Here is a list of all the postings Martin Kyte has made in our forums. Click on a thread name to jump to the thread.
|Thread: stamford show vandals|
Not always the case. Consider the Bullingdon club.
|Thread: Soft Solder v Silver Solder|
The driver for the move to lead free solder is the desire to eliminate lead from land fill where it contaminates surface water. Much of the consumer electronics ends up in landfill so commercial electronics is now produced using lead free solder. As to the word for word details of the legislation you can look this up for yourself. But that is the why. Leaded solders are still freely available.
|Thread: Myford raising blocks|
Well not exactly. Myford raising blocks are threaded to take jacking screws which have hexagonal spanner flats in the top so they may be raised or lowered into or out of the block. The lathe foot sits on the top of the jacking screw with the stud part of the screw through the fixing holes in the lathe feet. To adjust the hold down nut on the top is loosened and the jacking screw is adjusted unsing a spanner under the foot to raise or lower the mounting surface. The hold down nut is tightened and the alignment checked by your favourite meathod. See recent extensive thread on this.
|Thread: Turning Cast Iron question - Health & Cleaning Up|
Making pastry will clean your hands.
|Thread: Larger VFD/Motors|
. . . . and most external power line filters will trip your RCCB's.
|Thread: 2mt Myford Collet|
Make a split collet by all means but for the 3 jaw. You get to choose your own wall thinkness then.
Alternatively buy an ER collet set for the Myford nose, use a 1/2' inch shank end mill or if you are making flat surfaces on your casting use a fly cutter.
|Thread: Precision Level or Precision Frame Level|
Lathes don't have to be 'level but they do need to be supported in such a way as to not impose a twist to the bed.
In order to do this each of the supporting points need to sit on a plane just as the bed did when the ways were ground. The plane need not be horizontally orientated but if it is then a level can be used on the ways in order to check this. In order to eliminate twist using a level the supporting plane only needs to be 'horizontal' across the ways, the longitudinal or spindle axis doesn't really matter.
If I could comment on the subject of bolting down or not as I see it and using the Myford as a 'test subject' there are a couple of points.
The lathe bed was originally ground flat and true by bolting upside down and grinding the feet level. The bed was then flipped the right way up and bolted down to the bed of the grinding machine and the ways brought true, by definition in relation to the feet.
When the rest of the lathe is assembled which includes having a large motorising 'lump' bolted over the back of the headstock this imposes a twisting force as much of the weight is transferred to the rear foot under the headstock. Correct bolting to a suitable stand counteracts this force and further stiffens the bed casting against cutting forces. It will also add mass to some degree which will help with vibration. This is a good enough reason as any for bolting down in my book. The main thing though is without some positive means of adjusting he support arrangements, in my case levelling jack feet there is no way to actively bring the lathe into 'perfect' alignment.
You would be surprised at how 'flexible' small lathes are. The Super 7 bed is quite a sizeable cast iron lump but just try taking a finishing whilst leaning in the headstock and then take the same cut standing clear and you will see a fraction go missing from the diameter.
I appologise to all who know all this already but I hope this helps those who are still figuring it out.
Edited By Martin Kyte on 01/05/2019 09:19:09
True, but not better than one that is well mounted and set up.
|Thread: A visit to Manchester Sci and Eng Museum|
Could I maybe put a slightly different view on all this. Many of us who actually build stuff would consider ourselves something of a specialist in whatever we do. Not neccesarily an 'expert' but generally more knowledgeable than the general interest public visitor of museums. It is therefor not really surprising, that often a visit to one of the more popular large museums, leaves one with some sense of superficiality or at least a mild dissapointment that our particular interest was not covered in much greater detail or the obscure artifact we wereparticularly interested in was not brought centre stage. Our Lab recently pensioned off an XRay plate microdensitometer which was of sufficient interest as being both part of the history of structural molecular biology and technologically unique enough to be of interest to the Science Museum. It is unlikely however to see much of the general public or indeed the general public to see much of it. However the museum considered it to be worth preserving along with it's documentation so as to make it available for historical research projects on into the future. With most of these museums what the public gets to see is just the tip of the iceberg as it were with vast numbers of artifacts squirreled away in reserve collections. In future years and to a certain extent today more and more of this is likely to be available in digital form accessable by all, and free at that. I have at home an engineering 'survey' of Rocket published in book form from such a research project. It's a facinating study of the 'artifact' that is Rocket today complete with full drawings and photographs and detailed analysis the locomotives engineering history born witness to by both the written documentation that still exists and the marks and spare holes still present in the structure of the loco itself. Without the museums this would not exist.
