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Member postings for mgnbuk

Here is a list of all the postings mgnbuk has made in our forums. Click on a thread name to jump to the thread.

Thread: Metric micrometer what t buy?
16/11/2019 14:24:36

1 - 2" ? Surely 0-2" I have 0 - 1", 0 - 2", 0 - 3", and 0 - 4 "

Nope - 1-2", 2-3", 3-4" etc. for me every time.

I hate,loath & detest replaceable anvil outside micrometers - a "kludge" solution to a problem if ever there was one. More often than not useless from an accessibility point of view, trying to get (say) a 4" frame with the 0-1" anvil in place into many situations is just not possible. The 0-6" Mitutoyo set that my previous employer had was even worse.

My current employer has a Mitutoyo 0-300mm set, but that is 12 individual micrometers from 0-25 through to 275-300 in a fitted box - a far better (though more expensive initially) solution.

To each their own, though.

Nigel B

16/11/2019 11:23:15

Old East German (DDR) mics are very nice to have

I am also a fan of DDR made KS Feinmessungsfabrik Suhl measuring equipment - I have 0-1", 1-2", 0-25mm, 25-50mm oustide micrometers and a 0-100mm depth mcirometer set. All have a good feel & are easy to read - on a par with or better than Mitutoyo IMO. That said, my "go to" 0-1" micromter that lives in it's wood box on the lathe suds tray is a Polish made one that was a "freeby" with a Model Engineer or MEW subscription many years ago !

G & M Tools had a lot of KS micrometers for sale some time ago & still show a NOS DDR production 0-25 outside micrometer on their website today for £15 + Vat.

The company survived reunification and is still in business :

**LINK**

I don't find metric mics as easy to read as Imperial ones - too easy misread & get 0.5mm out (a problem that my workplace colleagues also face). I always do a quick check of the micrometer anvils with a digital caliper now to guard against this.

Nigel B

(edit for spelling)

Edited By mgnbuk on 16/11/2019 11:24:41

Thread: Tramming The WM18 mill head
11/11/2019 20:25:35

So the question is, is there a way to adjust the quill?

To be able to swivel the head, you have two parts - the base casting that moves on the dovetailed column & the quill carrier / spindle motor mount casting. One of these will probably have a spigot to locate in a hole in the other to act as the swivel bearing & a couple of tee bolts to hold the two parts together. From your description, it would seem that one or other (or both) of the faces on these parts that bolt together is out of alignment. You will have to dig deeper to find out where the error lies in order to determine how to improve the situation

I would proceed like this :

Firstly, completely separate the two castings, thoroughly clean both faces of paint, swarf etc. and deburr. Might be worthwhile to blue up one part & offer it up to the other to see how well the two faces fit together. Re-assemble and recheck the head / quill / spindle alignments to see if the test results have changed. Bear in mind that to separate the two parts to work on them you may need to disconnect wiring & that the quill carrier casting is probably heavy. If your alignments were OK before you set the head at an angle, it might be just contamination of the joint that has caused the current issue - you might get lucky !

If the results are still not acceptable, split the castings again and carry out a check on the base casting joint face to make sure that it is parallel to the dovetail ways / column. Put a dial gauge magnetic base on the table, adjust to touch the joint face at , say, the 3 o'clock position. Zero the dial gauge after locking the Y axis, then manipulate the X and Z axes to move the dial gauge around the joint face to the 6, 9 & 12 o'clock positions. If the 12 & 6 o'clock readings are different from the readings off your square, it would suggest that the joint face is not parallel to the dovetails. To keep track of the numbers, use a marker pen to write directly on to the casting face - saves messing about with scraps of paper.

If you have a surface plate, place the quill carrier casting joint face down on the plate - if there is a spigot to centre the casting preventing the joint face sitting on the plate, use parallels. Fully extend the quill & lock it. With the dial gauge mounted on a surface gauge (or use a magnetic base on wide parallel) slide the dial gauge back & forth across the top of the quill nearest the casting & set zero. Repeat the check at the outermost end of the quill - the quill should be parallel to the joint face. If you don't have a surface plate, there may be room to do this on the table top, which should be flat.

It would probably be worth while to check that the outside of the quill is parallel & check the fit of the quill in the casting bore with the return spring & pinion removed. Bit difficult to sort a loose quill, though, as you need a "putting on" tool ! At the last employment we sent them (and tailstock barrels) out to a specialist firm who honed the bores, hard chrome plated the quill & ground back to get the correct fit. As you might expect, not a cheap option.

