Member postings for Ajohnw

Out of curiosity and to put what seems to be the latest wonder couple for use in batteries diesel gives over 13,000 wh/kg.

Liquid hydrogen or the gas which has it's problems around 3 times as much. Metal hydrides are much safer and no figures for those.

Numbers from the wiki via a web converter as they were in Mj. Joules are an unknown for me as never used them for this anyway.

John

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There is a link to there site which has this video animation

**LINK**

Watching full screen the chamber seems to change size but if they have cracked that aspect I doubt if they would want every one to know how. It gives the impression that the "tips" are stationary.These look a bit weird in the video too.

Mazda when they were selling them just kept repairing the engines for customers. I did know some figures but they have departed my grey matter probably because they were nothing short of mad.

I worked on electric vehicles for some time. The volume and weight energy density Jeff wants would need Dr Who's Tardis technology and if it's still heavy zero energy anti gravity. I'm not sure about the weight of the Tardis. What might happen is quick change battery packs but somehow I don't think any current battery technology could work that well even then. All forms tend to be a pain if they are flattened too much for one thing and they can't be got going again with a 5L can of fuel. One of the problems is voltage. To keep the current levels low the volts need to be high which in turn needs loads of cells in series which mean oh dear and all sorts of problems keeping each cell perfectly topped up - that's what they need because if some aren't they will flatten before the others do. Some charging up before others tends to prevent the flatter ones from fully charging too - an electronic/electrical nightmare when I saw solutions and probably still is.

Hybrids are more feasible really and gain because the engine runs over a much more restricted regime so can be a lot more efficient. Talking to some one who owns one it seems that they don't own the battery pack. Interesting if true. As I am also a bit of a software buff I spent some time modelling hybrids for Fiat and others. They did seem to offer a gain even what, 20 odd years ago. Electric vehicles going from production of the electricity to the results on the road was not so clear - dubious really.

I have seen some spectacular batteries. One of instance would replace a car battery and could easily be held in one hand. Cost of the materials was pretty extreme and in terms of deeply discharging them torpedoes and ballistic missiles etc are a bit one shot.

Fuel cells might be the answer one day - they need fuel.

John

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Edited By Ajohnw on 12/01/2016 17:37:54

I feel it should be possible to make up the difference between 40 tpi and 0.5mm pitch by increasing the diameter to over what the usual simple imperial boring heads use.

I have the older model engineer design boring and facing head that could be used on a myford lathe. It uses a pretty simple arrangement for facing and has also been adapted to be used on a milling machine. My over all feeling as I have thought about making one is that it should be possible to arrange for the part that fits on the lathe bed or on a milling machine to be incorporated into the head itself and just holding it in position when facing.

Probably needing to lock it in position when not facing too but things can be spring loaded.

Gears can also allow the sort of thing that Emgee mentions. I get the impression this is usually done by rotating a sort of cap on the top which in turn drives a lead screw some how. I have wondered if there is some sort of planetary gear arrangement inside. Gears do allow any lead screw pitch to be used within reason. Point taken but gears have play, have to be made or bought etc. Also where does it stop. Robust lead screws such as cross slides and screw cutting lead screws use pretty coarse pitches.

John

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The whacking great wheel is good for making very fine adjustments when boring but a big dial with a hex socket and a long reach hex key is also good.

0.5mm pitch taps are available in a number of sizes up to 12mm dia at reasonable prices of late. Used for cctv board lenses. They seem to have standardised on the pitch to some extent.

Rather than gripping a knurled rim to face - have holes and put a piece of bar in.

John

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Edited By Ajohnw on 11/01/2016 17:04:31

2nd Hopper's comment but on small thread and crap dies I might reverse every 1/4 to 1/3 turn.

Keeping the die square to the axis is really important especially when starting and until the die has cut most of it's own depth. The work can be held in the chuck and the nose of the tail stock used to help with that aspect. Advance tail stock, take a cut, back off the tail stock, break the chip, wind forwards again, advance tail stock, take a cut and so on.

Dies are sometimes one sided when used - one side has a bit of a lead in chamfer, the other hasn't. The sharp side can sometimes be used to clear the last part of the thread up to a shoulder with care.

John

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You forgot the Boxford ME 10, ME for model engineer Neil. There detail differs on all of their lathes. The main ones on the ME10 is back gear engagement and minor maintenance areas plus being Boxford's last bench lathe They often come with the power feeds and the gearbox due to the nature of many people who bought them.

As a bits and pieces as needed type home machinist I couldn't fit the bill. Latest maybe is part of an astro telescope mount - would an engineer do it like that - NO WAY. Milling job anyway.

John

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Trike is known to be addictive. They have tried all sorts of things as anaesthetics and it sometimes takes them a while to find out if they cause more serious problems than others.