So I would consider that the museums do a great job in both th epreservation of the material itself, telling the story of life gone by and making much of it accessable to the general public and particularly children in a form which is entertaining and informative.
We who yearn for more specialist detail maybe should just do a little more digging.
|Thread: Notre Dame|
Well the 100,000,000 euro's just pledged by a single family wasn't on offer before this happened so you cannot really demand it be spent at all let alone on something else.
|Thread: Machine reamer vs Chucking reamer|
My understanding is that hand reamers have a long lead taper to align the reamer whereas machine reamers have a much shorter lead taper for the obvious reason that the machine does the gross allignment. Floating reamer holders are to ensure that any minor misalignment of the tailstock/headstock on a lathe or the head on a mill is compensated for and will produce the best finish on the hole. Machine reamers can have any shank shape consitant with concentricity and fitment to the machine of choice.
|Thread: Knurling speed|
Do you suppose that the 'myth' arose because when the first knurl went wrong, the surface was machined off and the next attempt was a success there is a tendency to believe it was because the second diameter was better suited.
It's kind of like you always find things in the last place you look because most normal mortals stop looking at that point rather than the thing kind of knows whitch end of the list of places you start at.
PS I don't calculate either but do sometimes get a duff knurl
|Thread: stepper driver|
Excitation is microspepping as you say. Stop current would be standby or holding current when not stepping. Set as low as you like to provide enough of a 'detent'. It's a worm drive so it's unlikely to move anyhow.
Don't know about the decay setting. I'd set it to 25% and see how you go. (tune for minimum buzz and check you are not losing any steps. What's the part number?
|Thread: Precision division plates|
Nice one Mike.
Fair comment Adrian regarding gear, shows I wasn't really thinking about that bit.
But back to your sun. The edge is not sharply defined. The telescope you use will have a limit to it's resolution. You have atmospheric distortion to consider. The rotaion of the earth is not constant. You have stabilty effects. The angular size of the sun is about 0.5 degrees so you need to fix the edge or the centre to better than 0.05 % of the disc to get an accuracy of 1 arc sec (if my maths is right) and the distortion in the atmosphere is going to be worse than that when the sun's out . Far better off using a big disc with graduations round the edge or ball bearings as has been suggested.
At least with the mirror and the wall you can put the wall as far away as you like to get the accuracy you want.
OK I'll bite
1. The sun is not a point object so you have to assess the centre of the disc.
2. You are still essentially measuring angles when you really want to measure distance of arc.
Ditch the sun and use a star
Ditch the astronomy and reduce to movements you can measure directly such as.
Fit a mirror to the centre of the plate and bounce a laser beam off it so that the beam is projected onto a distant wall. Make a mark.
Measure the distance to the wall from the mirror. Calculate how far you need the spot to move to give you your required angle. Make a second mark on the wall at that distanceTurn the plate so that the spot falls on the new mark. Drill your hole or cut your tooth. adjust the mirror so that the spot falls on the first mark again and repeat.
Or you may like to think that you could make a second worm wheel from your supposedly inaccurate head which by the logic of your first paragraph is going to be 40 times as good as the old one.
|Thread: Lathe screwcutting|
Are you using any cutting oil?
|Thread: Just Done Something Stupid!!|
Purely as an academic question as you have settled on a solution.
What would people think about fitting an additional access bush in the crown. One could drill the required holes in the original steam pipe through the hole and then fit a bush and blanking plug. I don't know how bothered boiler inspectors get about additional bushes. Not very I suspect and of course there needs to be space in which to fit the said bush.
|Thread: Silver soldering a blind 'mortise and tenon' joint.|
I wouldn't bother with the thread just a cylindrical loctite joint.
|Thread: Machining cork!|
Razer blada mounted vertically. Feed slowly and run the lathe fast. Essentially you take small slices from the face of the cork to full depth required. Either Geo Thomas or more probably Tubal Cain described this eons ago. Works on rubber too.
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