I would probably scrape out any errors in the joint faces, as the amounts to be removed are probably not that great, though it may be possible to machine them - depends on your equipment etc. It is worthwhile double checking your readings before putting scraper to metal - it is easy to knock the dial gauge, so I always go back to the initial zero setting position to check it is still zero. If you don't get reliably repeatable results, re-assess your methods.

HTH

Nigel B

10/11/2019 12:22:32

As often seems to be the case, you appear to be trying to correct one error by introducing another - in this case mucking up the column to table squareness to "solve" a spindle alignment issue.

As a former colleague ( a machine tool fitter who did his apprenticeship at Asquiths in the late '50s) used to say - "build 'em right from the base up or you are just making problems for yourself " So ...

First check that the table top is parallel to the base in both X (table left-right) and Y (table front-back) directions. Adjust as required.

Then check that the column is perpendicular to the table top in both planes (used to be refered to as "front square" (X-Z) and "side square" (Y-Z) at my last employer) using a known good square of suitable accuracy. Adjust as required.

Then check the quill alignment to the table top in both planes using the square. Adjust as required.

Finally, check the spindle alignment (trammel). Adjust as required, but adjust at the point that doesn't muck up the previuosly set alignments - it is pretty pointless having a spindle that "trams" perfectly if the column or quill is not square to the table top.

We did, on occasions, tweak different alignments to one end or the other of the acceptable range to get machines "in spec" overall, but as the acceptable limits were (at their most lenient) around a thou per foot (and frequently half that - or tighter still if the ward "borer" appeared in a machine description) there was not much leeway. Better to fix the actual problem at it's source as you work upwards than try to introduce errors elsewhere to compensate.

There are no shortcuts to doing it right - if there were, the Yorkshire-based machine tool builders would doubtless have found them by now !

Nigel B

(who, in a former life, had to get rebuilt CNC machines accepted by some very picky customers)

Thread: Another unfortunate milestone reached?
08/11/2019 12:32:12

It is quite normal for industrial machine tool dealers not to state a price in adverts. The size of the machines that Electromtion seemed to specialise in would not be of interest to model engineers

My current employer has enquired of Electromotion on a couple of occasions, but the quoted prices were high enough to ensure that the enquiry progressed no further.

Manual machine tools in industry ? Probably not first choice these days. At work we have 9 lathes & 6 milling machines, with 1 lathe (Harrison 330) and 1 milling machine (XYZ KRV2000) being the only manuals - both see very little use. I would guess that I use them most for maintenance & simple tooling jobs, though they are used occasionally for simple, short run parts. Most jobs go on the CNCs - even one offs -because it is easier. Modern CNC controls are much easier to set up and program "at the control" than earlier versions. Everything is programmed at the machine in this company - the parts are usually quite straightforward & don't require the use of CAM to generate complex paths. Worst we get are drawings that don't have the required information, but usually a few minutes on CAD can get intersect co-ordinates etc.

The industrial world has moved on.

Nigel B

Thread: Slideways oil
21/10/2019 09:14:41

Well essentially because the Atlas shaper manual advises the use of "a good grade No 10 Motor Oil or its equivalent" - which sounds like a very thin single-weight oil. SAE30 is therefore a bit thicker than Atlas recommend but as I use it for most of my other machinery too and it's what's in my oil cans) - that's what I use. I'm not sure a heavy oil would work as well with the flip-top oiling points fitted either (??).

The usually recommended ISO VG 68 slideway oil would appear to be slightly lower viscosity than SAE 30 engine oil, so hardly a "heavy oil " ?

Nigel B

20/10/2019 15:13:24

Of course where I have sliding surfaces designed to be 'total-loss' - for instance the Shapers ram slideways - I'll continue to use a thin oil (SAE 30) there...

Why ? Most machine tools have a total loss slideway oiling system & most recommend using slideway oil. I have come across a few that bled hydraulic oil to the slideways from a continuously operating hydraulic system, but most industrial machines recommend using a 68 viscosity slidway oil - heavier machines can use 150 or 220 grades to support greater loads, though. Wierdest one I came across was for Keller copy mills, which wouldn't work properly with anything other than a specific manufacturer's Sperm whale oil based product. Butler used to recommend another specific oil (Germ Dynobear 68 IIRC) for their travelling column milling machines as it substantially reduced stiction compared to "generic" oils in that application.

FWIW I use a 46 viscosity slideway oil on my Super 7, Boxford shaper & FB2 clone milling machine (Millers Oils Millway 3 IIRC) - no point in using a heavy oil on lightly loaded slideways.

While I would agree that any oil is better than no oil at all, if a product is available at a reasonable cost that is optimised for a specific area of operation, why not use it ?

