Member postings for Ajohnw

Genuine Mitutoyo items are sometimes sold at substantially reduced prices. This might even because the shelf life is up. They will have one. Sometimes manufactureres discount goods to suppliers as well. Personally I wouldn't rule out buying them. All of mine have come like that. After a number of items have been measured including various setting bars, reamers and what ever I think rubbish would easily be sorted out. As a for instance I tested the setting bar that came with the super cheap draper mic I posted about recently. Mitutoyo reckons it's 1um out. The mitutoyo was at it's max measurement range.

John

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Set a myford spindle on a V block on my surface plate with the holder on it. Measurement errors less than 1/2 thou over the chuck length and double that checking run out further from the chuck. The V block is about 2/10 thou out.

Run out of bar at the nose of the collet holder circa 0.005" and double that 2" from the end of the chuck.

I rotated the collet to check that and didn't see anything to suggest the claimed when I bought them 0.0005" is incorrect. The high spots on the test bar hardly changed.

If I locate the test bar in the collet and stick that in the V block there is negligible run out on the register. What's there might be due to the collet or the chuck. It's around 3/10 thou.

The screw thread must be off centre. I can't think of any other way of checking that. It must tip the entire holder when it's fitted on a spindle. That would also explain things not going in that should.

John

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If you get a good clean shot Neil and post it on CambridgeInColour there is a man about that will id it. He's part of an insect survey but some buzzing things need a very clear photo to be entirely certain.

There standards of photography are rather high. There are a lot of tutorials on all sorts of things on there - probably the best on the web really. Very Photoshop though. They can be pretty helpful in that area. Not much use to me as I run Linux but I have fun finding out how to match it using entirely open source software.

John

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Edited By John W1 on 24/10/2015 11:09:53

Edited By John W1 on 24/10/2015 11:10:58

I use an 8" mitutoyo as well. Coolant Proof, Absolute. Several years and no problems. I changed the battery the other day - not that the original one was flat.

I feel the extra 2in is worth having but some who use them for everything might find them cumbersome. I use mic's on a lathe what ever I am turning.

John

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They don't seem to provide any information on them even the type with a lever - they do give the hinge point for those, or at least one of them but that's about it. Any further and it's a case of dismantling and finding out for yourself.

John

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it arrived from Warco. It's a should fit but doesn't fit size. A Myford spindle 1/2 thou under size goes in but is noticeably loose.

Measurements suggest it's register bore is 1.8 thou over size but a plus 1 thou oversized register wont go in cleanly. Neither will the milling spindle.

A 2/10 thou oversized myford spindle nose on a dividing head does just about go in cleanly. A Myford chuck is a touch tight on that. The mechanical advantage of the thread is needed to get it on - ideal.

Via a mic on the OD and a ball end mic to check thickness there is some taper in the register hole, circa 7/10 thou over a distance that shouldn't matter and the register isn't central to the OD. Not that this matters but maybe the thread isn't concentric to the register. That would explain the fit being a bit strange. If I check with blue which isn't that easy this seems to be the case.

Grrrrrrrrrrrrrrr

More measurements tomorrow. Another explanation could be that the hole isn't round.

John

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A roll pin would be a lot easier. A TDO I worked near started using them instead of dowels in the 80's. Big, plastic moulding tools producing thin wall containers for batteries. The hammered another down the centre and this was reckoned to be a as good as press fit dowelling. The splits in them were arranged at circa 180 degrees

John

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The trouble with stick welding is the striking voltage. It needs to be good bit higher than the working voltage and on many it's just not high enough to make it easier. I'd guess it comes down to transformer cost. If some one buys the old style ones that's the thing to check. Get one where it's as high as possible. They do vary. I haven't done any for ages as no need but due to a vat free event bought an ac / dc fairly low power unit and am hoping that the striking voltage is adequate. It should be via an inverter. Rumour has it that these can be used with a tig torch. I might try it one day, welding without a filler rod. Having spent some hours trying to master welding 1/4" aluminium plate this way I know that very little current is actually needed to go to full depth. I doubt if much more is needed for steel either. The problem with aluminium is that the arc has to be moved more quickly as the metal heats up - one day I might get it right, Trouble is it would be my own plate rather than scrap bits at work.