Smoking around it has been a no no in some factories for a long long time. I think it's trike but not totally sure but once the fumes pass through a lit cigarette it can turn into something akin to mustard gas.

John

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Sounds like I get the chance to try out toad in the hole in that ace pan I mentioned tonight. It'll include 1 and 1/2 packs of some rather strange thin sausages Lidl do, flat packed that can be kept in the freezer.The fat ones are no good for this sort of thing.

My wife went into hospital earlier this week for an operation to clear a nerve in her arm. She wont be cooking for a couple of weeks at least. I looked forwards to throwing in beef stroganoff done properly with soured cream and vodka, kedgeree with smoked haddock, baked unsmoked gammon using some of the left overs for tagliatelle carbornara, my idea of cumberland pie - plenty of cheese on top, corn beef hash using mashed potatoes and tomatoes, and as some turkey fritters turned out fairly well have another go at making scalloped potatoes. My dad used to do them and haven't had them for years. My mom couldn't stand the pain of getting the batter to cook correctly. Then egg and cheese and potato pie using plenty of good west country cheddar. (Lidl again, but only in small pieces). There is also this curry that uses a disgusting amount of butter.

However about the time I expected her to phone to tell me that she was about to have the op she came back through the front door. Cancelled. The surgeon had run out of theatre time so now going to have it done next month.

Really I wish she didn't need to have it done. Carpel tunnel too at the same time but that is an easy op. The similar problem up her arm isn't but at least they are going to do it with a local.

John

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You'll probably think too messy but any fairly runny oil will stop emery cloth from clogging. Cycle oil / 3 in 1 is ok. It will also cut more efficiently. Water with a drop of liquid soap prevents clogging too, useful for painted surfaces and metal too but for rust.

A related aspect. I honed something down to remove a very large fraction of a thou with a fine ARC diamond stick and was getting no where. Dipped them in honing oil, which they no longer sell, and was amazed how quickly they removed metal. I went 2um too far expecting to have to remove more.

John

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I mostly use 4" files on the lathe plus a 6" with a safe edge. I also use 6" in round, 3 square and half round.but not much. The 4" are the set of Vallorbe that Axminster offer.

Personally I think that Vallorbe are well priced really. There are some cheap decent sets of 4" 100mm usually referred to as warding or machinists files that can be ok. The have orange dimpled plastic handles with a "keyhole" in the end of them for hanging them up.

These seem to be they - ebay number 301835661840 - except for the handle colour.

"Dirty job files". I've had my set for a very long time and am pretty sure I paid more than £1.50 for them. Mine came off Graham Engineering when they had a showroom in West Brom and they assured me that they were ok. They have been too.

John

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Edited By Ajohnw on 08/01/2016 16:50:39

Vallorbe from Axminster. 2nd cut for larger sizes and maybe 1st cut for 100mm ones but 2nd cut are ok at that size too but smoother than I expected.

Forget slightly bent Stubbs files that flatten with the right pressure on them at larger sizes - these are Swiss so may well bend. However I haven't bought a 12" or larger so they might. I have a huge Polish 3 square one that can remove serious amounts.

John

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There is still some BSA alive and kicking but it isn't clear how much

http://www.bsamachinetools.co.uk/

John

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Having been told by some one who would be extremely old now if still alive that sperm whale oil is best for taps and dies I've bought a bottle of jojoba oil. Going on it's properties it might make a very good rather low speed cutting oil.

It's mentioned here https://en.wikipedia.org/wiki/Sperm_oil

I bought organic of course.

Any good - TBD but the hand soap we use is excellent on aluminium. Not so keen on tap and die stuff that can be bought but it may work more effectively on some materials.

Taps and dies pulling themselves in Tut Tut bad practice. They will back cut threads already cut and "forward" cut these if people press too hard.

John

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I suggested 800rpm as during my training few lathes went significantly faster than that. Turning mostly various steel alloys and also mild steel. Hand fed initially as well. I've stuck with that sort of range with my Boxford and may make rude noises when some one says that materials must be cut at higher speeds. As used my Boxford has a top speed of 650rpm but I can push that up with the inverter but generally don't. To get the belt drive set up to a max speed of 1300 rpm I need to change the pulleys on the motor as you do. Otherwise they can be changed from 200 to 650 via the counter shaft. If 200 proved to be too fast for some material when HSS is used I simply stick a carbide one in.

This does cause me a bit of a problem at times. Microscopes for instance often use 6mm dia thumbs screws, knurled for for circa 25mm along their length with a variable length M2.5 or M3 thread on the end and even a longish at this scale reduced size plain section in between. I could remove the material with rather light cuts which would take a long time unless I upped the speed a lot. If I tried to just take 2 the stuff would probably bend so I size it in one go. It's probably quicker this way actually.