Nigel B

Thread: Turning between centres on Super 7
01/10/2019 14:25:23

The driving teeth are the sprung parts.

Not on Rohm face drivers - see page 39 on Rohm face drivers

for a cross sectional diagram which shows the spring loaded centre. The centre has to move to allow the part to contact the drive dogs under tailstock pressure.

The Rohm driving disc can "wobble" to take up out-of-square bar ends, which makes for rather pricey items at larger sizes - I have designed a simpler, lighter duty version for turning graphite blanks at work with fixed driving dogs, where an out-of-square end is taken care of by the initially contacting dogs slipping & digging further in to the blank under hydraulic tailstock pressure under cutting conditions. When all 6 dogs are engaged, the blank doesn't slip any further and, as the initial heavy roughing cuts just produce a parallel cylinder, the axial displacement of the blank caused by the dogs digging in under load is of no consequence. The sliding centre is a parallel Morse taper 1 sleeve, with a die spring behind it - the spring rate was determined by trial & error (die springs are suprisingly cheap), with a Morse taper 1 centre providing an easily replaceable "point" if required (which it hasn't been for over 6 years that the home made unit has been in service).

Nigel B

Thread: DraftSight no longer free
25/09/2019 07:39:04

I had a look at the Drafsight website yesterday & see that the free version is no longer available - the "free" option now is for a 30 day trial, then an ongoing $99 a year. As I said initially, the "pop-up" that appeared for me which prompted this thread stated that all "free" versions would cease to function at the end of the year - nothing on the website suggests otherwise.

Nigel B

Thread: Heidenhain scale repair
01/09/2019 13:17:41

John,

I have not had to use a Heidenhain agent, though I don't doubt what you say from recent experience - I just bought heads direct from Heidenhain to exchange myself. I have dealt with Heidenhain for a long time (since 1983) through my previous employment (a CNC retrofit company) & have just continued to do so where I am currently (maintenance for a machine shop). The last scale I bought was several years ago to replace one that had been damaged on a Cincinnati machining centre - the machine head had dropped during transport & punched the read head through the bottom of the scale, damaging the glass in the process - about £1500 + Vat for an 1100-ish long TTL output scale with distance coded reference marks IIRC.

Dave,

Sounds like your scale itself is OK. It is a long time since I had the conversation, but I have a recollection that the reason that the lamp was not user replaceable was that precise focussing was required. Being a good Yorkshireman, I had enquired why a £300 (at the time ! ) replacement head was required because of a failed £1 lamp. As the 11 micro amp scale signal is the un-amplified output from the photo cells, the lamp position had to be set precisely on a test rig to get the correct signal output - it would have cost more to send a head back to have the lamp changed & reset than a new replacement head mass produced at the factory cost. From an industrial point of view, I can get a machine up & running more cost effectively by fitting a new head if one fails - OK £500 or so isn't cheap, but it doesn't take long to cost a lot more than that if a machine is out of production.

I don't know enough about the components used in the heads, but could it be that your Led is too bright, too diffuse, or the wrong colour temperature ? My recollection of the originals with the lamp is that they were a very dim yellowish light - as you would expect from an incandescent lamp running at less than half it's rated voltage. Could you mask the Led to replicate the illuminated area produced by your good head with the lamp ? And / or dim the Led with a series resistor ?

The last time I had a DRO related failure (the counter failed on an Anilam readout on a Harrison lathe) I didn't bother getting a price to have the counter repaired or replaced, just bought a complete system from Machine DRO at around £400 including Vat and delivery. A bit more fitting time to swap both scales & mount the new counter, but the new installation was warranted & has proven reliable.

Nigel B

31/08/2019 13:53:19

Heidenhain used to use a 12v lamp running on 5v in read heads and encoders - they were just a dim glow, but lasted thousands of hours (20,000 hours was quoted IIRC). When a lamp failed, the read head or encoder was replaced. IIRC the lamp positon was adjusted at the factory to position it correctly behing the read head grating to optimise the signal output. As far as I can remember it was only the very high line count rotary encoders intended for direct mounting on rotary tables that had the lamp changed when they failed, but it required the encoder to be sent back to Heidenhain for repair - as these encoders cost many thousands of pounds, a repair of several hundred was cost effective. Scales were able to be repaired relatively cheaply by the end user by replacing the read head.

Have you tried cleaning the the scale grating if you only have a localised problem ? I have done this on contaminated scales that read intermittently by removing the head assembly & the sealing lips, then carefully cleaning the grating with tissues and IPA. Go easy. don't apply a lot of pressure or use sharp tools and beware the sharp edges of the glass ! With the sealing lips out you can examine the glass grating for contamination & obvious damage - the grating should look like a contiuous grey band down the length of the glass strip. Any scratches or discontinuities here would scrap the scale.

