Member postings for Robert Dodds

Ian P,
Were you perhaps dreaming about MEW 224? By some strange coincidence there is just such a vertical lathe on the cover, courtesy of Jock Miller. Unfortunately its the wrong way up as its sited down under in New Zealand.
If you don't get MEW there is a preview description of the lathe on this site's home page.

Bob D

Ian,
You would do well to heed Bazyle's words. It is after all a 60 year old plain flat bed lathe. I have the Atlas version and enjoy using it but its not an ultra precision lathe! As long as you get the bed to be reasonably level at either end it will produce good parallel work for the hobbyist. It was never intended as a heavyweight machine and lacks the rigidity to take heavy cuts or carry heavy components.
They are useful machines but just don't expect too much from them.
Bob D

Graham,

I do hope 2015 is more pleasurable for you than 2014. I held off from contacting you but , as with several others I have heard nothing since your December note that only the difficult ones remain and now that certain delivery firms are in troubleI I am strating to have concern about whether my parcel is lost in transit
Please give us all an update on where things are upto

Bob D

I think there is a clue to the problem in Russell's title , Euro Ing. Some of the continental countries that respect the qualification retain the "Ingenious" root of the word. The UK and several other countries blur the word with the word "engine" and in so doing merge mechanics, technicians, designers smiths etc. etc.all into one title, "Engineer"
Bob D

U J,
I'm not clear what stage you're at. Does your little lathe let the small end of an M0 into it's sockets or are you, like me, unable to even start the standard M0 into the hole. Neil called the Adept a M00 and thats not a bad definition.
If Adept is what you've got then taper turning is probably involved but if you can get an M0 stubby into the headstock spindle taper you can proceed from there. cut off the excess leaving enough to turn a screwed spigot, say M4 or M5 on the end.
Now make a screwed bush out of say 15mm dia bar, matching your M4/M5 and rough turn to size for your drill chuck. To get best concentricity mount the part finished bush on the stubby arbor, put it back in your headstock spindle and turn the remaining dias true. Die the thread for your chuck, assemble it and go drill some holes.
I would not do any welding, too many stresses and distorsion. All normal cutting tends to tighten the threads up so there is little chance of things coming loose unexpectedly.
If you are stuck wiith lathe that has no facility for offsetting the tailstock, like the Adept, and want to do a slow taper there are simple attachments to put an adjustable centre on the tailstock barrel. these often use the MT hole but can also mount straight onto the outside diameter of the barrel. Making from scratch can be a bit involved but simpler designs should be possible with little more than a lathe with chuck and a pillar drill.
The frustrating part is setting it up to accurately match an existing, M00 say, taper

Bob D

A photo of my turned down, cut down RDG arbor ready to fit to the chuck
The as turned taper needed a bit of lapping paste and polishing up to get it to grip reasonably in the tailstock socket
Note the  flats on the 15mm shoulder dia. to allow a13mm spanner to tighten/undo the arbor from the drill chuck

Bob D

Edited By Robert Dodds on 18/12/2014 19:39:23

Jonathon,

The RDG arbor is long, about 1 5/8". I am going through a similar exercise with a Super Adept and that has a short hole for a stubby centre in both tailstock and headstock and in my instance, although the taper is M0 the top dia is 0.25"and just about coincides with the bottom dia of the RDG arbor. The first job was to set up another machine, I have a little Zyto with offsetting tailstock, match up the taper with a dti and then turn down the top portion of the arbor till I got to the required 0.25 dia, cutting off the remnant after double checking I got the taper and dia right as there is no going back!! I was lucky to have rescued a suitable 0 -1/4" chuck from a dead pistol drill some time ago so I only spent money on the arbor.
I hope you dont have the small hole as on my machine but there is a way round it.
Bob D
Does any one else only see spelling errors after printing/posting?

Edited By Robert Dodds on 18/12/2014 15:05:26

Hi,

I've recently joined the Super Adept owners club and amongst the little bag of extras that goes with these things I spotted this little plate. I recollect that style of scribing being on old plastic 12" school rulers and the angled lines allowed you to split a dimension to 1/100" pretty easily. What type of craftsman would be likely to make and use something like this after school days?
I don't know the history of the Adept but is this plate typical of perhaps a watchmaker's toolkit or is there a better explanation of its history?

Bob D

Michael,
There is little evidence now of the P&W machines. I have just one photo of the prototype as we were building it but it shows most of the features of the machine. It was designed to drill upto 4 holes simultaneously in each of two multilayer motherboards destined for 1960/70s mainframe computers
Holes on a .100” pitch were drilled for mounting the sockets to take 4 rows of plugin boards plus additional holes for intersect connections that were through hole plated on the buried pcb layers.