I work colleague set up his own business making welders and did pretty well. It read settings from a bar code stuck on the job. He used an automotive spark coil to strike the arc. Maybe that could be added to a transformer type.

John

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Just as it's best to do that with the other slides too. Fed up of repeating that.

John

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If it's stiff you may have got some swarf in the nut. Over tightening the grub screw might distort the bush. If the edges of the clutch parts burr over that would stiffen things up too.

I suppose the best way to locate the bush would be a dowel that just passes through the body of the bush missing it's bore but going as close to that as possible. The same sort of thing is sometimes done with a grub screw in a tapped hole. Easier in some ways as no need for the tolerance dowelled holes need. Drill through stopping short of breaking all of the way through with the bush in place and tap. The existing grub screw could be used to keep it in place as I doubt if it's a very precise fit. A roll pin is another and easire option - designed to be driven into drilled holes so drill all of the way through.

Maybe very loosely knit thin jumpers made up of holes ?

John

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My first job with a file was an around 4" cube of mild steel that finished up at just under a 2" cube with dice dots on it. I'd hate to do any job like that with anything other than a Stub's file. This was well past WW2. I don't think anybody used any other brand in the UK for serious work. Swiss brands sometimes came into riflers and needle files.

It's easy to spot a real Stubs file - run your finger over it and it will feel very sharp. Oddly they remove metal more efficiently after some use. The only problem really is the need to be pretty fit and strong to make good use of them. A few weeks of 8hr a day filing soon does that and blisters turn into calluses. I did buy some used ones that were supposed to be ok. They were well worn out.

The curve in them allows things to be worked flat with light pressure. It's also there so that the file flattens when used correctly. That aspect is unique as far as I am aware.

They also made silver steel. Sizes were always very close and it worked well.

One odd thing is that I'm always inclined to spell it with a double b. No idea why. It might come from looking for silver steel and some one trying to make use of the name.

John

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It sounds to me Brian that you will have to check that all of the parts that make up the dog clutch still fit together and in the holes they fit in. Parts 324, 322, 310 and 311. Could be that you may need to clean up the the edges of some of them with a file. If the lead screw wont go back in when they are all aligned that is probably the problem. Also things may have happened around the lever that engages the dog clutch. Strip it all and put them back one at a time. For instance 324 might not be engaging with 322 any more.

John

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Edited By John W1 on 22/10/2015 23:04:16

I like the scallops in those welds Nick - I pulled a face when I watched the virtual stick welding. They should have got a welder in to do it.

I tried mig but don't like it. It's too easy to not really weld at all. So it's stick for me but the inverter I have will do tig.

John

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Vallorbe are the ones that Axminster stock. I can never remember the name. They are nice and sharp. Bastard cut though - never used it even though I spent around 5 month on a bench learning to file and removing some really serious amounts of metal. Wish I still could. Second cut other than smaller sizes. I don't think bastard is really suitable for mild steel. My father used to have some about for wood - ex bench fitter amongst other things. The school I went to used 1st cut for finishing wood edges - in a grooved holder to straighten them. Stubbs files were curved so that the flattened when the correct working pressure was applied. Going on the ones I have Vallorbe don't do that. I bought 2nd cut and they feel as expected.

John

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The well known Swiss brand of Axminster tools but being swiss they are not so hefty as stubbs. They do cut well though.

John

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If anyone is interested in smelting / casting etc the myfordboy video's are well worth watching. His rolls and power hacksaw are worth a look too. The rolls appeared in model engineer some time ago.

He tales a dim view of me trying to do an electric furnace for aluminium, probably right too but .......... I suspect he had to use electric for brass because of temperature control. Electric is slower than propane or waste oil but easier to control.

There is also a very good video on a propane torch on youtube. For a forge but burns well into enclosed spaces so should be ok for furnaces too. It's a bit of a black art. Very slowly explained so easy to tell which one it is. Source north america.

I did know some one who managed to do cast iron. Charcoal and a hair drier for the draught. It doesn't need to be too close to the hole in the furnace for heat to be a problem. He also used an oil sand to get a better finish.

