was some of the work on the electronics to get reliability up to well over 1,000,000 total fleet miles. Not much of the work as that isn't really my field. Then it folded. Biggest problem really - suitable batteries. Lead acid doesn't take kindly to charge discharge cycling. Sodium sulphur has been around the corner for donkeys years. Many other couples have been around for a very long time. Some interesting ones are used to power torpedoes but they only have to discharge once. Charging is the catch. Lots of cells in series are needed to get high voltages to keep the currents down. Fixes for that problem - not all of the cells being exactly identical in several respects tend to be belts and braces. Fuel cells just need fuel. It might happen one day.

John

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I suspect that the bolts would be the weak points providing thickness was as would be expected. The problem is the area of the diameter of the cores of the bolts used being equal or greater than the bursting point of the boiler itself. Just look at the number of rivets used on an old boiler on this page for similar reasons.

**LINK**

That's why I feel a sort of screw on or in cap idea would be better.

There is something like a flash boiler shown here - water tube boiler. The flash boilers are sometime called monotube boilers.

**LINK**

The curious thing about the tube boiler is the water in the tubes may not boil or needn't. Just heated to a point where it will boil when the pressure drops on the way to the engine it's driving. I can't see how it could work if the water boils directly in the tubes.

John

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if water boils it produces steam. The idea of the inner tube is to provide more area to catch heat than if for instance it just had a flat bottom. Another technique is to run a number of tubes up through what is basically a water tank. That can give a more effective increase in surface area to take in heat.

The catches with a boiler intended to produce steam at some pressure is that the boiling point of the water increases with pressure. As soon as steam is taken off heat is taken away as well so then the heating source has to have enough power to replace it. The bigger the engine being driven / the faster it runs the greater the heat loss. You shouldn't have any problem finding the boiling point at various pressures on the web. Sizing the heating to suit the steam output - currently black magical as far as I am concerned.

A far as I am aware the surface area of the water in terms of say the diameter of a vertical boiler has nothing to do with it's ability to generate steam. The main aspect is the surface area of the boiler that can take in heat from tit's source and how efficiently it does this. There may be some problem with water getting into the steam outlet due to it boiling and splashing about but as soon as it's pressure is allowed to drop it will boil. I think I have come across the term dry steam at some point. I suspect that relates to super heating it, maybe deliberately running it through something hotter than it's pressure related boiling point.

Other than principles this isn't really an area I know much about so if I did it I would have to suck it and see. One thing I would most certainly do is add a safety valve. In principle a candle flame could get the temperature of the water up to very high levels. It wont really boil if it's contained. The whole thing could explode.

Hopefully if there is something wrong in the above some one will comment. There was a book shop not far from me that had a lot of rather old books - steam plant information was in some of them and I can't resist looking at stuff like that.

Vertical boilers - I probably mention those as to me they are the only ones that can look nice especially with wood lagging. I'd guess to work out they have to be significantly bigger than the engine and proportioned just like the images of real ones that will be about.

John

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I don't think you would need to go to 10mm wall thickness. Even aluminium would take rather a lot of pressure that thick.

I sometimes wonder about using 10swg brass tube and screwing the parts together plus some automotive cylinder head type gasket glue.

It seems that the biggest problem with brass is zinc leeching out and high temperature with coal firing etc and isn't so bad with simpler heating even gas.

The simplest type of vertical boiler looks to be a tube within a tube, the heat being applied to the inside of the inner one. The gap between the outside of the inner tube should be fairly low extending about 1/2 way up the height of the boiler then on to a chimney. There are a few free designs about on the web. I would wonder if stuffing the inner tube moderately with wire wool would improve the efficiency.

I've managed to avoid making either a steam or a stirling engine for a very long time. Probably wont last though.

John

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I doubt if you will have that problem with any continuously cast iron such as meehanite. Wall thickness and cracking is more of a problem with castings especially if they have been cooled quickly. It can leave a lot of stress. Obviously hit hard enough it will crack rather than bend.

John

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It's easy to buy a test tube - ebay. I've not done this for a long time but to shorten it use a 3 square file to cut a notch then touch with a red hot piece of wire / low diameter bar. You'll find other ideas on the web and may need them if it's not soda glass.

Rather than buying a kit why not try this one. I'm particularly keen on this design. It looks good.

**LINK**

The flywheel might be difficult for some but the spokes could be omitted or done some other way.