Since that period manufacturers started fitting 2 speed motor on many medium sized lathes due to the use of carbide tools but people managed without that previously. Jobs may take longer - so what as far as I am concerned. If I'm boring thin shell and things start chattering I just stick the back gear in even when using indexed tipped tools. That brings the max speed down to 127 rpm.

John

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Off Topic. Who's spell checker aluminium doesn't underline for me as the spell checker on my machine is Brit English. Aluminum does. However if I right click to correct an error the forum just comes up with paste for some reason or the other. This is the only site this happens on.  or should this be that

On Topic

The oil works on this material too.

John

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Edited By Ajohnw on 07/01/2016 18:01:28

I don't think that these oils are really suitable for what might be called high speeds smoky machiners and are at their best smokeless I suppose people could fill there suds tank with it for that.

The price doesn't bug me as poor as I am Neil. It's cheap anyway. I just find little is needed in practice. Some pound shops sell wooden handled kiddies paste etc brushes around 10mm dia. I find a well drained brush of that is usually more than enough for one cut and way too much if the brush drips.

All I put on the lathe is slideway oil. I wanted a more viscus grade of that after using the one on ebay for some time now so had to sort out another supplier. Alexoil. Not sure how good it is yet and didn't fancy the sticky versions. Their Rustfee seems to be pretty good for preventing rust on things that have been completely degreased. I put 1L in a pump up garden spray bottle.

John

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Edited By Ajohnw on 07/01/2016 15:54:50

I your lathe in the low speed range via the belt Brian ?

Whoops - Just found the 2 speed ranges in the manual though. Low speed 120-1500 and high 320 to 3000 rpm.

At some point you might want to look to see if there is any chance of making a pulley to give you circa 800rpm max. I suspect you would find that more useful.

John

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You'll probably still have problems with aluminium unless the tool is suitable Brian. If you can't polish them and keep a sharp edge it might be better to really slow the machine down. That's more on the lines of what I do on my Boxford to save grinding different angles but they still need to polished. Ordinary parting off blades are more of a problem - really good at getting it to stick to the tip. Just have to watch for when and if this happens. I suspect it's related to feed rate but sometimes I get a bit stick. The problem is a little like the one when it's drilled.

The angles Michael's post suggests in the first link for aluminium would be ok on mild steel really or brass. For aluminium I would increase the side rake into the cut to circa 20 degrees on a small machine to limit the load on it. Then try that and if there was any signs of self feeding - unlikely - reduce that angle. Same with other material. This is what this angle controls. This worked rather well on a peatol.

You might find that 35 degrees back rake weakens your tools too much. A decent amount is 15 degrees for most materials. All of my turning during training was done with that amount of material. Big lathes with a tool holder that held 5/16 bits at 15 degrees.

If you have a grinder what you could try is grinding the top angles first and then polishing it on emery with a bit of cycle oil on it on something fairly flat. Then grind the sides. It's very easy to round off cutting edges when a stone is used and this will leave you with a sharp edge. If you choose to also polish the side that cuts just do it enough to polish up a short distance from the edge - pushing the tool back and forth and not side to side. Using the round edge of the wheel for grinding leaves a depression but that doesn't matter on the sides - things aren't so good on the top. It has to be polished for a decent distance in from the edge.

John

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Edited By Ajohnw on 07/01/2016 11:08:40

Put something on top of it that is held by the vice and drill through that. The stuff underneath needn't be held tight.

So much trouble you probably wouldn't have done it in the first place and made the part from a decent sized sheet.

John

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As this started life as a kit they may well have provided a suitable grade of aluminium so was that any different when it was machined compared with what you have bought.

The usual problem with machining it is melting and sticking to the tool. Also the fact that it's rather abrasive - aluminium oxide forms on fresh surfaces virtually immediately causing other problems. This boils down to the need to polish HSS tool surfaces with a slip stone. Given a suitable speed that should work out well. If it still melts and sticks slow things down.

It often doesn't take well to the use of abrasive cloths of one sort or another. 3in 1 oil or any old cycle oil helps

Drilling has similar problems but rather than messing with a decent sharp drill it just takes practice. Not too fast and a higher feed rate than some one might use on say mild steel. The drill has to keep cutting and mustn't rub. There will still be a need to flick swarf out of the flutes with something sharp - say a scriber but it shouldn't stick but will if people get it wrong.

Can't understand why some one should have trouble tapping it. Hand soap makes a decent lubricant. One problem might be not applying the right amount of pressure. Taps don't pull themselves in - they can but results are likely to be poor. Same with dies.

Going back to earlier suggestions about indexed tipped tools that was probably ignored this type removes the need for polishing hss and works well on other materials as well.

**LINK**

These will fit the el chepo 10mm indexed tip holders sets. I think they supply this size of tip on the smaller ones as well. They are micro polished because aluminium does tend to wear coatings off. There are several similar tips available. Also different shapes.

John

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Edited By Ajohnw on 07/01/2016 09:47:58