Your scale must be old to have a lamp, as Heidenhain went to Leds many years ago - maybe IR Leds, as I don't recall seeing the dim glow when looking down the length of a scale with an end cap removed on later scales. Be aware that Heidenhain counters were usually sine wave input, not square wave. Early units were 11 micro amp output, current items are 1v peak-to-peak . Various signal converters are available - I have used 5v TTL square wave to 1v peak-to-peak converters on retrofits.

Given Heidenhain repair & new part prices, it would probably be cheaper to replace the entire setup with a new Chinese counter & scales and sell on the working parts of the Heidenhain setup to recoup some of the cost. Not knocking Heidenhain in any way here - they are a very professional producer of high quality industrial equipment and their service is second to non, but their pricing reflects that and isn't exactly "home workshop friendly".

You could give them a ring on 01444 247711 and ask the Service Department for advice - they don't bite.

Nigel B

Thread: Exhaust Gasket
25/07/2019 13:26:52

Standard "gasket" on two stroke trials bikes I have had was a smear of clear silicone sealant on the joints at assembly.

Nigel B

Thread: Colchester Lathe Factory
31/05/2019 14:11:41

That doesn't look a whole lot different than Boxfords at Boxtrees Mill in the early '80s, though Boxford didn't have their own foundy & all the castings were "weathered" outside for months before clean-up in a similar shot blaster. The filler used then was two part polyester body filler, still rubbed down by hand.

Today's Student and M300 are badge engineered clones of each other. And currently built in Taiwan. They have also variously been built in recent years in Russia, Czech Republic & China. The TS Harrison plant in Heckmondwike, which is where Colchester Lathes production was re-located after the site shown was sold (IIRC to become a Tesco supermarket) was closed last year. The last products made there were the Harrison Alpha "manual plus" lathes & Colchester Tornado slant bed CNCs - it is probably at least 15 years since the last manual lathe was made there. My brother in law served his time at TS Harrison & was charge hand on the small turned parts & gear cutting section - he left when production of the manual machines ceased, as the variety of parts for the CNC machines was very small. Even then the M250 was made in Russia & I recall around the same time the owner of a machine shop I used in my last employment being very unhappy to find that the "top of the range" Colchester he bought new was actually a re-badged Czech machine.

The graphite product used to face the sand mould was probably DAG colloidal graphite suspension, which is supended in alchohol. It is still available & we have a 205 litre drum at work for use in vacuum furnace applications.

The paint used to seal gearbox internals was also spirit based. When I worked at Broadbent Machine Tools as an electrician wiring heavy duty lathes, we used to use it to paint out the insides of the electrical sections of castings (the fitters did the gearbox castings & didn't touch "electrical" bits !). It was quite a "claggy" paint that dried very fast - clean-up & thinning was done with methylated spirit. When dried oil didn't soften it & one of it's purposes was to bind any sand remaining in the casting to prevent it getting in to the oil and causing wear.

Nigel B

Thread: An old Shaper found in Phuket Town
22/05/2019 18:58:17

I worked for the Cincinnati Milacron Electronic controls div which had a UK centre in Bedford

The Technical director at my previous employer worked there. I guess he would have been there in the late 70's - do you recall Dave Crewe at all ?

Nigel B

Thread: What Did You Do Today 2019
21/05/2019 20:35:24

The lead pellet weighs about 1.2 grams and would have been travelling at about 220mph on impact, about 8J of energy.

I don't think that your energy calculation is right, Dave.

Working in the more conventional units for airguns in the UK, 1.2 grammes pellet weight equates to 18.52 grains. This seems high for a .22 wadcutter. The pellet you show looks like a H & N Excite (12.82 grains) or RWS Hobby (11.9 grains) ? 220mph equates to 323 feet per second, which is round about what my recently departed Webley Tempest put .22 Hobbies over the chrono at, so seems about right..

However, 11.9 grains at 323fps works out at 2.76 ft pounds energy (3.74 Joules) - quite a bit short of 8 Joules. Even if your pellets are 18.52 grains, that is still only 4.29 ft pounds (5.82 Joules) - closer, but still no cigar. Still, you do seem to be comfortably on the right side of the law for the UK air pistol power limit of 6 ft pounds (approx. 8.13 Joules).

I don't think you should be too suprised that 3.5mm of polycarbonate stopped a pellet - I seem to recall seeing a demonstration on TV some years ago of a 1.5mm polycarbonate visor designed to clip on to a standard UK policemans helmet stopping a full power air pistol pellet at point blank range.