John

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I've always thought those were a bit daft - the hockey stick shape increases the min bore sizes. Lots of boring bars are made with that sort of problem. Done sensibly the bar could have a bigger section. They are good for making internal screw cutting tools. Lots can usually be ground off the tip.

The smallest and stiffest boring bar are probably best made of of round HSS. Grind half way through the thickness to form the cutting end then flatten one side of the the bar to provide some clearance.

John

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i initially had a message saying couldn't obtain something or the other so access denied for safety reasons. Might help.

as I run Linux and often use Opera I thought oh no not another internet explorer change. This site isn't very opera friendly either.

John

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Edited By John W1 on 29/07/2015 11:37:35

At least the English on this one is a bit weird, just one slip really. It could even be genuine. It might just be some one hoping to gain an email address from the reply but they get that anyway. Must admit I prefer set ups where the forum masks that by handling the communications.

One of the things I find odd about that type is that when I have experienced it and I look at the email headers often N. America is involved. Also when my yahoo email was hacked and I sent out a lot of spam from some where in America at some un earthly hour here. Something like 100 odd emails in seconds.

John

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I suppose some one could take cuts so fine that a boring tool like this doesn't bend. It projects about 60mm and is made from a 1/4 hhs tool bit. That tends to be stiffer than typical dedicated boring tools.

Even if it didn't flex the work itself depending on size might bend due to the cutting forces or there might be slight looseness in head stock bearings so the chuck and work is likely to lift.

The bar may also flex away from the cut. I tend to angle the end of them to provide some force that will counteract that. It also allows bored recesses to be finished at the bottom with the same tool. Many boring tools assume that the cut will pass all the way through the work - even RGD indexed tip ones to my annoyance.

The normal technique to take care of accuracy variation is to take at least 3 cuts of very similar sizes measuring and refining the results. I find with what I have at home though that if I want say a 0.001" fit the best option is to get close and then reduce the cut to 0.001" or even less. I also find that when boring cuts often need to be taken repeatedly at the same setting to run them completely out. In my case this is probably because the front headstock bearing on my Boxford has work very slightly oval as all lathe bearings do.

John

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That's weird - from that link it seem to be complete - same reader as I used on the others. My default reader is Foxit but I also have adobe and a linux kde specific one. The djvu I downloaded had images blanked out as well.

Out of curiosity I changed that link to .djvu and the images are blanked out again Also earlier on I downloaded the original tiff's and the same images were blanked out in that. There is nothing wrong with my tiff browser.

I've come across several instances of blanked out images in several different subjects. So often that I have always avoided ones digitised by Google and gone for Microsoft or others. I have seen some removed for probably pseudo legal reasons such as Texereau's 1st book on telescope making - not many people would buy the 2nd book if that was available. As I see it once a copy right has lapsed it's lapsed but I doubt of the archive argues if anyone questions anything that is on there. Many have probable seen the google no ebook available as well when it is.

John

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A lot of the drawings in the Hasluck steam engine book have been blanked out Richard. There is enough to get proportions of some engines but not much else. Interestingly the twin cylinder engine seems to be entirely blanked out. I've generally only seen this sort of thing on Google scans. At times there has been scans from several sources but when this happens the complete ones tend to disappear.

John

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It's pretty standard to set it a some thou over centre when boring and the opposite when turning. The reason is simple in both cases and sometimes boring needs more. When boring if the tool deflects down from on centre it will take a deeper cut and deflect some more etc etc. Set it above and if it deflects the cut reduces.

Turning should be set on or below because above reduces the front clearance and what happens if things do deflect when it's above centre - deeper cut.

It's no urban myth. It's often impossible to bore a hole without some deflection and often the result is that the same cut may have to be run several times to actually remove as much metal as the cut should take. Sometimes if the boring bar is going to bend rather a lot when it takes a cut there are 2 options - set it even higher or accept that it will take a bigger cut. The other factor though is that once it goes below centre the clearance angle is reduced - rapidly on smaller holes. The tool can easily finish up rubbing and scraping rather than cutting,

How much above centre - depends on how much the boring tool will bend.

John

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7 pages put me off back reading. Must be great minds think alike.

John

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Square head high tensile screws used to be used on most tool posts along with a special key for them. Also hex at times - longer head than usual but not as long as the usual qctp holder locking screw.

You could always make some out of key steel.