John

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Boxford do hold spares for the older machines. Rather a lot of them. There is a parts list on their web site with if I remember correctly prices and superseded etc. They will also recon machines. Might even have stock, never asked. One problem might be that the old boxfords are essentially a more expensive lathe than myfords. They did cut prices of the ME10 to similar levels. Rumour has it to reduce stocks of casting for the rear drive machines.

Actually I feel that if Boxford bought up old ones and recon'd them they would sell well. They can be good as a used buy. Bed wear apart from the error it introduces into the work isn't such a problem on this style of bed. That's why it's generally used. Cross slides wear just like any other lathe. Often headstock bearings have never been adjusted. It can be difficult. While they maintain the size of the spindle nose to very fine limits they have to account for bearing tolerances as they are outside of their control. I suspect many are too tight to allow easy adjustment. This is true of many lathes.

John Ward will make bits and pieces for many lathes. Including T slotted cross slides for ones that have never come with one.

There is another option on Myfords. Buy one and have the needed bit's recon'd. That's likely to be cross slide, bed regrind, saddle fit and spindle. They may tweak up the tail stock centre but that's easy to do with a morse taper reamer providing it's not been done too often. A test mandrel will be needed to align the head and some seem to have problems doing that and wont accept that the grub screws that come in from the side are intended for tweaking and think they use some sort of magic on them. No doubt they would quote a price for doing this anyway. The prices they quote are still very reasonable. I wouldn't want an ordinary machine tool recon' company to do it as I doubt if they would take the care needed for minor regrinds.

There are signs people can look for when buying a used lathe. Take my ME10 off ebay. The pictures showed a hand turning rest and several well made home made tools. It had most of the bits and pieces people can buy for them. This all strongly suggests model engineer. The serial number dates it to 1977. Minor wear to the cross slide, no wear I am aware of to the bed, headstock bearings never adjusted. A wobble on a rather large pulley on the countershaft that so far I haven't managed to fix but I recently found that the motor needs swinging through 180 degrees and doing that may well fix that - it sets up a vibration that leaves vague marks on work when very light cuts are taken. Then there is the other type of model engineer lathe - few bit and maybe hardly used at all. It happens but it's hard to be certain.

John

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A myford reconditioned one without a doubt and look after it.

Also don't be too sure that a lathe from a bereavement sale will be wonderful. It might be or it might not be. It is more likely if the previous owner bought it new.

Hard to explain but a dealers view of a functional lathe that is capable of doing work is for instance rather different to mine.

One thing to remember though. The cost of fully equipping a lathe is generally reckoned to be the same as the lathe. It probably still is if top line equipment is bought along with a full set of collets etc. Often used privately sold machines will come with all or most of the bits and pieces that are generally needed - but then their is the risk of all not being as it ideally should be.

John

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If some one wants to try rouge there is plenty on ebay. The seller I bought some off also sold cerium oxide. I asked what the grain size was and also if he had anything finer. If I remember correctly the rouge was 1um. I bought some. Wear rubber gloves if handling it. It's incredibly messy.

There are red versions of cerium oxide available. Grain size of that will be a few um. Lot less messy and might even be suitable mixed in oil.

John

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An old model engineer magazine gave details of a small furnace. He used K type, the fibre glass covered ones which are cheap and allowed it to burn/melt off.. K is ok up to about 1300C and it's usually the casing that limits it. You might find some enclosed in ceramic that can go to 1300. The ones in a stainless tube are limited to 1250C.

There is plenty of info on the wiki about thermocouple materials.

Actually I would suspect your furnace uses nichrome elements and gets to about 1100C -1200C. It needs to be kanthal a1 to be able to get a furnace to 1300C and more exotic material to go higher - graphite for instance.

K is usually the thermocouple that the controllers are intended to work with. No harm at looking for ones that can be used with a selection of thermocouples but take care that it's not an option when bought. The data sheets can be confusing in that respect as can ebay listings. Some times used controllers with a high temperature thermocouple crop up on ebay in the pottery section. They tend to fetch pretty high prices.

Myfordboy on youtube has done a video of brass casting using a small furnace.

I have the materials about me to cast my own furnace. On my list of things to do.

John

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