Nigel B (now enjoying a Weihrauch HW40 in .177)

Thread: An old Shaper found in Phuket Town
21/05/2019 20:07:41

Quite a small planer & quite basic - most (probably more recent than this) that I came across had at least two toolboxes on the crossrail and one one each vertical way on the columns. This one doesn't look like it was intended to have the vertical running toolboxes, as the crossrail ways (also used for the vertical toolboxes) don't go below the top of the table. I have seen one operating with all 4 tools at once roughing out the top & both sides lathe bed casting - quite a time saver if the job allowed it.

At my last employment we converted a Butler planer (8' x 8' x 40' IIRC - rescued from "outside storage" at a paper machinery manufacturer) to CNC operation. While primarily a milling machine (a new milling head replaced one of the toolboxes), the customer wanted to retain the planing operation. The customer made points & crossings for railways & tramways and thought that they could plane the wheel flange clearance groove in large radius crossing castings. It did work after a fashion, but the problem was tool clearance in the groove - the tool really needed an additional rotation axis to keep the tool perpendicular to the rail face as it went round the curve & as it didn't have one the tool had to be ground back so much to give clearance that it was too weak.. We used a 37Kw AC spindle motor in servo mode though a ZF low backlash reduction gearbox to drive the table, with two sets of parameters for planing or milling operation.

Sadly now a largely dissappeared breed - not "cost effective" enough for a modern production environment that seemingly doesn't value their strengths & capabilities. A situation that I have, unhappily, helped along at my current employment when the owner decided to scrap a very tidy, one previous owner Swift Summerskill planer rather than convert it to a milling machine. There have been a number of machines I have been glad to see the scrap man take away in bits, but that wasn't one of them & I still feel bad about it.

Nigel B

Thread: DC Treadmill Motor
16/05/2019 19:39:36

I have tested it with a 12v DC model railway controller. It goes forward and backwards OK but without any great power.

Fixed field DC motors are constant torque devices, so power reduces as rpm reduces. Rpm is dependant on the voltage applied & the torque comes from the current - so if the motor is 1.75hp @ 4400 rpm from its rated current at 180VDC as suggested, then at 12V you would get around 300rpm and around 0.12hp assuming you supplied the rated current (7.25ish amps).

1.3Kw (as suggested above) at 4400 rpm is around 2.8Nm torque - should be enough to move the head on an FB2, but you would be running the motor at a very low voltage to get the motor to run slowly enough (unless you require very rapid retractions !) . It doesn't strike me as being the ideal motor for the job - FWIW I have bought a 3Nm stepper motor to do the same job on my FB2 clone, but I particularly want to use mine to get a constant downwards cutting feedrate (I have it in mind to try boring motorcycle cylinders, so need to be able to feed at a constant rate for around 160mm) - powered elevation will be a bonus . I have all the bits, just need the "round tuit" now to get it mounted on the machine !

Nigel B

16/05/2019 10:27:46

At this power rating the motor probably has a would field

Motor part no includes "MOTOR P.M.D.C. POWER 1.75HP "

PMDC = Permanent magnet DC ? The small wound field DC motors I have come across have had the field as a separate enity, not connected to the armature. Frame size looks rather compact to have a wound field as well + no apparent cooling slots - wound fields tend to run warm & require ventilating.

Nigel B

Thread: Parkson M1250 Beast
14/05/2019 16:24:34

Indramat 3TRM2 drive amplifiers (3 axis - 2 pulse thyristor drive) are pretty bullet-proof. Previous employer used them as standard (used to buy the 20 off at a time) & I can't recall having to change one out. Can't see if the DC servo motors are Indramat or "other" - we used to use SEM but both wer reliable. Likewise Heidenhain TNC controls. All are now obsolete, so getting repairs done if they are faulty could be either expensive or not possible.

If you have a 3 phase supply, hook it up & give it a try. The 3TRM2 is not polarity sensitive & is actually single phase (IIRC 160V-170V AC input from a transformer), though the transformer Parkson used may not have a tapping to run off 240V.

Replacing with modern drives of similar capability will not be cheap.

Nigel B

Thread: Myford ML7 - Size of Mandrel Through Drilling?
11/05/2019 15:11:51

How can you miss it Nigel? It's on the front shear vertical face

Not on mine, Brian.

Its at the back of the rear shear at the tailstock end of the bed and my lathe is close to a wall, so I can't get my head in the space far enough away to be able to focus on it (one of the "pleasures" of getting old ! ) . However, use of the camera in my phone has allowed me to see the number remotely , which is SK78311.

Nigel B

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