Referring to the photo the Tape-o-matic was fed an input off 8 hole teleprinter punched tape to define X and Y position data and also the sequence of the two banks of 4 high speed drills to deploy at each stop position. These were powered by the 8 solenoid valves on top of the arms feeding an air cylinder attached to each drill head. Heads typically run at 20,000 rpm for 0.042” carbide drills but had a max speed of 45,000rpm.
The frame design bore some resemblance to a railway buffers structure and seemed to be quite stable but in the end the machines proved to be distorting with the arms swinging side to side on a random basis, making the overall +/- 0.003” positional tolerance very difficult to achieve.
Eventually this was found to be caused by movement in the building. The machines were sited on the first floor of a steel framed building, one corner of which was on a clay bed that moved with the seasons and the weather. It applied sufficient twist to the floor plane to influence the drilling machine frame and caused the movement of the arms carrying the drill heads.
The solution was to mount the entire machines on pneumatic cushions that isolated them from the twisting floor. Each machine had three reference levelling pads to keep them stable and in normal incremental table movements this was fine, however they had also got a high speed jog mode with a supplementary AC drive and magnetic braking. This movement would cause the machines to rock to and fro in an alarming manner on the very flexible air cushions for a few moments but fortunately without detriment to the machine accuracy as it resumed drilling.
A further machine was taken from P&W that had a smaller table and came with a rear pillar to which we attached a custom designed head to carry the multiple drill spindles.
Bob D

Michael,
The Tony Griffith description suggests that the pitch correcting idea was superceded in the thirties. In the late sixties I was involved with using a trio of Pratt and Whitney Jig /Drill positioning tables as multi spindle drilling machines for pcb's They were driven by NC controls from 8 hole paper tape and the 40" x 20" table traverse was through recirculating ball screws. It was early days for this type of screw and P&W used exactly the same pitch correcting method to acheive a +/- .001" positional toleance over the whole table travel, each machine having its own calibrated cam track to turn the ball nut. Needless to say they didn't have additional proportional pitch variable feature.
Bob D

Hi,

Not as cheap as Len P's but at 4.37 ex Toolstation the Wera magnetiser/demagnetiser does the job for me on screwdrivers etc
I have an old transformer that I modified some years ago that demags bigger stuff Needless to say I can't find the detail of the mod but feel it must have been in an old ME. I remember cutting a slot through some or all of the laminations and then back filled with araldite. Ring any bells with any one? (Preferably not alarm bells since its lasted for at least 20 years)

Bob D

Does anyone practice the art of using simple internal calipers and a micrometer to measure hole size?
Your vernier caliper is all well and good but it will only give you the "max metal condition". You won't detect that a hole is big at the back edge, it is not easy to find a bell mouth hole with the vernier caliper and its unlikely that you will spot any out of roundness with the vernier caliper.
OK the spring bow caliper requires a bit more practice and feel to transfer the size to a micrometer but once mastered it can be as consistent as your typical digital caliper and more importantly tell you a lot more about the geometric shape of the hole.
Gauges, plug gauges, ring gauges, gap gauges etc. all need calibration and in some instances, setting on a regular basis to be meaningful but are really intended for use in volume production environments rather than for use in model shops or toolrooms. The toolroom is where many are made for use on the production line.

Bob D

Edited By Robert Dodds on 01/10/2014 22:57:52

My personal archive has two little pocket books from the Henry Ford Trade School. One is a 6 figure log and Antilog book and the other is its matching Trig tables complete with diagrams for solving triangles, escribed and inscribed circles etc. These were given out as part of the training of apprentices at Radway Green in the 1950s, sadly no longer offered today.
I remember that the badge of office of all aspiring draffies was the Faber Castell 5" slide rule hidden in its little green pouch, usually in the breast pocket of a laundered overall. It was not particularly accurate, but with regular use good meaningful answers to problems could be quickly arrived at. A 10" version was kept in the drawer under the drawing board for more serious calculations!

Bob D

Chris
According to google it is probably known as a "stainless skew proof spring pin" and comes from anzor.com.au
there are two or three images on google of this style of pin but I dont see any UK stockists.

Maybe you are in Brisbane!!!

Bob D

.

You may be right, Neil

... In which case the answer, most surely, should be Yes!

Michael,

I thought I was picking up, perhaps imperfectly, on your reference to needing a special thread for beginners with maybe reference to levelling an ML7. You are well able navigate this site and I, too can hack my way around. But what about the beginner, perhaps new to the site who finds his way to the forum with its limited search facilities. That was the one I was referring to as needing a make over. It has a beginners section but search there and I don't get 306 hits, just 1 for levelling and none for ml7 levelling !

Bob D

,

Michael,

3rd topic down the list is Beginners Questions.

I think its the ME site search engine that needs an upgrade so that a wider range of words will bring up results.
I seldom have any success with it.

Bob D

Eric,

It's just possible that some ally may have galled up onto your tap and as you came out it tore the thread, making it oversize,It's not easy to spot at these small sizes and it is important to keep some cutting fluid around specially with aluminium

Bob D

Bob H,

one method that would get you closer to a first time fit would be to wrap a piece of wire of known dia into the thread groove, long enough to overlap and then use an inside vernier caliper to measure "inside the wires". You would then need to do some calcs to work out the effective diameter and from that decide on your OD

Piano wire would be best but you could work with a piece of copper or soft iron wire as long as it had no kinks in it

Bob D

Hi,

1 : 1.078 corresponds with the typical shrinkage factor for Aluminium castings so it is quite possible that this caliper is made for someone producing small patterns for aluminium castings, perhaps even 1" to the Foot scale models. Patternmakers rulers certainly exist, with different shrinkage ratios for each different material that they are associated with but it is an inexact science due to the effect of different cooling rates, depending on the cast section and also influenced by the alloying of different melts. Additional allowances are also made to leave metal for fettling in some applications but this is very much a matter of whether "as cast" or machined finishes are specified.

Bob D

Me too, PM sent

Regards Bob D