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: Exhaust Gasket|
Standard "gasket" on two stroke trials bikes I have had was a smear of clear silicone sealant on the joints at assembly.
|Thread: Colchester Lathe Factory|
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.
|Thread: An old Shaper found in Phuket Town|
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 ?
|Thread: What Did You Do Today 2019|
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|
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.
|Thread: DC Treadmill Motor|
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 !
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.
|Thread: Parkson M1250 Beast|
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.
|Thread: Myford ML7 - Size of Mandrel Through Drilling?|
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.
0.630" from a quick digital caliper measurement on my mid-60s Super 7 (can't easily get to see the serial number).
|Thread: Honing motor cycle small ends|
As Mr Harley said to Mr Davidson, a little extra clearance never got in the way.
I doubt that Mr Honda ever said that !
|Thread: Bore micrometer|
Are these not "comparators", rather than "micrometers" ?
To use them, a ring gauge of known size is used to set the zero on the dial gauge on the comparator, then the deviations from the setting gauge in the bore to be checked are read off the dial gauge. The comparator in itself is not an "absolute" device.
|Thread: A visit to Manchester Sci and Eng Museum|
Not true, according to Wikipedia 160,000 built in the UK and 55,000 Packard versions in the USA and production in the USA did not start until late 1941.
Ford built Merlins in quantity at Trafford Park.
This machine looks similar to the Grizzly G0761, for which a manual & parts list can be downloaded here
To remove the quill it looks (from the parts list exploded diagram) that you remove the feed pinion assembly, return spring & depth stop and the quill should drop out from the bottom of the head. It may also be possible to access the preload locknut from above with the quill in place by removing the gearbox top cover.
The quill design seems similar to my RF30 mill/drill.
|Thread: Lathe bed regrind|
R Skinner Slideway grinding are in Halifax
Not for a long time. Bob Skinner sold out to Bob Pickles IIRC over 10 years ago - the Shay Lane address is where Bob Pickles operated from after Bob Skinner's machines were relocated (Bob Skinner chose to sell up & retire when he had to move from his rented premises). As far as I have been able to ascertain, I don't think Bob Pickles is trading any more either.
Bob Skinner was the primary regrinder we used at my previous employment (CNC machine tool rebuild & retrofit) & I had the pleasure of working with him to solve some "interesting" problems that came up from time to time. He set the highest standards & was extremely tenacious in getting to the bottom of problems. He delighted in getting me to work out solutions & set-ups when there were problems, gently prompting or offering advice, but making me work things out - it was always a pleasure to work with him. IIRC he had been the planing shop foreman at Butler Machine Tools in Halifax before starting up on his own. At the time he was served notice to leave the premises (the landlord wanted to do other things with the building) he was not far short of retirement age & had had health problems, hence selling the business.
I can only recall using Bob Pickles once after he took over from Bob Skinner & visited his premises on Shay Lane to discuss our requirements. IIRC he only took one or two of Bob Skinner's 3 planers & was a sole trader. He offered additional services like applying & pre-machining anti-friction coatings (Turcite etc.) to minimise fitting time. The job he did at that time was also to a high standard. I can't find any current information about this business from local sources.
|Thread: Does anyone know where I can source a Myford 34t change gear?|
I asked RDG about availability of this gear on the 26th March & was told "around 6 weeks" - so possibly mid May, though if a 30th January enquiry suggested "at least 8 weeks" maybe mid June ?
I had a look around the usual secondhand suppliers yesterday & couldn't find one. I have a "commission" to make a wood lathe chuck adapter for one of my wife's colleagues that has 3 and 3.5mm pitch threads, so both gears required.
|Thread: Pendent control box for a VFD|
A quick search on Ebay using "22mm push button" came up with quite a few options from under £2 each delivered (from China). Change the search term to "16mm" if you want more compact switches.
|Thread: DraftSight no longer free|
My copy of Draftsight is copyrighted 2012 and, as far as I know, has no connectivity to Dassault Systems. It is a 2D only version. I don't expect this to disappear. Time. of course, will tell.
The "Important Notice" I received says "all free versions of DraftSight will cease to run after 31.12.2019", so you could be disappointed come the end of the year - that statement doesn't leave much room for misunderstanding, though maybe not if your copy of DS can't "phone home" ?. I couldn't copy & paste the contents of the message box & have yet to find a way of saving a screenshot as a picture to be able to upload it here, unfortunately.
The reason given for the change to a charging model is due to DS2019 having been "extensively re-written to provide 3D functionality and investing in other technologies including a Cloud based version" - Solidworks Lite, maybe ? It seems a bit mean to me to disable the 2D versions, many of the users of which (me included) would not be interested in the "robust 3D capabilities" for the 2D drawings they produce.
Just opened mine and cannot see a message - is it hidden somewhere?
A pop-up window down the RHS of mine headed "DraftNews" & then in red "Important Notice" appeared when I opened the program. I am using DS 2018 X64 SP3
Fusion 360 no use in my working environment, I'm afraid Brian. I use DraftSight for the odd drawing I need to do mainly for maintenance purposes, but with the odd project. I have downloaded DesignSpark Mechanical, but now find that requires a £500+ "upgrade" to get 2D.
Time to trial QCad & LibreCad for basic 2D, I think.
I had reason to open Draftsight today & there is a message informing that all free versions of Draftsight will cease functioning at the end of this year.
The least expensive version will be DraftSight 2019 Standard edition at $99 a year.
Looks like I will have to get to grips with DesignSpark Mechanical sooner than I thought !
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