John

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I just tried to explain why this happens in general terms Jason and to explain why metric coarse is ok when that is used as in real terms it's close to BA - an instrumentation thread unless you are Colin Chapman and decide to use it to attach the rather long massive radius arms on the rear wheels of a Lotus Europa. That really caused me some grief once,

My immediate thought once metric became more popular was where are the metric model engineering threads ? As far as I am aware this is purely a UK invention, a very convenient one so looked for all of those 0.5mm pitch taps and dies or such like that would be needed. Then tried brass. No luck. I expected a search like this to bring something suitable up

**LINK**

Remove the set from the search and some metric fine will be found.

Perhaps the answer to the John engine for some one who had the cutters available would be to replace 5mm with 3/16 ME 40 and M8 with 5/16 same, 32tpi or brass. They are so close on diameter it makes me wonder if it's a metricated imperial design. The 3/16 is .010 low on diameter though.

Rule Britannia - seems to be the only country that took model engineering seriously.

John

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Edited By John W1 on 27/07/2015 20:38:53

I don't think you really need metric fine generally Brian but it would be best to canvas opinions on that.

Personally if metric fine is ever needed I would buy them separately. Using the BA argument again M2 is close to 9BA which has a pitch of .391mm. BA is one of the most used standards on models especially at small thread sizes. At this sort of size 40 tpi is too coarse really.

However -

Looking on the pages for the John engine you want to build the ones where the pitch is specified may be metric fine not the others. This is fairly normal. With spec's like M2, M3 etc metric coarse can be assumed. If the pitch is specified it might even be none standard let alone metric fine. In this case M5x0.5 and M8x0.75 is needed. The reasons that it happens on larger sizes is usually down to scale. Threads might be visible but more often the size of the part concerned in some one's opinion is too small to have sufficient threads engaging if a normal pitch is used. The normal metric sizes would be M5x0.8 and M8x1.25. When other pitches are given they may or may not be metric fine. There has been a mad range of standard metric diameter and pitch arrangements. There still is but ISO have limited the pitches that can be used - they hope.

The screwfix set I mentioned has some unusual sizes in it. A coarser M5 and a finer M8 plus others.

If you are thinking about buying Arc's M1 to M2.5 set be careful with the smaller sizes. They can snap rather easily unless the tap is very well axially aligned with the hole it's going in.

The downside of cheaper sets is usually accuracy. In other words better quality ones MAY produce parts which will fit more closely together but very accurate ground thread taps and dies don't seem to exist any more. The dies generally cut undersized and taps over. In the past taps have been made exactly on size - where ever they come from now they always seem to be over.

John

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My workshop is a wall in the house Jason so an orderly arrangement of bits and pieces is rather difficult. My lathe sits on a very old kitchen unit. I do have a few of the same draws as you show and less of the deeper ones but they soon fill up. I recently added a 15 draw one which might help.

Workshop? well

More shelves higher up and a handy step ladder near by. This images title is a part tidy up. Finished long ago and I am currently in the middle of another one.

John

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The tap and die co Jason linked to sell decent kit and the finer taps at the small end in that set look like they come as plug and taper which can be very handy and split dies as well. These can be adjusted a touch but the die holders usually have to be modified. One let down on the screwfix kit is the tap and die holders but they are usable. Jason is correct on sizes used on many things not just steam engines but my feeling were that I just wanted to be able use larger sizes if needed without having to go out and buy which would cost more in the long run.

I would say that Tracey Tools are pretty cheap even for the industrial items that they sell, sometimes have to ask for those. They sold me the 2 metric left hand spit HSS dies I needed to go with my taps. £20 each. It's possible to pay rather a lot more if some one looks in the wrong place.

RScomponents also have a number of tap and die sets even high end brands if some one wants to pay that sort of money out.

Actually there is nothing wrong with good quality carbon steel taps and dies providing they aren't used heavily and very often and on more difficult materials such as stainless. Finding a decent set is tricky though.

Personally if I was starting again I would buy a boxed set. It's nice to pick up the box and choose which one is wanted rather than tipping the lot out of a bag etc. At times it has taken me longer to find the tap or die than actually make use of it.

If some one really is on a budget I would suggest Arceuro. They too have sets

**LINK**

I have bought numerous tools of them over rather a long time now and so far I have been pleased with the items. The other budget seller I have used is Harry??? on ebay. The ??? is some number. I got fed up of needing specific reamers at times. His sets for what they cost seem pretty good to me. Again in a box and handy that way for the same reason.

John

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